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Ecological Problems Associated With Agricultural Development: Some Examples in the United States WARREN E. JOHNSTON University of California, Davis The primordial symbiotic relationship between agriculture and envi- ronment is one that has been respected by centuries of traditional farmers. Modern agriculture, however, appears to be responsible for a number of significant environmental problems that deer easy explanation and/or mitigation. Idday's agriculture, engaging only three percent of the U.S. population, differs substantially from earlier structures which occupied the majority of the population in "hunter and gatherer" or in "husbander" roles. The agricultural sector now consists of a mosaic of specialized types of farms ranging in size and intensity from part-time operators of small farm units with only modest economic outputs to large-scale, industrialized farms with significant economic presence in the agricultural sector, and which are sometimes involved in nonagricultural production activities, as well. The sector's evolution to one dominated by large, economically efficient "industrialized" farms is revealed by the statistic that roughly one-eighth of America's farms produce two-thirds of the total U.S. agricultural output. Technological innovations and national agricultural policies of this century have had significant impacts on agricultural productivity and on the structure of agriculture (Carter and Johnston, 1978~. However, there are increasing sectorial and societal concerns about the longer-term ecological consequences of recent cultural, mechanical, and biological innovations and attendant scales of development in the U.S. agricultural sector (Johnston and Carter, 1983~. Agriculture is essentially a land-based enterprise, though it is depen- dent on the total endowment of natural and environmental resources to define both the set of production possibilities and effective natural con- straints to production (e.g., soil fertility, growing season, drainage, climate, 265

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266 ECOLOGICAL RISKS etc.~. In the United States, all but 12% of nonfederal land was devoted to either agricultural or forestry uses in 1977 (USDA, 1981~. Human actions have expanded the possibilities, reduced the influence of natural constraints, and increased productivity per unit of land and of other scarce or costly economic inputs. Unfortunately, human actions with respect to agricultural development have also resulted in certain unfavorable impacts, some of which were unanticipated in their severity or in the speed with which they have negatively impacted on the environment. Ecological systems require diversity and balance in order to support the interactions of living organisms. Agricultural practices can alter ecological balances and diversity, as well as modify basic agroecosystem properties of productivity, stability, sustainability, and equitability (Altieri, 1986~. Recent interests in organic farming and sustainable agricultural systems are efforts to examine alternative production systems (University of California, 1986; Carter, 1988~. Production systems which adversely affect sensitive ecological systems in severe and nonreversible ways burden both present and future gen- erations. Ecological impacts can occur-both on-site and off-site from agricultural land. On-site impacts generally result from land use patterns, including the decision to develop land for more intensive agricultural uses. These impacts are localized and generally result in reduced productivity or in the displacement of wildlife and native plant species due to altered site habitat They may also cause long-term changes in agricultural productiv- ity. Off-site impacts can occur both nearby and at great distances from the farming operation. For example, agriculture can change the ecology of wa- terways and groundwater basins via changes in rates of flows or in amounts of sediment and chemicals which may, in turn, contribute to turbidity, eu- trophication, biochemical oxygen demand, or toxicity, and ultimately may affect many downstream users of water in the same drainage system. AGRICULTURAL AND ENVIRONMENTAL POLICY ISSUES There are a number of areas in which agricultural and environmental problems and policies seem to be in conflict. A recent Organization for Economic Cooperation and Development (OECD) draft report (1988) discusses major agricultural and environmental policy issues in developed economies under the following classifications: intensive crop production and the use of agricultural chemicals; intensive animal production and the management of animal ma- nure; dryland farming, soil conservation and erosion; and changing landscapes, land-use patterns and the quality of rural landscapes.

