Effects of NMUrea on nitrogen runoff losses of surface water and nitrogen fertilizer efficiency in paddy feild

To elucidate the effects of NMUrea on the N runoff losses characteristics and nitrogen use efficiency, the experiment was carried out and the nitrogen concentration, nitrogen runoff losses character, and grain yield were studied, with common Urea as control(CK). The results showed that total nitrogen (TN) concentration increased sharply after nitrogen fertilizer application. At the same nitrogen rate, the TN concentration in the NMUrea treatments decreased significantly faster than those of the normal Urea. Based on a logarithm model, the safe drainage time was 11.5-15.9 d after nitrogen application for NMUrea and 12.5-17.3 d after nitrogen application for Urea, respectively. The amount of N loss from drainage increased with the increase of nitrogen fertilizer rate. At the same N fertilizer rate, N loss in NMUrea treatment was less than that in the Urea treatment, and that was 70.6%-74.3% of Urea’s. It was also indicated that grain yield and N agronomic efficiency of NMUrea treatment were higher than those of Urea treatments. On the above basis, it was concluded that NMUrea treatments gained higher grain yield and N agronomic efficiency, and lower N loss compared with the normal Urea treatments. The treatment with 225 kg/hm2 NMUrea-N was recommended as the best rate for achieving high-yield, high-N efficiency and safe cultivation technique in hybrid rice.