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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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Suggested Citation:"Production of Food and Feed Crops." National Research Council. 1975. World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and. Washington, DC: The National Academies Press. doi: 10.17226/18644.
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SECTION III: PRODUCTION OF FOOD AND FEED CROPS INTRODUCTION The world's food supply begins with crops harvested from the land. However, the basic requirements and research needs for crops grown for human consumption are similar to those for feed, fiber, and fuel. Plants are a renewable resource and an increase in productivity will benefit food, feed, and biomass uses. But plants require, and may compete for, the nonrenewable resources of land, water, energy, fertilizer, and chemicals. Many plants (e.g., feed grains and grain legumes) can be routed as either food for man or feed for livestock. Others, such as the grasses and forages, are useful only to livestock. Biomass production of plants is already widely used for fiber and may again be more extensively used for fuels. The significance of food and feed crops is that they provide, directly or indirectly, about 90 percent of the world's food supply. Chief among the major food crops are rice, wheat, maize, sorghum, millet, barley, rye, oats, soybeans, field beans, chick peas, pigeon peas, peanuts, cassava, sweet potatoes, potatoes, sugar beets, sugarcane, coconuts, and bananas. A variety of fruits and vegetables, processed and fresh, adds personal enrichment and pleasure in eating and provides essential dietary nutrients. Hay and pastures (grazing crops) provide most of the feed units for cattle and sheep. Current rates of population growth and changes in dietary habits will double the need for these crops during the final quarter of the twentieth century. Our forests and tree plantations provide fiber, as do some feed and food crops. New fast-growing, high-yielding crops will have to be developed for biomass production of fuel, as well as food and feed. Crop production is a central issue. Global production of grain must be increased at the rate of 25 million metric tons per year just to keep pace with population increases and rising demands. Fuel production will become critical as we exhaust our oil and gas reserves. Chemists, microbiologists, and engineers will have to convert massive amounts of organic plant material to basic chemicals for industry and fuel. Nature did this slowly in the past from plants. Now man will have to do it quickly as he increasingly uses plants for food, feed, fiber, and fuel. There are major uncertainties involving future agricultural needs, including adequacy of land, water, -117-

energy, fertilizer, and pesticide resources. There are environmental, social, political, legal, and economic constraints, and numerous disincentives in agricultural food production. Weather and changing climatic patterns continue to play a predominant but unpredictable role in dictating the selection of crops tolerant to change. A national program for greater food production and improved nutrition must focus on the major food and feed crops. Research investments are needed to maximize or optimize the production of food crops per unit of time, with the least expenditure or commitment of land, water, fuel, and fertilizer. The two most important processes that use solar energy are photosynthesis and biological nitrogen fixation; research on these processes can be expected to lead to greater production of carbohydrates, proteins, fiber, and energy. -119-

CHAPTER 14 PHOTOSYNTHETIC PRODUCTIVITY RECOMMENDATIONS 1: Efficiency of the Photosynthetic Process. The impressive yield increases of the past 25 years have come from a combination of new varieties, high rates of fertilization, high plant populations, disease resistance, and control of insects and weeds. Further significant yield increases will require greater photosynthetic efficiency. Therefore, need is great to expand research on the factors which control the photosynthetic process, especially in four areas: (1) control by source-sink relationships; (2) control of photorespiration; (3) control of plant senescence; and (4) carbon dioxide enrichment and other improvements of field techniques for crop production. 2: Use of the Seasonal Potential. In much of the U.S. there is a waste of potential photosynthetic production because the photosynthetic system in the crops grown is poorly adapted to either warm or cool weather or length of growing seasons; whereas other species may have their most rapid growth during those times. The potential needs to be evaluated for developing crop varieties which can produce rapidly in both cool and warm weather and in variable growing seasons. Planting designs and multiple cropping should be developed to capture maximum solar energy. INTRODUCTION It is estimated that world food production must double by the year 2000. Adoption of currently available agricultural technology could alter yields in the agriculturally developing nations by a significant amount; but for yields to double in the U.S. or other developed countries, which produce much of the total and all of exportable food, will require a marked increase in photosyn- thetic productivity over the levels achieved in current agricultural practice. We often hear faith expressed in the ingenuity of American agriculture. Many knowledgeable people suggest, on the basis of past performance, that the percentage gains in -119-

crop yields over the past 25 years will be repeated in the 25 years ahead. Such projections need careful analysis. One of the better examples of success in agriculture is the yield increase that has occurred in corn production in the U.S. In 1950, average yields were 57 bushels per acre (bu/A). The estimated yield for 1975 is 93 bu/A. That impressive increase has been due to new disease resistant varieties which are responsive to narrow row spacing and high fertility as now practiced. Extremely effective chemicals for controlling weeds are now almost universally in use. This combination of variety, spacing, high fertility, and freedom from weeds has resulted in the current high yields. It is that technology which could contribute to yield increases in the agriculturally developing countries. Could corn yields be increased in the U.S. by the year 2000? With the high price of grain and the removal of acreage controls, all crop land readily and presently available is being farmed. Increases in crop acreage will come slowly and at considerable cost. Thus, about the only possibility for exploitation of further yield increases on our most highly productive land is to develop higher yielding varieties. Where can the varietal input to yield come from in a crop such as corn? Considerable progress has been made in recent years by developing varieties which put more of the photosynthetic yield into grain. Today, about one half of the total plant weight at corn harvest is grain, the remainder being stalks, leaves, and roots. The roots, stalks, and leaves are absolutely essential to the plant. Possibly this proportion can be somewhat further reduced, but in order for grain yield of corn to double, an increase in the photosynthetic yield of the crop also must be attained. Thus, the future of the world's food supply may lie squarely at the door of photosynthesis and its partitioning into the harvested part. What has been the history of photosynthetic yields while these remarkable successes in grain yield have been obtained in corn? They have increased, but the startling fact is that the biochemical capacity of corn for photosynthesis has not changed at all. The photosynthetic yield increase has been achieved by more dense plantings, earlier plantings, later harvests, steadily increasing rates of fertilizer application, and the relative freedom of the crop from pests and disease. While we are faced with need in the future to drastically alter the capacity of crop varieties for photosynthesis, we have made no progress in increasing the efficiency of the process in the past 25 years, and we are nearing the limit of exploitation through technology. To make further progress we must improve the photosynthetic process itself, yet we have currently only a token research effort on photosynthetic productivity. -120-

The photosynthetic yield of an acre is derived from the photosynthetic rate per unit area and time of individual leaves multiplied by the area of those leaves contained on an acre (the leaf area index or LAI) and the length of time the system functions. The entire system is driven by solar energy. Although the preceding statements seem obvious, each of these points becomes important when we consider potential research on photosynthesis. EFFICIENCY OF THE PHOTOSYNTHETIC PROCESS Rationale As indicated above, the biochemical efficiency of the photosynthetic process in major crops has not changed in the last 25 years. Yet great differences in efficiency exist between crops. In the warmth of midsummer, corn and sorghum and sugarcane are highly efficient, greatly surpassing such summer crops as soybeans or potatoes. In cool spring weather, however, photosynthesis in wheat, barley, or rye greatly surpasses that in the warm season crops. In the past decade it has been discovered that corn, sugarcane, and some other crops have photosynthetic systems that consist of a sequence of biochemical events strikingly different from that which occurs in wheat or barley. The enzymes involved have high optimum temperatures and function very effectively in high temperatures and intense sunlight. The relationship with season is not clearcut, however; soybeans do best in warm weather, although they possess the same biochemical system for photosynthesis as wheat or barley. Since striking differences exist among crop species in efficiency or photosynthesis and in the adaptability of the photosynthetic enzyme systems to seasons, the potential to alter the photosynthetic process in ways useful to man seems great indeed. Yet progress has been nil in breeding crop varieties which have superior photosynthetic yield capacity. The photosynthetic rate in crop species has proven to be highly variable in time and subject to enormous environmental influence. Progress in vital areas is unlikely until the factors that control photosynthesis are understood. Implementa tion Research on factors that control photosynthesis is sorely needed in four different areas. -121-

1. Control by source-sink relationships New growth or the development of fruit or grain enhances leaf photosynthetic rates. On the other hand, ample photosynthesis is necessary to produce the potential for a large fruit or grain yield. The signals that pass between leaves and other organs which tell the leaf to increase or decrease its photosynthesis are not understood. The factors that control the fate of photosynthate—whether it goes to storage in grain or fruit, becomes part of the plant structure as new leaves or roots, or is respired, wastefully or to provide plant energy—are largely unknown. It is critical that research efforts be greatly expanded in this area. 2. Control of photorespiration In plants such as wheat or soybeans the enzyme responsible for fixing carbon dioxide and forming carbohydrates can also react with oxygen. When this happens, carbohydrates are destroyed—not produced—and as far as is known, wastefully so. When this destruction of carbohydrates occurs, the process is called photo- respiration. Corn, sugarcane, and several other highly productive crop species have evolved a photosynthetic system which protects its carboxylating enzyme from photo- respiration. It is estimated that the photosynthetic yield of wheat, rice, soybeans, and many other crops could be increased by up to 100 percent if a genetic or chemical inhibition of photorespiration could be attained. Research on this topic needs much more emphasis than it is now getting. 3. Control of senescence The photosynthetic capacity of all the grain crops (including soybeans and other legumes) decreases precipitously during the grain-filling period, exactly at the time when the need for photosynthesis is greatest. It appears that, in selecting crops for uniform ripening so that they are amenable to machine harvesting, varieties of many crops have been developed which are now limited in their yield because their photosynthetic factories close down too soon. We must understand the control mechanisms within plants that tell it to mature and die. The potential seems great to markedly alter yields simply by keeping the photosynthetic factor going for a longer period of time. This area also needs research effort. -122-

4. Carbon Dioxide Enrichment The carbon dioxide concentration available to plant foliage is the most important variable determining the rate of photosynthesis. For example, a sixfold increase in N~ fixation for soybeans has been achieved by a threefold increase in atmospheric carbon dioxide (Evans 1975). Experimental and commercial results confirm that major growth increases, often exceeding 100 percent, can occur with increases in the carbon dioxide concentrations in the atmosphere. Heretofore, textbooks on crop fertilization, with few exceptions, have ignored carbon dioxide as a plant nutrient from which growth responses may be derived. This blind spot in management for food producing systems needs serious reappraisal. Although the knowledge of carbon dioxide benefit by crops grown in greenhouses has been known for half a century, and was put to use to a limited extent during World War II in Germany, it has not been pursued as a researchable means of maximizing the productivity of field food crops. Massive supplies of carbon dioxide are dumped into the atmosphere and could potentially be used for enhancing crop production. There are also large geological resources of carbon dioxide adjacent to major food producing areas in Texas and the Mississippi Delta. USE OF THE SEASONAL POTENTIAL Rationale Since photosynthetic yield is a product of rate and time, one obvious way to increase biomass production is to increase the proportion of the time that a crop occupies the soil. The practice of multiple cropping which is practiced intensively in some subtropical areas has the potential for much wider application in the world. If varieties of summer crops could be developed which had a cool season capability for photosynthesis, plantings could be earlier and seasons extended on many millions of acres. Research in this area is almost nonexistent in temperate climates. Yet crops such as winter wheat or rye are capable of producing tons of biomass per acre each spring before corn is even planted in the Corn Belt. Obviously, such crops do not mature grain before corn is planted, but the point to be made is that large amounts of solar energy go unharnessed because the summer crops lack a cool season photosynthetic capacity. The potential needs to be evaluated for using the seasons more fully. -123-

