Review on calculation method of nitrogen fertilizer utilization rate Tian Changyu, Lin Zuoyubao, Sun, by car, Zhao Abstract: Nitrogen fertilizer utilization rate is an important index related to fertilization, agricultural product production and environmental protection. There are problems to be further studied in the difference subtraction method and tracer method for calculating nitrogen utilization rate, and the calculated results of nitrogen utilization rate are low. The application and calculation methods of difference subtraction and tracer method in the determination of nitrogen fertilizer utilization rate are summarized respectively. Tracer method can be used to study the transformation and movement of nitrogen fertilizer in soil, but the determined nitrogen fertilizer utilization rate is only 15N, which is a part of nitrogen fertilizer utilization rate and cannot represent nitrogen fertilizer absorption utilization rate. This paper discusses in detail the reasons for the low result of calculating nitrogen utilization rate by difference subtraction method, introduces and comments on the existing improvement methods, and puts forward the principles for further improvement. Authors: Dezhou Experimental Station of China Academy of Agricultural Sciences; Institute of Agricultural Resources and Agricultural Regionalization; China Academy of Agricultural Sciences;

Keywords: nitrogen tracer subtraction of nitrogen utilization rate

Fund: National Science and Technology Support Program Project "Research on Formula Fertilizer Production and Supporting Application Technology System (2008BADA4B04) Special Fund for Basic Research Business Expenses of Central Public Welfare Research Institute (Project of Agricultural Resources and Agricultural Regionalization Institute of China Academy of Agricultural Sciences (20 10-5)) Supported by Texas Comprehensive Experimental Station of National Wheat Industry Technology System.

Classification number: S 143. 1

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Nitrogen utilization rate refers to nitrogen absorption utilization rate or nitrogen recovery rate. The study of nitrogen fertilizer utilization rate began with 1945, and the United States and the Soviet Union conducted a lot of research with 15N. Lu Rukun (1960 a) summarized the results of studying nitrogen use efficiency by tracer method abroad, and extracted the main problems as follows: the calculated nitrogen use efficiency varies greatly (from 10% to 100%), and the calculated nitrogen use efficiency has nothing to do with crop growth.