Effects of a urease inhibitor NBPT on the growth and quality of rape.

Reducing nitrate concentration and improving the quality of vegetable crops have been two areas of major research effort. The aim of this study was to determine the effects of adding a urease inhibitor NBPT (N-(nbutyl) thiophosphoric triamide) to urea on the growth and quality of rape plants in a pot experiment. The amount of NBPT added was equivalent to 0.5%, 1.0%, 1.5%, 2.0% and 2.5% of the total nitrogen (N) applied. Results showed that NBPT significantly increased crop yield by 22.67%~27.82%, and decreased nitrate concentration in the crop by 4.19%~32.63%. Total N, N up-taken and N use efficiency were also increased by the NBPT treatments. Rape Vc had the highest uptake when the amount of NBPT was 1.0% of the total N applied, while other treatments were equivalent or lower. The highest N uptake and N recovery by the plants was when the amount of NBPT added was 0.5% of the total urea-N applied. Therefore, a suitable amount of NBPT applied could not only reduce nitrate content and increase yield, but also improve N use efficiency.