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Impacts of Air Pollution on Agriculture in North America
Pages 171-195

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From page 171...
... Department of Agriculture This chapter highlights our current understanding of the effects of anthropogenic air pollutants on agriculture in the United States and assesses their impact on crop productivity. Information from a cross section of crop-oriented review articles has been used to help define the problem (Altshuller and Linthurst, 1984; Dochinger and Seliga, 1976; Evans, 1984; Guderian, 1985; Heck 1984; Heck and Brandt, 1977; Heck et al., 1977, 1982a, 1982b, 1983a, 1984a, 1984b, 1984c, 1986; Irving, 1987; Jager and Klein, 1980; National Academy Sciences, 1977; Roberts, 1984; Shupe et al., 1983; Shriner et al., 1980; Reshow, 1984; Unsworth and Ormrod, 1982; U.S.
From page 172...
... Secondary Primary Primary and secondary Primary Primary Secondary Primary Primary Primary Primary Primary Secondary Secondary Primary Primary Primary Gas (;as Gas Gas particulate Gas Gas Gas Gas Gas Particulate Gas Aerosol Aerosol Gas Gas Radiation Atmospheric transformation (associated with automotive emissions, NO2, hydrocarbons) Power generation, smelter operations From direct release and atmospheric transformation ~igh-temperature combustion, from NO)
From page 173...
... Space does not permit a discussion of the many air pollutants that have damaged plants due to accidental releases or on a fairly local basis. However, a brief discussion of NO2, acidic deposition, and SO2 are included in this section.
From page 174...
... The pollution control strategy of using tall stacks to reduce groundlevel concentrations of sulfur and nitrogen oxides near fossil fuel combustion sources is a contributing factor to the long-range transport of acidic substances. The transformed products may be deposited hundreds of kilometers downwind in precipitation.
From page 175...
... Plants are generally more sensitive to SO2 as light intensity, wind speed, temperature, and humidity increase; elevated CO2 levels protect plants; and freezing may increase plant sensitivity, while low soil moisture tends to make plants more resistant. The effect on plants of mixtures of pollutants (i.e., SO2 and 03)
From page 176...
... L~liw? ~ Constant SO2 concentration underestimated effects compared to the time series treatments; excellent discussion of time series concept; interpretation of results difficult.
From page 177...
... EFFECTS OF OZONE ON AGRICULTURAL PRODUCTIVITY This section presents summary information on the effects of O3 on crop growth and productivity. It also provides background information on plant response, including some review of field research that supports efforts to assess O3 dose, and crop yield responses for assessment purposes.
From page 178...
... Chlorosis may be associated with acute exposure to O3. Chronic injury may cause chlorosis or other color or pigment changes that may eventually lead to cell death; early senescence with or without leaf abscission may occur.
From page 179...
... and plant response to O3 must be understood as part of a crop-loss assessment effort. Available information regarding effects of O3 on plant parasites suggest that obligate fungal parasitism is generally inhibited and that some facultative parasites may benefit; these effects are probably indirect through the host.
From page 180...
... response. The term synergistic, although statistically appropriate, is not necessarily biologically appropriate since response functions may not be linearly related to pollutant concentration.
From page 181...
... greenhouses. Yield reductions of 3.4 to 68.5% were found across the 8 genotypes (Meredith et al., 1986)
From page 182...
... developed O3 dose/crop yield response functions for use in assessing the economic effects of O3 on crop production. The NCLAN program started in 1980 and ended in 1988 after seven years of intensive field research and two years of data analysis and writing to complete the documentation of results from all research sites (Heck et al., 1982b, 1983a, 1984b, 1984c, 1988a, 1988b)
From page 183...
... METHODOLOGY FOR ASSESSMENT OF THE IMPACT OF AIR POLLUTANTS SUCH AS OZONE ON CROPS An assessment of impact, by implication, includes an economic aspect as a final step; however, an in-depth assessment of effects can be done without economics. The NCLAN program included an economic analysis that utilized an assessment of crop losses as a basis for the assessment.
From page 184...
... (1984, 1988~. The Needs of an Assessment Program Local, regional, national, or international assessments of crop losses require three basic types of information: a response function relating crop yield to an exposure statistic; · an air quality database that can be used to estimate crop exposure on a county level using the same exposure statistic as used in the response function; and · a crop-census, i.e.` what crops are grown and their yield within a county (Heck et al., 1984b; Shriner et al., 1984~.
From page 185...
... , many of the combined data sets were homogeneous; in the 1988 economic assessment, however, heterogeneous data sets were used where necessary to describe the effects on a single species (Adams et al., 1988~. Ozone dose/crop yield response functions can take on a variety of forms depending upon the dose statistic used.
From page 186...
... but it should utilize an exposure statistic that adequately describes the biological response to O3. The N CLAN program used 7-hr/day and 12hr/day seasonal mean O3 values because they adequately described the yield responses of the crops tested.
From page 187...
... County estimates are adjusted for nonrespondents. Analysis of Crop Yield Reductions Ozone dose/crop yield response functions, crop yields at the county level, and seasonal 7-hr/day mean O3 concentrations at the county level are
From page 188...
... I I , , , 002 004 0C>6 008 0 10 012 014 12 ~ 6~' S£aSONa~ - ~~N as cot~cE~TR^rio~ I Pam ) FIGURE 5 Proportional yield response to O3 of cotton grown with intermittent periods of soil-moisture stress (WS)
From page 189...
... and used 1982 as the base year for O3. The Economic Erects of Ozone on Agriculture Based on crop response data from many experimental designs, a number of regional and national economic assessments have been made since 1980 (Table 7~.
From page 190...
... · Pollutant dose/crop yield response functions are essential for predicting yield losses; non-linear models give the best fit to available field data for O3. · Based on available technology, the open-top chamber system is the best approach for the development of predictive models for O3, but open release systems may function well for other pollutants.
From page 191...
... · The NCLAN data base has permitted a reasonable first estimate of crop yield losses associated with O3 as an air pollutant of national and international importance. Areas of Uncertainty in Assessing the Effects of Air Pollutants on Crop Production · The available data base is small and thus is not fully representative of North America.
From page 192...
... 1988. Factors inDuencing ozone doselyield response relationships in open-top field chamber studies.
From page 193...
... 1986. Effects of increasing doses of sulfur dioxide and ambient ozone on tomatoes: plant growth, leaf injuty, elemental composition, fruit yield and quality.
From page 194...
... 1983. Increased success of the Mexican bean beetle on field grown soybeans exposed to sulfur dioxide.
From page 195...
... 1981. Biochemical explanations of more than additive inhibitory effects of low atmospheric levels of sulfur dioxide plus nitrogen dioxide upon plants.


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