Drylands Research Working Paper 36
Are smallholder farmers mining their soils and causing irreversible land degradation, or are they adapting soil fertility management practices to enable sustainable agricultural intensification? This report compares indigenous soil fertility management strategies in northern Nigeria and the Department of Maradi, Niger. Within this region there are variations in population density, rainfall, land tenure and economy (due largely to differing colonial agendas in Nigeria and Niger). This review aims to contribute to the debate concerning the effect of changes in agricultural production on soil fertility and land use management.
Analysis of empirical data from several sites in north-east Nigeria and the Department of Maradi in Niger show that the range of soil fertility management technologies practised in each village increases with the intensity of the farming system. All of the farming systems studied are low input-low output farming systems.
Individual farmers and farming communities must be responsive to their environments, resulting in a dynamic process of soil fertility management. Crop-livestock integration overcomes the initial constraints to agricultural intensification by providing organic matter, transportation, income diversification (through production of livestock as well as crops) and animal traction (McIntyre, Bourzat and Pingali, 1992). Successful integration also involves an increase in legume production within the system, which provides fodder for livestock (and organic matter to be recycled to the fields as manure), increases inputs of nitrogen through nitrogen fixation, and, through the sale of legume grain, provides cash which may be used to invest in inorganic fertilisers. Integrated nutrient management uses all the resources available to farmers, such as labour (depending on family size and ability to hire labour), livestock manure, draught animal power, crop varieties, fertilisers and knowledge, to work on the land to which they have access. The availability of these resources will vary according to the prevailing natural and socio-economic environment: rainfall, availability of purchased inputs, economics of the farming system, and population pressure.
Due to economic conditions in the study area, low external input strategies are more common than those requiring high investment or cash expenditure. Strategies which are highly dependent on external inputs are not viable at present in this region. Fertiliser is scarce, and its availability at appropriate times in the agricultural calendar unreliable. Low external input farming systems are more suited to the economics and infrastructure under which smallholder farmers operate in Africa. Unless the constraints to increased use of inorganic fertiliser can be resolved, these farming systems can only rely on low-external input strategies to maintain soil fertility.