New Fertilization Approach Improves Okra (Abelmoschus esculentus L. Moench) Production on Acidic and Degraded Soil in Cameroon

Soil acidity, combined with high aluminum toxicity, is one of the major problems limiting agricultural productivity. The objective of this work was to improve growth and yields of okra on acidic and degraded soil in the Center region, Cameroon, using an innovative fertilization approach and lime material. The soil is ferralitic, very acidic, with aluminum toxicity and significant imbalance in the (Ca/Mg/K) ratio of (55/15/30). Seven fertilization treatments were applied: Control without fertilizer; arbuscular mycorrhizal fungi (AMF); AMF+50% poultry manure (AMF+½ PM); mineral fertilizers with cation balance at 100% (MF100 %); AMF+50% mineral fertilizers (AMF+50 % MF); poultry manure at 50%+50 % mineral fertilizers (MF50%+½ PM) and poultry manure (PM). Two varieties of okra were used (Kirikou F1 and Local). The experimental design was a split-plot with two factors. Considering MF, an innovative Ca/Mg/K ratio of 68/23/9 was applied. The results showed that the applied fertilizers had a significant effect on the agronomic parameters of okra with MF50%+½ PM followed by PM and MF100% as the best treatments. An average increase in fresh yield from 111% to 1840% over the control was recorded and the best symbiotic parameters were observed at the AMF treatment associated with the Local variety. This variety responds better to organic matter intake while Kirikou F1 is more favorable to chemical fertilizer addition.