Effects of real-time and site-specific nitrogen management on rice yield and nitrogen use efficiency.

Qianyouliangyou 58,a hybrid rice variety,planted in the field with yellow soil,which is the largest rice field area with middle-low production in Guizhou,was tested to study effects of different nitrogen application amount,real-time and site-specific nitrogen management on leaf chlorophyll content,yield,nitrogen absorption amount of rice plants and nitrogen use efficiency of rice for reducing nitrogen application amount,raising nitrogen use rate and diseasing nitrogen environment pollution.The results showed that the leaf chlorophyll content of rice at the heading and filling stages under the real-time and site-specific nitrogen management was higher,its yield was significantly higher than that of 3 conventional nitrogen application levels,the nitrogen absorption amount of rice plants at main growth stages under the real-time and site-specific nitrogen management was between N8 and N16 treatments,its nitrogen physiological use efficiency,nitrogen agronomic use efficiency and nitrogen harvest index were the highest and there was significant difference in nitrogen physiological use efficiency,nitrogen agronomic use efficiency and nitrogen harvest index between the real-time and site-specific nitrogen management treatment and three conventional application level treatments.