A Framework for Assessing Effects of the Food System (2015) / Chapter Skim
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4 Environmental Effects of the U.S. Food System
4 Environmental Effects of the U.S. Food System
Pages 127-166
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From page 127... ...
GHG emissions also can result from the burning of fossil fuels in the food manufacturing process and during food distribution. The ongoing intensification of agricultural production1 has had particularly notable effects on the environment.
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From page 128... ...
. An ecological approach requires actors to recognize not only how management choices affect the environment, both temporally and spatially but also how managing the system for multiple ecosystem services3 can often result in significant mitigation of these impacts, acknowledging also that trade-offs are inevitable (Robertson and Swinton, 2005)
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From page 129... ...
The chapter further discusses the dynamic nature of environmental effects, including the importance of understanding how human behavior influences direct and indirect, and positive and negative, impacts on the environment. The chapter concludes with a basic overview of the various approaches used to quantify the performance of a dynamic environmental system, including direct measurement, the use of indicators, and simulation modeling.
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From page 130... ...
, pesticides, pharmaceuticals, pathogens, gases and inhalants (i.e., ammonia, nitrogen oxide, methane, odors, and fine particulate matter, or PM) , and soil sediment (including the chemicals and organisms it may contain)
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From page 131... ...
For example, nutrient-laden runoff can lead to eutrophication4 of downstream waters (EPA, 2011) , excessive GHG emissions can contribute to global warming (EPA, 2013)
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From page 132... ...
, or when surface water quality is impaired due to runoff or drainage discharge from agricultural land. Major issues related to water quality in agricultural production focus on nitrogen, phosphorus, salinity, and pathogen occurrence.
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From page 133... ...
Other pathogens of major importance are Norovirus, Clostridia, and Staphylococcus. Concentrated animal feeding operations, grazing lands, and lands receiving animal waste are all potential sources of pathogens to waterways and agricultural products.
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From page 134... ...
Additionally, organochlorine compounds, the majority Bitmapped of which are no longer used and which are considered "legacy" pesticides, were detected in 92 percent of fish tissue samples and 57 percent of aquatic bed sediment samples. Because ecosystems are generally exposed to mixtures of pesticide com pounds and their degradation products at varying concentrations, assessing environmental toxicity can be difficult, especially if only a single pesticide is evaluated (Gilliom, 2007)
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From page 135... ...
For example, aquatic toxicity and human health concerns attributed to chlorpyrifos and diazinon resulted in a shift away from these organophosphate insecticides to pyrethroid insecticides, which are less water soluble and have lower mammalian toxicity characteristics (Anderson et al., 2003; Bradman et al., 2011; Fenske et al., 2005; Hunt et al., 2003; Loewenherz et al., 1997)
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From page 136... ...
Alternatively, rates of resource depletion can exceed rates of recharge, leading to slow or rapid degradation of the resource base on which agricultural production depends. The recognition of the need to better manage soil and water resources on farms, on grazing lands, and in forests began formally in the United States with the formation of the U.S.
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From page 137... ...
Soil Resources Disruption of the balance between soil erosion and soil formation illustrates how agriculture can have a profound effect on the environment through net resource depletion. Erosion is a natural process that occurs on nearly all soils, though rates depend on multiple site-specific factors that include climate conditions and topography.
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From page 138... ...
Erosion due to water in ephemeral gullies can also be an important form of soil loss (Cruse et al., 2013; Gordon et al., 2008) , but it is not assessed in widely used soil erosion assessment tools such as the Revised Universal Soil Loss Equation 2 (USDA, 2008)
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From page 139... ...
. Changes in irrigation technology, competition for water between urban and agricultural users, spatial and temporal patterns of drought, biofuel production from irrigated crops such as corn, and shifts in domestic and international markets for crops with different water use efficiencies and profit characteristics now intersect with the need to balance between water resource use and water resource replenishment.
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From page 140... ...
Some of these innovations include soil- and plant-moisture–sensing devices, commercial irrigation-scheduling services, and simulation models that help producers with irrigation decisions, among others. Another approach, currently being assessed in the Central Valley of California, is the artificial recharge of groundwater using excess surface water in non-drought years (Scanlon et al., 2012)
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From page 141... ...
Vast acres of farmland in the southern Central Valley of California depend on water withdrawals from the Delta, as do two-thirds of the state's households. At the same time, the Delta provides critical habitat to a number of native fish, birds, mammals, and reptiles.
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From page 142... ...
