氮肥利用率的问题与改进

传统差减法计算氮肥利用率变异较大,影响了氮肥利用率的应用,科学的氮肥利用率计算方法对氮肥的合理施用十分重要。本文概述了氮肥利用率50多年的研究过程,并划分为3个创新研究阶段,提出差减法计算氮肥利用率各个创新研究阶段的主要创新点。采用常规计算方法和定位试验研究资料计算了氮肥利用率,阐明常规计算方法计算的氮肥利用率结果存在的问题;归纳了氮肥利用率变异较大的主要原因:1)采用土壤氮素养分系统没有达到平衡或接近平衡的试验结果;2)常规计算方法仅考虑氮肥用量和作物吸收氮量,没有考虑土壤残留氮(或消耗土壤氮)。建立了2个氮肥利用率计算的新方法:1)土壤氮素养分系统平衡状态计算公式:氮肥利用率=(施肥作物吸收氮-报酬递减系数×对照作物吸收氮)/施肥氮;2)土壤氮素养分未达到平衡状态计算公式:氮肥利用率=(施肥作物吸收氮-报酬递减系数×对照作物吸收氮)/(施肥氮+施肥处理土壤氮素消耗量-对照处理土壤氮素消耗量)。

Problems and improvements of recovery efficiency of applied N

Apparent recovery efficiency of applied N ( REN) is an important parameter among nitrogen fertilizer utilization ef-ficiency ( NUE) . As the REN value calculated by traditional subtraction was lower with a larger variation, the range of REN applications was limited. A reasonable method to calculate REN is especially important. After overviewed research process on REN over 50 years, 3 research stages had been divided, and main innovations had been refined about REN calculating meth-od. Using the long-term experiment research data, REN was calculated by conventional calculation method and some problems was presented. Two factors affected REN value, one was that the result was calculated by imbanlance soil nitrogen nutrient sys-tem. The other was that only the fertilization N and crop absorption N were considered to calculate the REN, without consider-ing the residual soil N ( or consumed soil N) . Two calculation method of REN were completed in this study, one was for soil N nutrient balanced system: REN= ( fertilizing crops N-decreasing returns factor × CK crop N) / fertilizer N;The other one was for unbanlanced soil N nutrient system: REN = ( fertilizing crops N-decreasing returns factor × CK crop N) / ( fertiliz-er N+fertilization soil N consumption-CK soil N consumption) .