12.6 A research agenda for a sustainable future
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UNCED's Agenda 21 provided a philosophy for sustainable development which may be interpreted to guide the direction of agricultural research. The first emphasis is on the improved management of biological systems, based on a better understanding of their dynamic processes. Examples are integrated plant nutrition systems (IPNS) and integrated pest management (IPM) to substitute for heavy reliance on chemical-based interventions. The second emphasis is on better information management, implying the need for sound data on natural resources, land use and farming systems, agrometeorology, etc., to improve environmental monitoring capability and make better use of natural resource potential. The third emphasis is on improved farm-household system management, in order to obtain a better understanding of the differing systems and hence considering in an integrated way household, farm and off farm activities. The emphasis also must be to obtain a fully participatory approach to development.
Moving to a more operational level, two central thrusts can be identified, each having a set of priorities. One thrust is aimed at promoting sustainable increases in productivity in the higher potential areas. The second should target marginal and fragile environments where current degradation must be reversed and production stabilized or raised. These must be supplemented by two crosscutting and highly complementary approaches: that of rehabilitation and restoration of ecology; and that of exploiting the synergism of indigenous technical knowledge and modern science. All four actions must be supported by international efforts to strengthen the national agricultural research systems, both institutionally and financially, since they will have to undertake much of the adaptive and applied research.
The priorities for making progress towards sustainable growth in productivity include: expanding on-farm biological production and recycling of inputs and lowering off-farm mineral fertilizer and pesticide needs; raising average yields and crop yield ceilings; improving irrigation water management; limiting soil acidification; using energy more efficiently and promoting renewable energy sources; and reducing labour inputs of some multiple cropping systems.
On-farm production or recycling of inputs can serve three main purposes. First, they can provide small-scale farmers with a profitable alternative to high cost external input systems, which though effective in technical terms, imply financial risks. Second, they can help to prevent soil nutrient mining and the excessive build-up of mineral fertilizer and pesticides residues in soil water, groundwater and surface water. Third, through the greater use of live leguminous mulches, green manures and other organic residues, they can improve soil structure, maintain soil fertility and enhance the soil's role as a sink for carbon dioxide. This requires a much deeper knowledge of agroecosystem functions but may also face severe labour constraints. It is difficult to imagine, for example, how some of the complex intercropping and relay planting systems currently used in China to achieve three crops a year, which require considerable labour inputs, can survive when labour opportunity cost rises. Research priorities include nutrient recycling processes and techniques, natural resources management at village level, and integrated crop/livestock management systems.
Raising yield ceilings in difficult environments has been an issue for a number of years. There is now a better understanding of the issues involved, and progress is being made with some crops like millet and legumes. In parallel, there is renewed emphasis on raising yield ceilings of staple food crops in the high potential areas, which have been at the centre of the successes of the "green revolution" (the irrigated rice and wheat areas of Asia) and where experimental yields seem to have reached a plateau and have been virtually static for the past 10 years or more (Pingali et al., 1990). Although average farm yields in these areas are still well below experimental yields, and so yield growth could continue to 2010, thereafter the decline in yield growth rates could accelerate unless research manages to break through the plateau and bring about another shift in the production frontier (Hayami and Otsuka, 1991). This challenge has become a major priority for IRRI and other research institutions, but their efforts must be backed up by national action. Recent widespread introduction of hybrid rice in China and other countries in Asia, first for temperate-zone rice but subsequently for tropical varieties, offers great promise of significantly raising the yield ceiling for rice (see Chapter 4). Priority research tasks include: (a) production of crop varieties with enhanced tolerance or resistance to moisture stress and soil nutrient constraints; (b) studies to overcome micronutrient deficiencies; and (c) investigating soil conditions under continuous intensive crop production as well as under low input conditions.
The research agenda for irrigation has three components. One is the use of cheap sources of low quality water in place of scarce high quality water. The second is raising water use efficiency so as to reduce unit costs. The third is to improve the management of irrigation systems. Existing technologies can go a long way to sustaining growth in the medium term, but accelerated research is needed to find more economic ways of preventing the further deterioration of existing water resources and to widen the technological options for the future. Key priorities are: (a) raising the efficiency of flood irrigation by practical methods of flood depth and seepage control, better land preparation, and the use of alternate wet and dry regimes; (b) adaptation of surge irrigation to developing country conditions; (c) development of simple, efficient and economical wastewater treatment methods so as to prevent or minimize adverse impacts on human health and the environment; and (d) identifying the main institutional characteristics of successful irrigation management systems and the effects of transferring management to farmers.
A common outcome of more intensive land use, whether it be through high or low external input systems, is increasing competition between crops and weeds for the available soil nutrients and water, and for light. The conventional responses are either more hand weeding or more herbicides. Labour for the former is becoming increasingly scarce and expensive, and the increasing quantities of pesticides are a growing threat to the environment and human health. Key priorities are (a) greater emphasis on weed management; (b) increased research on biological control methods and biodegradable herbicides; and (c) researching innovative ways to reduce herbicide applications.
Fulfilling the energy needs of agriculture and of rural services is at the core of improving productivity. Land preparation, harvesting, irrigation and processing require different types and levels of energy inputs, both in direct (mechanical, thermal, fossil and electrical energy) and indirect (fertilizer) forms. Without these energy inputs, agricultural productivity will remain low and probably well below its full potential. At the same time, unsustainable practices based on unnecessarily high energy inputs lead to resource depletion. There is the need, therefore, to understand better the energy-agriculture links and the potential of sustainable energy systems based on renewable energy sources, mainly biomass, solar and wind energies. The potential of agriculture itself as an energy producer requires further studies and research into the use of biomass residues, energy plantations and combined energy and food production schemes. Key priorities are (a) evaluation of the energy agriculture interrelationships for different ecosystems, and in relation to high and low potential areas; (b) better understanding of the integrated management of energy and other inputs (water, fertilizer, pesticides, mechanization); and (c) assessment of the potential of biofuels for different environmental and land-use policy situations.
