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3年小麦/玉米带田定位试验研究明确了①每公顷总量分别为450、900和1350kgN的氮肥第1年一次性施用和分年施用的增产效果,每公顷450kg左右N为带田适宜施氮量;②一次性施用氮肥后的残效、影响残效大小及持续性的主要因素是氮肥用量及土壤保肥性;③不同用量及不同分配方式氮肥的当年利用率比累积利用率低5.7%~2.0%,评价氮肥利用率的高低时,应将残效考虑在内;④等量氮肥分年施用与一次性施用相比,增产效果及氮肥利用率高得多
3 years of wheat / corn belt field positioning test clear ① the total amount per hectare of 450,900 and 1350kgN nitrogen fertilizer in the first year of single-time application and annual application of about 450kg per hectare N is appropriate Nitrogen content; ② After a one-time application of nitrogen fertilizers, the main factors that affect the residual size and sustainability are the amount of nitrogen fertilizer and soil fertility conservation; ③ The utilization of nitrogen fertilizer in different dosage and different ways of allocation is lower than the cumulative utilization rate of 5.7 % ~ 2.0%. When assessing the level of nitrogen use efficiency, the residual effect should be taken into account. ④ The annual yield increase and nitrogen use efficiency of the same amount of nitrogen fertilizer are much higher than that of one-time application