Performance of rice-wheat cropping system under resource conservation and various nutrient management practices

Abstract

A field study was conducted during three consecutive years of 2016-17, 2017-18 and 2018-19 at university farm at Bihar Agricultural University, to assess the impact of resource conservation and nutrient management on yield, economics, and energetics of rice-wheat cropping system. The experiment was conducted in split plot design replicated thrice with three cropping system establishment methods viz. system of rice intensification + conventional wheat, transplanted rice + conventional wheat with 30% rice residue incorporation and direct seeded rice + zero tilled wheat with 30% rice residue incorporation as main plot and with three nutrient management practices viz. 100% of Recommended dose of fertilizer (RDF) through inorganic sources, 75% of RDF through inorganic sources + 25% of RDF through organic sources (vermicompost), 50% of RDF through inorganic sources + 50% of RDF through organic sources (vermicompost) and 100% of RDF through inorganic sources + mungbean as green manuring. It was obvious from the result that highest rice yield (48.7 qha-1) was from system of rice intensification + conventional wheat meanwhile highest wheat yield (47.0 qha-1) and system productivity (rice equivalent yield) (91.3 qha-1) was from direct seeded rice + zero tilled wheat with 30% rice residue incorporation. Moreover, the dominance of resource conservation practices on other practices was prevalent in the cropping system as highest B:C ratio (1.92) was obtained from direct seeded rice + zero tilled wheat with 30% rice residue incorporation. Lowest greenhouse gas emission i.e. CH4, CO2, N2O was from direct seeded rice with zero tilled wheat and residue incorporation at different stages of crop growth. Among different nutrient management practices highest yield both for rice (48.3qha-1) wheat (43.9qha-1) and rice equivalent yield (95.2 qha-1) was obtained from 100% of RDF through inorganic sources + mungbean as green manuring. Adding to this the B:C ratio was also least (1.84) from same, whereas lowest greenhouse gas emission (CH4, CO2) was from 100% inorganic fertilizers. And lowest nitrous oxide emission was from 50% inorganic and 50% organic fertilizers.