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Ingredients of sustainable farming systems and issues to be considered in the design of these systems

The overall objective of agricultural or farming system design and management is the creation of environmental conditions that remain favourable for crop and animal production or even increase their productivity in perpetuity while at the same time minimizing adverse impacts on the resource base or, where possible, enhancing it. Consequently, it is necessary in any effort at designing sustainable farming systems to begin with:

• reviewing the characteristics of environmental resources and ways of managing and manipulating them to achieve specific results;
• selection characteristics of inputs, practices and technologies that in tropical Africa can be used to render outmoded and new farming systems sustainable. Table 4.2 lists resource characteristics, practices that render them unsustainable and restorative measures for dealing with the undesirable changes.

In addition to the various causes of unsustainability indicated in figure 4.1, or the characteristics of resources and inputs which may, in association with certain practices cause unsustainability for which remedies are given (table 4.2), there are overall general issues that need to be taken into account in designing sustainable agricultural systems. These include:

• The need for low resource farmers in developing countries to minimize use of external inputs such as fertilizers and herbicides by increasing reliance on internal inputs, because of lack of credit and foreign exchange. In this regard, we can also regard the buying of stakes from neighbours or the local market as purchase of an external input which can be internalized by using agroforestry systems such as alley cropping, which supplies stakes and even fuelwood that is home grown.
• Increase reliance on biological processes such as biological nitrogen fixation, nutrient cycling mechanisms and mycorrhizal phosphate nutrition for minimizing the amount and cost of fertilizer use.
• The fact that the use of fertilizers (organic or synthetic) in tropical agriculture is imperative and that the only options we have are how to optimize the use and increase the efficiency of fertilizer use.
• In some situations we may resort to the growing of crops (e.g. cassava) that are adapted to soil acidity wherever possible rather than always resorting to liming in dealing with soil acidity.
• Use of integrated approaches in agriculture systems, e.g. integrated watershed development;
  • integrated pest, disease and weed management (IPM);
  • integrated field crop and shrub/tree (ligneous species) production systems agroforestry;
  • integrated crops, trees, pastures/animal systems (agrosilvopasture);
  • mixed cropping systems and rotational sequences rather than monoculture;
  • integrated land use planning; - integration of traditional, "modern" and emerging technologies;
  • minimal and strategic use of pesticides and chemicals associated with a spectrum of compatible physical, cultural and biological methods;
  • combination of manual and appropriate mechanization systems;
  • need for intensification of production and use of appropriate technologies under increasing population pressures, since shifting cultivation and related fallow systems cannot meet the demands of higher carrying capacity (table 4.3);
  • elimination of gender bias in technology development and extension;
  • need for adequate level of human resources development and institutional capacities in research and development to keep up with changing needs of farmers and changing circumstances;
  • research of sufficient scope on research stations and on the farm level with increasing farmer participation;
  • balance between production research and post-harvest-phase research and development necessary for successful agribusiness growth;
  • need for policy umbrella in support of sustainable agriculture and one which ensures compatibility among agriculture, forestry, fisheries, etc., in order to render practices more environmentally friendly;
  • need for suitable infrastructure in support of sustainable agriculture, including roads from farms to markets and effective pricing and market structure.

Table 4.2 Selected Sustainable Agriculture Resource Input Features and Practices, Effects and Remedies

Sources: Adapted from SCA (1991) and Lal and Okigbo (1990).

Table 4.3 Yield in Gram Equivalents and Percentage of Crop Land for Various Levels of Production Inputs in the World

Source: FAO (1991b).

Sectorial interface requirements

However appropriate and realistic the design of a sustainable farming system may be, it is necessary to ensure that threats to it from other sectors are eliminated or significantly minimized. For example, poor road construction could result in flooding, eutrophication and erosion, all of which can seriously damage farm land and even fish-ponds or stream fisheries. A related example is a policy issue such as structural adjustment aimed at increasing export earnings or at reducing debt burdens. This may result in a lot of forest areas being cleared for the commercial row-growing crops, which will expose the soil to erosion. Similarly, removal of subsidies may result in farmers not using fertilizers which, in turn, will result in environmental degradation. Therefore, designing sustainable agricultural or farming systems and adhering to the design alone will not ensure sustainability unless policies, strategies, technologies, systems and components of resource management, and input/technology use in other sectors such as forestry, fisheries, animal production, manufacturing industries, tourism and management of nature reserves and trade are designed to ensure sustainability in development devoid of adverse impacts on the other sectors. A few examples of sectoral activities in one sector which affect other sectors are presented below:

Uncontrolled expansion of agricultural land reduces land available for reserves, forestry and other multiple land use requirements.