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AGRICULTURAL IMPACTS 2~7 Observers from the arid west of the United States might also add as an equally important issue: increased competition for scarce water supplies and water quality. The traditional approach to many environmental problems associated with agriculture has been "effect" oriented (Young, 1988~. As problems emerged, environmental policies were implemented to control and prevent the perceived negative impacts of agriculture on the environment. This often resulted in partial and piecemeal approaches. For example, prescrip- tions for testing and registration of agricultural chemicals and governmental regulations for application and handling of chemicals have been designed to protect the health of farm workers and consumers of food products. Public zoning policies were developed to restrict concentrations of animal production units and control the collection and disposal of animal wastes. Conservation of soil has been attempted by providing economic incentives and by mandated farming practices to reduce erosion. Land-use zoning by local and state governments often seeks simultaneously to maintain a viable agriculture sector and a pleasing rural landscape, but is often ineffective when confronted by decisions that either intensify agricultural uses or de- velop higher, economically valued nonagricultural uses. Resource policies to maintain air and water quality sometimes prohibit certain agricultural practices. Throughout the recent experience in the United States, there has been an the uneasy awareness that linkages between agricultural price and income policies and resource and environmental policies have been inadequate. In fact, numerous examples can be cited in which independent agricultural and environmental policies have been in direct convict (Phipps et al., 1986; National Research Council, 1974; National Research Council, 1982~. For example, agricultural price policies and world market conditions in the 1970s increased incentives for farmers to both intensify production on cropped acreage and expand agricultural production onto marginal lands, leading to increases in chemical applications and soil erosion. At the same time, environmental policies sought increased water quality and soil conservation. A current assessment of environmental issues in agriculture in a period of apparent global agricultural surplus capacity is that this "effect- oriented" and uncoordinated approach to environmental issues has been inadequate. Unacceptable levels of agricultural pollution, soil erosion, and degradation in water quality continue, while landscape quality continues to decline. Young (19~) notes four reasons for the failure of environmental regulations which were designed to protect the environment against impacts from agricultural development and production activities:

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268 ECOLOGICAL RISKS failure to enforce existing regulations and to introduce regulations necessary to keep agricultural practices within sustainable limits; the reluctance of governments to use economic instruments to internalize the external costs of many agricultural practices; the existence of a wide range of price support, market interven- tion, and tariff policies which tend to stimulate and intensify agricultural production; and the dominance of agricultural policy instruments over environ- mental instruments and, in particular, the failure to develop integrated agricultural and environmental policies. The remainder of this chapter discusses some of the more prominent issues in the recent U.S. experience, addresses the need for integration of envi- ronmental and agricultural policies, and presents a selected bibliography for the interested reader. NEGATIVE IMPACTS OF AGRICULTURE ON THE ENVIRONMENT The physical processes of erosion of agricultural lands and runoff of sediment and nutrient or pesticidal chemicals create impacts that are felt both on-site and ofI-site. Most individual farmers' decisions to invest in soil conservation measures are made primarily to avoid on-site productivity declines. Erosion generally affects soil productivity lay depleting and/or degrading the inherent physical, biological, and chemical characteristics of the surface layer of the soil (USDA, 1986~. Incentives to promote good soil management via conservation investments have, for much of the 1980s, been blunted by the depressed financial situation affecting much of U.S. agriculture. The problem is compounded by the off-site (and therefore externalized) water pollution and sedimentation problems which affect downstream users and ecological systems. Agricultural Runoff When the United States enacted the Federal Water Pollution Control Act in 1972, the nation's waterways were under tremendous assault from the industrial development that had occurred since World War II. The leg- islation set forth a mandate to improve water qualifier and reduce pollution. Sources of water pollution can be attributed to point sources (where there is an identifiable discharge) and to nonpoint sources that contribute to water- quality degradation through diffuse mechanisms. Regulations and standards set controls on the quantities and methods of disposing of waste products and discharges. The initial target for implementing the law addressed point source polluters, primarily industrial sources that were discharging wastes

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AGRICULTlJRAL IMPACTS 269 into water systems. Point source polluters, though still major sources of bi- ological oxidation damage and dissolved heavy metals, are relatively minor contributors of other pollutants, suspended and dissolved solids, phospho- rus, and nitrogen which stem mainly from nonpoint sources (USDA, 1981~. Erosion and runoff from agricultural lands are leading sources of nonpoint pollutants. They make up about 50% of the total sediment load carried by waterways, and contribute significant amounts of pesticides, fertilizers, salts, and metals that affect the ecology of both water and land environments (Clark, 1985~. Pollution problems from nonpoint sources, nutrients, suspended solids, total dissolved solids (salts), pesticides, and bacteria affect nearly every region of the country. Soil Erosion Erosion generally occurs via one of four modes: sheet, fill, gully (i.e., water-induced modes), and wind erosion. In an attempt to estimate the amounts of soil erosion from various lands, the National Runoff and Soil Loss Data Center developed the Universal Soil Loss Equation (USLE). This formula estimates soil erosion loss as a multiplicative function of six variables: rainfall intensity and duration, soil erodibility, slope length, slope grade, vegetative cover, and tillage practices (USDA, 1981~. Additionally, in order to identify problem areas, the U.S. Department of Agriculture (USDA) has estimated the maximum annual soil losses that can be sustained on a land area without adversely affecting soil productivity. These are referred to as tolerance values (t-values) and usually range from one to five tons per acre per year depending on climate and soil charac- teristics. In 1977, the national average soil erosion loss from croplands was estimated to be about 4.8 tons per acre (TPA), equivalent to about 1.75 metric tons per hectare, which is approximately 1/30 of an inch (0.84 mm) of topsoil per year. Local erosion rates can range from insignificant amounts to well over 100 I PA (36.7 metric tons per hectare) in some areas, depending upon local conditions (Katie, 1983~. Soil Sedimentation The USDA Soil Conservation Service's appraisal of soil and water resources in the United States, which was carried out in response to the Soil and Water Resource Conservation Act of 1977, identified agriculture as the primary cause of nonpoint water pollution for more than 68% of the nation's watershed areas (USDA, 1981~. The most significant constituents with respect to volume were suspended solids, which contributed approximately 50% (i.e., about 760 million tons) of the total sediment load. Increased amounts of sediment decrease the viability of aquatic ecosystems and can

