Direct and residual effects of fertilizers and biofertilizers on yield, nutrient uptake and economics of groundnut (Arachis hypogaea)rice (Oryza sativa) cropping system

A two-year field experiment was conducted during the winter ( rabi) and rainy ( khar if) seasons of 201012 at Deodhe, Ratnagiri (Maharashtra), to study the direct and residual effects of different doses of fertilizers and . biofertilizers on yield, nutrient uptake and economics of groundnut ( ArachishypogaeaL.)rice ( Or yza sativa L ) cropping system. Increasing dose of fertilizers up to 125% recommended dose of fertilizers (RDF) significantly in- creased pod yield by 79.7% and haulm yield by 63.5% of groundnut over the control. Uptake of N, P and K by groundnut also improved significantly with successive increase in doses of fertilizers up to 125% RDF. Succeeding rice showed significant response to residual fertilizer levels up to 100% RDF in grain yield and up to 125% in straw yield and registered 16.9 and 25.4% increase over the control respectively. The N, P and K uptake by succeeding rice and total NPK uptake, rice-grain equivalent yield, production efficiency, net returns and benefit: cost ratio in groundnutrice cropping system also improved significantly with increase in doses of fertilizers up to 125% RDF applied to groundnut. The crop inoculated with biofertilizers ( Rhizobium+phosphate-solubilizing bacteria) recorded significantly higher pod (1.74 t/ha) and haulm yields (3.64 t/ha) of groundnut and grain (5.34 t/ha) and straw yields (5.52 t/ha) of succeeding rice over the control. Inoculation of groundnut with biofertilizers significantly increased N, P, K uptake by groundnut and succeeding rice (except N uptake by rice straw) as well as total N, P and K uptake (393.1 kg/ha), ricegrain equivalent yield (9.92 t/ha), net returns (66.8103 /ha) and benefit: cost ratio (2.01) in groundnutrice cropping system over no inoculation. This treatment also recorded the maximum production effi- ciency of the system (38.8 kg/ha/day). Rice crop responded significantly to each higher level of fertilizer up to 125% RDF (direct) in terms of grain and straw yields as well as N, P and K uptake. Application of 125% RDF to rice recorded significantly higher total N, P and K uptake (447.1 kg/ha), ricegrain equivalent yield (10.89 t/ha), production efficiency (42.6 kg/ha/day), net returns ( 78.3103/ha) and benefit: cost ratio (2.17) in groundnutrice cropping system.