Exploring options for integrated nutrient management in semi-arid tropics using farmer field schools: a case study in Mbeere District, eastern Kenya

Abstract

The farmer field school (FFS) approach was used in semi-arid eastern Kenya in the period 2002–2003 to explore technology options for addressing declining soil fertility and to institute learning processes on integrated nutrient management (INM). Participatory diagnosis of soil fertility constraints and experimental design workshops led to the formulation of the INM-FFS learning curriculum and choice of INM technologies for testing in the central learning plot. INM technologies jointly chosen for testing included farmyard manure (FYM = T1), diammonium phosphate (DAP = T2), combined application of FYM and DAP (T3); and T3 combined with Tithonia diversifolia applied as green manure (T4). Maize was used as a test crop. The treatments were replicated twice using a pair-wise design and data collected, bi-weekly, using the agroecosystem analysis (AESA) framework to aid learning and data analysis with farmers. Farmers' evaluation of the trials was conducted at the end of the study period using matrix scoring and ranking. Treatments with combined application of organic and inorganic materials had better agro-economic performance than sole application of either FYM or DAP (T4 > T3 > T2 and T1) and they had a high value cost ratio (VCR > 2). The technologies of T1 to T3 did not have a positive impact on either nitrogen or phosphorus balances. However, T4 resulted in a positive partial N balance. Farmers' evaluation corresponded well with the majority of the quantitative agro-economic analysis. The study showed that there is a potential to use FFS for INM technology development and testing by stimulating interactions, farmer learning and closer working relationships between farmers, research scientists, extension and the institutions that they represent.