Knowledge and management of soil fertility by farmers in western Cameroon

This study was conducted to assess farmers' perceptions of soil fertility, identify major soil fertility management (SFM) practices and to evaluate the effects of dominant SFM practices on soil quality. Field data were obtained using semi-structured questionnaires in seven localities: Nyassosso, Mbabe, Mbule, Nsuke, Ngab, Tombel and Kupe. The impact of dominant SFM practices on soil quality in various land use types was evaluated using the deterioration index (DI). Soil sampling and laboratory analysis were performed following standard procedures. Soil properties considered were bulk density (BD), organic carbon (OC), available P, total N, exchangeable bases (Ca2+, Mg2+, K+) and cation exchange capacity (CEC). Farmers make use of at least seven indicators to differentiate between fertile and infertile soils. Out of 256 farmers surveyed, 91.4% use minimum tillage as a technique for maintaining soil fertility, while 18.8% use chemical fertilizers to improve soil fertility. Compared to reference sites, overall DI values were: +224.4% (Tombel) < +133.7% (Nsuke) < +62.6% (Nyassosso) < −26.0% (Kupe) < −57.8% (Mbule) < −99.6% (Ngab) < −124.9% (Mbabe). The variations in soil attributes observed at the different sites is indicative of the complexity of nutrient dynamics following land use changes, coupled with farmer-specific SFM practices. For effective and sustainable SFM, site specific soil fertility investigations are imperative for efficient management of soil nutrients.