Effect of rice (Oryza sativa) straw removal, burning and incorporation on soil properties and crop productivity under rice-wheat (Triticum aestivum) system

A long-term field experiment was conducted during 1996-97 to 2000-2001 on a Typic Ustrochrept soil at the experimental farm of the Directorate of Wheat Research, Karnal, Haryana, to study the potential of rice (Oryza saliva L.) residue in the presence as well in the absence of green-manure crop prickly sesban or dhaincha [Sesbania cannabina (Retz.) Pers.; syn S. aculeata Pers.] as a soil amendment to improve soil and crop productivity under rice-wheat (Triticum aestivum L.emend. Fiori & Paol.) cropping system. Rice straw was incorporated in the soil before sowing of wheat, while Sesbania cannabina was incorporated before puddling for rice. Wheat yield under straw-incorporated plots was low (6.7-9.1%) in the initial 2 years compared to rice residue removal and burning of rice straw treatments, but the yield started improving (4%) in the third cropping season in the straw-incorporated treatment-both in the presence as well absence of green-manure. Green-manuring alone had little effect (8.0% increase) on organic carbon content of soil and availability of phosphorus (4.8%) and potash (1.3%) in the soil. Incorporation of crop residue alone or in combination with green-manure increased the organic matter (21%) content of soil and available P (12.7) and K content (14.3%) of soil. Green-manuring and straw incorporation had a favourable effect on bulk density (1.9% decrease:) of soil.