CHAPTER 15 BIOLOGICAL NITROGEN FIXATION RECOMMENDATIONS 1: Research Teams in Nitrogen Fixation. Research teams should be established for the purpose of conducting coordinated efforts toward obtaining in-depth knowledge of the nitrogen fixation process and its application in production of food, feed, and fiber; control of soil erosion; and maintenance of ecological balance. 2: Rhizobial Technical Center. A rhizobial center should be established to provide leadership and expertise in the technology essential to effective legume inoculation. INTRODUCTION The major portion of all nitrogen required for the production of food, fiber, and other plant products is derived from the atmospheric reservoir through biological nitrogen fixation and industrial chemical fixation. The biological fixation process is indirectly dependent upon solar energy that is stored by plants in products of photo- synthesis. Organisms capable of using atmospheric nitrogen ordinarily are not dependent upon another source, but those lacking this capability require nitrogen from fertilizer or from soil reserves. The chemical synthesis of compounds of nitrogen and their distribution for fertilizer require enormous quanti- ties of hydrogen from natural gas plus additional energy expenditure to maintain the temperature and pressure for synthesis and to transport the products to their destination. In 1972, 465 billion cubic feet of natural gas or 2 percent of all the natural gas used in that year was consumed for the production of anhydrous ammonia. New methods have revealed that biological nitrogen fixation is more widespread than originally imagined. In the U.S. alone, the quantity of nitrogen fixed by agri- cultural and nonagricultural species has been estimated to exceed 23 million U.S. tons annually (Evans 1975). In addition to agricultural legumes, biological nitrogen fixa- tion also is of major importance in forests, woodlands, arid regions, and in fresh water and marine habitats where the -124-

quantity fixed per year may approach that fixed annually by agricultural legumes. Since nitrogen is the major plant nutrient limiting the production of food, fiber, and other products for an expanding population, it is essential to exert maximum effort to increase the supply of a usable form of this element by both biological and chemical means. An increased supply of biologically fixed nitrogen may be accomplished without excessive use of our energy resources. Furthermore, biological nitrogen fixation takes place in the fields, forests, and other environments where it is used. Transportation is not a major factor, and most importantly the capital investment for the construction of factories for nitrogen fixation is unnecessary. Expansion of biological nitrogen fixation capabilities in the agriculturally developing countries is now being and should continue to be vigorously encouraged. RESEARCH TEAMS IN NITROGEN FIXATION Rationale During the past 30 years, agriculturists have used relatively inexpensive fertilizer nitrogen for their crops, and research on such practical problems as legume ino- culation, rhizobium strain effectiveness, and use of legume cover and green manure crops has declined. Responsibility for the manufacture, testing, and maintenance of the quality of rhizobium inoculants has been delegated to commercial manufacturers. Many of our well known experts in rhizobium bacteriology have retired, and the supply of well-trained young scientists in the field is at a low level. During the past two years the price of fertilizer nitrogen has more than quadrupled, and the current cost to farmers of nitrogen as anhydrous ammonia is $250 per ton. Fossil fuels represent 50 percent of the current cost of ammonia manufacture, and fossil fuels are becoming scarce and more expensive. While there has been a declining interest in the more applied areas of biological nitrogen fixation, research on the detailed biochemical properties of the nitrogen-fixing complex and related enzymes has proceeded at a rapid rate, and new methodology for the investigation of broad aspects of the process is now available. The acetylene reduction technique for measuring nitrogenase activity and relatively new methods for transferring nitrogen-fixing genes from one bacterium to another, for example, provide an opportunity for some major advances in the field. These opportunities include: (a) the improvement of nitrogen fixation by leguminous crop plants, (b) extension of the nitrogen-fixing capability to additional plants, (c) discovery of new and use of existing nitrogen-fixing organisms in nature, and (d) discovery of new chemical mechanisms of nitrogen fixation -125-

based on the chemical process that occurs in nitrogen-fixing microorganisms or on the development of the chemistry of nitrogen fixation under mild conditions (of temperature and pressure) by homogenous catalysts. In order to take advantage of these opportunities, training programs in some areas need to be encouraged and interdisciplinary research teams need to be organized. A rhizobium technical center is needed as a service to research workers in this and other countries, to manufacturers of inoculants, and to farmers. Implementation Federal and state agencies already have a substantial investment in facilities and personnel now conducting research in several aspects of nitrogen fixation. Therefore, research teams of 10 to 12 scientists should be organized by supplementation, where possible, of staff and facilities that are already in operation in laboratories and field stations with strengths in areas such as microbial genetics. In some areas new teams will need to be organized while in others, additional staff appointments and/or additional facilities could create dynamic research units. Success will require coordination of efforts by several agencies such as CSRS, ARS, USAID, and NSF. 1. Teams Assigned to Forage and Grain Legumes A team consisting of agronomists, soil scientists, plant nutritionists, bacteriologists, bacterial geneticists, plant geneticists, plant physiologists, biochemists, and extension specialists (the number to be determined by the need) should be located in each particular region of the country where grain and forage legumes are of major importance. The primary goal of each group should be to develop new and/or use existing bacterial strains and host cultivars and the most efficient agronomic practices for the production of maximum quantity of high quality food and feed. Since many of our legume cultivars have been developed in areas where high populations of indigenous rhizobia of unknown effectiveness were present, plant geneticists, bac- teriologists, and agronomists must reevaluate efficiency of nitrogen fixation by leguminous crops in order to determine whether or not the most effective combinations of rhizobium strains and leguminous hosts are being used. Also they must determine the factors that influence the survival and competitiveness of rhizobium strains in different environments and whether present inoculation techniques are adequate to insure that applied inoculum is capable of com- peting with existing populations of indigenous rhizobia. Plant physiologists, plant nutritionists, and biochemists, -126-

for example, should contribute to the team effort to enhance nitrogen-fixing capability by identification of those physiological, nutritional, and environmental factors that limit the process and by a search for methods for the alleviation of limitations. These endeavors will include the identification of the products of photosynthesis that are transferred to nodules as sources of energy for the support of nitrogen fixation and the definition of environmental and physiological conditions that limit nodule photosynthate supply under both laboratory and field conditions. Also the metabolic systems that participate in the transfer of products of nitrogen fixation out of nodules and the control mechanisms that influence the nitrogen- fixing process and closely related processes need to be characterized. The biochemical basis for the specificity of the infection of legumes by rhizobium species and strains needs to be understood. The information obtained may then be used in attaining the primary goal listed under Recommendation 1. 2. Teams for Grain and Forage Grasses A team located in the subtropical region of the U.S. should be organized to determine the magnitude and potential importance of biological nitrogen fixation on the roots of grasses and other species of agricultural importance. This team should include plant geneticists, microbiologists, agronomists, and plant physiologists who should direct their efforts toward such goals as determination of the magnitude of nitrogen fixation on the roots of corn, sugar cane, and subtropical forage grasses. Microorganisms responsible for fixation should be identified, compatibility of grass cultivars and bacterial strains should be tested, and the optimum environmental and other conditions for nitrogen fixation on or within grass roots should be defined. These investigations are particularly pertinent since Dobereiner in Brazil (Evans 1975) recently has described associations of bacteria on roots of Paspalurn notatum and Digitaria decumbens that are claimed to fix nitrogen at rates up to 100 kg of N per year. Measurements of field increases, however, have not been reported. Nitrogen fixation is known to occur on roots of grasses in temperate zones, but rates reported are relatively low. 3. Teams for Forests, Woodlands, Aquatic, and other Habitats Research teams consisting of phycologists, microbiologists, physiologists, mycologists, ecologists, foresters, and statisticians should be organized for the purpose of evaluating in quantative terms the contribution -127-

of fixed nitrogen to our non-arable lands, forests, aquatic, and other environments by the variety of non-leguminous nitrogen-fixing systems that are now known to exist. This is necessary in order to evaluate their contribution to food, feed, and fiber production and their role in controlling soil erosion and maintaining of ecological balance. Some of these systems include: free-living blue- green algae; nitrogen-fixing bacteria; associations of nitrogen-fixing bacteria with roots of herbaceous species and with fungi in rotting wood; associations of blue-green algae with fungi, liverworts, mosses, and ferns; and symbiotic associations between unidentified microorganisms and woody species, such as Alnus, Ceanothus, Purshia, Mvrica, and Dryas. If the basic biological characteristics of these nitrogen-fixing systems were understood, intelligent management and therefore maximum use of them could be made. A major objective, for example, would be to obtain pure cultures in laboratory media of the nitrogen- fixing endophytes of Alnus, Ceanothus, Myrica, Purshia, Dryas, and Comptonia. None of the endophytes in nodules of nitrogen-fixing woody species can be cultured at present, and as a consequence, methods for preparation of inocula that could be used to increase the extent of nodulation of these species have not been perfected. Also a search should be made for new naturally occurring nitrogen-fixing systems that are closely associated with plants. 4. Basic Genetics Teams Teams should be organized for the purpose of using genetic and cell-fusion techniques in extension of the range, extent, and usefulness of biological nitrogen-fixing capability. For example, genetic techniques should be employed to attempt to transfer nitrogen-fixing genes into additional bacteria of economic importance and to enhance biological nitrogen-fixing capability of organisms already known to fix nitrogen, by genetically altering control mechanisms that influence nitrogenase synthesis. Efforts should be directed toward the development of mutant strains of rhizobium with advantageous alterations in their specificity toward hosts. As a long-term objective this team also should attempt to incorporate nitrogen-fixing capability into tissues of crop plants, such as corn, wheat, or sorghum, and to develop strains of nitrogen-fixing bacteria with a capability of invading or associating themselves with roots of grass species and establishing effective nitrogen-fixing associations. -128-

5. Basic Biochemical and Chemical Research Teams Research teams should be organized for the purpose of continued improvement of understanding of the chemistry and biochemistry of biological nitrogen fixation by elucidation of detailed chemical changes that take place during the reduction of nitrogen gas to ammonia by nitrogenase and by chemical model systems. This objective requires collaboration of physical chemists, inorganic chemists with expertise in metal complexes, protein chemists, and enzymologists who are familiar with the detailed properties of nitrogenase. In addition to providing a basic understanding of the biological nitrogen-fixing process, this research offers the possiblity for discovery of new chemical mechanisms of reducing nitrogen. 6. Nitrogen Fixation in Conjunction with the Micro- biological Degradation of Waste Carbohydrates A team consisting of microbiologists, microbial geneticists, physiologists, biochemists, and engineers should be organized for the purpose of increasing the availability of fixed nitrogen by utilization of the energy in waste materials, such as corn stalks, grass straws, and wood products as substrates for the support of microorganisms, including those capable of nitrogen fixation. Precedent for this research already has been provided by the discovery of large populations of nitrogen-fixing bacteria in the decaying heartwood of forest trees (Evans 1975). The economic feasibility of these principles in the use of cellulose and other components of waste materials needs to be evaluated. The magnitude of operations could range from those designed to use large-scale industrial and farm by- products to small compost units for home gardens. RHIZOBIAL TECHNICAL CENTER Functions of a rhizobial technical center should include: (a) acquisition and storage of a world collection of rhizobia to insure the availability of a valuable collection of diverse types of rhizobia to researchers in this country and other countries; (b) collection of new rhizobial isolates to enable improved strain selection; (c) evaluation of rhizobial accessions; (d) training of technologists to work on the many aspects of selection, production, testing, and distribution of rhizobia; and (e) aid to the responsible government agency in the control of the quality of commercial inoculants. This center would provide technical service to the research teams listed above (1 through 5) and also services concerned with the use of microorganisms for the inoculation of non-leguminous species -129-

if justification for this is provided by current and future research. -130-

CHAPTER 16 CROP IMPROVEMENT RECOMMENDATIONS 1: Plant Genetic Resource Management. An immediate program of systematic assembly, maintenance, evaluation, and use of plant genetic resources should be undertaken, including the development of improved techniques for exploiting plant genetic resources. 2: In Vitro Techniques. Studies should be supported on technology for genetic transfer in plants through in vitro techniques for crop improvement, with emphasis at centers where interdisciplinary teams already exist or can be formed. 3: Chemical Control. Efficient and practical methods for the chemical control of plant growth should be developed. 4: Micronutrient Elements. The possibility that food and feed crops require additional micronutrient elements should be investigated. 5: Protein Quality and Quantity and Nutritional Availability. Research should be intensified on the genetic improvement of protein quality and quantity in cereals and cereal legumes, and on the biological verification of the nutritional value of the modified protein. 6: Protein from Oilseeds. Research should be intensified on increasing the protein in oilseeds by improving gossypol-free varieties of cotton, on yields and changes in types of fatty acids in sunflower, and on new varieties of soybeans to increase their range and yield. -131-