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270 ECOLOGICAL RISKS produce both direct and indirect impacts on living systems. In very heavy concentrations, sediment can clog the gills, and thus, decrease the uptake of oxygen by fish. More likely, however, are indirect effects that arise from increased water turbidity. Increased turbidity reduces the penetration of sunlight and consequently the primary production of photosynthetic plants and algae, which in turn reduces the productivity of higher trophic levels. In addition to a general decrease in the biomass sustained in the system, shifts in the biological mix of species is also likely to occur in which sediment-tolerant and adaptive species replace less tolerant organisms. METHODS FOR REDUCING SOIL EROSION AND RUNOFFS Clearly, erosion from agricultural lands severely impacts the ecology of U.S. waterways. Negative off-site impacts affect recreation, flood control, municipal and industrial water use, navigation, and other water-based or water-dependent economic activities. However, these negative off-site ef- fects are generally not considered by individual farmers or nonfarm owners of agricultural lands. Thus, they are not likely to utilize soil conservation techniques to as large an extent as is socially optimal. Such erosion is seen as an "externality" which adversely effects other members of society, but has no direct impact on the farmer who has a vested (ownership) interest in agricultural land. The "external" nature of this problem suggests that governments may need to develop incentives that will encourage erosion control and reduce agricultural runoffs. National agricultural policies in the 1970s encouraged production on marginal lands that were previously un- cultivated. New land development activities, sometimes called "sodbusting" and "swampbusting," increased soil erosion and agricultural runoffs, and adversely impacted wildlife habitats (National Research Council, 1982~. Idling of Highly Erodible Marginal Lands Some highly erodible lands should not be used for crop production and therefore should be returned to native grass or forest cover (Webb et al., 1986~. Identification and retirement of marginal lands is a key component of current agricultural policy in the United States which also seeks to reduce excess productive capacity in U.S. agriculture. Supporting studies have indicated that soil conservation policies are effective in reducing off-site erosion problems and, simultaneously, in decreasing agricultural production and government expenditures for purchasing, storing, and disposing of crop surpluses. Soil conservation policies include the Conservation Reserve Program, the Sodbuster Provision, and the Conservation Compliance Provision of the Food Security Act of 1985, which established current U.S. agricultural

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AGRICULTURAL IMPACTS 271 policy. While the law is in effect through 1990, it may be extended without major revision for another four- to five-year period. The Conservation Reserve Program pays farmers annual rental payments and one-half the cost of establishing permanent cover to retire highly credible cropland for 10 years. About 100 million acres are eligible for enrollment. The goal is to enroll 45 million acres, and approximately 28 million acres have been enrolled since the program began in 1986. The Sodbuster Provision denies price support and deficiency payments, farm storage facility loans, crop insurance, disaster payments, and FmHA- insured loans to any person producing an agricultural commodity on highly erodible land converted since December 23, 1985, unless an approved con- servation plan is adopted and implemented (USDA, 1988~. This provision affects about 227 million acres with some potential for conversion. The Conservation Compliance Provision of the Food Security Act re- quires that farmers with highly credible cropland begin implementation of a conservation plan by 1990 and complete it by 1995 in order to retain eli- gibility for programs identified under the Sodbuster Provision. This policy could affect production possibilities and costs on up to 65 million acres, and as many as 10 million acres could drop out of production or out of government programs (USDA, 1988~. Erosion Control Practices A number of physical techniques have been developed and utilized to control erosion and stabilize the movement of soil. These techniques include tillage, cropping, and structural measures that limit undesirable soil transport. Tilling of the soil is a primary factor that mobilizes soil particles and reduces or eliminates ground cover and cover crops that oth- envise would stabilize the soil and decrease erosion, especially during rainy seasons. Conservation tillage practices ("no-till" and "minimum tillage" practices) have increased in terms of farmer acceptance and use over the past several years, for both economic and soil-conserving reasons. The effectiveness of conservation tillage techniques varies by region and by crop, and is also related to the amount of crop residues retained in fields. Studies have shown that sediment losses can be reduced by 15% to 90%. However, these consecration tillage practices often include increased use of herbicides to control weeds (Clark, 1985~. Thus, reduced soil erosion practices may transfer the relative balance of agricultural runoff problems from sedimentation to higher concentrations of pesticides in runoffs. Contour farming can also be used to substantially reduce erosion rates on lands that are sloping and are consequently more susceptible to erosion processes. The principle of contouring involves cultivating lands in a pattern to reduce the effects of the slope by farming along natural

