Effect of tillage, rice residue and nitrogen-management practice on yield of wheat (Triticum aestivum) and chemical properties of soil under rice (Oryza sativa)-wheat system

For analyzing the effect of tillage, rice (Oryza sativa L.) residue and nitrogen management on wheat (Triticum aestivum L. emend. Firoi & Paol.) productivity and soil chemical properties, a field trial was conducted during rainy and winter seasons of 1999-2000 and 2000-2001, consisting of 7 tillage types with residue-management options in main plots and 3 nitrogen-management schedules in subplots, replicated 4 times in split-plot design. Incorporation, retention at soil surface and burning of rice residues in succeeding wheat field remarkably enhanced the grain yield over residue removal. Deep incorporation of rice residue improved the growth and yield attributes, which led to higher grain yield over others. Conservation tillage produced dwarf plants and smaller grains. Management of residue either by deep tillage or by conservation tillage yielded broader flag leaves. The fertility status of soil after wheat harvest in terms of organic carbon, available N, P and K got enriched by the incorporation or retention of residue, irrespective of tillage types, being the highest under conservation tillage. Residue burning and removal did not show any variation in organic carbon and available N content of surface soil, but in case of available P and K, residue burning substantiated its superiority to residue removal. The effect of starter dose of 20 kg N/ha could be nullified by applying 75% of total recommended dose of nitrogen to wheat crop at sowing and rest at crown root initiation stage.