PLANT GENETIC RESOURCE MANAGEMENT Rationale The important food crops grown in the U.S. originated outside the U.S. and have been imported. The genetic lines of these crops are becoming increasingly uniform. An important aspect in maintaining the genetic variability upon which man depends for future breeding programs is the preservation of a maximal range of genetic stocks. It will be important to provide adequate steps for preserving genetic materials. The Agricultural Research Policy Advisory Committee (ARPAC) of the Agricultural Research Service (ARS/USDA) has recommended a genetic resources board to devise a national plan and program of genetic resource management. It is important that such a plan be implemented in order that germ plasm from centers of diversity will not be lost. Crop productivity at the genetic level is limited by the genetically-controlled growth responses to environmental resources and stresses. Sufficient information is available to support the expectation of high sustained yields if the physiologic genetic processes regulating the vigor of plant growth could be understood and brought under agronomic control. Most frequently, specific useful characters or combina- tions of characters occur in only a small fraction of a population of basic stocks or endemic strains of a species. Ways need to be found to simplify and expedite the identifi- cation of characteristics useful for meeting given objec- tives. Environmental stresses on crop plants are a fact of life that must be faced as we seek knowledge and develop technology for meeting our basic needs for sustenance. The genetic approach is ecologically nonpolluting and energy conserving. Sustained, debilitating drought may occur again over major parts of our most important crop production areas. Air pollution is limiting crop production in some areas (Benedict et al. 1973). Widespread culture of genetically similar varieties may result in greater losses from environmental stresses than would otherwise be the case, particularly if the varieties have not been selected for stress tolerance. Rather than add chemicals to change the soil to fit the plant, it now appears wiser in some uses to change the plant to fit the soil. Selecting or breeding plants more tolerant to salinity is a case in point. Better understanding must be sought of (a) differences among strains and varieties in their ability to withstand stresses, and (b) the alternatives that are available for continuing to produce adequate supplies of food, feed, and fiber in situations of extreme environmental stress. We need to strengthen current efforts to transfer genetic material from one species (or genus) to another by means of conventional crossing procedures. Dramatic examples of successful transfer can be cited: leaf rust -132-

resistance from wild Aegilops species into wheat and golden nematode resistance from wild Solanum species into potatoes. Related wild species of our crop plants represent a source of genetic material that has hardly been tapped. IN VITRO TECHNIQUES Rationale Great strides have been made in what is being called the "new botany," that is, the production of new types of plants without recourse to sexual reproduction by using the in vitro techniques of cell and tissue culture. The approaches afforded by these recent advances have great potential for plant breeders. New techniques are now feasible because of the progress made in plant cell culture during the past decade (Chellef and Carlson 1974). These include: (1) meristem culture for the propagation of plants difficult to multiply and to free infected plants of viral, bacterial, and/or fungal contaminants; (2) embryo culture for growth of plants which naturally abort before or soon after germination (because of incompatibility with maternal tissue or because of the production of toxic materials by the maternal tissue); and (3) the long time storage under liquid nitrogen of germplasm of vegetatively propagated plants, such as fruit trees, shrubs, and potatoes. In addition, there are techniques which can be used at the cellular level for the manipulation of plant systems including: (1) exploitation of spontaneous variation in cell and tissue culture, polyploidy, aneuploidy, and chromosomal mosaics; (2) induced mutations; (3) induced polyploidy (particularly doubling of chromosomes through the use of the alkaloid colchicine); (1) haploids (individuals with only one set of chromosomes in the vegetative state, a condition in higher plants usually reserved for sex cells) plants from pollen or from anthers; (5) fusion of protoplasts produced from vegetative cells; (6) transformation (to change the heritage of one strain by introducing the chemical carrier of heredity from another strain); and (7) efficient selection and screening procedures to recover desired cell or plant types from large populations. New plants have already been obtained using these approaches. Success has been achieved in obtaining mutants resistant to several diseases and to environmental stresses. Fusion of protoplasts from vegetative cells from different species of Nicotiana to produce a hybrid plant has been demonstrated. The hybrids are similar to those produced by sexual methods, demonstrating that the approach is theoretically sound. Transformation in higher plants is in infancy, but some investigators believe this approach to be the most effective because it should allow more directed change with better control and definition of the desired modification. -133-

The most effective use of these new techniques will be realized when selection can be coupled with directed change. Support is needed for studies of selection methods at the cellular level. The agricultural implications appear to be significant: possibilities include not only new plants not possible through the sexual process, but also higher yielding lines, increased disease resistance, and even production of desirable products in more than one part of the plant. CHEMICAL CONTROL Rationale Compounds that control crop maturity could have an important economic impact in the foreseeable future. These chemicals can increase yields by effecting metabolism, preventing losses due to failure to achieve maturity or to the delay of the timing of maturity, limiting fruit set, and delaying fruit drop. An excellent example of the positive results achieved in the recent past is the use of chemical ripening compounds in sugarcane resulting in a 10 to 15 percent increase in yield of the economic product, in this case sucrose (Nickell 1974). There is every reason to believe that changes in cultural practices to adjust to this new approach will give additional yield increases. Similarly, the use of a naturally occurring growth stimulant nearly doubles both yield and sugar content of seedless grapes (Weaver 1972). The success in sugarcane and grapes strongly suggests the desirability of studying other systems in increasing metabolic products in the vegetative stage of crop production, and it is not unrealistic to propose inaugurating similar approaches to sexually produced crops. Recent studies have shown that the inhibition (or delay) of senescence in small grains substantially increases yield (Weaver 1972). It has also been found that legume nodules cease fixing nitrogen and start to disintegrate when their carbohydrate supply decreases from the shoot. In addition to these direct effects on yield increases, there are other indirect ways to improve yields or to pre- vent losses. One is to delay or speed up the flowering time in crops, such as cotton, so that there are no developing young fruit to serve as hosts for the insect pests. Another is to control the germination, growth, and development of plant vegetation to synchronize with the rainfall distribution pattern for semi-arid areas. A combination of chemical control over plant growth with development of new plants through in vitro techniques may enhance the potential of both approaches to crop improvement. Development of specific chemicals to adjust the physiological mechanisms of new plants should be moved -134-

ahead concurrently and with close liaison among the researchers involved in both activities. MICRONUTRIENT ELEMENTS Rationale The first step in meeting the mineral nutrient requirements of man and animals is the absorption of the required minerals by plants growing on soil. In many instances, the concentrations and ratios of the minerals in the plant are not those most desirable in human and animal diets. The problem is most critical with some of the so- called "trace elements"—iron, zinc, selenium, copper, iodine, cobalt, and others. Recognition and correction of some mineral deficiencies in animals that stem from deficiency in soils and are reflected in plant composition have increased food production and permitted animal agriculture to expand into new areas (Allaway 1975). But mineral deficiencies in humans and animals still persist as evidenced by widespread iron deficiency or by the recently established zinc deficiency in people. Correction of these deficiencies by direct supplementation of people and animals has met with mixed success in the developed countries and will face additional difficulties in developing countries where food technology is not advanced. In addition, the people of many developing countries must depend primarily on direct consumption of plants to meet calorie requirements, without the animal acting as an intermediate collector of essential minerals and a barrier to the transfer of toxic minerals and antimetabolites. Several elements—silicon, chromium, vanadium, nickel, and others—have recently been added to the list of those essential or probably essential, for man and animals, but relatively little is known about how these elements move through food chains. Other elements will undoubtably be added to the list of those essential for plants or animals. It is now appropriate to try to improve plants as sources of dietary trace elements for people and animals, to identify and correct malfunctions of the trace element food chain that are unique to certain geographic regions, and to develop plants that will be better sources of minerals than any of those grown up to now. The research should include efforts to control the concentration of minerals in food and feed crops plus efforts to improve the digestibility and nutritional value of minerals in plants. -135-

Implementation Nutritional researchers should attempt to control movement of essential and toxic minerals from soils to plants to animals. The approach should include studies of the chemistry of these elements in soils directed toward development of soil tests that can be used to predict the concentration of specific elements in the edible parts of plants, and to predict how this concentration will change under different fertilizer additions or soil management practices. The processes of uptake and translocation of these elements in plants should be investigated along with the factors affecting the chemical combinations of these elements in the plant. Plant breeders should be assigned to develop food and feed crops that are adapted to specific trace element environments or may be efficient accumulators of different minerals. The work of these scientists should be supplemented by nutritionists who investigate the digestibility and nutritional function of elements contained in different plants and who establish plant composition goals based on human and animal requirements for different elements, or on critical concentrations to prevent toxicity from others. PROTEIN QUALITY AND QUANTITY AND NUTRITIONAL AVAILABILITY Rationale In a world in which animal protein will become increasingly costly, plant proteins will have to provide a greater share of the protein intake of people everywhere. This requires that plant proteins be of adequate nutritional value when ingested in diets of adequate caloric value. In classic cases, particular amino acids have been shown to be nutritionally limiting, and genetic mutants have been found which alter their levels in seeds. The different cereals of economic importance all have one characteristic in common— they are low in the essential amino acid, lysine. Because of the lack of adequate lysine, cereal proteins are inferior nutritionally to the proteins found in milk, meat, eggs, and grain legumes. With the discovery 10 years ago that the maize mutant opaque-2 had nearly twice as much lysine as ordinary maize, scientists realized that cereal grain proteins could be im- proved in quality by genetic manipulation. The recent discovery of high lysine mutants of barley and sorghum raises the hope that all cereals of economic importance may eventually be improved in protein quality by genetic selection. Grain legumes, including dry beans, dry peas, pigeon peas, chick peas, and mung beans, have high protein contents and are rich sources of protein to large segments of the -136-

world's population. These proteins in general supplement those in cereal grains because they are relatively high in lysine content, with the result that when the edible legumes are consumed in conjunction with the cereal grains, a far better balanced protein diet is attained. A greater research effort is needed to improve the protein quality and quantity in food legumes. Other plant protein sources are not fully exploited. For example, mutant types of pumpkins are known which contain seeds without a seed coat. These seeds contain over 30 percent protein and over 40 percent oil content. The quality of both oil and protein surpasses that from peanuts and soybeans. Cucurbits such as pumpkins require less water per unit of production and are adapted to arid areas. Plant selection programs which ignore grain yield or amino acid balance and are directed solely at protein content of cereals and grain legumes could be counterproductive. Increased protein content at the expense of an essential amino acid bearing fraction may lower the overall biological value of the protein. In like manner the digestibility of the protein and its availability when used in the normal dietary pattern is an equally important consideration in product improvement; but overall yield of calories and balanced protein is the most important objective. The biological value of a protein is the ultimate mea- sure of its worth in human and animal diets. Protein is often not fully available, and the reasons for this are in most cases not understood. The evaluation of protein availability in these systems must be an integral part of any plant breeding program designed to affect protein quality and/or quantity. To date, biological evaluations have been limited largely to the testing of products from a research program at a time they were nearing commercial production. Biological testing capabilities in the early stages of a breeding and selection program must receive renewed attention. Implementation Successful genetic modification of protein quality and/or quantity can be maximized by interactions between the disciplines of plant genetics, biochemistry, human and animal physiology, human and animal nutrition, and agronomic production when members of each disciplinary area are aware of and appreciate problems of the interacting group. Progress in the successful development of nutritionally superior varieties of basic food crops could be accelerated. Integrated research in this area can be developed by the establishment of funded core projects which can, in turn, fund research in supporting project areas with each project area participating in the evaluation of the overall project. -137-

