Efforts Toward Improving Maize Yields on Smallholder Farms in Uasin Gishu County, Kenya, through Site-specific, Soil-testing-based Fertiliser Recommendations: A Transdisciplinary Approach

Abstract

ABSTRACT This study evaluated the effects of site-specific, soil-testing-based fertiliser recommendations on maize yields using the transdisciplinary (TD) process. The TD process utilizes knowledge from science and practice. Farmers, extension officers, local financial institutions, and other practitioners collaborated with local scientists from the University of Eldoret in the process of financing, purchasing, and applying fertilisers in adequate amounts and composition. A total of 144 farmers participated in the study, which lasted for two seasons. The data sampling was based on a randomized 2 × 3 × 4 × 2 factorial complete block design, including the following factors: TD (non-participation vs participation in the TD process); ST (soil testing in the following categories: fertiliser application with no soil testing, fertiliser application following government recommendations, and application of site-specific, soil-testing-based fertiliser recommendations), and location (Kapyemit, Kipsomba, Ng’enyilel, and Ziwa). The “no soil testing” (ST1) category refers to farmers’ own practices at an average fertilisation of about 60 kg N ha−1 and 15 kg P ha−1. The government recommendation (ST2) calls for 75 kg N ha−1, 25 kg P ha−1, and 6 t ha−1 manure, and site-specific fertiliser recommendations (ST3) were based on actual soil-testing results; generally, this resulted in the recommendation of 90 kg N ha−1, 30 kg P ha−1, 25 kg K ha−1, 2 t ha−1 lime, and 1 t ha−1 manure. Highly significant effects were seen where farmers participated in the TD process (TD) for soil testing (ST). The farmers’ yields in Uasin Gishu County of 4.5 t ha−1 increased by approximately 1.5 t ha−1 based on site-specific, soil-testing fertilisation recommendations and by approximately 1.0 t ha−1 based on participation in the transdisciplinary process. However, as indicated by a significant interaction of the variables ST and TD—and while there is a significant main effect of participating in a TD process—the latter increase occurs only if site-specific, soil-testing-based recommendations can be used in the transdisciplinary process with farmers.