2.1. Agricultural Land Types
2.2. The Scope of S&W Research
2.3. The Research Approach
Most of the programmatic and financial information available from Centres follows the five categories identified in the CGIAR's classification of research activities. It is recognized, however, that in processes related to the management of natural resources for agricultural production many of such activities are interrelated. Consequently, it would not be appropriate to include only a few of the CGIAR activities as S&W-related in a resource-conserving context (e.g., 2.3, Land resources conservation and management, or 2.5 on Processes and mechanisms of sustainable resource systems). There was a need to design a conceptual framework to characterize current CGIAR Centre activities so that the particular objectives of this study could be addressed.
The analysis necessary to deal with the above questions requires a three-dimensional framework, that addresses the demands for international research derived from prevailing systems in the most relevant agricultural land types; the scope of S&W research in the hierarchy of agricultural systems, and the applied or strategic nature of the approach Centres are following in their S&W research. These three dimensions are briefly discussed in the following sections.
Identified land types are derived from the basic criteria followed by TAC in its latest review of priorities and strategies, by Greenland et. al. 2, and the TAC document SDR/TAC:IAR/96.9; but an effort was made to link them with the operational approach pursued in the Centre's MTPs. One of the difficulties in the application of S&W-related research is its location-specificity. Management practices thus respond to variations in soils, climates, land forms and human behaviour with the result that S&W management problems differ considerably in significance and extent in different parts of the globe. To assess their relative significance, it is therefore necessary to categorize them in relation to major land and land-use characteristics. The following land types were selected for having some internal consistency in S&W issues, and linked to TAC-defined agroecozones:
2 Greenland, D.J., G. Bowen, H. Eswaran, R. Rhoades, C. Valentin, 1994. Soil, Water and Nutrient Management Research - A New Agenda. IBSRAM Position Paper
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Warm arid and semi-arid tropics and sub-tropics |
* semi-arid lands |
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Warm sub-humid tropics and sub-tropics |
* savannas |
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* hillsides |
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Warm humid tropics and sub-tropics |
* rainfed lowlands |
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* forest margins |
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Cool tropics and sub-tropics |
* highlands |
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Cool sub-tropics, winter rainfall |
* semi-arid lands, winter rainfall |
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Cross agroecozones |
* irrigated |
The dominant farming systems in the desert margins are animal-based, ranging from nomadism to improved pastures in mixed farms. Shifting systems prevail in the wetter savannas and humid forests, with grazed fallows in the savannas and tree-fallows in the forests. Rice predominates in the lowlands, while sedentary agriculture and livestock are the main systems of land use in the heterogeneous steeplands. In general, methods to keep soil nutrient levels as cultivation pressures increase are critical. Manure or fallow organic matter becomes critical to nutrient cycling and water retention, as well as to erosion control and biological activity. Water shortage dominates drier areas, while excesses are a major concern in the wetter lands, exacerbated on a landscape scale by sedimentation.
Semi-arid Lands. Most of the soils are sandy or gravelly and shallow, but there are also large areas of potentially productive and difficult to manage vertisols. Water scarcity is the major resource problem, compounded with loss of organic matter, erosion and crust formation in soils. In warmer areas during the short wet seasons soils are susceptible to waterlogging or erosion, while winds are a threat to erosion in sandy soils during the long dry season.
Savannas. In the higher rainfall areas soils are severely leached, acid and of a low inherent fertility, showing signs of soil chemical and physical degradation with increasing pressures. Farming systems are in the transition from grazed fallows to improved pastures and crop-livestock systems. In zones with moderate rainfall soils are less acid, but still have problems of poor structure and low nutrient content. Increasing pressure on the prevailing subsistence-oriented agriculture is shortening fallow periods, exposing soils to compaction and erosion. The Inland Valleys are an important land form that cuts across this agroecological zone and that of the Rainfed Lowlands. They offer considerable potential for increasing productivity because of higher soil fertility and opportunities for dry-season cash cropping.
Hillsides. Soil erosion is the main problem in this land type, not only because it undermines agricultural productivity, but also because it can cause downstream problems for hydroelectric generation, irrigation and urban water supplies. As fallows shorten, cropping intensifies, and more marginal lands are brought into cultivation, soil erosion compounds nutrient depletion problems.
Rainfed Lowlands. Soils vary across the different regions, but rainfed ecosystems share one major characteristic: uncertain moisture supply. Fields may have too much water, too little water, or both, within the same cropping season. The concern for sustainability in this land type is not about raising very low yields, but maintaining and increasing existing high levels. Yields are stagnating or showing a downward trend. In the uplands soil erosion and degradation could be a special problem following logging. As mentioned for the Savannas, the Inland Valleys offer considerable potential for increasing productivity because of higher soil fertility and opportunities for dry-season cash cropping.
Forest Margins. Soils are mostly of low inherent fertility with low activity clays. Those in the drier part are very easily eroded. Farming systems are tree-based shifting cultivation. When the vegetative cover is removed, heavy rainfalls induce the collapse of the structure of the surface soil. Lower organic matter replenishment leads to soil compaction and heavier leaching causes nutrient depletion.
Highlands. The characteristics of the soils and the climate differ widely, but the slopes result in a common problem of water erosion. Farming systems are based on mixed crop/animal/tree systems. Unsustainability in these steeplands can have an impact at different spatial scales. As in the case of the hillsides, problems are compounded by increasing rates of deforestation.