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272 ECOLOGICAL RISKS gradients and topography. Contouring can result in erosion reductions of 25% to 50%, with concomitant decreases in the transport of nutrients and pesticides (Clark et al., 1985). The practice of mechanical levelling of fields is also effective in reducing agricultural runoffs in irrigated areas and making possible the more efficient application of irrigation water. There are also benefits with respect to mechanization of cultural and harvesting operations. Other structural possibilities include the construction of diversion chan- nels and sediment basins that catch runoff and decrease sediment loads. Planting grass along waterways and irrigation canals also will reduce erosion losses from stream banks. Altered cropping rotations may also decrease soil erosion losses. Clark et al. (1985) found a decrease in soil loss from 19.7 tons per acre with continuous corn cultivation to 2.7 tons per acre with a corn, wheat, and clover rotation. Soil conservation policies of the sort required for highly credible lands under the Sodbuster and Conservation Compliance Provisions of the Food Security Act can include prescriptions that will mandate conservation tillage, structural modifications, and changes in cropping systems singly or in combination to reduce soil erosion and agricultural runoff. Batie (1985) estimates that soil erosion rates can be reduced by 60-95% by a combination of conservation tillage, contour planting, strip cropping, terracing, and other known conservation techniques. One USDA study concludes that modification of USDA commodity and conservation programs to achieve greater consistency in program objectives could affect one-third to one- half of the nation's cropland acres that are eroding at unacceptable rates (Reichelderfer, 1985). 1 CHEMICAL CONSEQUENCES OF AGRICULTURAL DEVELOPMENT AND PRODUCTION ACTIVITIES Fertilizers and pesticides are important nonpoint pollutants in surface waters. More recently, however, concern about chemical pollution from agriculture has spread to include the nation's groundwaters. The seri- ousness of many of these problems is still not certain, though they have emerged rapidly as important environmental issues. Accelerated erosion processes, in addition to carrying sediment into waterways, also bring other constituents of the soil including agricultural chemicals. The U.S. agricultural system is highly reliant on the use of chemical inputs to provide nutrients for growth and production as well as pesticides to control destructive plant and animal infestations. ('~Pesticide" is the term used to describe general classes of chemical-controlled agents, such as herbicides, insecticides, fungicides, nematocides, and rodenticides). These chemicals can be carried into aquatic ecosystems either directly

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AGRICULTU~4L IMPACTS 273 through runoff or by absorption to soil particles that are subsequently eroded. The 1977 amendments to the Federal Water Pollution Control Act of 1972 expanded the regulation of pollutants in groundwater, surface water, and coastal waters by providing stronger incentives to protect water quality from agricultural sources of pollution than had been provided by any previous national legislation (Crowder et al., 1988~. The Act extends emphasis beyond point sources of pollution to nonpoint agricultural sources. In areas where nonpoint source pollutants endanger water quality, farmers could be subject to state or local restrictions on land use and agricultural chemical use (USDA, 1988~ Fertilizers Farming accounts for roughly 97% of all fertilizer use. Fertilizers containing nitrogen, phosphorus, and potassium are often applied to soils to increase crop yields. total application of nitrogen and phosphate in 1983 was in excess of nine and four million tons, respectively (USDA, 1986~. In the United States, fertilizer use in kilograms of plant nutrient per hectare of arable and permanent cropland increased by 50% in a 20-year period, from 63 kilograms in 1964-66 to 94 kilograms in 1981-83 (World Resources Institute, 1986~. Corresponding values for Poland were 84 kilograms per hectare in 1961-63, rising by nearly threefold to 237 kilograms in 1974-76, and declining somewhat to 220 kilograms in 1981-83. The application of large amounts of fertilizers in intensive agricultural production activities creates a situation where water transport of soluble chemicals can easily occur. Once carried into an aquatic ecosystem, these nutrients are available for aquatic plant and algae growth. Phosphorus is the most common limiting nutrient in aquatic systems. Increased amounts of phosphorus and nitrogen increase biological production and the aging process (eutrophication) in lakes and reservoirs. Eutrophication is a natural process in many lakes and streams, but the influx of nutrients from agri- cultural sources greatly accelerates the process. Eutrophication of streams, lakes, and reservoirs usually results in excessive growth of aquatic weeds and algae, which in turn can create toxins and remove available oxygen, thereby killing fish and greatly reducing the recreational value of lakes and reservoirs (Clark et al., 1985~. The USDA estimates that between 15% and 54% of all nutrients applied to agricultural lands reach surface water systems. This tremendous inflow of agricultural nutrients creates a significant impact on the nation's waterways, its surface-water supplies, and the ecological composition and maturation of water bodies.

