Integrated nutrient management for sustaining the productivity of pigeonpea (Cajanus cajan) based intercropping systems under rainfed condition

A field experiment to study the effect of integrated nutrient management for sustaining the productivity of pigeonpea [Cajanus cajan (L.) Millsp.] based intercropping systems was conducted for six consecutive years during 2005–06 to 2010–11 at Tirhut College of Agriculture, Dholi, Bihar. Pigeonpea + urdbean [Vigna mungo (L.) Hepper] intercropping system, recorded higher yield of pigeonpea (1.85 t/ha), pigeonpea equivalent yield (2.17 t/ha), LER (2.29), production efficiency (8.56 Kg/ha/day), water use efficiency (2.96 Kg grain/ha/mm), fruiting efficiency (17.16%) net return (67.3×10³/ha) and net return per rupee investment (3.05) as compared to pigeonpea + maize (Zea mays L.) intercropping and sole pigeonpea. Pigeonpea + urdbean intercropping enhanced total nitrogen uptake and reduced total potassium uptake by the system, than pigeonpea + maize intercropping. Integration of FYM 5.0 tonnes or vermicompost 2.5 tonnes together with RDF proved effective and recorded significantly higher yields of pigeonpea, pigeonpea equivalent yield, LER, production efficiency, fruiting efficiency, water use efficiency, net returns and total NPK uptake by the system than RDF alone. However, higher net returns per rupee investment was recorded in combined application of FYM 5.0 t/ha and RDF (3.01). Seed inoculation with PSB exerted significant effect only on net return (64.4×10³/ha) than un inoculated seed (60.2×10³/ha). Lower value of aggressivity was recorded under combined application of FYM 5.0 tonnes/ha or vermicompost 2.5 tonnes/ha and RDF. Pigeonpea + Urdbean intercropping and combined application of FYM 5.0 tonnes/ha or vermicompost 2.5 tonne/ha and RDF improved bulk density and organic carbon and increased available N,P, K content of the soil over initial soil value.