Optimising potassium fertilizer rates for maize (Zea mays L.) production on the volcanic soils of Buea, Cameroon.

Maize (Zea mays L.) production contributes to food security and income generation for many farmers, but productivity is constrained by soil infertility, with potassium (K) deficiency partly accounting for the huge gap between potential and actual yields. This is resolved with K fertilizer input that require appropriate K rates. This study was aimed at determining the optimum K fertilizer rate for maize production on the volcanic soils of Buea in Cameroon. The experiment was setup as randomized complete block design with five K fertilizer rates (0, 30, 60, 90, and 120 kg K ha-1) and four replications. Results reveal increased earthworm abundance at higher K rates (P