Craig Cox and Susan E. Offutt
Farming and ranching can degrade soil, pollute groundwater and surface water, and disrupt terrestrial and aquatic ecosystems. The effort to develop farming and ranching systems that sustain the natural resource base and reduce the adverse effects of agricultural production on the environment has highlighted the need for better measures of resource condition and, ultimately, for indicators of environmental performance.
Two National Research Council (NRC) reports address the scientific basis for constructing condition and performance measures for farming and ranching. Soil and Water Quality: An Agenda for Agriculture (1993a) considers the biological, chemical, and physical processes that determine the effect of farming on soil and water quality. The report emphasizes the fundamental importance of soil and the linkage among soil, water quality, and water pollution. It also proposes a set of measurable criteria as a starting point for a more comprehensive set of environmental performance standards for farming systems. Rangeland Health: New Methods to Classify, Inventory, and Monitor Rangelands (1994) recognizes that the productivity of extensively managed systems such as rangelands depends on the maintenance of the integrity of soil and ecological processes. The report contains criteria and indicators for assessing whether the productive capacity of a rangeland is being sustained. These NRC efforts represent steps in the evolution of performance standards for farm and ranch management.
Each study took a functional approach to the development of standards. In the soil and water study, the NRC committee identified three primary functions carried out by these two resources: (1) promotion of plant growth, (2) regulation and partition of water through watersheds, (3) and buffering the effect of agricultural chemicals or other inputs to production on the environment. In the range-
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--> Environmental Performance Standards for Farming and Ranching Craig Cox and Susan E. Offutt Farming and ranching can degrade soil, pollute groundwater and surface water, and disrupt terrestrial and aquatic ecosystems. The effort to develop farming and ranching systems that sustain the natural resource base and reduce the adverse effects of agricultural production on the environment has highlighted the need for better measures of resource condition and, ultimately, for indicators of environmental performance. Two National Research Council (NRC) reports address the scientific basis for constructing condition and performance measures for farming and ranching. Soil and Water Quality: An Agenda for Agriculture (1993a) considers the biological, chemical, and physical processes that determine the effect of farming on soil and water quality. The report emphasizes the fundamental importance of soil and the linkage among soil, water quality, and water pollution. It also proposes a set of measurable criteria as a starting point for a more comprehensive set of environmental performance standards for farming systems. Rangeland Health: New Methods to Classify, Inventory, and Monitor Rangelands (1994) recognizes that the productivity of extensively managed systems such as rangelands depends on the maintenance of the integrity of soil and ecological processes. The report contains criteria and indicators for assessing whether the productive capacity of a rangeland is being sustained. These NRC efforts represent steps in the evolution of performance standards for farm and ranch management. Each study took a functional approach to the development of standards. In the soil and water study, the NRC committee identified three primary functions carried out by these two resources: (1) promotion of plant growth, (2) regulation and partition of water through watersheds, (3) and buffering the effect of agricultural chemicals or other inputs to production on the environment. In the range-
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--> land study, the committee considered primarily one resource function: the production of different kinds, amounts, and arrangements of vegetation. The characterization of resource functions is mostly a scientific endeavor, but the development of standards requires explicit value judgments. So, although soils perform many functions, the three selected as a basis for measuring performance were those considered most important for sustaining agricultural productivity and protecting water quality. The selection of performance standards depends, fundamentally, on the economic and noneconomic values placed on the use and existence of the natural resource in question. Soil Quality As embodied in such laws as the Clean Air Act and the Clean Water Act, national policy has recognized the importance of air and water quality to the country's well-being. However, there is no equivalent federal "Soil Quality Act," despite the critical role soil plays in mediating both water and air quality. Soil and Water Quality urges that soil quality be a national environmental priority: The quality of a soil depends on attributes such as the soil's texture, depth, permeability, biological activity, capacity to store water and nutrients, and the amount of organic matter contained in the soil. Soils are living, dynamic systems that are the interface between agriculture and the environment. High-quality soils promote the growth of crops and make farming systems more productive. High-quality soils also prevent water pollution by resisting erosion, absorbing and partitioning rainfall, and degrading or immobilizing agricultural chemicals, wastes, or other potential pollutants. (National Research Council, 1993a, p. 2) Traditionally, soil quality has been equated with soil productivity, a measure of promotion of plant growth. Soils perform a much broader range of functions in the environment, however, including regulation of water flow in watersheds and of greenhouse gas emission, attenuation of natural and artificial wastes, and regulation of air and water quality (National Research Council, 1993a). Consequently, measures of soil quality will have to be altered to reflect these aspects. No comprehensive index of soil quality yet exists that captures fully soil's function in the ecosystem. Soil and Water Quality notes that it would be "impossible and unnecessary to monitor changes" in all of the soil attributes that relate to critical ecosystem functions (National Research Council, 1993a, p. 205). Moreover, the set of relevant indicators can be expected to change with geographic variation in soil types. The report does suggest a set of indicators that includes the most relevant physical, chemical, and biological attributes of the soil: nutrient availability, organic carbon, labile carbon, texture, water-holding capacity, soil
