Effect of chiselling, green-manuring and planting methods on productivity and profitability of rice (Oryza sativa) - wheat (Triticum aestivum) cropping system

A field experiment was conducted at Karnal during 2000-01 to 2003-04 to assess the effect of alternate-year chiselling (after rice crop) in rice-wheat system. Rice (Oryza sativa L.) - wheat (Triticum aestivum L. emend. Fiori & Paol.) - greengram (Phaseolus radiatus), rice - wheat - Sesbania aculeata and rice-wheat were tried on flat- and bed-planting systems for improving the productivity of rice-wheat system. Combined analysis showed that alter- nate year chiselling produced at par rice and wheat yields and rice-equivalent yield compared with non-chiselled one. Green-manuring saved 25% N for rice crop and recorded higher rice equivalent yield (15.30 to 15.41 Vha) compared with rice-wheat system (15.03 Vha) under flat planting. Bed-planting of wheat recorded 6.5% lower grain yield than flat-planting system. Growing green manure crops improved the land-use efficiency and decreased the production efficiency due to higher duration. Taking green-manure crops increased the cost of cultivation (7.7%), and hence decreased the net returns and benefit : cost ratio compared with the conventional rice-wheat system. Introduction of greengram either under flat or bed planting and Sesbania aculeata incorporation under flat planting increased the organic C content by 13.2O/0 than rice-wheat system. The chiselled plot gave 17-23% higher cumula- tive infiltration at later stages than non-chiselled plot. It was concluded that wheat on bed produces slightly lower grain yield, chiselling increases infiltration rate and green-manuring saves N and improves the organic C content of the soil.