Semi-arid Lands, winter rainfall. Agriculture is based on soils that are calcareous, and low in clay and organic matter. The resource base shows signs of deterioration, with expansion of cultivation into marginal zones leading to serious erosion on rainfed lands, while overgrazing causes the rangelands to deteriorate. Shorter fallows reduce their capacity to conserve soil moisture and improve fertility, and the potential of integrated crop-livestock systems is not fully exploited.
Irrigated. The threat to this land type arises mainly from waterlogging and salinization, reservoir siltation, and decreasing capacity of soils to release nutrients. Inadequate drainage of the irrigated area, leads to waterlogging or a rising in the water table. If the latter contains saline water, as it often does in arid and semi-arid areas, the soil will be salinized and productivity severely reduced. An additional problem is that of reservoir sedimentation, caused by the increased intensity of deforestation in catchment areas. In the intensive rice systems of Asia, soils are showing an increasingly lower capacity to release nutrients, indicated by divergent trends of higher soil organic matter and lower N supply to the crop.
There is an increasing awareness about the socioecological nature of agricultural land use systems, which is shaped by interdependencies among agricultural, environmental and socioeconomic factors. This multidimensional and interactive nature of agricultural systems emphasizes the need to incorporate a spatial dimension in the understanding of the structure and function of such systems. Agricultural, environmental and socioeconomic factors have an impact on the sustainable management of S&W resources. But their relative importance and the nature of the impact tends to differ according to levels in the hierarchy of production systems (e.g., water erosion affects crop production in the upstream fields, and power-generating capacity in the downstream dam).
The main part of this TAC study advocates an integrated approach to NRM research in the CGIAR, as an "organizing framework within which to consider a number of critical linkages and subjects in the natural resources area". It is further argued that research should be prioritized within the context of four sets of linkages: the linkages between productivity-enhancing and resource-conserving research; between spatial levels in the landscape (e.g., upstream-downstream); between research and adoption; and between present and future users. From the point of view of the actual management of natural resources, these linkages represent interactions across different levels of decision-making in the systems hierarchy. In this context the proposed linkages could be organized as:
- links between productivity enhancement and resource-conserving research in developing S&W management alternatives (field level);- links between research on resource management options and that on farmer's decision about production systems (farm level);
- links between "on-" and "off-site" research to estimate private/social benefits/costs of resource management options, often dealt at community levels of decision-making (watershed/landscape level); and
- links between farmer/community level(s) of decision-making and policy issues (normally at country/regional levels of decision-making).
Against this background, we believe that the scope dimension of the analytical framework should take into account scales in the systems hierarchy at which research activities are carried out by CGIAR Centres. Here four scale levels are proposed for the categorization of the S&W research in the CGIAR. Each one of the scales includes a set of research activities which are identifiable, to a certain extent, with those included in CGIAR's existing research categories. The adopted scales and corresponding research activities are presented in Table 1:
Table 1: S&W-related Activities in a Hierarchical System context
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System Level |
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Research Activities |
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Field |
1.2.3/5.a) |
soil nutrient dynamics |
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2.3 |
maintenance and improvement of the resource base |
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2.5 |
processes and mechanisms |
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Farm |
1.2.1 |
production systems studies |
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1.2.2 |
farming systems, technology evaluation |
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4.1 |
microeconomic analysis, technology implications |
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Watershed/Landscape |
2.1 |
characterize ecosystems |
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2.4 |
management of aquatic resources |
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2.6 |
modelling landscape and watershed phenomena |
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Country/Region |
4.2 |
policy analysis |
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4.3 |
public systems management |
The research approach adopted for this study is already followed by some of the CGIAR Centres in their research on natural resource management. It derives from a macro perspective at the agroecosystem level and focuses on biophysical and socioeconomic processes and mechanisms regulating S&W management. This "systems-and-processes paradigm" (Scholes, M.C. et. al.) 3 recognizes the limitations of empirical research for the development of information-based management technologies. These require a deeper understanding of agroecosystem functions at the process level.
3 Scholes, M.C., M.J. Swift, O.W. Heal, P.A. Sanchez, J.S.I. Ingram and R. Dalal, 1995. Soil Fertility Research in Response to the Demand for Sustainability. In The Biological Management of Soil Fertility, Ed. by P.L. Woomer and M.J. Swift. John Wiley & Sons.
As mentioned, the sustainable management of agricultural systems is influenced by the interrelationships between different factors of an agroecological and socioeconomic nature, as well as by constraints and opportunities surrounding the systems at the particular hierarchical level being addressed. Given the multifactor and interactive nature of agricultural systems, their sustainable management could best be implemented if based on an understanding of mechanisms governing their functioning. In the hierarchical context this means understanding the processes operating at the scale below the level being managed. That is, if the scale to be predicted is that of the farm, a degree of process-level understanding at the field level is required.
In this context, relevant CGIAR activities were categorized according to their expected contributions to two main research approaches: applied, concerned principally with the development of technologies and practices; and strategic, aimed at the understanding of processes and mechanisms to predict the system's behaviour under alternative managements. Table 2 presents CGIAR activities according to their expected contribution to either applied or strategic research at the four scale levels.
Table 2: CGIAR activities by research approach and system scale
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System Level |
Research Activities |
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applied-oriented |
strategic-oriented |
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Field |
2.3 maintenance and improvement of the resource base |
1.2.3/5-a) soil nutrient dynamics |
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2.5 processes and mechanisms |
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Farm |
1.2.2 farming systems (+ baseline) |
1.2.1 production systems trends |
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4.1 microeconomic analysis |
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Watershed/Landscape |
2.1 characterize ecosystems |
2.6 modelling landscape |
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2.4 management of aquatic resources |
4.3 community-based organizations |
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Country/Region |
4.2 policy analysis |
4.3 public systems management |