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274 ECOLOGICAL RISKS Pesticides Agriculture accounts for about 75% of all pesticide use in the United States, equivalent to about 725 million pounds of active ingredients (USDA, 1986~. Prior to World War II, pest control was largely accomplished through a variety of cultural, mechanical, and tillage practices. However, the advent of the chemical pest-control era brought abrupt changes in agricultural systems which resulted in increased production, increased quality, and greater efficiency in the production of food. Almost all crops are subject to attack by diseases, insects, and weeds. This susceptibility often increases when mixed croping is replaced by con- tinuous monocultures (Altieri, 1986~. Efforts to control pests have included the application of various toxic chemicals. More than 1,800 biologically ac- tive compounds have been developed to protect agricultural crops. In 1977, herbicides were applied to more than 200 million acres, insecticides to over 75 million acres, and fungicides to 8 million acres in the United States. Eichers (1981) estimated that 5% of applied herbicides and insecticides eventually reach surface waters, but the USDA has estimated that, under normal rainfall conditions, pesticide losses in runoff tend to average no more more than 0.5% of the quantities applied (USDA, 1986~. However, the latter source notes differences in losses depending on type of substance, with wettable powders having runoff rates of up to 5.053. Pesticides may enter other environments from spray drift, soil erosion, precipitation and irrigation runoff, soil moisture seepage, groundwater flow, direct contact with animals and humans, or by other means (USDA, 1986~. Monitored concentrations of pesticides in waterways has generally been low except when heavy rains follow applications (USDA, 1981~. However, this observation can be deceptive due to the relatively high toxicity of these chemicals and the unknown or unmonitored potential of a number of these compounds to accumulate at very high concentrations as they rise through the food chain. While pesticide use has become prevalent in modern agricultural systems, it is not uniformly applied to all crops. For example, Eichers (1981) estimates that cotton represented the largest share of insecticide use in 1976, accounting for nearly 40% of the total, while corn accounted for another 20%. He also estimated that corn accounted for 52% of total herbicide use while soybeans accounted for 20%. Environmental effects of pesticides can vale substantially. Regulations often favor less persistent and more selective compounds in order to be less environmentally disruptive. In general, insecticide use has trended away from the persistent, biomagnifiable organochlorine compounds that are suspected of causing chronic diseases to nonpersistent substances such as carbonate and organophosphate products (USDA, 1986~. The Federal Insecticide, Fungicide, and Rodenticide Act (FIFING) empowers the U.S.

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AGRICULTURAL IMPACTS 275 Environmental Protection Agency (EPA) to curb the use of a pesticide if, among other affects, it poses undue risk to human health or is an imminent hazard in the environment because of its persistence or toxic effects (Crowder et al., 1988; Chapter 6, this volume). Salinity and Heavy Metals In addition to sediment and chemical intrusion into surface water systems, suspended solids such as salts and heavy metals are also carried into waterways by erosion. Salinity problems are common in the arid western United States and can significantly affect the aquatic environment. For example, it is estimated that between 24% and 41% of the total salt load in the Colorado River results from percolation of agricultural drainage water through salt-laden soils (USDA, 1981~. Alterations in diversity and patterns of species dominance can also occur with the replacement of less salt-tolerant species by more salt-tolerant species. These changes can also negatively affect the food chain and the higher trophic levels that depend on the aquatic systems for food. While the erosion of heavy metals from agricultural lands does not appear to be a widespread problem, regional soil differences and irriga- tion patterns can create potential heavy-metal problems in water systems. For example, elevated soil selenium levels in the Westlands area of the San Joaquin Valley in California~ombined with high soil salinity, saline irrigation water, distinct irrigation patterns, and a high water table have created a situation where high concentrations of selenium have accumulated in drainage water and have consequently severely affected the ecosystem at Kesterson reservoir. Impacts have included deformities in birds and signif- icant declines in fish reproduction (University of California, 1987~. Interim policies have led to the cessation of off-farm drainage flows, to increased on-farm investments in drainage ponds, and to more precise management of applied irrigation water and drainage flows. Groundwater Contamination Although groundwater has many sources of contamination, evidence suggests that agricultural pesticides and fertilizers are significant sources (Nielsen and Lee, 1987~. The United States relies heavily on its ground- water. Over 97% of rural drinking water comes from groundwater sources and 40% of the population served by public water supplies (i.e., nearly 74 million people) use groundwater sources. The distribution of potentially affected groundwater areas is influenced by the magnitude, extent, and duration of contamination, and conditioned

