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Introduction

Soil and water are critical components of the resource base upon which agriculture depends. To move toward sustainability, agriculture and natural resource management interests must recognize that they are equal partners in the effort. The challenge is to adapt and extend our knowledge about soil and water to develop economically productive, culturally appropriate, and environmentally sound agricultural systems. A flexible, ongoing process is necessary to set research priorities to support inherently dynamic agricultural systems.

In this final decade of the 20th century, there is a penchant for looking forward to a new millennium. The turning of the calendar in such a significant way offers a natural pause—an opportunity to reflect on the past and to anticipate the future. This report looks to the future with emphasis on the soil and water resources that support agriculture. With world population now more than five billion, and some three billion people entering their reproductive years, it is a timely moment for such an assessment. Population growth and economic demands are exerting mounting pressures on the earth's soil, water, and other natural systems. The specter of possible changes in climate can only add to these pressures. It is time to consider how we can move "toward sustainability," toward a vision of natural resource management that supports current populations while leaving future generations an equitable share of the earth's great wealth.

Although the most alarmist headlines portending environmental doom are probably overdrawn, many scientists are concerned about the steady decline in basic productivity of many soil and water systems, particularly those in the high population growth regions—Africa, Asia, and Latin America. In the humid tropics, rain forests are converted to agriculture and, in some places, large-scale ranching, bringing losses of topsoil and the depletion of nutrients, especially nitrogen (Lal, 1988; Pimentel et al., 1987; Sanchez and



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Toward Sustainability: Soil and Water Research Priorities for Developing Countries 1 Introduction Soil and water are critical components of the resource base upon which agriculture depends. To move toward sustainability, agriculture and natural resource management interests must recognize that they are equal partners in the effort. The challenge is to adapt and extend our knowledge about soil and water to develop economically productive, culturally appropriate, and environmentally sound agricultural systems. A flexible, ongoing process is necessary to set research priorities to support inherently dynamic agricultural systems. In this final decade of the 20th century, there is a penchant for looking forward to a new millennium. The turning of the calendar in such a significant way offers a natural pause—an opportunity to reflect on the past and to anticipate the future. This report looks to the future with emphasis on the soil and water resources that support agriculture. With world population now more than five billion, and some three billion people entering their reproductive years, it is a timely moment for such an assessment. Population growth and economic demands are exerting mounting pressures on the earth's soil, water, and other natural systems. The specter of possible changes in climate can only add to these pressures. It is time to consider how we can move "toward sustainability," toward a vision of natural resource management that supports current populations while leaving future generations an equitable share of the earth's great wealth. Although the most alarmist headlines portending environmental doom are probably overdrawn, many scientists are concerned about the steady decline in basic productivity of many soil and water systems, particularly those in the high population growth regions—Africa, Asia, and Latin America. In the humid tropics, rain forests are converted to agriculture and, in some places, large-scale ranching, bringing losses of topsoil and the depletion of nutrients, especially nitrogen (Lal, 1988; Pimentel et al., 1987; Sanchez and

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Toward Sustainability: Soil and Water Research Priorities for Developing Countries Benites, 1987). In aird and semiarid areas, increased demands for food, fodder, fuel, and materials bring analogous degradation (NRC, 1984). In hill lands, problems are exaggerated because the slopes accentuate runoff and erosion (Jodha, 1990). Soil compaction and crusting, loss of soil organic matter, reduced activity by soil organisms, nutrient deficiencies and imbalances—these are examples of the many forms of soil resource degradation. The interrelated issues of population growth, economic pressures, intensified land use, and environmental degradation at local and regional levels are serious causes for concern. Although these issues are universal, they are of particular concern in the developing nations of the tropics where the economic constraints of largely agrarian societies and the needs of expanding human populations are most pressing (NRC, 1991b). Some experts worry that continued population growth may make sustainable development all but impossible (Doyle, 1991). While current agricultural and biological technology has performed well in the last 20 years in meeting the growing needs of a vastly larger world population, there is concern that those initiatives are losing energy. In Degradation of soil and water resources is a serious concern throughout the world. In the Philippines, as in mountainous regions everywhere, deforestation of the up-lands leads to soil loss and sedimentation of waterways. Credit: Michael McD. Dow, National Research Council.