Biological as contrasted to chemical evaluation of plant products used for food is a necessary step in any im- provement program. The digestive process can be affected by composition, quantity, and competitive interactions with the various components of the heterogenous food source. While the quality of the human diet is the ultimate factor to be evaluated, animal experimentation must provide the bulk of the information. Plant breeding improvements in nutritional quality are difficult to detect unless they are associated with an easily detected chemical change. Because of the quantities of materials required for early testing of plant materials, nutritional data from existing animal systems are too costly to collect. Rapid, low feed requiring animal systems need to be developed to support and verify plant modification studies. PROTEIN FROM OILSEEDS Rationale The potential protein supply for human use from present production of oilseeds is high. However, only a small fraction of these proteins is now consumed directly by humans. The major oilseeds in terms of total protein are soybeans, cottonseed, and peanuts. Other oilseed plants include sunflower, safflower, rapeseed, sesame, olive oil, palm oil, and copra. Cottonseed oil accounts for about 10 percent of the world's edible vegetable oil production. Cottonseed meal is a largely untapped source of protein for humans; it currently goes into livestock feeds. Gossypol, a phenolic pigment that is toxic to man and some animals, is a problem in both cottonseed oil and meal. Techniques for removal of gossypol and the development of gossypol-free varieties of cotton will increase the usefulness of cottonseed oil and meal. Sunflower seed has become the world's second most im- portant source of edible vegetable oil and must rank high in any priority list for research attention. Sunflowers have a large unexplored genetic variability, which will allow breeders the chance to breed for particular climatic zones and environments. Soybean oil accounts for one-fifth of total edible veg- etable oil production, while soybean meal accounts for ap- proximately one-haIf of total world oilseed meal production. The meal in terms of amino acid balance is of the best of the vegetable protein family. Even so, soy protein is deficient in sulfur amino acids. A modest improvement in the concentration of methionine and cystine in soybeans would enhance the value of these proteins, minimize the amount of protein that must be eaten in order to meet essential amino acid requirements, and decrease the -138-

potential hazards of overconsumption of total protein. Its use is primarily for feed of livestock and poultry. Any significant breakthrough to increase production could profoundly affect the food and feed industry of this country and the world. Implementation Processing technology needs to be implemented which would provide for greater and more flexible use of the by- products of oilseeds. These efforts should be coordinated with plant breeding and selection which would provide not only the maximum yield of oil but would also contain the lowest possible levels of undesirable, naturally occurring constituents. -139-

CHAPTER 17 FORAGE AND RANGELAND IMPROVEMENT, HARVEST AND PROCESSING TECHNOLOGY RECOMMENDATIONS 1: Genetic Improvement. Research should be intensified on the genetic understanding as well as the genetic improvement of forage yield, quality, adaptability, and pest resistance of important forage and range species. 2: Germplasm and Seeding Technology. Germplasm and seeding technology should be developed to improve rangeland productivity. 3: Production Systems. Forage and livestock systems should be developed that utilize the full potentials of forage, range, and livestock management capabilities to meet most economically the various nutritional requirements of animals for various physiological functions. 4: Harvest and Processing Technology. Harvest and processing technology should be developed that (1) in- creases the efficiency of use of labor and/or energy; (2) minimizes losses of biologically fixed nutrients; (3) is independent of weather hazards; and (4) increases forage output quantity and quality. GENETIC IMPROVEMENT Rationale Forages (harvested forages, pastures, rangelands, silages, and crop residues) are major crops in terms of total value of production and acreage. Some 245 million hectares in the U.S. are used for silage, hay, or grazing. More than 50 percent of all feed units (corn equivalent) consumed by all U.S. livestock are derived from forages. Beef cattle and dairy cattle obtain about 73 and 63 percent, respectively, of their feed units from range and forages, while sheep obtain about 89 percent from these sources (Hodgson 1968). In most other countries of the world, ruminant livestock is even more heavily dependent on range and forages—in some countries almost completely so. -140-

In recent years, there has been a rapid increase in the world's demand for the meat and milk of ruminant livestock. Correspondingly, the numbers of such animals have increased dramatically to supply those demands. Plentiful, cheap grain supplies were used to partially sustain animal population increases; but, in the U.S., that population increased to more than our grasslands could support. Projections are that world demand for meat and milk will continue to grow. Increasing prices have reduced the amounts of grain available for feeding cattle in the U.S., and the same situation prevails to a degree in other countries. Such pressures may well continue into the future with only occasional fluctuations. Thus, the high dependency of ruminant animals on range and forages, the increasing demand for the meat and milk of these animals, and the current and projected reduced avail- ability of cereal grains to feed them all point clearly to the urgent need to increase the capacity of forage lands throughout the world. There is a need for higher levels of productivity and better quality of forage crops. Current animal populations will experience a sharp de- cline unless this increased range and forage capacity is achieved. while the animal population reduction is occurring, meat supplies will be plentiful and consumer prices relatively cheap. But after the reduction has run its course, meat and milk supplies are likely to be reduced to levels below needs; and in a market of scarcity, consumer prices will escalate substantially with consequential serious impacts on the nutrition of major segments of our population. There are two principal methods of forage and range improvement: (1) genetic improvement and (2) seeding improved species into permanent grasslands. The breeding and genetic effort on forage and range species is generally low. There is no effort on some species of major importance; on others the effort may be only a very few scientist man years—well below the necessary critical mass required for reasonable progress. On few, if any, is the effort adequate to approach capturing the potential of the species. Only limited basic genetic information (considered so essential for grain crops) is available for any forage species. While it should not be construed that other potentials for improvement are not present or of considerable magnitude, the potential for genetic improvement of forage and range species is great and centers around four main thrusts. 1. Increasing the genetic potential for yield of herbage will be a basic component in increasing total production. Selection criteria for herbage yield are different from those for seed yield and not well understood. The perennial and polyploid nature of many forage and range species complicates the selection process. -141-

2. Improving the quality of forage and range has potential for increasing performance per animal on high forage rations. Opportunities exist in such areas as (a) improving dry matter digestibility, (b) increasing animal intake potential by increasing palatability, (c) reducing lignin and silicon content, and (d) eliminating or reducing antimetabolites in some species. The potential from such efforts is indicated by one example. An improved cultivar of bermudagrass with about 10 percent increased digestibility produced a 30 percent increase in weight gain of grazing animals (Burton et al. 1967). Considerable research is needed to develop methodologies and genetic data for use in breeding for improved yield and quality. 3. Forages usually are grown on inferior sites and with a lower order of environmental control than are most annual cultivated crops. This requires a wide adaptability potential in useful cultivars and a large number of cultivars. Forage crop improvement efforts must accommodate these needs. H. Pest resistance also offers great potential for success because of the large number of pests that attack the wide range of forage and range species and cause serious losses. In addition, perennial plants provide a year-round host for many pests and can make pest impact more debilitating. GERMPLASM AND SEEDING TECHNOLOGY Rationale Overuse of many of the world's grasslands has resulted in deterioration of plant cover and productivity. Restoration of much of this important resource will require or be enhanced by improved seeding or superior natural forage and range species. The beneficial results could come rapidly, but the task is immense and should proceed without delay on the most responsive sites wherever ownership, social, or political constraints permit. PRODUCTION SYSTEMS Rationale Of particular importance is the definition and application of optimum improvement and management strategies for permanent grasslands that will permit increased animal production while preventing deterioration of the resource or, in many cases, even improving it. Such activities should receive high priority for prompt and sizeable attention. -142-

A wealth of forage and grazing management technology is available. Yet, certain cultural and use refinements will be needed as better cultivars are available and as dependence on herbage increases. Special emphasis is needed now to capitalize on the potential of innovative forage and range and livestock management practices to develop highly sophisticated production systems. These potentials should match herbage availability and quality on a year-round basis to the nutritional needs of animals for the various physiological functions of maintenance, reproduction, growth, and milk production. Similarly, there is opportunity to develop and apply animal management strategies to better use forage and range potential in different environments, types of production systems, and so on. HARVEST AND PROCESSING TECHNOLOGY Rationale Large volumes of forages are harvested annually in humid or irrigated areas of the world. Harvest practices are generally labor and energy intensive, time consuming, and in humid areas subject to physical and chemical crop losses during the harvest process. It has been estimated that annual protein losses in harvesting the U.S. alfalfa crop may be equivalent to half the yearly protein intake requirement of the U.S. human population. Losses of soluble carbohydrates are also large. Such losses mean high risk potential for harvested forages with resultant decreases in production inputs and thus lower than potential yields. Harvest technologies are needed that: (1) minimize time, labor, and energy inputs; (2) reduce losses of biologically fixed proteins, carbohydrates, and other nutritional factors; (3) are resistant to stresses from weather; and (d) increase the quantity and quality of forage output. One approach that offers great potential but which re- quires more research and development is that of mechanical removal of water from the harvested forage. The process not only promises to accomplish the above aims, but also produces, from the expressed juices, a low fiber, high protein product of exceptional biological value that can be used as feed for certain high producing ruminants or monogastric animals or as a valuable new source of protein for humans. This concept offers great promise for simplification in technology and scale and, for that reason, for rapid adaptation to many developing nations. -143-

