Abstract

A field experiment was conducted during rabi 2016-17 and 2017-18 on sandy loam soils of the Agricultural College Farm, Bapatla to study the phosphorus management practices in groundnut (Arachis hypogaea) under rice-groundnut sequence. The present investigation was conducted to find out the residual effect of phosphorus applied to kharif rice on succeeding groundnut crop and to work out the economics of different treatments in rice-groundnut cropping system. The treatments consisted of four main plots sources of phosphorus i.e. S1 : Inorganic fertilizer phosphorus through SSP, S2: Green manuring in-situ with dhaincha @ 25 kg seed/ha, S3 : Biofertilizer (PSB) @ 750 mL/ha, S4: Green manuring in-situ with dhaincha @ 25 kg seed/ha + Biofertilizer (PSB) @ 750 mL/ha and three levels of phosphorus i.e. L1: 50 % recommended dose of P L:2 100% recommended dose of P and L3 : 150 % recommended dose of P applied to rice during kharif alloted to sub-plots and during rabi season three doses of phosphorus i.e. F1 (control) F2 (50 % RDP) and F3 (100 % RDP) applied to groundnut, alloted to sub-sub plots was laid out in split-split plot design with three replications. Results of the experiment showed that residual sources and levels of phosphorus to preceding rice crop i.e., in-situ green manuring + PSB showed superior performance in terms of (yield attributes like number of filled pods/plant (29.4), number of kernels/pod (1.94), 100 kernel weight (46 g) and yield (1970 kg/ha)) of groundnut but was at par with that of application of in-situ green manuring and, significantly superior over inorganic fertilizer through SSP and biofertilizer (PSB) alone during both the years. During rabi treatments among the dose of phosphorus 100 % RDP showed significantly higher [filled pods / plant (27.6), number of kernels/pod (1.95), 100 kernel weight (44.9 g) and yield (1781 kg/ ha)] over control and it was at par with 50 % RDP during both the years. Hence, no need to go for 100 % RDP in groundnut under rice-groundnut cropping system, 50 % RDP was sufficient realizing higher yields.