土壤水分条件对氮肥利用率影响的研究

THE EFFECTS OF SOIL WATER CONDITIONS ON NITROGEN FERTILIZATION USE EFFICIENCY

Concerning with applied nitrogen fertilizer,the uptake as well as loss of nitrogen ismainly related to soil water content. The effects of soil water condition in wheat field on theuptake, leach and loss of nitrogen fertilizer were studied in this paper using 15N tracing tech-nique. The results showed that within certain range of soil water supply, from 180 to 360mmof available water storage, the loss of nitrogen was in direct proportlon to the amount of fer-tilizer application and the nitrogen use efficlency decreased with the increase of nitrogen ap-plication. In other words, the nitrogen use efficiency descended with the nitrogen applicationinreased in an order of 75 kgN/ha , 150 kgN/ha,225 kgN/ha. One interesting result wasthat the nitrogen use efficiencies ranged from 17.9%to 30.5%for the treatments receivingthe same appllcation rate of 75 kgN/ha.