SELECTED REFERENCES Allaway, W.H. (1975) The Effect of Soils and Fertilizers on Human and Animal Nutrition. Washington, D.C.: USDA Agricultural Information Bulletin 378. Benedict, H.M., C.J. Miller, and J.S. Smith (1973) Assessment of Economic Impact of Air Pollutants on Vegetation in the United States: 1969 and 1971. Palo Alto: Stanford Research Institute. Burns, R.C. and R.W.F. Hardy (1973) Nitrogen Fixation in Higher Plants. Berlin: Springer-Verlag. Burton, G.W., R.H. Hart, and R.D. Lowery. (1967) Improving Forage Quality in Bermuda Grass by Breeding. Crop Science 7:329-332. Chellef, R.S. and P.S. Carlson (1974) Ann. Rev. Genetics 8:267-278. CIMMYT (1972) Purdue International Symposium on Protein Quality in Maize, High Quality Protein Maize. El Batan, Mexico. Evans, H.J., ed. (1974) Proceedings of a Workshop, "Enhancing Biological Nitrogen Fixation." National Science Foundation, Division of Biological and Medical Sciences. Washington, D.C.: National Science Foundation. Heimer, D., C. Thomas, and P.S. Carlson (1975) Personal communication. Harvard University and Michigan State University. Also, R. Mengher and H. Boyer (19"?5) Personal communication. University of California, San Francisco. Hodgson, H.J. (1968) Importance of Forages in Livestock Production in the United States Forages: Economics/Quality. Amer. Soc. of Agronomy Spec. Pub. 13. National Academy of Sciences (1972) Genetic Vulnerability of Major Crops. Washington, D.C.: National Academy of Sciences National Academy of Sciences (in press) Genetic Improvement of Seed Proteins. Washington, D.C.: National Academy of Sciences. Nickell, L.G. (1974) Plant Growth Regulators in Sugar Cane. Bulletin, Plant Growth Regulators, Vol. 2. Pimentel, D., L.E. Kurd, A.C. Bellotti, M.J. Forster, I.N. Oka, O.D. Sholes, and R.J. Whitman (1973) Food Production and the Energy Crisis. Science 182: 443-448 Sprague, H.B. (1975) The Contributions of Legumes to Continuously Productive Agricultural Systems for the Tropics and Subtropics. Technical Series Bulletin 12, Office of Agriculture, Technical Assistance Bureau. Washington, D.C.: USAID, Stone, J.F., ed. (1974) Plant modification for more efficient water use. Agric. Meteorology 14 1/2. U.S. Department of Agriculture (1974a) Opportunities to Increase Red Meat Production from Ranges ot the United -144-

States, Prepared by USDA Inter-Agency Work Group on Range Production. U.S. Department of Agriculture (1974b) Agricultural Prices, Pr (4-74). USDA-SRS Agricultural Prices, Pr 1 (9-74) . Statistical Reporting Service. Washington, D.C.: U.S. Government Printing Office,. Weaver, R.J. (1972) Plant Growth Substances in Agriculture. San Francisco: W.H. Freeman and Co. Zelitch, I. (1971) Photosynthesis, Photorespiration, and Plant Productivity. New York: Academic Press. -145-

SECTION IV; LIVESTOCK, POULTRY, AND FISH PRODUCTION INTRODUCTION Animal products comprise significant portions of the food supply in the U.S., supplying two-thirds of the protein consumed, one-third of the energy, one-half of the fat, four-fifths of the calcium, nearly two-thirds of the phosphorus, and significant quantities of essential min- erals, micronutrients, and vitamins. The amino acid composition of animal proteins is of high biological value to man. In some countries, animal products supply much smaller proportions of the diet; in others, the dependency on animal products, especially fish, is much greater than in the U.S. Further, a high proportion of people prefer to eat animal products. The production, processing, transportation, and marketing of these products provides employment for a large segment of the population of the U.S. Thus, the viability of the livestock industry is of significant economic importance to the country. Ruminants can convert cellulosic or concentrated feeds to food, while monogastrics require concentrated feeds for the most part. For most of man's history, and even today in much of the world, domesticated animals have consumed feedstuffs not usable by man—fibrous plant materials and the wastes. In recent times a few countries, including the U.S., have achieved the capacity to produce cereal grains, especially maize and sorghum, in quantities in excess of food needs. Livestock has played a significant role as a residual user of surplus feeds. Prices have been low enough to make such grains important animal feeds, and animal productivity has increased. But within the past few years world demand for all grains, both as food and feed (together with changes in world market structures), have resulted in price increases. As a result, a new look is being taken at the use of grain, improved forages, crop residues and by- products as ration constituents. A large part of the earth's land surface can only infrequently produce cultivated crops directly usable by man, but it can produce high cellulose plant material that can be converted economically to food only by animals. Other land, that could regularly produce food crops, finds its greatest economic value in producing forages. Also, most plant food crops produce large volumes of cellulosic residues usable by ruminant animals. Rangelands are one of the world's greatest untapped sources of feed for livestock, -146-

and improved rangeland management could greatly enhance food production. (See Chapter 17, Forage and Rangeland Improvement, Harvest and Processing Technology.) The world livestock population exceeds the human popu- lation by two to three times. The number of ruminants (cattle, buffalo, sheep, goats, and camels) alone approximates the human population of 3.5 billion, and there are about 0.6 billion swine and 5.3 billion poultry. Livestock constitutes a storehouse of food available to man, reducing his vulnerability to periods of poor crop production. It is important to emphasize that increasing livestock productivity is dependent upon improving the total food production system.

CHAPTER 18 REPRODUCTIVE EFFICIENCY RECOMMENDATIONS 1: Reproductive Diseases. Research is needed on reducing losses and controlling diseases during gestation or incubation. 2: Number and Sex of Progeny. Studies are needed on increasing the number of progeny per breeding female as well as on the sex control of the progeny. 3: Genetically Superior Animals. Research is needed on increasing the reproductive capacity of selected genetically superior mammalian animals and on estrus synchronization of females for insemination. REPRODUCTIVE DISEASES Rationale The first step is to control diseases causing abortion in mammals, hatching failure in poultry, and male or female sterility. Much of the technology to detect such diseases and substances that cause abortions or infertility and to control them within economic levels is available, but much basic research is still necessary to gain sufficient understanding for their control. The second step is management for reproduction and providing breeding females with essential nutrients. For example, it is well documented that in some areas of the tropics, provision of the minimum essential levels of the phosphorus in supplemental feed to cattle on deficient pastures has raised the calving levels. Constraints on the reproductive efficiency of animals result from improper breeding management, infections, toxic diseases, and nutritive deficiencies. Procedures should be developed for early and rapid diagnosis of incipient infertility, and for the determination of the etiology, incidence, and control of diseases, toxins, and deficiencies which induce male or female infertility and cause abortion or stillbirth, or the birth of defective offspring. Infectious diseases include brucellosis, vibriosis, -148-

leptospirosis, foot and mouth disease, and many others; toxins involved include the mycotoxins of moldy feed. Many nutritive deficiencies affect reproduction, of which insufficient phosphorus intake, for example, is well known. Some control measures are already known and others should be developed for all of these. NUMBER AND SEX OF PROGENY Rationale Techniques for increasing the number of progeny produced by each female reduce the cost of maintaining the breeding herd or flock, but technical skills and materials required may not decrease the basic cost of each progeny. Thus, economic studies are needed. Areas of research should include: (a) increasing the number of young produced from each gestation: for example, increasing litter size in swine, the incidence of twinning in cattle, and of twins and triplets in sheep and goats; amd (b) shortening the gestation interval by terminating gestation at optimum periods and still allowing satisfactory offspring survival: the objective is to increase the number of gestations per lifetime of each female. For some purposes control of the sex of the progeny would be economically and genetically advantageous. Conflicting results are reported for the techniques employed, but much more research is necessary to make the process feasible. GENETICALLY SUPERIOR ANIMALS Rationale Studies are needed on how to rapidly increase the number of genetically superior animals by (a) hormone treatments to induce multiple ovulation, (b) artificial fertilization, (c) removal of embryos to "incubator females" for gestation, and (d) reduction of periods of reproductive quiescence in genetically superior females. Artificial insemination, which is a long established and viable technique for increasing the number of progeny from genetically superior males, is an expensive technical service. The costs could be reduced in this procedure and in management of parturition and of resulting newborn if optimum numbers of females at each farm unit could be bred in one short interval. -149-

CHAPTER 19 IMPROVED EFFICIENCY OF LIVESTOCK PRODUCTION RECOMMENDATIONS 1: Genetic Improvement. Research is needed on genetic selection of animals with desirable production traits including rapid growth, efficient feed conversion, high production per animal, and disease resistance. 2: Nutrition Efficiency. Research on nutrition efficiency should be carried out on nutritional requirements, use of nonprotein nitrogen, rumen bypass, greater use of forage, and unconventional feedstuffs. 3: Disease Prevention and Control. Research should be increased on disease prevention and control, such as systems to reduce prevalence of disease, detection and elimination of carriers, nature of defense mechanisms, and drugs and chemicals for control of diseases. GENETIC IMPROVEMENT Rationale Artificial insemination in dairy cattle has permitted highly effective selection on males (from one male per five to twenty females, to one male per three thousand or more females). This, coupled with precise mathematical studies of records of related females, has permitted marked improvement in milk production (doubling of the average milk yield of American dairy cattle in five generations) and reduction of the national breeding herd from about 25 million to about 11 million milk cows. For poultry the time required to produce a broiler has been reduced from 14 weeks to 8 weeks, with feed efficiency being increased twofold (U kg feed/kg broiler to 2 kg feed/kg broiler). Crossbreeding has wide potential applicability for improving production. Crossing of widely divergent lines often leads to increased survival and vigorous growth of the progeny and increased feed efficiency, which results in increased production of human food from a fixed breeding population. But to achieve this, an investment is required in a scientifically oriented system of providing the necessary inputs to manage, feed, and garner the harvest -150-

from the improved progeny. It is also necessary to maintain breeding herds with resistance to disease, parasites, and stresses of climate and environment. The necessary steps involve: (a) description of the characteristics desired; (b) measurements of such characteristics in a standard manner, to reduce variation due to environment; (c) determination of the heritability of the desired characteristic; (d) generation of means for rigorous selection for the characteristics; and (e) implementation of the operation on a broad scale. NUTRITION EFFICIENCY Rationale Quantitation of nutrient requirements is a complex area of research, because of the variety of factors that influence requirements, the criteria for nutritive adequacy, and the variability within and among animal species. Continued changes in breeding, management, and introduction of new feedstuffs and methods of feed processing bring with them new factors or introduce extreme situations that influence nutrient metabolism and requirements; hence, there is a continuing need for reevaluation. For example, deliberate alteration of the gene pool of a meat-producing animal species to attain greater production and more desirable carcass characteristics may influence specific nutrient requirements in as yet unknown ways. This fact is well recognized in poultry, in which strain differences are known to influence arginine, zinc, manganese, and riboflavin requirements. What is the extent of variation in specific requirements within other animal species? Is it feasible to employ selection techniques to develop strains with lower nutrient requirements? Many problem areas where research should be implemented were identified by the NRC Committee on Animal Nutrition (NAS 1974) . Four of the most important are discussed below. 1. Define Nutritional Requirements for Optimal Production and Optimal Use of Feedstuffs In our knowledge of nutritional requirements of animals there are many gaps that must be eliminated before optimal use of feedstuffs and optimal animal production can occur. -151-

