Effect of crop sequence and crop residues on soil C,soil N and yield of maize

Improved management of nitrogen (n) in low n soils is critical for increased soil productivity and crop sustainability. the objective of the present study was to evaluate the effects of residues incorporation,residues retention on soil surface as mulch,fertilizer n and legumes in crop rotation on soil fertility and yield of maize (zea may l.). fertilizer n was applied to maize @ 160 kg ha -1,and to wheat @ 120 kg ha -1 or no fertilizer n application. crop rotation with the sequence of maize after wheat (triticum aestivum l.),maize after lentil (lens culinaris medic) or wheat after mash bean (vigna mungo l.) arranged in a split plot design was followed. post-harvest incorporation of crop residues and residues retention on soil surface as mulch had significantly (p≤0.05) affected grain and stover yield during 2004 and 2005. two years average data revealed that grain yield was increased by 3.31 and 6.72% due to mulch and residues incorporation. similarly,stover yield was also enhanced by 5.39 and 10.27% due to the same treatment respectively. mulch and residues incorporation also improved stover n uptake by 2.23 and 6.58%,respectively. total soil n and organic matter was non significantly (p≥0.05) increased by 5.63 and 2.38% due to mulch and 4.13,7.75% because of crop residues incorporation in the soil. maize grain and stover yield responded significantly (p≤0.05) to the previous legume (lentil) crop when compared with the previous cereal crop (wheat). the treatment of lentil - maize(+n),on the average,increased grain yield of maize by 15.35%,stover yield by 16.84%,total soil n by 10.31% and organic matter by 10.17%. similarly,fertilizer n applied to the previous wheat showed carry over effect on grain yield (6.82%) and stover yield (11.37%) of the following maize crop. the present study suggested that retention of residues on soil surface as mulch,incorporation of residues in soil and legume (lentil - maize) rotation improved the n economy of the cropping system and enhances crop productivity.