The cowpea-bean, known in the Brazilian Northeast as 'macassar-bean' or rope bean is one of the main crops of this region being consumed as dry beans or green beans (pods and/or immature grain). In Paraíba, it is cultivated in almost all regions, representing 75% of the area cultivated with common dry beans. The low yield is due to the lack of a program of mineral nutrition. This experiment was carried out to evaluate the effect of different levels of bovine manure in the presence or absence of mineral fertilizer on pods and green and dry grains yield of the cowpea-bean, cv. IPA 206. The experiment was performed in the Federal University of Paraíba, in Brazil, from September/1998 to January/1999, in a randomized blocks design, where the treatments were distributed in a factorial scheme 5 x 2, with the first factor corresponding to levels of bovine manure (0, 10, 20, 30 and 40 t/ha) and, the second factor, the presence or absence of mineral fertilizer, in four replications. Each plot consisted of 20 plants, spaced 0.80 x 0.40 m apart. The estimated maximum yield of pods (9.64 t/ha) was obtained with 25 t/ha of bovine manure in the presence of mineral fertilizer, while in the absence of mineral fertilizer, the yield of pods, increased with the increasing levels of bovine manure, in the order of 49.3 kg/ha to each ton of bovine manure added to the soil. The yield of green grains in the presence of mineral fertilizer reached estimated maximum value (6.8 t/ha) in the estimated optimum level of 17 t/ha of bovine manure. In the absence of mineral fertilizer, the yield of green grains, increased with the increasing of the levels of bovine manure in the order of 47.9 kg/ha to each ton of bovine manure added to soil. The yield of dry grains in the presence of mineral fertilizer reached estimated maximum value (3.03 t/ha) in the level of 21 t/ha of bovine manure. In the absence of mineral fertilizer, the level of 25 t/ha of bovine manure was responsible for the maximum yield of dry grains (2.00 t/ha).
Vigna unguiculata Walp; organic-mineral fertilization; pods; green grains; dry grains; yield
