Soil fertility management strategies and practices by smallholder farmers in semi-arid areas of Zimbabwe

Indigenous soil fertility management strategies in semi-arid Communal Areas of Zimbabwe have largely been driven by an extensive use of resources. The shrinking of common property resources (CPRs) due to expansion of cultivated lands, the general loss of productivity in natural ecosystems (e.g., poor grazing) and increasing demand for nutrient sources due to the increased number of farming households have resulted in a critical scarcity of the traditional sources of nutrients. Although farmers use many locally derived fertilizers (e.g., leaf litter, manure or termitaria), they do so more in desperation than by choice. Because of their low quality and declining availability, locally derived fertilizers fall short of satisfying crop growth requirements for the current market-oriented economy. Such inputs also require a lot of labor for collection and transport, often for little return in soil fertility improvement. There should therefore be a limit to which we can expect to manipulate farmer innovativeness or exploit indigenous knowledge systems in order to sustainably manage soil fertility. Farmers have probably done their best under the prevailing circumstances. The study by Scoones et al. (1996) gives examples of how farmers have adopted and fine-tuned technologies to suit a variety of circumstances. This raises a major issue of whether indigenous soil fertility management and practices in semi-arid Communal Areas can be improved without introducing major changes to the farming systems. The answer depends on the level of production that it is hoped farmers can achieve. If yields above subsistence production levels are expected, then the idea of low-input agriculture in these marginal environments is nonsensical. As population pressure continues to increase, the major challenge in semi-arid communal Areas is that of transforming an extensive management system into an intensive one. This involves changes in extension strategies, farmers attitudes and perceptions and a concomitant change in resource utilization. It therefore requires an interdisciplinary and integrated approach and should be expected to take time. Current indigenous soil fertility management practices are dependent on CPRs. Net nutrient outflows from these ecosystems are likely to result in declining productivity of CPRs. Households in semi-arid areas get significant income from forestry products (Clarke et al. 1996) e.g., crafts and wood carvings. Intensification of soil fertility management on arable lands will save forestry resources and spare these ecosystems from degradation. Under the current management practices, the only viable nutrient sources are manure and crop residue