Effect of integrated nutrient management on system productivity, nutrient uptake, nitrogen balance, soil structural properties and nitrogen use efficiency under wheat-rice cropping system

Abstract

A field experiment was conducted at BCKV, Kalyani (West Bengal) on medium loam soil during rabi seasons 2013-14 to kharif seasons of 2014-15 under upland situation to study the effect of integrated nutrient management on system productivity system, nutrient uptake, nitrogen balance, soil structural properties and nitrogen use efficiency and apparent nutrient recovery % in wheat-rice cropping system. The experiment was laid out in Split-Split Plot design with twenty four treatments having three replications. The treatments comprised of organic source in Main plot viz. No FYM and FYM (10 t ha-1 Farm yard manure), Sub plot treatments consist of No Fertilizers (NPK), 75% NPK and 100% NPK whereas Sub-sub plot treatments comprised of No biofertilizers, Azotobacter, PSB and Azotobacter+PSB. Whereas, in kharif season, direct seeded rice crop got only 100% RDF in all treatments. Experimental findings revealed that FYM at 10 t, 100% RDF and combined application of bio-fertilizers recorded 16.22, 75.97 and 12.04 % higher wheat equivalent yield (WEY) over treatments of without FYM, 0% RDF and no inoculation. The maximum build-up of soil aggregation and uptake of NPK were observed in the plots receiving FYM @ 10 t ha-1,100% RDF and combined application of Azotobacter and PSB but the effect was statistically at par when compared with 100 and 75% RDF. N-use efficiency and apparent recovery % were much better under FYM, 75% RDF and combined inoculation of Azotobacter and PSB. Negative N-balance was noted in control plots after two years of the experiment but it was positive in the plots treated with FYM, chemical fertilizers and bio-fertilizers. Based on these findings, it is concluded that application of 10 t FYM ha-1 and dual inoculation of Azotobacter and PSB along with 75 % RDF maximized system productivity, nutrient uptake, nitrogen balance, soil structural properties and nitrogen use efficiency and apparent nutrient recovery %, economized fertilizer use to the extent of 25% and ultimate improved soil health in wheat-rice cropping system.