Yield, quality and nutrient status of soil under different integrated nitrogen management practices in wheat (Triticum aestivum) - forage cowpea (Vigna unguiculata) cropping sequence

A field experiment was conducted during winter and summer season of 2011–12 and 2012–13 at college Agronomy farm, B. A. College of Agriculture, Anand Agricultural University, Anand, Gujarat, to study the yield, quality and nutrient status of soil under different integrated nitrogen management practices in wheat (Triticum aestivum L.) — forage cowpea [Vigna unguiculata (L.) Walp.] cropping sequence. The experiment was laid out in randomized block design with 21 treatment combinations, comprising 7 nitrogen management through chemical fertilizer and organic manures and 3 bio-fertilizer inoculants. Application of 75% RDN from chemical fertilizer + 25% RDN from FYM followed by 100% RDN from chemical fertilizer and 75% RDN from chemical fertilizer + 25% from vermicompost resulted significantly higher grain yield with protein content in wheat. Significantly higher nutrient contents were recorded in the plots fertilized with 25% RDN from chemical fertilizer + 25% RDN from FYM + 25% RDN from vermicompost + 25% RDN from castor cake followed by 50% RDN from chemical fertilizer + 25% vermicompost + 25% castor cake. Seed inoculation with Azotobacter chroococcum + Azospirillum lipoferum resulted in the higher grain yields and protein content in wheat. This treatment also showed higher available nitrogen, potassium and phosphorus status of soil. Significantly higher green and dry fodder yield, and protein content in forage cowpea were recorded owing to residual effect of combined seed inoculation with Azotobacter chroococcum + Azospirillum lipoferum. Application of 25% RDN chemical fertilizer + 25% from FYM + 25% from vermicompost + 25% from castor cake along with combined seed inoculation with Azotobacter chroococcum + Azospirillum lipoferum improved nutrient status of soil in wheat—forage cowpea sequence.