2. Improve Use of Nonprotein Nitrogen (NPN) Sources Ruminants, through their ruminal microorganisms, can use NPN compounds to synthesize body proteins and convert these proteins to milk, meat, and fiber. Basic research on the biochemistry and physiology of NPN use is needed to improve the efficiency of NPN use by ruminants, and to a lesser extent, by non-ruminants. 3. Develop Rumen Bypass Technology to Improve Amino Acid Use This is an area of research that could increase the efficiency of feed use by ruminants. Preliminary studies indicate that certain amino acids may benefit ruminants, particularly at high levels of productivity, if they are treated so that they bypass the rumen (preventing bacterial degradation) and become available in the fourth stomach and lower intestinal tract. 4. Develop Systems for Greater Forage Use Ruminants can digest fibrous feeds which humans do not eat and cannot digest. Most of the forage ruminants consume is grown in land areas where the best and sometimes only use of them is in forage production. Approximately one-half of the land area in the U.S. produces forage. Therefore, ruminants are important in converting inedible forage into animal protein. As grains and other feeds are increasingly consumed directly by humans, more forages and unconventional feedstuffs will be used in the rations of all animals. Research is needed to develop rations, as well as management and production programs, which make use of different forages at varying levels of intake. Special emphasis should be given to the following: (a) Develop improved forage preservation methods and delivery systems. Development of organic acids by bacterial breakdown of carbohydrates is a classic method of feed preservation. Direct addition of organic acids is being used to preserve forages, offering possibilities for eliminating molds and for increasing the feeding value of forages. Other additives and treatments have also been used to decrease ensiling losses and to improve silage quality. Improved methods of ensiling, dehydration, and other methods of handling forages will increase their feeding value and use and decrease nutrient losses. (b) Improve crop residue utilization by chemical, physical, or other treatments. The feeding value of high fiber crop residues (e.g., straws, corn stalks, and low quality forages) can be increased by chemical treatments, -152-

such as the process developed in Germany involving the use of sodium hydroxide. These treatments would increase the digestibility of cellulose, hemicellulose, and other nutrients, thereby enhancing their value. Physical treatments, such as pelleting, are especially helpful in in- creasing the palatability, intake, and feeding value of low quality, high fiber feeds. DISEASE PREVENTION AND CONTROL Rationale Diseases retard maturity, decrease feed efficiency, increase overhead costs, and result in wastage from condemnation. This results in the loss of at least one out of every ten animals each year in the U.S. An unanticipated temporary impact of the highly effective control of one disease of poultry, Marek's disease, with the introduction of a vaccine was the depression of the market price caused by rapid overproduction resulting from increased survival. This situation has developed into decreased costs of poultry production to the benefit of both producer and consumer. Many of the discoveries of methods for controlling diseases of livestock and poultry have been applied to the control of disease in humans. Implementation Research emphasis should be given to the following areas: A. Eradicable Diseases Some preventable diseases have been eradicated in many nations, but they remain as primary constraints on livestock productivity in many agriculturally developing countries. Consequently, they have led to the imposition of quarantines that seriously restrict international commerce. A report by the American Veterinary Medical Council (AVMC) in 1974 showed that systems that were successful in ridding the U.S. of foot and mouth disease, babesiosis (Texas cattle fever), vesicular exanthema, and exotic Newcastle disease, and in reducing brucellosis, tuberculosis, screwworm, and hog cholera to rare infections can be applied to developing nations. To protect the U.S. against reestablishment of these plagues, to assist other nations in eliminating these diseases, and to make possible the eradication of other infections enzootic to the U.S., three research objectives should be satisfied: -153-

1. identification of diseases and their epide- miologies; 2. creation of systems that reduce the prevalence of disease to a level that makes eradication feasible, such as the development of effective vaccines and methods of environmental management; and 3. development of methods that will detect and eliminate carriers and vectors of disease so that effective quarantine can be established and maintained. Before the usefulness of a method can be fully evaluated, the findings from the fundamental studies required to achieve the three research objectives must be applied to specific diseases in specific hosts, first under controlled conditions and later with field conditions under adequate supervision. The primary criterion for selection of subjects for ap- plied research should be the identification of a specific disease for an official control program. The establishment of an official program should be made only after the above research objectives have been satisfied. B. Diseases with Complex Etiology The major unsolved disease problems in intensively reared livestock are the result of interaction of one or more pathogens with the stressor effects of environment or crowding on host animals. In this group we find many of the neonatal diseases, all of the diseases associated with animal transport, and many of those found in large dense populations. Fundamental research is needed on: (1) the nature and inheritance of innate defense mechanisms of livestock and poultry species, (2) methods of effectively stimulating specific immunity, and (3) the contributions of environmental and behavioral stressors on the susceptibility of animals to disease. This research will require federal funds not now available for staff and materials, and for sophisticated and expensive environmental facilities, such as high temperature and controlled humidity chambers. Applied research is needed on neonatal diseases of swine and cattle and on respiratory and enteric diseases of swine, cattle, and poultry. C. Diseases Controllable by Drugs and Chemicals Diseases in this group, caused by parasites and certain bacteria, contribute in a major way to the loss of efficiency in feed conversion and to lesions that are a significant cause of condemnation. Drugs and chemicals, while often effective, are expensive if used at high levels and may leave undesirable residues in meat, milk, or eggs if -154-

improperly used. Research is needed that will: (a) reduce the requirement for high level use of chemotherapeutic substances by developing management systems that reduce the exposure to parasites; (b) breed for increased resistance of the animal to parasites; and (c) develop drug regimes that will provide adequate protection against parasitism without leaving drug residues. The second of these objectives would require the systematic study of the potential for breeding animals for disease resistance. It may necessitate the assembly, preservation, and inventory of gene pools of food animal species for factors that determine resistance to disease. The long-term costs of controlling disease in terms of labor, drugs, and food safety justify serious consideration of breeding for animals resistant to disease. -155-

CHAPTER 20 PRODUCT QUALITY AND CONSUMER ACCEPTABILITY RECOMMENDATIONS 1: Human Health. More emphasis should be placed on studies on the effect of animal products on human health. 2: Fat in Beef and Pork. Feeding, management, and production programs should be developed for decreasing excess, trimmable fat in beef and pork. 3: Safety in Foods. Criteria should be developed for determining biological safety in foods. HUMAN HEALTH Rationale Much is still to be learned about the relationship of animal products, saturated fats, and cholesterol to heart disease. It is still unclear whether dietary changes, such as substituting unsaturated fats for saturated fats, can significantly reduce cardiovascular problems. Feeding diets high in saturated fatty acids to experimental animals over a long period of time indicates that serious problems may develop. It has been demonstrated that the linoleic acid (unsaturated) content of milk, eggs, and body fat can be increased by dietary control of farm animals. But before this is recommended to the farmer it should first be demonstrated that it is advantageous to human health to do so. Moreover, scientists need to determine whether animal products containing unsaturated fats will be accepted by the public as readily as those with saturated fats. Studies are needed on the effects of feeding products at varying levels and for varying periods of time to experimental animals, and on the application of these to human health. -156-

FAT IN BEEF AND PORK Rationale Much of the beef and pork produced in the U.S. is fatter than the consumer wants. Thus, grain and other energy feeds are being wasted by overfinishing cattle and swi ne. Approximately 20 percent of excess fat is trimmed in choice beef carcasses. In 1973, the resultant waste amounted to a $1.15 billion loss which was ultimately absorbed by the consumer (NAS/in press). Similarly, nearly 90 percent of the barrows and gilts marketed in the U.S. have more separable fat than lean in their carcasses, leaving only 10 percent to grade USDA number 1—the only grade with more lean than fat. Similarly, the waste fat content of the approximately 14 billion pounds of carcass pork produced annually in the U.S. could be reduced by 5 percent. An increase in the lean and decrease in the waste fat by 5 percent would result in a saving of $0.5 billion per year in lower feed costs. SAFETY IN FOODS Rationale As new feed additives, animal wastes, by-product feeds, and alternative feed sources are used, the possibility of harmful residues occurring in animal products needs to be guarded against. Research is required on procedures that could safely salvage for human consumption animal protein that would otherwise be destroyed to eradicate animal diseases. It is recommended that more adequate methods be devel- oped for determining the biological safety of foods for human consumption. A concept of biological zero should be established with regard to residues in food. This would be defined as the level which a panel of competent scientists, after examining adequate data, would determine as having no harmful effect on humans. -157-

CHAPTER 21 FISH PRODUCTION RECOMMENDATIONS 1: Wild Stocks. A research program should be implemented to increase food production from wild stocks of fish, including the increased harvest and efficiency of underutilized species. The creation of a national fisheries management regime should also be undertaken. 2: Aquaculture. Support should be given to the development of technological and scientific bases for aguaculture, and pilot plants and culture systems should be developed in conjunction with industry. WILD STOCKS Rationale Concern that society has generally failed to conserve and allocate fisheries resources in an effective manner under existing institutions (both domestic and international) reflects a lack of centralized policy for fisheries management in the U.S. and a lack of coordinated, effective management. In the U.S. this is a consequence of historical practice whereby the states were given responsibility for and authority over fisheries management out to the limit of territorial waters, while the federal government had no authority except where international fisheries were involved. The fragmentation of authority and management and the general lack of cooperation among states for the regulation of fish stocks that cross state borders have made it difficult to implement workable management programs within state waters. It has also been a tradition in this country that resources of marine fish are available to all, with the result that no limit could be placed on the number of boats allowed to engage in a fishery. The outcome has been exploitation and overcapitalization, in many cases seriously damaging the stocks biologically and wasting labor and financial resources. Other natural resources have not faced this handicap in the U.S., nor is this practice common to many of the other principal fishing nations. It will be necessary to alter the system eventually, and an opportunity -158-

is offered to make the change now when the U.S. is being obliged by international events, including the Law of the Sea Conference, to make significant changes in its national fishery policies. In the field of international fisheries conservation, the U.S. has relied on international commissions and bilateral agreements to control fishing and to protect stocks. To varying degrees, none of these arrangements has been fully satisfactory, principally because insufficient authority has been given to the management bodies. As a consequence, some international fisheries stocks have been damaged—in some cases perhaps irreparably. Implementation There are three ways to increase the production of pro- tein from wild stocks: (1) use species not being used, or only partially used; (2) develop more efficient systems of recovery of protein in harvesting and processing; and (3) develop effective management. These three ways are discussed below. 1. Underutilized Species The present world catch of marine fish and shellfish is about 60 million metric tons per year, according to data supplied by the Food and Agriculture Organization (FAO). FAO estimates of the potential world catch of conventional species are from 100 to 115 million metric tons. If unconventional species such as krill and lantern fish are included, the potential is much larger. In U.S. coastal waters the current annual harvest by U.S. and foreign fleets is 5.5 million metric tons, from statistics provided by the U.S. National Marine Fisheries Service (NMFS). NMFS estimates that this could be increased to at least 8.6 million metric tons. 2. More Efficient Recovery Greater use of fish could be achieved through more efficient recovery from current harvests. For example, flesh-separating machines which squeeze the flesh from the skin and bones of fish and pass it through perforations on stainless steel plates may increase the useable yield by as much as 40 to 50 percent. Fully automated mechanized methods would also maximize cost effectiveness. Information dissemination and research can help to greatly reduce the present waste of fish protein through spoilage. Preservation techniques should be taught to fishermen and others in the coastal communities. -159-