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Toward Sustainability: Soil and Water Research Priorities for Developing Countries addition, pressures are mounting on more environmentally fragile lands, and this trend will surely continue. A three-pronged approach will be necessary to increase agricultural production, with research supporting each path. First, farmers must intensify their use of good quality lands, with an eye toward ameliorating problems in areas with the best resources. Second, farmers will be forced to expand, maintain, and enhance production on lands previously viewed as "marginal"—such as steep lands, tropical forest zones, and the semiarid tropics. When misused, such lands often experience high levels of degradation, yet they already support a significant portion of the world's population. Finally, new emphasis will need to be focused on restoring degraded lands. It will truly be a challenge to increase or intensify production on environmentally fragile lands—lands that traditionally have been judged economically unsuitable for agriculture. Without significant industrial input, these lands often have low productivity potential and, in any case, are highly vulnerable to degradation; many areas already require some form of recuperative intervention. Environmental concerns in these areas are of special importance where they encompass high biological and cultural diversity, including some areas of extraordinary endemic resources. These areas demand a delicate approach to both research and technical interventions. They require a research thrust that focuses on sustainability, both in terms of economics and natural resource management. Local participation in the design of research goals is essential. It is within the context of these realities, therefore, that the Agency for International Development (AID) asked the National Research Council "to develop a broad agenda for directing worldwide international research and development efforts related to the use of soil and water resources to sustain agriculture, outlining both short-and long-term priorities." The NRC's Committee on Soil and Water Research and Development (CISWRD) was established in 1990 to undertake this task and prepare a report. Such a study is timely because while we have gained a much better understanding of soil and water systems in the developing world over the past few decades, too little of this new knowledge has been successfully applied to fundamental management problems. There also are gaps in our basic understanding of the ecology of these systems and of the social complexity inherent in resource use. The gravity of these issues is apparent from the attention being focused on sustainable agriculture and sustainable natural resource management. Even within the National Research Council, two committees in addition to CISWRD are active in these areas. The Committee on Sustainable Agriculture and the Humid Tropics is charged to identify and analyze agricultural practices that contribute to environmental degradation and declining agricultural production in humid tropical environments worldwide. The Com

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Toward Sustainability: Soil and Water Research Priorities for Developing Countries mittee for Collaborative Research Support for AID's Sustainable Agriculture and Natural Resource Management Program (SANREM) focused on the task of designing a Collaborative Research Support Program dedicated to agriculture and natural resource management. This committee began its work with a clear charge to look at soil and water research priorities that would contribute to "sustainable agriculture." The quest for sustainable agriculture had become a major policy thrust for the Agency for International Development and many other organizations in the development community. But it was soon clear to the committee that the rift that often separates those interested in agriculture from those interested in natural resources needs now—more than ever—to be bridged. For if sustainability is a goal, agriculture and natural resource management interests must recognize that they are equal partners in the effort. Competition for "ownership" of the issue is counter productive. These interests must be willing to negotiate a coordinated strategy that includes the strengths of both orientations. Rather than debate the definition of sustainable agriculture,1 the committee elected to accept the definition in use at AID while our work was occurring (Department of State, 1990): "sustainable agriculture is a management system for renewable natural resources that provides food, income, and livelihood for present and future generations and that maintains or improves the economic productivity and ecosystem services of these resources." This definition carries several implications. It requires sustainable agricultural systems to be both economically and ecologically viable. Management choices must give priority attention to maintaining the renewable resource base and its ability to meet the changing needs of humankind. The definition also recognizes that natural resources perform ecosystem services beyond the production of food, fiber, fuel, and income. These additional contributions include the recycling of nutrients, detoxification of noxious chemicals, continuation of evolutionary processes, purification of water, and regulation of the hydrological processes within watersheds and across the landscape. 1   The definition of agricultural sustainability, it is frequently noted, varies by individual, discipline, profession, and area of concern. The literature offers hundreds of definitions of sustainable agriculture. Virtually all definitions, however, incorporate the following characteristics: long-term maintenance of natural resources and agricultural productivity, minimal environmental impacts, adequate economic returns to farmers, optimal production with minimized chemical inputs, satisfaction of human needs for food and income, and provision for the social needs of farm families and communities. All definitions, in other words, explicitly promote environmental, economic, and social goals in their efforts to clarify and interpret the meaning of sustainability. In addition, all definitions implicitly suggest the need to ensure flexibility within the agroecosystem in order to respond effectively to stresses (NRC, 1991b).

