Short-term influences of straw and nitrogen cooperation on nitrogen use and soil nitrate content in North Henan

As a large amount crop straw is returned to soil in North Henan,there is an urgent need to develop new techniques for improving nitrogen use efficiency.This study was concerned about the differences in nitrogen use,grain yield and quality of winter wheat and soil nitrate content when using different quantities if straw and nitrogen fertilizer together.The used nitrogen rates were 0,90,180,270 and 360 kg/hm2,with and without crop residue incorporation to soil.The results showed that,comparing with nitrogen fertilizer only,straw and nitrogen cooperation enhanced nitrogen harvest index by 16.7%,13.4%,9.1% and 6.2%,respectively.Crude protein content in grains were also increased by 0.58%,3.79%,3.35%,and 2.27%,respectively,grain yield by 7.7%,8.4%,11.0% and 10.2%,respectively.Meanwhile,Nitrate content in 0~200 cm soil decreased by 6.7~131.9 kg/hm2 at the end of winter wheat harvest.