Changes Rule of Content of NO_3~--N and Inorganic-N in the Soil and Plant Analysis during the Growing Seasons of Soybean

This study was conducted with two soybean cultivars and nitrogen treatments(N0:0 kg hm-2,N75:75 kg hm-2,N150:150 kg hm-2)t,o study the content of NO3--N in the soil and plant during the growth period.The results showed that the contents of NO3--N in the soil and plant were downtrend,and the contents of NH4+-N in the soil were N150N75N0.The contents of NO3--N in the soil and plant were no obvious differences among different nitrogen treatments,and there were highly significant correlations between the contents of NO3--N in stem and petioles and in soil(r=0.9316** and r=0.9355** respectively),and the correlation between the contents of NH4+-N and NO3--N in soil reached the positive correlative level(r=0.8746**.) In conclusion,the contents of NO3--N in stem and petioles could be used to characterize the nitrogen nutritional status.