• Unplanned land use and expansion of agricultural land may result in reduc ing land available for pastures, culminating in overgrazing.
• Deforestation and inappropriate logging practices could cause erosion, landslides, siltation of streams, etc.
• Poorly managed industrial expansion could result in chemical pollution of the air and streams.
• Unregulated hunting and collection of trophies for sale to tourists or for export could result in loss of biodiversity and in ecosystem deterioration.
• Lack of family planning and uncontrolled population growth causes increased pressures on land resources, shortening the duration of periods of fallow and resulting in poor vegetation cover and erosion.

All these call for not only integrated land use planning but also adoption of a holistic approach in development planning, in policy formulation and in selecting strategies and the execution of development programmes. The earlier we pay attention to these, the better.

Conclusions and recommendations

In designing sustainable agricultural production systems, it is necessary to give due consideration to the characteristics of various resources used in production, the ways they are managed or manipulated in the production process and the technologies and practices which render the resultant production system unsustainable. Unsustainability results when impacts of practices and technologies used are economically not feasible and sometimes also culturally unacceptable. In addition to the selection of methods for manipulation of resources and use of practices and technologies which ensure sustainability, there is a need to ensure that other sectoral activities do not render the farming systems unsustainable. At the same time measures must be taken to ensure that various accelerators of agricultural development and factors which ensure enabling the environment for agricultural production for a majority of farmers are present. These include:

• effective marketing and pricing system for agricultural produce;
• continuous and systematic research that generates new agricultural practices and technology;
• presence of adequate incentive for farmers to increase output or for operators of agricultural services to perform their tasks efficiently;
• effective transportation and communication system that reaches most farms; and
• local availability at reasonable prices through manufacturing or importation of equipment and farm inputs needed by farmers (Mosher 19 70).

The effectiveness of these are accelerated by:

• presence of adequate educational and training facilities for agricultural technicians and experts in supporting services;
• effective input distribution mechanisms;
• opportunities for farmer group action through cooperatives and similar organizations;
• means for improving and expanding agricultural land; and
• mechanism for planning and directing agricultural development programmes as integral components of overall economic development (Mosher 1970).

Recommendations on Principles for Designing Sustainable Farming Systems in Tropical Africa

In designing sustainable farming systems there are five principles or objectives that should be aimed at, namely:

1. maintenance or enhancement of farm productivity in the long term;
2. amelioration, minimization or avoidance of adverse impacts on natural resource base for agriculture and associated ecosystem;
3. minimization of residues from chemicals in agriculture or of adverse effects of practices;
4. maximization of the net social benefit derived from farming, which involves considering net social benefits of agriculture when positive and negative effects are considered and making such choices among alternatives as to maximize benefits by using certain production systems and practices; and
5. rendering farming systems sufficiently flexible to manage risks associated with vagaries of climate and markets (SCA 1991).

Guidelines for Designing Sustainable Systems

The main guidelines to follow in designing sustainable agricultural systems are to:

• gather and obtain all available information on the environmental resources (climate, land/soil, water, diseases, pests, ecosystems, etc.);
• ensure that the land use capability of the area to be farmed or used is well known;
• use land clearing methods that cause minimal disruption of soil structure;
• ensure the matching or the compatibility of the land use with the land use capability and, where possible, on the micro level, relate land use to the characteristics of the toposequence in the watershed;
• give due consideration to prevailing environmental conditions in choosing the commodities to be produced, varieties to be produced and the timing of sequences of operations and nature of operations to be performed, from clearing to harvesting and storage (table 4.4);
• give due consideration to the probable environmental impacts of the practice or technology associated with each operation to be performed, and the choice to be made of the option with minimal adverse environmental impact;
• minimize overreliance on external inputs (i.e. inputs obtained from outside the farm ecosystem);
• as much as possible, use integrated approaches such as:
  • integration of traditional and modern or emerging technologies, e.g., use of partially manual and partially mechanical clearing;
  • integrated land use planning;
  • integrated watershed development;
  • integration of biological (nitrogen fixation) and chemical fertilizers and nutrient cycling;
  • integrated pest, disease and weed management, e.g., use of intercropping and manual methods in weed control;
  • integrated production systems, e.g. arable crops and woody tree/shrub agroforestry; crops and livestock (mixed farming); crops, shrubs and trees, pasture and livestock (agrosilvopasture); crops, animals and fish;
• as much as possible use biological approaches and processes while minimizing reliance on chemical and synthetic methods in soil fertility management, pest management, etc.;

