A comparative effect of legume-based cropping association on the productivity of Manihot esculenta Crantz in the forest and savanna zones of the Central African Republic

Abstract

The objective of this study, conducted under integrated management in forest and savanna zones, is to improve cassava yields in rural areas of the Central African Republic using a comparative approach. The study design is a randomized block design with eight treatments (0 to 7) and four randomized replications, comprising 32 elementary plots. The different doses of PK or NPK fertilizers and/or those associated with legumes (0-0-0, legumes, legumes-30-180, legumes-90-30-180 and 90-30-180) were tested in the districts of Damara and Pissa. The trial was conducted over one agricultural season. The analyses were done using R software version 4.1.0 and Excel 2010. The results show that the doses of 90 kg.ha-1 of Nitrogen, 30 kg.ha-1 of Phosphorus and 180 kg.ha-1 of Potassium gave good productions in fresh roots at the scale of the two localities with average yields of 60 t. ha-1 (T3: cassava + groundnut + NPK) compared to 29 t.ha-1 (T0: cassava) in the forest zone and 37 t.ha-1 (T3: cassava + groundnut + NPK) compared to 23 t.ha-1 (T0: cassava) in the savanna zone. Economically, after the sale in pods, the cassava + legume treatments (T1: cassava + groundnut with a profit of 765,000 F CFA in the forest and 435,455 F CFA in the savanna and T4: cassava + cowpea with a profit of 78,725 F CFA in the forest and 265,000 F CFA in the savanna) are profitable for the farmer-producers in the study area. The use of the results of this study in rural areas of the Central African Republic can improve the production of fresh roots and pods. In any case, a study on spatial arrangements in cropping associations (strip cropping, intercropping) can be envisaged in order to better manage the soil and optimize production in rural areas.