Abstract:

The long-term field experiment on planting and turning over Chinese milk vetch was conducted to explore the effects of different incorporation amount of Chinese milk vetch on nutrient uptake,nutrient use efficiency,and yield of single cropping rice and to determine the optimal application rate of fresh Chinese milk vetch in south Henan rice area.There were eight treatments,CK(no fertilizers),CF(conventional fertilization),and six application levels(22.5,30.0,37.5,45.0,52.5 and 60.0 t/ha)of Chinese milk vetch.Experimental results showed that compared with CK,the conventional fertilization treatment and Chinese milk vetch treatments increased rice grain yields by 21.72% and 19.23%—29.20%(P<0.05),respectively.In all the treatments of application of Chinese milk vetch,the maximum N,P and K content and accumulation in rice grains were obtained under the treatment of Chinese milk vetch application at 52.5 t/ha,but when continuing to increase the application rate,the nutrient content and accumulation in rice grains were significantly reduced(P<0.05).The application of Chinese milk vetch at 37.5—60.0 t/ha significantly increased the above-ground nitrogen,phosphorus and potassium accumulation compared with CK.The application of Chinese milk vetch at 22.5—37.5 t/ha significantly improved the agronomic efficiency and partial factor productivity of P and K(P<0.05).Comprehensively,the long-term incorporation of Chinese milk vetch at 22.5—37.5 t/ha is conducive to the stable production of rice yield and the absorption of N,P and K,thereby improving the rice nutrient utilization efficiency of N,P and K in south Henan Province.

Key words: Chinese milk vetch, Incorporation amounts, Single cropping rice, Nutrient use efficiency, Nutrient uptake, Yield