• relate the choice of commodities to be produced and their characteristics to the post-harvest objectives and uses, e.g. storage, processing, planting, etc.;
• diversify production either through mixed cropping/intercropping, rotations of sole cropping, or mixed cropping, but also bearing in mind that row cropping is soil degradative;
• make as much effort as possible in all operations in soil management to keep the soil covered with crop residues and to maintain reasonable levels of soil organic matter;
• give fire management and control serious consideration in clearing, hunting, pasture management and in dealing with accidental fires;
• control soil surface cover in livestock management by control of stocking rate or by controlled grazing;
• intensify production in the wake of rapid population growth and decline in available land, introduce land saving technologies to increase carrying capacity, and promote family planning;
• improve sustainable agricultural design through monitoring of impacts of various practices and technologies in addition to changes in the resource base under different land use systems; refinement and changes should be backed up with research of sufficient scope and environmental monitoring activities based on standardized and reliable methods.

Table 4.4 Different Operations Performed during Different Stages of Crop Production and Utilization and Extent of Likely Erosion Hazard Involved

Source: Okigbo (1985,1993).
a. Extent of erosion hazard depends on interaction of operations with environment and other factors.

The above principles and guidelines are by no means exhaustive but they are illustrative of the principles and procedures involved in determining: the management schedules; the manipulations of resources; and the input orches tration in amounts, sequences and timing in order to satisfy objectives in pro ducing desirable levels of food, fibre, and other products or otherwise satisfy ing the farmers' objectives. The design can only operate with success where there is an appropriate policy umbrella in the presence of all the accelerators of agricultural development and compatibility among all sectors.

References

BOA/NRC. 1989. Alternative Agriculture. Committee on the Role of Alternative Farming Methods in Modern Production Agriculture, Board on Agriculture, National Research Council (BOA/NRC). Washington, DC: National Academy Press.

Board for International Food and Agriculture (BIFAD) Task Force. 1988. Environment and Natural Resources: Strategies for Sustainable Agriculture. Washington, DC: United States Agency for International Development (USAID).

Dover, M. and Talbot, L.M. 1987. To Feed This Earth: Agroecology for Sustainable Development. Washington, DC: World Resources Institute.

FAO. 1991a. Issues and perspectives in sustainable agriculture and rural development. Main Document No. 1, FAO/Netherlands Conference on Agriculture and the Environment, s'Hertogenbosch, Netherlands. Rome: FAO, and The Hague: Ministry of Nature Management and Fisheries of the Netherlands.

FAO. 1991b. Sustainable development and management of land and water resources. Background Document No. 1, FAO/Netherlands Conference on Agriculture and Environment, s' Hertogenbosch, Netherlands, 15-19 April 1991. Rome: FAO, and The Hague: Ministry of Nature Management and Fisheries of the Netherlands.

Lal, R. and Okigbo, B.N. 1990. Assessment of soil degradation in the southern states of Nigeria. Environment Working Paper, No. 39, World Bank Sector Policy and Research Staff. Washington, DC: The World Bank.

Okigbo, B.N. 1984. Improved permanent production systems as an alternative to shifting intermittent cultivation. FAO Improved Production Systems as an Alternative to Shifting Cultivation, FAO Soils Bulletin 53: 1-100.

Okigbo, B.N. 1985. Food self-sufficiency in West Africa: an overview with agenda for the future. In K. Ewusi, ea., Towards Food Self-sufficiency in West Africa. Tema: Tema Press of the Ghana Publishing Corporation.

Okigbo, B.N. 1986. Cropping systems and land degradation in the tropics. Ibadan: IITA. Mimeo.

Okigbo, B.N. 1993. The African dilemma and the quest for appropriate technologies for sustainable agriculture and food. In: Marini-Bettolo, ea., Study Week on Agriculture and the Quality of Life: New Global Trends, 17-22 October, pp. 53-96.

Standing Committee on Agriculture (SCA). 1991. Sustainable agriculture. SCA Technical Report Series, No. 36, Report of the Working Group on Sustainable Agriculture, Standing Committee on Agriculture. East Melbourne: Council for Scientific and Industrial Research.

World Commission on Environment and Development (WCED). 1987. Our Common Future. Oxford: Oxford University Press.

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