Effect of Organic Sources of Nitrogen on Soil Fertility of Cowpea [Vigna unguiculata (L.) Walp]

Abstract

Background: Cowpea [Vigna unguiculata (L.) Walp] is most widely grown pulse-cum-vegetable crop. It plays an important role in maintaining soil fertility. Besides, nitrogen which is fixed in the soil from the atmosphere by the crop specific Rhizobium found in root nodules of this crop, phosphorus is another important element which inter-alia enhances the nitrogen fixation capability of the crop. In addition to biologically fixed nitrogen, crop also requires nitrogen through fertilization to meet its initial requirement (Mishra and Baboo, 1999). Methods: A field experiment was on conducted during kharif season of the year 2015 at Agronomy Instructional Farm, C.P. College of Agriculture, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar Gujarat. The experiment was laid out in randomized block design with four replications and 10 treatments comprising of integration of different organic sources. Result: Our investigation in the significant improvement in N content in seed and N uptake by cowpea were noted with the application of 50% N through FYM + 50% N through vermicompost + PSB (T8), whereas, higher N content in stover and P content in seed were recorded under treatment T9 (50% N through castor cake + 50% N through vermicompost + PSB) and T10: RDF (20+40+00 kg ha-1 NPK through Fertilizer), respectively. Treatment T10 contributed to raise potassium content in seed, uptake of P and K by cowpea and available NPK in soil after harvest of crop.