USE OF BIOFERTILIZERS FOR IMPROVING PRODUCTIVITY OF COWPEA IN CEREAL-BASED CROPPING SYSTEMS IN NIGERIA.

Abstract

Nitrogen is one of the most frequently deficient nutrienst in tropical soils, and to optimize the supply of this nutrient in agricultural systems, legumes, such as cowpea that biologically fix nitrogen are integrated as part of the cropping systems. The objective of this study was to determine the response of cowpea to the use of biofertilizers for improving productivity in cereal-based cropping systems of some soils in Sudan savanna of Nigeria.A greenhouse study was carried out at the International Institute of Tropical Agriculture Kano.The experiment was laid out in a 15 x 2 x 4 factorial fitted to a completely randomized design (CRD) replicated three times. Theyconsisted of 15 locations, 2 proximity to homestead and 4 nitrogen sources. The locations were Bunkure, Rano, Bebeji, Tudun Wada, Kiru, Wudil, Gaya, Garko, Warawa, Albasu, Sumaila, Gezawa, Minjibir, Bichi, Bagwai, proximity to homestead (close to homestead < 50 m, and far from homestead > 250 m).Nitrogen sources were control, + N at the rate of 80 kg N/ha using Urea, Inoculation with strain USDA 3384 and strain USDA 3451. Result from this experiment shows that inoculation of cowpea withstrain USDA 3384 or strain USDA 3451 significantly (p ≤ 0.05) increased the nodule dry weight of cowpea. The nodule dry weight and nodule number of cowpea inoculated with eitherstrain USDA 3384 or USDA 3451 were marginally higher than the N-supplied treatments in at least one of the location. Nodule dry weight inoculated with eitherstrain USDA 3384 or USDA was (0.73 and 0.65 g/plant) while the Nitrogentreated was (0.40 and 0.47g/plant)for bothclose and far proximity to homestead at Albasu, suggesting the effectiveness of the introduced strain. Soils sampled close to homestead had better physicochemical properties than those sampled away from homestead. There exist a significant relationship between location and proximity to homestead the close to homestead was greater in shoot and nodule dry weight in most of the locations.Inoculation is not a common practice in Nigeria, although field trials involving cowpea have been mixed. In this study, there was a response of cowpea to either strain USDA 3384 or USDA 3451 suggesting their suitability for use in Sudan Guinea Savanna of Nigeria.