Concerning the need to safeguard the marginal areas, there are two facets to this problem. The first concerns those areas that need not be permanently marginal, since with suitable investments, institutional changes and technologies they could become moderate to high potential areas (see Box 12.1). The second relates to areas that are inherently marginal because of severe aridity constraints that cannot be overcome by irrigation, or adverse soil types that cannot be exploited economically. Here priority must be given to limiting degradation while non-agricultural employment opportunities are created, so that people can afford to buy food from the better endowed areas, instead of being forced to over-exploit the land to meet basic needs.
It is increasingly acknowledged that there are many indigenous techniques for on-farm or local water conservation that can be used now or quickly adapted to complement the above actions. Maintaining progress after 2010 will, however, require more basic and applied research in the next two decades.
As with plant breeding, lead times can be 10 to 15 years or more. Some of the minimal tillage techniques, for example, that have transformed dryland crop production in parts of the USA, took some 20 years to develop and implement. And since they are low input systems, they are much more sustainable in terms of fossil energy needs and soil fertility maintenance than the farming practices they have replaced. Research priorities include: (a) development of minimal tillage systems for low-income farmers in the drylands of developing countries; and (b) methods to improve pastures in the extensive range areas, both under tropical and temperate conditions.
While there are substantial opportunities for developing sustainable low input systems, complete independence from external inputs is not possible except in a few special circumstances such as volcanic and aeolic dust deposition or sediment-loaded flooding. More research is required on lowering the relative costs of external inputs, or achieving the same objective by raising input use efficiency, or reducing needs through innovative ways of overcoming the factors that currently cause marginality. Some of the opportunities are well illustrated by the widespread problem of phosphate-deficient soils. Phosphate is an essential chemical for plant growth but many soils are highly deficient in it, or the phosphate present is not available to plants because of other soil factors such as aluminum or iron toxicity. Organic manures are seldom the long-term solution if high yields are to be achieved, while manure made from biomass grown on phosphorus-deficient soils will itself be deficient in phosphorus.
The conventional production of phosphate fertilizers is expensive, and when long distance transport costs are added, they tend to become even more uneconomic for farmers in marginal areas. Many countries, however, have low grade phosphate rock or other phosphate-bearing materials that could be used if cheap methods could be found for treating them so that the phosphate becomes readily available to plants. Alternatively, and in the longer term, there seem to be possibilities for genetically transferring to other crops the properties of pigeon-peas to release bound phosphates in the soil and make them available for plant growth. Without such technological breakthroughs, however, sustainable development in many marginal areas will be impossible. Research priorities therefore include: (a) development of cheap techniques for improving the effectiveness of using low-grade phosphate-bearing rocks, such as incorporating organic matter and promoting mycorrhiza activity in the soil; and (b) identifying the pigeon-peas mechanism for releasing bound soil phosphate, and possible transfer of the mechanism to other crops.
Increasing competition between crop and livestock production for land in both high potential and marginal areas, combined with the threat to crop yields from declining soil fertility, will be a positive force for integrating the two systems. This will, however' intensify the demands on research to come up with more satisfactory solutions to a number of problems and opportunities, notably: (a) reduction in the labour needs and other constraints to the adoption of livestock-oriented alley cropping and other sylvo-pastoral systems, taking into account competition for water, light and plant nutrients; (b) development of legume-based relay, intercropping, soil conservation, and other practices to raise the supply of high protein feeds and forages; and (c) introduction and refinement of ley farming systems for acid and other low-fertility soils based on legume and grass pastures. This chapter focused on the needs and opportunities for producing the projected output in a sustainable way and for laying the foundation for sustainable agriculture in the twenty-first century. The needs, however, are not only those of research and technology development. Unless technological progress is accompanied by institutional changes and other improvements in the incentives for agricultural development, many of the research findings will not leave the laboratory or the experiment station, or be developed on farms themselves. These aspects, some of which have been already discussed in earlier chapters, will be further explored in the next, concluding chapter.
1. In fact the peak in US timber prices lasted barely a month, March 1993, and by May they had returned to their level of late 1992. The "spotted owl" controversy added further uncertainty to an already uncertain market. There were costs nevertheless.
2. The HIV/AIDS pandemic sweeping many rural communities in affected African countries is having a similar effect on labour supplies leading to less labour-intensive but less productive farming systems (see Chapter 3, note 2).
3. Low growing crops, which fully cover the ground and protect the soil surface against rainfall impact and wind erosion, provide nitrogen to the associated crops, food for earthworms, and raise soil organic matter levels so as to increase soil porosity, rainfall infiltration and retention.
4. These are: irrigated or well-watered conditions, relay cropping with two or more harvests a year; crops at different stages of maturity in close proximity; no or limited fallows. All favour the substantial carryover of pests from one crop to the next, and the early infection of young plants or competition with them, in the case of weeds.
5. The requirements for sustainable water use are not just technological. The institutional and policy dimensions are equally important and are dealt with in Chapter 13.
6. Recent studies have shown that, among the ruminants, buffaloes and camelids have a greater efficiency in digesting fibrous feeds and recycling urea.
7. For example, in the "Cerrado" area of Brazil, soybean farmers practicing minimum tillage methods, spray herbicides at night (calm, cool and damp conditions) and successfully reduce application rates to a quarter of those recommended.
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