Effect of different covering methods on nitrogen fertilizer use efficiency in dryland rice

Character of utilization rate of nitrogen fertilizer of rice by 15N tr acer techniques were studied under the conditions of dryland rice covered with s traw, plastic film , straw and plastic film, without cover and normal irrigation cultivation of rice in the field. The results showed that the NUR of normal irr igation cultivation(15.30%) was lower than that dryland rice without cover (23.56%)and dryland rice covered with plastic film (23.10%); dryland rice covered with plastic film was higher than that with straw (19.07%) and straw and film ( 18.41%). NDFF value of root, stem and grain under the condition of dryland ric e with cover were lower than that without cover, and the rice dryland cultivation was significantly higher normal irrigation cultivation. Under the condition of dryland, the rice yield with cover was higher than that without cover, however, the yield of normal irrigation cultivation was higher than that dryland under wi thout cover condition.