Abstract:The effects of the fourth type of Schiff base complex urease inhibitors with different concentrations on rape growth and soil nitrogen transformation were studied to provide a basis for the promotion and application of such novel urease inhibitors in agriculture. The effects of new urease inhibitor (SU) and commercially available urease inhibitor acetohydroxamic acid (AHA) on the yield, quality, growth, nitrogen uptake and utilization of rapeseed and apparent nitrification rate of soil were compared through outdoor potting methods. The results showed that SU and AHA both could increase rapeseed yield and improve quality index and nutrient index of rapeseed, but SU had a better effect on increasing yield and nutrient efficiency of rapeseed than AHA. SU increased the yield of rapeseed by 28.0% on average, and significantly reduced the nitrate content by 28.8%~50.8%. At the same time, it promoted the absorption of nitrogen and phosphorus in rapeseed, the utilization rate of nitrogen fertilizer increased by about 68.0% on average, and also reduced the apparent nitrification rate of soil by about 35.2% on average. The novel inhibitors with different concentrations had different effects on the indicators of rapeseed and the inhibition of urea hydrolysis. The effects of low-medium concentration inhibitors on rapeseed yield increasing and nutrient efficiency were better than those of high concentration inhibitors, and the inhibitory effect of inhibitors on the urea hydrolysis was the best when the amount of inhibitor was 1% of pure nitrogen application, so the best amount of inhibitor was 1% of pure nitrogen.