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--> structure; maximum rooting depth, salinity, and acidity/alkalinity (National Research Council, 1993a, p. 208). The report further recommends the development of "pedotransfer functions" that could be used to link quantitatively the measurement of soil quality to the functions soils perform. Efforts are under way to develop such an index, but these will entail a significant amount of research. National assessments of soil resources are conducted currently, but the kind of data collected and the approaches used to analyze the data (which focus largely on descriptions of soil types and on assessments of soil loss) do not facilitate a comprehensive assessment of soil quality. Water Quality The difficulties involved in developing performance standards for water quality are even more daunting than those related to standards for soil quality. Numerical criteria for water quality are set by regulatory agencies primarily to protect human health. Numerical criteria or other indicators related to the function of aquatic ecosystems, however, are not as well developed. Another recent NRC report, Restoration of Aquatic Ecosystems (1993b), stresses the need to develop both structural and functional criteria to assess the success of aquatic restoration projects. The absence of criteria for aquatic ecosystems makes it difficult to develop performance standards for farming and ranching. This problem is compounded by the difficulty in linking pollutants leaving a particular farm or ranch to their effect on the environment. For example, what level of total dissolved nitrate entering a tributary to the Susquehanna River from an adjacent dairy farm threatens water quality in the Chesapeake Bay? The difficulty of quantifying these linkages has led researchers to propose qualitative standards that could be applied in more systematic ways to farming and ranching systems. The NRC soil and water quality report proposed two such criteria: the efficiency with which pesticides, nutrients, and irrigation water are used in farming systems; and the degree to which farming systems resist erosion and runoff. The efficiency criterion addresses the inputs to the farming system, whereas the resistance criterion addresses outputs. Quantitative measures of input efficiency and of erosion resistance are available and have been incorporated in models that predict the delivery of agricultural chemicals and sediment to groundwater or surface water. These measures are useful for indicating progress toward alleviating environmental degradation by farming, but the question of how much improvement has occurred remains unresolved. Agreement on nonpoint-source control provisions in the reauthorization of the Clean Water Act has been hampered by such uncertainty. Soil and Water Quality recognizes that the inability to relate changes in farming practices to changes in soil and water quality will ultimately hamper attainment of environmental goals. The lack of quantifiable performance standards
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--> prevents the evaluation of integrated farm plans, plans that can address the range of soil functions and avoid the inconsistencies that can result from a focus on single best-management practices. Current understanding of the effect of farming systems on soil and water quality is generally sufficient to identify the best available production practices or management systems; it is not, however, sufficient for making quantitative estimates of how much soil and water quality will improve as a result of the use of alternative practices or management methods. (National Research Council, 1993a, p. 11) The Health of Rangeland The debate over the use of public grazing lands is a manifestation of the larger issue of performance standards for managed ecosystems. Indeed, much of the controversy over Interior Secretary Bruce Babbit's proposal for rangeland reform centers on the development and application of "standards and guidelines" for rangeland managed by federal agencies. Rangeland Health observes that overgrazing, drought, erosion, and other human and naturally induced stresses have resulted in degradation in the past, though the "present state of health of U.S. rangelands is a matter of sharp debate" (National Research Council, 1994, p. 1). Diverse rangeland ecosystems produce both tangible commodities with economic value (forage for livestock, for example) and intangible products, such as natural beauty and wilderness, that may have economic value but that also satisfy other important societal values. Protection of the capacity of rangelands to produce commodities and satisfy societal values is the congressionally established mandate for federal range management. In its report, the NRC committee attempted to identify criteria that could be used to monitor that capacity. As contrasted with cropped farming systems, which to greater or lesser extent depend on external inputs such as fertilizers, rangelands do not generally receive such supplements. The capacity of rangelands to produce commodities and satisfy societal values depends on the integrity of internal nutrient cycles, energy flows, plant community dynamics, an intact soil profile, and stores of nutrients and wastes. (National Research Council, 1994, p. 5) The report defines rangeland health as "the degree to which the integrity of the soil and the ecological processes of rangeland ecosystems are sustained" (National Research Council, 1994, p. 2), and it argues for the establishment of a minimum standard of rangeland management that would protect against humaninduced loss of rangeland health. This minimum is to be an ecological standard,
