The productivity of the smallholder farming system in Ghana is under threat due to soil fertility decline. Mineral fertilizer is sparingly being used by smallholder farmers because of prohibitive cost. Grain legumes such as pigeonpea can play a complementary or alternative role as a source of organic fertilizer due to its ability to enhance soil fertility. Despite its importance, the potential of pigeonpea as a soil fertility improvement crop has not been exploited to any appreciable extent and the amount of land cultivated to pigeonpea in Ghana is vey negligible. This paper synthesizes recent studies that have been carried out on pigeonpea in Ghana and discusses the role of pigeonpea cultivation in soil fertility management and its implication for farming system sustainability. The paper shows that recent field studies conducted in both the semi-deciduous forest and the forest/savanna transitional agro-ecological zones of Ghana indicate that pigeonpea/maize rotations can increase maize yield by 75–200%. Barrier to widespread adoption of pigeonpea include land tenure, market, and accessibility to early maturing and high yielding varieties. The paper concludes among other things that in order to promote the cultivation of pigeonpea in Ghana, there is the need to introduce varieties that combine early maturity with high yields and other desirable traits based on farmers preferences. 1. Introduction Agricultural productivity in the smallholder farming systems in Ghana is under threat due to declining soil fertility. In the past, smallholder farmers in Ghana relied on the extended bush fallow system for maintaining the productivity of their farmlands . This system allowed restoration of phosphorus (P) and nitrogen (N), the most limiting nutrients. However, over the years, the population growth-induced scarcity of suitable farmland has led to the shortening of the fallow period making it difficult to manage soil fertility in smallholder farming systems. The problem is compounded by the increasing cost of inputs at the farm level due to structural adjustment programmes that have removed subsidies and increased supply costs due to the deterioration conditions of rural infrastructure . For instance, in 2002, whereas a metric tonne of urea cost about US$90 FOB (free on board) in Europe , the same quantity cost a Ghanaian farmer about US$308 at the farm level . Most farmers, especially the smallholder farmers, do not have access to formal credit and therefore cannot afford to buy mineral fertilizers even when it has been demonstrated to be profitable
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