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276 ECOLOGICAL RISKS by land use, agricultural practices, climate, hydrogeology, soil characteris- tics, net aquifer recharge rate, depth to the water table, and characteristics of the unsaturated zone and the aquifer (Nielsen and Lee, 1987~. Char- acteristics of the potential pollutant (i.e., water solubility, adsorption, and persistence) strongly affect its ultimate fate. About 800 of the 3,000 coun- ties in the United States have potential for contamination by pesticides; another 300 have potential for nitrate contamination; and 300 more have potential for both types of contamination. More than 50 million people rely on groundwater for drinking in these 1,400 potentially affected counties (USDA, 1988~. As mentioned previously, the 1977 amendments to the Federal Water Pollution Control Act applies to groundwater and specifies that agricultural practices may be subject to state or local restrictions on land and agricultural chemical uses. Under FIESTA, more attention has generally been given to pesticides that are known to leach into groundwater than to chemicals which primarily run off cropland. The Safe Drinking Water Act also deals with the possibility that nonpoint sources could contaminate groundwater sources of public wells (Crowder et al., 1988~. The rising concern about contamination of groundwater especially because contamination can persist for many years and cleanup costs can be prohibitively expensive has heightened awareness of rural and urban inhabitants. REDUCING CHEMICAL DEPENDENCE Since intrusion by agricultural chemicals is a one of the serious off-site impacts affecting surface water and groundwater quality, a reduction in the use of environmentally damaging chemicals should help enhance water quality. A number of techniques have been developed that can, in some cases, reduce use and need for chemicals, as well as encourage the use and safe application of less environmentally damaging chemicals. These techniques include biological control, host resistance, cultural control, and physical and mechanical control, in addition to use of chemical pesticides. Additionally, application modes can also have a significant effect on the efficiency of chemical use and reducing off-site migration. Integrated pest management (IPM) techniques have increased in use as farmers realize the economic and environmental advantages of combining biological pest controls and management practices with reduced chemical use. IPM seeks to control pests in an economically efficient and environ- mentally sound manner by maximizing the use of natural control agents (i.e., predators, parasites, weather, crop varieties, tillage, etc.) before re- sorting to the use of chemical controls (Smith and Pimentel, 1978; Pimentel, 1981~.

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AGRICULTURAL IMPACTS 277 In many instances, IPM is a viable alternative to chemical pest man- agement. This is true especially because of rising chemical costs, increased genetic resistance of pests to pesticides, and the presence of significant external impacts. IPM can often achieve equal yields at reduced costs, thereby increasing the profitability of the operation (Archibald, 1984; Bot- trell, 1979~. IPM uses both biological and economic criteria to gauge the ability of a crop to tolerate pests. The economic threshold sought in the control of pests is the density of the pest population below which the cost of applying control measures exceeds the losses caused by the pest. These economic threshold values are derived by assessing the potential value of the pest damage and the ecological, social, and economic costs of controls. Successes in the use and implementation of IPM have occurred with many crops including cotton, citrus, walnuts, almonds, fruits, soybeans, and alfalfa. In Texas, it has been demonstrated that cotton (the major target of insecticides in the United States) can be produced with 50-75% less insecticides, thus increasing farmers' profits from $62 to $170 per acre (Bottrell, 1979~. Archibald (1984) has also demonstrated the efficacy of IPM as an optimal strategy for pest management in California cotton, especially in light of the dynamic nature of insect resistance to chemical controls. The results of IPM research indicate that it is both possible and economically feasible to pursue environmentally sound agricultural practices with lesser applications of agricultural chemicals. Social concern about adverse consequences of agricultural technolo- gies, including but not restricted to heightened levels of agricultural chemi- cal applications, has lead to recent emphasis on "agricultural sustainability." Carter (1988) discusses the various perceptions of "sustainable" agriculture and notes that other terms for agricultural sustainability include alterna- tive, regenerative, low-input, ecological, environmentally sound, and even organic agriculture. He notes: These terms are used by people interested primarily in alternative systems of farming that will feed expanding populations while minimizing potential negative effects whatever they might be. Defining negative ejects essentially separates or categorizes the venous proponents of sustainable agricultural systems. Other definitions of sustainability place emphasis on resource stewardship, rural community sustainability, food self-sufficiency, and energy conserva- tion. Use of these terms illustrate the social, ecological, economic, and emotional connotations of concern about current agricultural practices. Harwood (1987) identifies the following dimensions of the agricultural sustainability concept: time; social sustainability; economic sustainability;