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--> independent of the rangeland's use and how it is managed, recognizing that if its health is preserved, the rangeland could accommodate a variety of uses (including livestock production and recreation, for example). As does the NRC report on soil and water quality, the rangeland report emphasizes that measures of condition would not be sufficient to guide decisions about uses and management practices, and it notes the need for other data and for aggregate assessments of rangeland health at the national level. The committee recommended three criteria for making a determination of the state of rangeland health: the degree of soil stability and watershed function, which is critical to the prevention of soil degradation; nutrient cycling and energy flow; and the ability of the rangeland to adapt to change, which is necessary to maintain or move toward a healthy state and might be indicated by increases in vegetative cover or changes in plant age-class distributions. Although it is not specific about how to quantify and combine indicators relevant to each criterion, the report does present an evaluation matrix that relates indicators to categories of ecosystem health. For example, the distribution and incorporation of plant litter in the soil could be used to assess the degree of nutrient cycling. Declines in production of plant matter and consequent reduction in the incorporation of plant litter into the soil may occur because of overgrazing by livestock. Such outcomes would indicate a diminution of the total volume of nutrients in the rangeland ecosystem. State-of-the-Art Measures of Conditions and Performance Even this cursory review of the findings of recent NRC reports on soil quality and rangeland health is sufficient to confirm the relatively undeveloped state of quantitative measures of environmental condition and performance for agriculture. That is not to say the lack of good measures should constrain immediate efforts to improve the environmental sensitivity of management practices. To the contrary, both reports address the current possibilities at length. However, both also call, with some degree of urgency, for intensification of efforts to understand the functioning of managed farm and ranch ecosystems. The selection both of indicators of condition and of performance standards is hampered by ignorance of the causal mechanisms that link farming and ranching practices with resource degradation. Although the general pathways are recognized—the action of heavy machinery in compacting soil, for example—it is usually less clear exactly what the practice contributes to the degradation of the resource. For instance, to continue the example, how much compaction can be tolerated before the soil loses its capacity to absorb rainfall or nutrients? The question of the adequacy of condition and performance measures is not simply academic. The reauthorization of the Clean Water Act focuses on nonpoint-source pollution. Agriculture is the nation's largest remaining unregulated
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--> source of non-point-source water pollution. Traditional environmental programs focused on agriculture have relied on financial incentives to encourage farmers to address conservation goals, mainly those associated with stopping soil loss. Constraints on public funds make the continuation of hefty incentive payments somewhat problematic and raise the possibility of regulatory fixes, similar to approaches adopted initially to deal with point-source pollution problems. There are two basic approaches to standard-setting for agriculture. One specifies the production practices or technologies that producers are encouraged or required to use. Such "design standards" are traditionally used in agriculture. The alternative is to establish performance standards. Such standards would set an acceptable level of emissions or some other measurable indicator of environmental quality—for example, nitrate levels in tile drainage, acceptable rates of erosion, or phosphorus levels in surface soils—and allow the producer to determine the best method of meeting those standards. Performance standards leave the producer with the most flexibility to adjust but require more sophisticated scientific and technical capacity to set and monitor. Design standards are easier to set but lock producers into fixed and perhaps more costly and less-effective solutions. Management of rangelands raises another set of public policy and institutional issues because about half of the nation's rangelands belong to federal or state government. Although private landholders may make management and use decisions with few constraints, public-land managers must often balance competing and conflicting claims advanced in statute or in practice. Consequently, the definition of the condition measure itself is controversial because selection of some indicators over others may imply that less weight is given to one set of values or uses over others. The NRC rangeland report attempts to address that possibility by providing the qualitative basis for a multidimensional index of rangeland health. If the complementary roles of condition and performance measures are applied to agriculture, the task should be simplified somewhat by the fact that there is usually little uncertainty about what human activity is affecting the ecosystem. Still, it is often difficult to determine the ecological consequences of a given action, and spatial aggregation is a particular difficulty for a site-specific activity such as farming or ranching. Although the scientific basis for performance standards is not well developed, ongoing efforts to manage and alter agricultural systems that pollute provide a wealth of information for designing workable standards. To date, the agricultural community has resisted the development of such standards, preferring voluntary adoption of best-management practices to what appears might be unprecedented mandatory regulation of farming practices. In the long run, though, it will likely be less costly to farming and ranching to work to performance standards rather than to design standards. As experience with other industries has shown, design standards tend to lock technologies in place and discourage development of new ones. As agriculture seeks to take advantage
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--> of new information and biotechnologies, impediments to the adoption of innovative management systems and practices could have serious consequences for both agricultural productivity and environmental protection. References National Research Council. 1993a. Soil and Water Quality: An Agenda for Agriculture. Washington, D.C.: National Academy Press. National Research Council. 1993b. Restoration of Aquatic Ecosystems. Washington, D.C.: National Academy Press. National Research Council. 1994. Rangeland Health: New Methods to Classify, Inventory, and Monitor Rangelands. Washington, D.C.: National Academy Press.