Other gains can be achieved through increased human consumption of fish now used for industrial products (principally fish meal) and through the use of species that are discarded at sea by developing new products, such as minced fish, and alternative methods of shipboard preservation. 3. Effective Management Better management is required to prevent the overfishing or the economic extinction of traditional stocks of fish. Sometime in 1976, the U.S. will probably assume some form of extended jurisdiction over the coastal fisheries resources out to 200 nautical miles from its shores. This will give us the first opportunity in our history to create coordinated and effective conservation measures in both domestic and international fisheries. The enormously increased areas over which the U.S. will exercise exclusive fisheries jurisdiction (approximately 2,222,000 square nautical miles of continental shelf and the overlying water) contain the largest fisheries resources of any nation in the world. This area has an annual potential production of at least 8.6 million metric tons of fish for food and recreation, more than 10 percent of the current world production. Other coastal nations will be offered the opportunity to apply conservation management to large areas of ocean off their coasts. The U.S. is thus obligated to reexamine its national policy because for the first time it would be responsible for managing the fisheries resources within a 12 to 200 mile zone. This obligation is a consequence of events that have taken place in this country and around the world in recent years altering domestic and foreign attitudes toward the rights to fisheries resources and their conservation. Many other countries will also be reexamining their fisheries management policies. AQUACULTURE Rationale World aquaculture production is 6 million metric tons (8.6 percent of seafood supplies). In the past five years production from aquaculture worldwide has doubled, and the proportion it produces may be as much as 10 percent of the world's aquatic-derived foods. In the U.S. the 1973 production of fish was 2,136,000 metric tons, of which 73,000 metric tons were produced by aquaculture; total U.S. consumption of fisheries products is about 3.2 million metric tons. Thus, aquaculture produces about 3.4 percent of U.S. production and a little over 2 percent of the -160-

supply. Because of the existence of very extensive areas of suitable aquatic habitat and the availability of proven technologies for several species, the potential exists for significant increases in fish production by culture, especially in the estuarine and marine environments. Although aquaculture has been slow in developing, fish farming on a small scale has existed for a long time; and the desirability of expanding its scope and production has been recognized, both by those engaged in the culture of such species as oysters, catfish, and trout, and by those attempting to develop industries for shrimp, mussels, and their products. In recent years in particular, there has been high interest in aquaculture and increased activity, during which government, academic, and industrial groups have engaged in aquaculture research and development. In many cases results were encouraging, but in others they fell short of expectations. Moreover, many of the problems, some of which had seemed near solution, proved intractable, often for economic reasons. Aquaculture development in the U.S. has therefore stagnated. While biological and technological information and culture methods are available to increase production of salmon, trout, catfish, oysters, and some species of clams, development of viable aquaculture of most other species will require research to provide adequate biological and technological bases and to develop and test culture systems on a pilot scale. Only then will private capital be attracted that will lead to the establishment of an industry. Much of this research, because of its nature and cost, should be performed by the government or by other research groups with government funds. Expanded aquaculture also requires unpolluted coastal or estuarine areas or supplies of high quality fresh water, but other users also want these limited resources. Where such problems cannot be resolved, closed systems will need to be developed, thereby releasing aquaculture from dependence on natural water supplies and expensive waterfront property. Urgent research areas on fish culture include: (a) Research on methods of increasing supplies of seed (eggs and larvae). This research should include reproductive physiology to develop the ability to induce maturation and spawning in captivity and for the development and maintenance of brood stocks. This is also a necessary prelude to genetic modification and selective breeding. (b) Research on nutrition of cultured animals including larval stages, and on the development of inexpensive and nutritionally effective feeds. (c) Research on disease control of hatchery fish and shellfish production. With the high density populations that result from intensive culture, disease incidence and severity increase markedly. Information on disease -161-

prevention and control is presently insufficient for cultured species. (d) Research on the nature of institutional and related constraints on aquaculture development and on methods of technology transfer. Implementation The federal government has an essential role to play in encouraging expansion of aquaculture. Private aquaculture in the U.S. is based primarily on systems developed and research conducted or sponsored by the federal government. Commercial salmon and trout culture became possible following government research and development for public hatchery programs, which solved problems such as nutrition and disease control. In 195**, l.U million pounds of trout were produced in private fish farms; in 1973, production was about 60 million pounds. Techniques for commercial rearing of salmon, recently developed in government programs, has started a new industry and about 10 companies are engaged in commercial salmon farming. In recent years the oyster culture industry has been strengthened by research in government laboratories on hatchery production of young. The importance of the federal government role in aquaculture is greater now than it will be in future years, since much basic and essential information is currently lacking and the industry is small. The appropriate role of the government now would appear to be to conduct long-term research, much of which is highly technical, requiring spe- cialized equipment and the multidisciplinary approach of highly trained scientists, engineers, and economists. These kinds of expertise are unavailable to industry at the present stage of aquaculture development. Later, when a larger and better organized industry exists, it can assume much of the government's responsibility. -162-

SELECTED REFERENCES Alverson, D.L. (1975) Opportunities to Increase Food Production from the World's Ocean. Marine Technology Society Journal 9(5): 33-40. Anonymous (1975) Fisheries Management Under Extended Jurisdiction: A Study of Principles and Policies. Staff Report to the Associate Administrator for Marine Resources National Oceanic and Atmospheric Administration. pp. 1-75. AVMA Council on Research (1974) Justification for Veterinary Animal Health Research, Am. J. Vet. Res. 35: pp. 875- 887. Bardach, J.E., J.H. Ryther, and W.O. McLarney (1972) Aquaculture. Wiley-Interscience, New York. pp. 868. Cole, H.H., G.H. Fass, R.J. Gerrits, H.D. Hafs, W.H. Hale, R.L. Preston, L.C. Ulberg (1975) On the safety of estrogenic hormone residues in edible animal products. BioScience, 25 (1): 19-25. January. Council for Agricultural Science and Technology (1974) Report 31, Zero Concept in Air, Water and Food Legislation, August 12. Council for Agricultural Science and Technology (1975) Ruminants As Food Producers - Now and for The Future. Council for Agricultural Science and Technology Special Publication, No. 4, March. Cunha, T.J. (1974) Role of Ruminant Production in Increasing Animal Foods in Latin America. Proc. International Conference on Nutrition and Agriculture and Economic Development in the Tropics. Guatemala City. December 2-6. Edwards, R. and R.H. Hennemitt (1975) Maximum Yield: Assessment and Attainment. Oceanus, 18 (2) . Guthrie, H.D., D.M. Henricks and D.L. Handlin (1974) Plasma hormone levels and fertility in pigs induced to superovulate with PMSG. J. Reprod. Fert. 41. 361. Idyll, C.P. (1975) The Sea Against Hunger: Harvesting the Oceans to Feed a Hungry World. New York: Thomas Y. Crowell Company. Idyll, C.P. (1973) Marine Aquaculture: Problems and Prospects. Journal Fisheries Research Board of Canada. 30(12) pt. 2: pp. 2178-2183. Inskeep, E.K. (1973) Potential uses of prostaglandins in control of reproduction cycles of domestic animals. J. Anim. Sci. 36, 1149. Kiddy, C.A. and H.D. Hafs (1971) Sex Ratio at Birth- Prospects for Control. Am. Soc. of Anim. Sci. Maurer, F.D. (1975) Livestock, a World Food Resource Threatened by Disease. J. Am. Vet. Med. Assn. 166:920-923. National Academy of Sciences (1973) Animal Disease Eradication: Evaluating Programs. Proceedings of a National Academy of Sciences' Workshop, University of -163-

Wisconsin-Madison, Wisconsin, April 12-13, 1973. Washington, D.C.: National Academy of Sciences. National Academy of Sciences (1974a) A Nationwide System for Animal Health Surveillance. Committee on Animal Health. Washington, D.C.: National Academy of Sciences, National Academy of Sciences (1974b) Research Needs in Animal Nutrition. Committee on Animal Nutrition. Washington, D.C.: National Academy of Sciences. National Academy of Sciences (in press) Changing the Fat Content and Composition of Animal Products. Board on Agriculture & Renewable Resources and Food & Nutrition Board, National Research Council. Washington, D.C.: National Academy of Sciences. Pillay, T.V.R. (1973) The Role of Aquaculture in Fishery Development and Management. Journal Fisheries Research Board of Canada. 30(12) pt. 2: pp. 2202-2217. Rowson, L.E.A., R.A.S. Lawson, and R.M. Moor (1971) Production of twins in cattle by egg transfer. J. Reprod. Fert. 25, 261. Rowson, L.E.A., R.A.S. Lawson, R.M. Moor, and A.A. Baker (1972) Egg transfer in the cost: Synchronization requirements. J. Reprod. Fert. 28, p. 427. Rowson, L.E.A., R.M. Moor, and R.A.S. Lawson (1969) Fertility following egg transfer in the cow; effect of method, medium, and synchronization of oestrus. J. Reprod. Fert. 18, 517. Salisbury, G.W., N.L. VanDemark and J.R. Lodge (in press) Reproductive physiology and artificial insemination of cattle. 2nd Edition. San Francisco: W.H. Freeman and Co. Salisbury, G.W., R.H. Hart, and J.R. Lodge (in press) The fertile life of spermatozoa. Perspectives in Biology and Medicine. Saulmon, E.E. (1973) A New World of Animal Health Program Financing. Proc. 77th Ann. Meeting. U.S. Animal Health Assoc., St. Louis, Missouri, October 14-19. Smith, L.E. Jr., G.D. Sitton, and C.K. Vincent (1973) Limited injections of follicle stimulating hormone for multiple births in beef cattle. J. Anim. Sci. 37, 523. U.S. Department of Agriculture (1974) Protecting American Agriculture - Inspection and Quarantine of Imported Plants and Animals. Agric. Econ. Report 266:1-58. Wa shington, D.C. U.S. Department of Agriculture (1975) Meat Research, ARS progress report. USDA Agriculture Information Bulletin, 375:1-83. Washington, D.C. -164-

SECTION V: FOOD SCIENCE AND TECHNOLOGY INTRODUCTION Primitive man had to forage for food in his natural en- vironment, feasting in times of plenty and starving in lean times. Gradually he learned the technology of food preservation and improved his ability to save plentiful foods for later use in time of shortage. In developed countries, food science and technology have done much to relieve the impact of hunger and malnutrition, but many developing countries do not enjoy such benefits. There the seasons still alternate from wet to dry or cold to warm, bringing the same stresses on man's food supply as in pre- historic times. The major goals of the food system other than food pro- duction can be listed as follows: 1. to maximize the availability of high quality, safe, nutritious foods at the least cost to consumers; 2. to improve the efficiency and dependability of food delivery systems; 3. to reduce food losses in distribution and storage; 4. to reduce resources needed in protection, storage, and distribution of food; and 5. to determine the comparative advantages of food production and distribution systems to minimize total inputs and maximize total outputs. Because of consumer concerns and government actions, food processors must be concerned, not only with the production of wholesome, safe foods, but also with pollution aspects of their process, with nutritional value, and with shelf life of the product. Pollution concerns not just industrial waste, but packaging as well and its effect on eventual solid waste disposal. Connected to this is the ecological problem of power and water use. Processing and preservation technology is aimed at storage stability of foodstuffs including packaging. The major issues involved are the safety of the food supply from pathogens, the maintenance of quality (i.e., no chemical or microbial decay), the prevention of losses from insects, and the maintenance of nutritional value. The primary principles of processing include the destruction of harmful microorganisms by sterilization, pasteurization, or blanching; separation processes, such as membrane processes, extraction and immobilized enzymes; environmental, temperature, and gaseous atmospheric control; chemical preservatives, fermentation, and/or alkali -165-

preservatives and additives; and control of water- dehydration, intermediate moisture foods, and freezing. The prime generic function of a commercially viable package is protection of the contents. Considerations in packaging research are energy and resource conservation needs, such as prevention of loss of foodstuff, quantity of packaging material, energy to create packaging material, and disposal or secondary use of used packaging materials. Other considerations include consumer acceptance, cost to the consumer, and the relationship of packaging technology to a large system of processing and preserving foods. Flexible pouches and thin-walled drawn containers with heat sealed lids for heat stabilized foods are being developed and show promise. They eliminate refrigeration; costs of material compare favorably with metal cans and their weight is about 10 percent that of cans; empty- container storage needs are fewer; and in the opinion of many food technologists, the products surpass frozen and canned foods. However, pouch output is slow and labor intensive, capital investment is high, and pouched products containing meat or poultry have not received USDA approval. The evaluation of new potential sources of food is particularly important in future development. Some important critieria are: increased growth potential, greater biological value in human nutrition, freedom from vicissitudes of weather, higher yields per unit area, utility in food formulation, and economy. -166-