In some cases, empirical experiments can be designed, implemented, and monitored to compare the performance of contrasting systems of agricultural production, processing, and distribution. In other cases, empirical data derived from a range of sources can be used to develop models with which to compare system performance characteristics.
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From page 143... ...
(2013) studied trends in sedimentation for 32 lakes in Iowa and found that agricultural intensification over the past 50 years had led to accelerating increases in soil sediment deposition in the lakes due to erosion, despite soil conservation efforts.
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From page 144... ...
Alternatively, biological control of crop pests by natural enemies may be enhanced by maintaining natural and seminatural vegetation in agricultural landscapes, thereby allowing natural enemies to move among habitats that provide them with refugia and resources that may be scarce in crop fields (Power, 2010)
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From page 145... ...
During 5 drought years when growing season precipitation was less than 70 percent of average levels, corn yields were 28 to 34 percent higher in the more diverse organic systems. This effect was attributed to higher levels of soil organic matter, with concomitant increases in soil water storage and plantavailable water.
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From page 146... ...
or the intensification of fertilizer and pesticide use on existing arable land, with attendant environmental problems such as elevated GHG emissions, loss of biodiversity, water contamination, and soil erosion. Food availability also can be increased by reducing food waste and shifting dietary patterns toward a greater proportion of plant-based foods (Foley et al., 2011)
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From page 147... ...
Like the environment as a dynamic system, human behavior also displays spatial displacement, temporal lags, and nonlinear feedbacks -- all peppered with random effects. Human decisions are made in the context of desires, incentives, constrained resources, imperfect information, and bounded rationality.
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From page 148... ...
In the century since farmers learned that the semiarid High Plains region was underlain by this vast aquifer, irrigation has dramatically expanded crop production. However, due to low rainfall in the current era, the aquifer's recharge rate is dwarfed by water withdrawals, resulting in a 30 percent depletion of the groundwater supply today in western Kansas, with continuing depletion expected despite rising private costs of withdrawing water from greater
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From page 149... ...
Although such markets are currently small, their emergence has raised a set of important questions about how to ensure that environmental stewardship practices truly add to environmental quality ("additionality") and whether it makes sense to pay separately for different services that arise from the same stewardship practice ("stacking" ecosystem services)
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• Conservation Stewardship Program (CSP) • Environmental Quality Incentives Program (EQIP)
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From page 151... ...
Non-point source pollutants arising from agricultural production and addressed by this program include nutrients, sediment, pathogens, and pesticides. Agricultural NPS continues to be a significant impairment to surface water quality, as stated in the 2004 National Water Quality Inventory Report to Congress (EPA, 2009b)
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From page 152... ...
. An advantage of the direct measurement approach is that it can result in the development of effective monitoring programs and successful implementation of management practices as long as the entities directly measured are selected based on answering carefully designed questions about the system being studied.
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From page 153... ...
Environmental and ecological indicators measure a variety of environmental parameters, including plant health (water stress, nutrient content, and pest damage) , biodiversity, ecosystem services, aquatic toxicity, soil erosion, emissions, and water quality.
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coli) Water quality Soil organic matter, pH, bulk density Soil health BOX 4-2 Daphnia, A Biological Indicator of Environmental Status Indicator species are frequently employed to evaluate ecosystem integrity in response to environmental stressors.
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From page 155... ...
into the plant and in the surrounding soil. They are often linked to erosion models (e.g., RUSLE2 [Revised Universal Soil Loss Equation 2]
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. Socioeconomic Models For environmental assessments, socioeconomic models aim to simulate human behavior and how it affects the environment.
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From page 157... ...
At the same time, many of these effects can be mitigated by management practices that promote soil and water conservation, minimize nutrient and pesticide emissions, foster sequestration of carbon, and allow appropriate manure disposal from animal feeding operations. This chapter reviews the environmental effects of food production systems and discusses their salient characteristics, along with drivers of human behavior that influence the environmental impact of food systems, including both the perspectives of private producers and broader societal goals.
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From page 158... ...
1988. Rates of soil formation: Implications for soil-loss tolerance.
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2012. Stacking ecosystem services payments: Risks and solutions.
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2010. Pyrethroid insecticide concentrations and toxicity in streambed sediments and loads in surface waters of the San Joaquin Valley, California, USA.
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2013. Watershed sediment losses to lakes accelerating despite agricultural soil conservation efforts.
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2011. Direct measurement versus surrogate indicator species for evaluating environmental change and biodiversity loss.
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2007. Soil erosion and agricultural sustainability.
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2014. Ecosystem services within agricultural landscapes -- farmers' perceptions.
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2007. Ecosystem services and dis-services to agriculture.
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