Journal of Experimental Agriculture International

The present study is reported at the Agronomy Instructional Farm of SDAU, Sardarkrushinagar during kharif season of 2020-2021. The experiment consisted of nine treatments viz., T₁-Absolute control, T₂-100% RDF (20 kg N + 40 kg P₂O₅ /ha), T₃- FYM @ 5.0 t/ha, T₄-FYM @ 2.5 t/ha + Rhizobium + PSB, T₅-vermicompost @ 2.0 t/ha, T₆-vermicompost @ 1.0 t/ha + Rhizobium + PSB, T₇-castor cake @ 2.0 t/ha, T₈-castor cake @ 1.0 t/ha + Rhizobium + PSB, T₉-Ghan Jeevamrut @ 250 kg/ha at sowing time + Seed treatment with Beejamrut @ 200 ml/kg seed+ Jeevamrut @ 500 lit/ha with irrigation at sowing and 30 DAS were tested in randomized block design with four replications. The result revealed that the application of T₈-castor cake @ 1.0 t/ha + Rhizobium + PSB showed a significant improvement. Application of castor cake @ 1.0 t/ha + Rhizobium + PSB (T₈) resulted a significantly higher nitrogen, phosphorus content, uptake and microbial population in seed and stover. While significantly higher available nitrogen and phosphorus status in soil after harvest of cowpea crop was obtained under the treatment of FYM @ 5.0 t/ha (T₃) which was at par with FYM @ 2.5 t/ha + Rhizobium + PSB (T₄). Research showed that the application of castor cake @ 1.0 t/ha + Rhizobium + PSB (T₈) significantly enhance nutrient content, its availability and economic returns.