基于叶面积指数（LAI）的小麦变量施氮模型研究

为探讨基于叶面积指数变化的小麦变量施氮技术,依据养分平衡原理和"作物-土壤-环境-技术"整体原则,采用土壤空间信息数据与小麦需氮量和各生育阶段叶面积指数相结合的方法,设计了小麦播前施氮总量和播后精确追氮的数量模型.根据拔节期和抽穗期小麦的长势,对施氮量的初值进行订正,确定小麦的最适追氮量.在河南郑州市和鹤壁市两地的试验验证结果表明:小麦产量模拟值与实测值间的相关系数分别为0.7799和0.7169,达显著水平.与传统施肥技术相比,在相同产量下,使用模型后每公顷施氮量减少43.5 kg.该研究提出的基于模型的变量施氮技术,可以兼顾天气、地力和作物长势三方面因素,最终实现小麦的精确施氮,对促进精确农业的发展具有重要意义.

Variable nitrogen fertilization model of wheat based on LAI

In order to study the variable nitrogen fertilization techniques based on LAI,the model on total amount of N fertilization before sowing and precise N amount after sowing was designed following the theory of nutrient balance and the principle of "crop-soil-environment-technology",taking spatial variability of soil nutrition,wheat N requirement and LAI in different development phrase into account.According to the growth status of elongation period and heading period of wheat,initial rate of N application was corrected,and optimum additional amount of N fertilizer was ensured.Field experiments of wheat with variable nitrogen fertilization model were respectively carried out at Henan Agricultural University Research Station and Agricultural Research Institute of Hebi from 2004 to 2005.The results showed that the simulated value of yield was significant correlated with that of field survey,and the correlation coefficient was 0.7799 and 0.7169 respectively.Compared with traditional N fertilization system,the variable nitrogen fertilization model can save 43.5 kg N per hm2 with the same yield.Variable nitrogen fertilization model based on this model can take weather,soil fertility and the growth status into account,and realize precise nitrogen fertilization in small size field at last,which means a lot to develop precise agriculture.