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.