Cropping systems, land tenure and social diversity in Wenchi, Ghana: implications for soil fertility management

The original entry point for this study was how to optimize long-term rotation strategies for addressing the problem of soil fertility decline inWenchi,Ghana. However, as the study progressed over time, it was realized that what we initially interpreted as soil fertility management strategies were closely intertwined with wider issues such as cropping systems, livelihood aspirations and land tenure relations. Exploration of farmers' soil fertility management practices revealed a link between tenure insecurity among migrant farmers especially, and limited attention for regeneration of soil fertility. The native farmers who own land tend to use rotations involving long-duration crops such as cassava and pigeonpea to improve their soils. In contrast, migrants who depend mostly on short-term rental or sharecropping arrangements, rely more on rotations with short- duration crops such as cowpea and groundnut to improve soil fertility. A study to examine diversity among farm households and their relevance and implications for orienting action research aimed at combating soil fertility decline revealed that historical, ethnic and gender dimensions of diversity provide additional insights in livelihood patterns and soil fertility management which are relevant for fine-tuning technical and social action research agendas. Relevant differences between farm households result from the interplay between structural conditions and the strategies of active agents. Five cowpea varieties were evaluated for their grain yield, Nsub>2 -fixation and their contribution to the productivity of subsequent maize crop grown in rotation. On both farmer and researcher-managed fields, there were no significant differences in grain yield among the different varieties. Using the 15 N natural abundance technique, the proportion of N 2 fixed by the different cowpea varieties ranged between 61 and 77%. On both farmer and researcher-managed fields, maize grain yield after cowpea without application of mineral N fertiliser was higher than maize after maize. Although farmers recognized the contribution of cowpea to soil fertility and yields of the subsequent maize crop, they did not consider this as an important criterion when selecting varieties for use in their own fields. The overriding criteria for selecting cowpea varieties were more related to their early harvest, seed quality in terms of taste and marketability and ease of production (low labour demand). The performance of maize under different cropping sequences was evaluated in both farmer and researcher-managed experiments. Yield of maize without N application was higher after cassava and pigeonpea compared to that after speargrass fallow, cowpea or maize in both researcher and farmer-managed experiments. A simple financial analysis performed to evaluate the profitability of the various rotational sequences showed cassava/maize rotation to be the most profitable rotational sequence while speargrass fallow/maize rotation was found to be the least profitable. Farmers' preferences for a particular practice were more related to accessibility to production resources and livelihood aspirations. An action research in the social realm was carried out to develop institutional arrangements beneficial for soil fertility. Initial efforts aimed at bringing stakeholders together in a platform to engage in a collaborative design of new arrangements were stranded mainly because conditions conducive for learning and negotiations were absent. The implementation of experimentation with alternative tenure arrangements initiated by individual landowners and tenant farmers too ran into difficulties due to intra-family dynamics and ambiguities regarding land tenure. Further investigations to find out how ambiguities could be tackled, revealed that the local actors themselves had worked towards institutional arrangements to reduce ambiguities. However, there is still considerable scope for further development of these self-organised innovations. The study stresses the need for continuous diagnosis and exploration in action research in order to steer research in a relevant direction.