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278 ECOLOGICAL RISKS maintenance of soil and genetic resource bases; minimization of environmental pollution; and lowered use of industrialized inputs. The USDA has recently developed the Low-Input Sustainable Agricul- ture (LISA) program which supports research and education programs in alternative farming systems that reduce the farmer's dependence on certain kinds of purchased inputs in ways that increase profits, reduce environmen- tal hazards, and ensure a more sustainable agriculture for generations to come. The goals of this program include the following: develop economically viable crop and livestock systems to reduce reliance on off-farm purchased inputs (especially synthetic chemical pesti- cides and fertilizers that may pose environmental or human health hazards); maintain and enhance soil productivity; reduce soil erosion and loss of water and nutrients; conserve energy and natural resources; and minimize environmental contamination. PROSPECTS We currently find ourselves in the situation of having globally over- responded in our efforts to meet the need for additional food and fiber production which arose in the 1970s. All developed nations and many less developed nations, as well, now find agricultural production capacities and commodity markets to have shifted from "shortfalls" to "surpluses." This achievement was possible in part due to food and agricultural policies which both intensified production on existing lands with the aid of pur- chased inputs, and expanded or developed additional cropland acreages, often with less than due regard for environmental and ecological conse- quences. However, the current costs of governmental policies to support agriculture via supply control, export assistance, and other price and income support programs are very large and are of concern not only in the United States, but also in the nations of the European Common Market, and to diverse members of the Cairns Group of developed and developing nations which seeks fundamental change in agricultural and trade policies within the current General Agreement on Tariffs and Trade (GATE negotiations. The cumulative effects of past agricultural development and production activities have brought into sharper focus some of the adverse environmen- tal impacts which now seem to arise more quickly and more severely than had been anticipated. It would appear that under such conditions of sur- plus capacity and environmental threat, there is opportunity for greater integration of agricultural and environmental policies. In fact, a recent report by the Organization for Economic Cooperation and Development

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AGRICULTURAL IMPACTS 279 (OECD) (1987) gives considerable attention to prospects for better inte- gration of agricultural and environmental policies among OECD nations. Young (19883 summarizes the OECD recommendations by noting that in the development of new agricultural, environmental and related regional development policies ". . . consideration needs to be given to a trilogy of three factors: the need to enhance the positive contribution which agriculture can make to the environment; the need to reduce agricultural pollution; and the importance of adapting all agricultural policies so that they take full account of the environment." The latter factor would involve targeting agricultural policies to be more effective by simultaneously reducing surpluses and agricultural pollution while enhancing environmental quality. Future examinations of ecological problems associated with agricultural development will be less critical if such holistic policy strategies are met with popular global support as well as farmer and taxpayer acceptance. REFERENCES Altieri, M.A. 1986. Ecological diversity and the sustainability of California agroecosystems. Proceedings of the Symposium on Sustainability of California Agriculture. University of California, Davy Archibald, S.O. 1984. A dynamic analysis of production externalities: Pesticide resistance in California cotton. Ph.D. Dissertation, Agricultural Economics, University of California, Davis. Batie, S.S. 1985. Environmental limits: The new constraints. Issues in Science and Technology II(1):134 143. Batie, S.S. 1983. Soil erosion: Crisis in America's croplands. The Conservation Foundation, Washington, D.C. Bottrell, D.R. 1979. Integrated pest management. Council on Environmental Quality. Washington, D.C.: U.S. Government Printing Office. Carter, H.O. 1988. The agricultural sustainability issue: An overview and research perspec- tive. Invited Paper Prepared for the Seminar on the Changing Dynamics of Global Agriculture: Research Policy Implications for National Agricultural Research Systems, Feldafing, Federal Republic of Gellllany, September 1988. Carter, H.O., and SUE. Johnston. 1978. Agricultural productivity and technological change: Some concepts, measures and implications. University California Priced Publication 4085, Berkeley. Clark, E.H. II, J.A. Haverkamp, and W. Chapman. 1985. Eroding soils: The off-farm impacts. The Conservation Foundation, Washington, D.C. Crowder, B.M., M.O. Bibaudo, and C.E. Young. 1988. Agriculture and water quality. Agricultural Information Bulletin Number 548, U.S. Department of Agriculture, Economic Research Service, Washington, D.C. Eichers, T.R. 1981. The use of pesticides by farmers. In the CRC Handbook of Pest Management in Agriculture Vol. II, D. Pimentel, ed. Boca Raton: CRC Press. Hatwood, R.R. 198;7. Low-input technologies for sustainable agricultural systems. In Policy for Agricultural Research, V.W. Ruttan and CE. Pray, eds. Boulder, Colorado: Westview Press.