CHAPTER 22 LOSSES IN THE FOOD SYSTEM RECOMMENDATIONS 1: Losses of Raw Product. Research must be increased to reduce losses during harvest or slaughter, handling, and storage of raw product. 2: Losses of Prepared Product. Research must be increased to minimize losses due to stress in packaging, storage, transportation, and distribution of processed foods. LOSSES OF RAW PRODUCT Rationale Rapid and large increases in available food supplies can be achieved by reducing losses incurred during harvest, slaughter, handling, and storage of the raw product. In addition, an effective reduction in losses and consequently an increase in yields represents a major conservation in energy. Inherent in the increased availability is also the potential for enhanced nutrient availability and consumer acceptability of the product. Implementation To reduce losses during harvest, slaughter, handling, and storage of the raw product, the following are recommended as major steps: 1. improve harvesting, slaughter, and handling systems; 2. expand knowledge of postharvest and postslaughter physiology; 3. increase knowledge of microbiological growth and control of toxicity; 4. improve pest control; and 5. evaluate the significance of the chemical activity of water in storage. -167-

LOSSES OF PREPARED PRODUCT Rationale The segments of packaging, storage, transportation, and distribution compose another area of our food system in which significant increases in availability of food supplies can be achieved through reductions in loss. Stress, the major cause of these losses, consists of primary and secondary factors which in most instances are additive. Stress, which occurs in each segment of this area, is usually initiated by mechanical or environmental effects (primary factors) which then induce chemical, biochemical, and biological effects (secondary factors). For example, mechanical stress can result in broken grain, bruised fruits and vegetables, or ruptured packages. Mechanical stress breaks down the protective barrier, be it natural or artificial, and allows chemical or biochemical reactions or microbial and pest invasion to destroy nutrients and consequently lower quality and acceptability. Environmental stress, such as significant changes in temperature, light, or atmospheric conditions, can induce chemical and biochemical reactions (e.g., enzymatic or nonenzymatic brownings) which destroy the quality of the product with or without permeating the protective barriers. Environmental stress can also produce physical, chemical, and physiological changes which create optimum conditions for loss due to microbiological proliferation and development of toxins. In addition, stress in one segment of the packaging, storage, transportation, and distribution area may induce loss in another segment. Stress, therefore, must be critically evaluated in a total system, ranging from harvest to consumption. In this way, the purpose of increased availability of supplies through reductions in loss can be achieved with a minimum of effort in each segment. -168-

CHAPTER 23 FOOD PRESERVATION AND PROCESSING RECOMMENDATIONS 1: Food Composition and Chemistry. Research must be expanded to increase our fundamental knowledge of food composition and chemistry. 2: Food Composition and Quality Assurance. Research and development are needed on rapid and quantitative methods of detection of food components and hazards associated with foods and their toxicological significance. FOOD COMPOSITION AND CHEMISTRY Rationale The development of the technology of food preservation and processing has evolved slowly. Significant improvement in the efficiency of current operations and the safety and quality of products cannot be achieved without a significant increase in our knowledge of food composition and chemistry, and without attention to types of waste and proper use of waste within the total farm-to-processor system. This knowledge base is also essential to the further development of food fabrication processing, i.e., the conversion of food components—carbohydrates, lipids, proteins, vitamins, and minerals—into products for the consumer. The process may become essential in meeting the world's need for food. But only with the processor's adequate knowledge of the composition and chemistry involved can the quality and safety of the products be assured for the consumer. Implementation Primary emphasis for research on food composition and chemistry should be placed on the following areas: 1. knowledge of the native structure and composition of plant and animal materials and the physical-chemical interactions of food components; -169-

2. knowledge of the effects of preservation and processing on the nutrients and physical-chemical interactions of food components; and 3. ways to minimize generation of waste and maximize use of waste. FOOD COMPOSITION AND QUALITY ASSURANCE Rationale Food composition and quality assurance are tangible terms which can be measured and related to set standards for various foods. Food safety is an abstract term and cannot be measured: it is the absence of hazard. The most fundamental problem in the area of food safety is that of quantifying hazards associated with foods. The critical problem area lies in determining, in a raw or processed food, the presence and extent of hazard which is either naturally present in the food or a by-product of processing. The second major problem in the area of food safety is that of establishing permissible levels of hazardous substances on the basis of scientifically defensible criteria. Extrapolation of toxicological, teratological, and/or oncological data from animals to humans is subject to debate. Exposure to zero levels of carcinogenic or toxic substances is scientifically untenable, thus scientific criteria for these substances must be established. There are six major classes of hazard in foods: (1) food borne diseases of microbiological origin; (2) malnutrition; (3) environmental contaminants; (U) naturally occurring toxicants in foods; (5) pesticide residues; and (6) food additives. Hazards 1, 3, 4, 5, and 6 can occur with a high rate of fre- quency; therefore, rapid, quantitative methods of detecting these hazards and their toxicological significance are needed, and their development should be given priority. Food composition and quality assurance of raw and processed foods are dependent on measuring the constituents of foods and their nutritional value chemically or microbiologically. The most important need in this area is the development of rapid, quantitative methods for the determination of protein, fat, carbohydrate, moisture content, water activity, vitamin and mineral content, dietary fiber, protein quality, heavy and trace mineral content, and the presence of intentional or unintentional food additives. It is also important to support research which will de- termine the biological availability of the nutrients in raw and processed foods, as well as identification of processing -170-

conditions which affect their biological availability during processing, distribution, and storage. Finally, such an encompassing research effort will create a problem unless computer technology (both hardware and software) is developed to provide analytical systems to collate, calculate, interpret, and evaluate the research data. Implementation The feasibility of developing a program to measure composition, quality assurance, and safety of our food supply from harvest or slaughter through consumer use is dependent upon three major points: (1) development of a useful computer storage and retrieval system for current and future scientific data; (2) federal support of research on food science and human nutrition in governmental agencies and universities; and (3) communication of this information to the public. This program will require a sizeable commitment of federal dollars. -171-

CHAPTER 24 DISTRIBUTION AND TRANSPORTATION RECOMMENDATIONS 1: The Packaging System. Research and development is urgently needed on standardization of our packaging system to improve handling in distribution. 2: National Transportation Plan. Research is needed for the development of a more detailed national transportation plan as it affects agriculture. THE PACKAGING SYSTEM Rationale The cost of distributing food and food products represents about half of the total cost of most food products. Many of the inefficiencies in materials handling can be traced to an industry pattern in which product variety was deliberately created to appeal to special buyers. More than 1,400 different container sizes are used by the fruit and vegetable industry alone. Apples are now packaged in 40 different shapes and sizes, none of which will fit the standard grocery shipping pallet. The lack of standardization in packaging is a serious obstacle to efficient materials handling and distribution. In certain instances, however, for the convenience of the consumer the packaging of the same product in a size that is enough for two servings, for one serving, or for a family of six, may serve a valuable purpose. Ideally, goods should be packed in cartons of standard dimensions that fit on a single-sized pallet, which in turn fits into standardized containers, railroad cars, and trailers. Implementation There should be a complete review of the possible sizes and shapes of all the various containers, packages, pallets, and transportation vehicles to determine the changes that would optimize distribution economics. The benefits and disadvantages of each pattern of standardization need to be -172-

carefully weighed. Industry participation in this endeavor is essential. NATIONAL TRANSPORTATION PLAN Rationale Transportation is a limiting factor in every part of our food system. Agriculture is pursued where the land is productive, but this productivity has no necessary relationship to the location of the ultimate consumer. The food system, therefore, is more dependent on transportation than most other parts of our economy. The rural railroad network has disintegrated as railroads have abandoned tracks that were not profitable. The rural highway system has not been improved sufficiently to take the heavy loads that were previously handled by rail. The problem is aggravated by transportation regula- tions, such as "tariffs" that define a set of conditions under which a shipper can ship goods, and the rates that will apply to those shipments. This allows only a portion of this already inadequate transportation system to be used in moving goods into the rural communities. From a long-range viewpoint, the food system cannot ignore the greater fuel efficiencies of moving foods by water and rail rather than by truck. We need to develop a transportation system that optimizes the flow of goods with a minimal expenditure of petroleum. This will require coordination of the regulatory powers of various agencies toward the common goal of a more efficient system. In the near future, however, improvements must be effected within this transportation system as it now exists. Such improvements will, of necessity, be made within one mode of transportation at a time. In view of the overall transportation plan, any action that is taken to increase the efficiency of railroads must be coordinated with corresponding necessary ICC regulations concerning changes in our truck system to realize the greatest overall gain in transportation efficiency (Miles 1974) . Implementation To design a more detailed national transportation plan as it affects agriculture, it is essential to know what commodities are being moved, in what quantities, between what points, and at what cost. It is important to know the relationship of the flow of agricultural products to the flow of other types of commodities and the way in which this interaction relates to the aggregate capacity of barge, rail, and truck transportation. -173-

SELECTED REFERENCES Berg, A. (1973) Problems and Resources of Private Industry. The Institution Factor. Washington, D.C.: The Brookings Insitution. Christensen, C.M. and H.H. Kaufmann (1969) Grain Storage—The Role of Fungi in Quality Loss. Minneapolis: University of Minnesota Press. 153 pages. Miles, G.H. (1974) The Federal Role in Increasing the Productivity of the U.S. Food System. A Report to the National Science Foundation, Order No. 75-WP-0344. National Commission on Productivity (1973) Productivity in the Food Industry: A Preliminary Study of Problems and Opportunities. Washington, D.C.: U.S. Government Printing Office. Panel on Nutrition and Food Availability (1974) National Nutrition Policy Study: Report and Recommendations—I prepared for the Senate Committee on Nutrition and Human Needs, U.S. Senate. June. Washington, D.C.: U.S. Government Printing Office. Ravenhold, R.T. (1971) War on Hunger, Office of Public Affairs, Agency for International Development, Department of State, October. 21 pages. U.S. Department of Agriculture (1967) Report of Task Force on Research on Reducing Waste in Foods Moving Through Marketing Channels. 28 pages. U.S. Senate Committee on Agriculture and Forestry (1974) Immovable Feast: Transportation, the Energy Crisis, and Rising Food Prices for the Consumer—Part 2. Committee Print for January 21, 1974, 93rd Congress, 2nd Session. Washington, D.C.: U.S. Government Printing Office. -174-

World Food and Nutrition Study: Enhancement of Food Production for the United States : a Report of the Board on Agriculture and Renewable Resources, Commission on Natural Resources, National Research Council, Prepared for the NRC Study on World Food and Get This Book
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