论文部分内容阅读
利用~(15)N技术在灌溉条件下研究施氮水平(75,150,225kg/hm~2)对冬小麦产量、氮素利用和土壤残留态无机态氮及其有效性的影响。结果表明:75kg/hm~2和150kg/hm~2施氮处理的冬小麦获得最高产量,二者没有显著性差异;而225kg/hm~2处理的冬小麦因过量施氮造成籽粒产量下降,并低于不施氮处理。植株对氮素的利用率随施氮水平的增加而下降,分别为38.5％,32.3％和22.4％。作物收获后发现,225kg/hm~2处理中所施氮的46％仍存在于50cm表土层中,高于其它施肥水平的处理。试验中仍有30.2％～36.7％的化学氮素通过各种途径损失而影响环境。在作物收获后,225kg/hm~2处理的土壤无机氮含量最高,并在玉米后效试验中获得最高产量,但土壤中较高的无机氮含量增加了对地下水污染的可能性。
The effects of nitrogen fertilization (75,150,225 kg / hm ~ 2) on yield, N recovery and residual N status of winter wheat and its availability were studied using ~ (15) N techniques under irrigation. The results showed that the highest yield of winter wheat with 75 kg / hm ~ 2 and 150 kg / hm ~ 2 nitrogen treatment was obtained, and no significant difference was found between the two treatments. However, the yield of 225 kg / hm ~ No nitrogen treatment. Nitrogen utilization rate decreased with the increase of N application rate, which was 38.5%, 32.3% and 22.4% respectively. After harvest, it was found that 46% of nitrogen applied in 225kg / hm ~ 2 treatment still existed in 50cm topsoil, which was higher than other fertilization levels. There are still 30.2% ~ 36.7% of the chemical nitrogen in the experiment lost through a variety of ways to affect the environment. After crop harvesting, 225kg / hm ~ 2 soil had the highest content of inorganic nitrogen and the highest yield in the corn after-effects test, but the higher inorganic nitrogen in the soil increased the possibility of contamination to groundwater.