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280 ECOLOGICAL RISKS Johnston, WE., and H.O. Carter. 1983. Policy issues. In a Guidebook to California Agnculture, A. Scheuring, ed. Berkeley: University of California Press. National Research Council. 1974. Productive Agriculture and A Quality Environment: Food Production, Living, Recreation and the Rural Urban Interface. Committee on Agriculture and the Environment, Division of Biology and Agriculture, National Academy Press, Washington, D.C. National Research Council. 1982. Impacts of Emerging Agricultural [lends on Fish and Wildlife Habitat. Committee on Impacts of Emerging Agricultural Trends on Fish and Wildlife Habitat, National Academy Press, Washington, D.C. Nielson, E.G., and L.K. Lee. 1987. The magnitude and costs of groundwater contamination from agricultural chemicals: A national perspective. U.S. Department of Agriculture, Natural Resource Economics Division, Economic Research Service, Washington, D.C. Organization for Economic Cooperation and Development (OECD). 1987. Opportunities for the integration of environmental and agricultural policies. Draft Anal Report, ENV/AGR/87.16. Ad Hoc Group on Agriculture and Environment, Environment Committee, Paris. OECD. 1988. Draft Report on selected policy issues relating to agriculture and environment. ENV(88~11. Environment Committee, Paris. Phipps, T.T., P.R. Crossman, and HA. Price, eds. 1986. Agriculture and the environment. Na- tional Center for Food and Agricultural Policy, Resources for the Future, Washington, D.C. Pimentel, D., ed. 1981. CRC Handbook of Pest Management in Agriculture. Vol. III. Boca Raton: CRC Press. Reichelderfer, KH. 1985. Do USDA farm program participants contribute to soil erosion? Economic Research Service, U.S. Department of Agriculture, Washington, D.C. Smith, E.H., and D. Pimentel. 1978. Pest Control Strategies. New York: Academic Press. University of California. 1986. Sustainability of California Agriculture: A Symposium. Proceedings, Sustainability of California Agnculture Research and Education Program, Davis, California. University of California. 1987. Resources at risk: Agricultural drainage in the San Joaquin Valley Vol.1. Agricultural Issues Center, Davis, California. U.S. Department of Agriculture (USDA). 1981. 1980 Appraisal: Soil, water, and related resources in the United States: Status, condition, and trends. Washington, D.C.: U.S. Government Printing Office. USDA. 1986. U.S. Department of Agriculture Acreage Adjustment Programs. Draft En- vironmental Impact Statement. Agricultural Stabilization and Conservation Service, Washington, D.C. USDA. 1988. Agricultural Chemicals and the Environment. Special Reprint of May 1988, Agricultural Outlook. Economic Research Service, Washington, D.C. U.S. Library of Congress. 1979. Agricultural and Environmental Relationships: Issues and Priorities. Congressional Research Service, Environmental and Natural Resources Policy Division, Washington, D.G Webb, S., C.W. Ogg, and W.Y. Huang. 1986. Idling erodible cropland: Impacts on production, prices, and government costs. Natural Resource Economics Division, Economic Research Service, U.S. Department of Agriculture. Washington, D.C: U.S. Government Printing Office. World Resources Institute. 1986. World Resources 1986: An assessment of the resource base that supports the global economy. International Institute for Environment and Development. New York: Basic Books Inc. Young, M.D. 1988. The integration of agricultural and environmental policies. 18th Eu- ropean Seminar of Agricultural Economists on Economic Aspects of Environmental Regulations, Copenhagen.