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Toward Sustainability: Soil and Water Research Priorities for Developing Countries The committee originally consisted of eight scientists, and despite a diversity of backgrounds its members soon realized their limitations in terms of topical and regional coverage (see Appendix A). Thus we sought ways to bring more diverse expertise into the process. The committee elected to host a workshop to solicit additional ideas, information, and strategies. The two-day workshop was held October 1–2, 1990, at the National Academies' Beckman Center in Irvine, California. The goal was to bring together a range of professionals in critical aspects of soil and water management, and use their input to develop a research agenda and priorities to help AID and other international development organizations plan an efficient strategy for promoting the use of soil and water to sustain agriculture. Approximately 30 scientists representing a wide range of disciplines in the physical, biological, and social sciences participated (see Appendix B). The workshop was structured to focus on the elements essential to sound soil and water management in the context of systems dynamics. Four working groups were organized to give attention to the following topics: The biotic environment; Water resources; Physical properties of soils; and Chemical properties of soils (salinity, acidity, nutrients). In the past, research on soil and water resources tended to focus on components (e.g., soil physics in irrigated systems) while neglecting the linkages among biotic, physical, and human factors that shape the way the agricultural system functions and determine how it adapts to stress. Committee members and workshop participants alike, however, stressed the need for a more integrative, systems approach both in this report and in soil and water research. Thus, even though the workshop structure at times divided participants into focused groups, the emphasis was on interactions across disciplines and ecosystems. Each group was chaired by a member of CISWRD and included participants with expertise in indigenous knowledge and agroecology, and specialists in the dissemination of agricultural and scientific information. The working groups were given four tasks: Discuss the nature of the assigned subset of the soil and water arena, including problems, scope, components, and relative importance; Review the state of the art of the related knowledge base, the adequacy of the knowledge base, and the degree to which the knowledge base is actually being used; Reflect on the priorities for research and development that are most appropriate within the topic; and

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Toward Sustainability: Soil and Water Research Priorities for Developing Countries Discuss communications as it affects, or could affect, the topic, including information synthesis and dissemination, possible networks, and alternative communications procedures. Several plenary sessions were included to facilitate close coordination among groups and to seek links between the various topics. Vital contributions were made by AID staff, including William Furtick, David Bathrick, James Bonner, and Thurman Grove. The workshop provided the committee with valuable resources for its subsequent attempt to outline an effective framework and suggest priorities for soil and water research. A recurring point that emerged during the committee's tenure was the need to integrate soil and water research with other elements of natural resource management. Soil and water practices are not stand-alone endeavors but rather are integral components of a total management scheme. Our understanding of the basic principles is fairly strong, but our ability to apply this knowledge to solve problems in complex local and cultural settings is weak. Experimental approaches that do not involve more systematic, integrated research strategies will not be particularly useful for supporting long-term sustainability. The reductionist approaches of the past brought great benefits, but the problems we face are changing and demand a more holistic vision. Some common themes emerged during the committee's deliberations, and these will be discussed in more detail in subsequent chapters: Major gaps still exist in our understanding of soil and water systems and processes, but more important are the gaps between what is known and what is applied. Indigenous knowledge and practice should always be assessed. It often can suggest promising research on ecosystem components and strategies, such as nitrogen fixing trees, nutrient accumulating species, and low input irrigation techniques. In some cases, it can provide a platform for the integration of traditional and new technologies. More effective links between the social and the natural science aspects of soil and water problems are needed. Social and economic contexts create constraints that can effectively limit the application of technical improvements unless such contexts are adequately understood and addressed. More effective ways to use research resources for long-term, practical ends are needed. How can better feedback and communication be established between the field and the research institution so research can be focused on real, practical problems? The weakest link in the research process is the dissemination of research findings to the farm or regional levels, given the great local physical and cultural diversity that occurs. Greater effort is needed to develop better ways to communicate results.

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Toward Sustainability: Soil and Water Research Priorities for Developing Countries Soil and water resources provide the foundation upon which agriculture is based. But it is a combination of biological and societal resources that are required to make successful agricultural production systems. This is a complex and dynamic mix of variables. In view of the evolutionary nature of agricultural systems and our knowledge of them, it is important that the setting of research priorities be an ongoing process. Research priorities must be reassessed and adjusted periodically to serve the problems at hand. Thus, a mechanism is needed for evaluating and establishing priorities to keep them fresh, flexible, and responsive to current needs. The challenge is to adapt and extend our scientific knowledge about soil and water to establish economically productive, environmentally sustainable agricultural systems. Sustainability requires careful selection of the production systems and development of associated husbandry programs that are sustainable within, and do not destroy, the resource base. An effective effort to build sustainability into our agricultural systems will require changes in the philosophy and operating procedures of development organizations. Program planners and implementers will need to be more responsive to the evolution of individual agricultural systems and to the broader aspirations, needs, and capabilities of the target populations. We believe this report can be useful to the scientific and development community during this transition and hope that it will stimulate comment and debate.