published on Nutrient Cycling in Agroecosystems February 2015
Low concentrations of phosphorus (P) also limit crop production on the acid, sandy soils in Sudano-Sahelian West Africa (SSWA). An increased P-use is thus a key leverage for enhancing food security and alleviating poverty. Therefore P-imports into the predominating agro-pastoral farming systems are indispensable, but most smallholders are cash-poor and risk averse, face labour-constraints, and P-fertiliser responses are site-specific. Key to the adoption of any new technology is a high financial performance with low risk levels of failure, low demands of labour and cash, and adaptation to the prevailing farming systems. Financial performances were assessed from nine, annually applied fertilising practices during four years in five SSWA zones. Information about the farming systems, labour demands, and input-output prices stem from secondary sources. The profitability largely depended on rainfall and location-specific soil conditions, but those of annually repeated mineral and organic P-strategies increased over time. Several P-fertilisations were profitable on a per land unit basis, but could not compete with farmers’ practices on a per labour unit basis. Mulching with and without P (13 kg P ha-1) were not financially superior, but the broadcast application of 13 kg P ha-1 became profitable over time. Hill-placed P (4 kg P ha-1), also known as micro-dosing, was a profitable alter¬native to farmers' practices particularly in the intermediate rainfall zone. The results showed the importance of recommendations following rainfall zones, which are of interest across a spectrum of users including policy makers, land use practitioners, private firms, NGOs and research for development implementers.