Study On Cultivation And Utilization Of The Mixture Cropping Of Chinese Milk Vetch With Rape And Ryegrass

Chinese milk vetch, rape and ryegrass are the traditional, common and easy to plant widely in south China. Field experiments were carried out to study the effects of different mixture combinations and ratios on the fresh grass yield and nutrients accumulation of green manure, by simulation experiment to study the decomposition character of mixed green manure, and using pot and field experiments to study the effects of mixed green manure on the yield, nutrients uptake and distribution of rice, hoping to provide theoretical and technical basis for the application and promotion of Chinese milk vetch mixture cropping. The main results showed as follows:1. Appropriate mixture could improved the fresh grass yield and nutrients accumulation of green manure. In different fertility level and fertilizer rates, suitable mixture combination and ratio were different. In the condition of higher fertilizer rates, the40%Chinese milk vetch mixed with60%rape treatment performed well in Gongan and Zhijiang that with higher fertility level. The fresh grass yield, C, N, P2O5, K2O accumulation arrived at46020kg/hm2-49487kg/hm2,2454.0kg/hm2-2776.2kg/hm2,67.8kg/hm2-98.0kg/hm2,30.3kg/hm2-33.2kg/hm2,104.5kg/hm2-117.3kg/hm2, respectively. The80%Chinese milk vetch mixed with20rape treatment performed well in Xishui and Chongyang that with lower fertility level. The fresh grass yield, C, N, P2O5, K2O accumulation arrived at25513kg/hm2-35820kg/hm2,1585.4kg/hm2～1864.8kg/hm2,58.2kg/hm2～93.6kg/hm2,14.7kg/hm2～17.4kg/hm2,80.3kg/hm2～95.2kg/hm2, respectively. In the condition of lower fertilizer rates, Chinese milk vetch mixed with ryegrass performed better in Honghu, and the fresh grass yield, C, N, P2O5, K2O accumulation of the80%Chinese milk vetch mixed with20%ryegrass treatment were higher, which arrived at20894kg/hm2,1832.8kg/hm2,50.3kg/hm2,17.6kg/hm2,140.4kg/hm2, respectively. Except for the C/N of the optimal mixture treatment in Gongan and Honghu was36.14～36.49that exceeded the proper decomposition value, in the other sites the C/N were suitable for decomposition.2. The application of green manure could significantly improve nutrients content in the soil surface solution and soil. For the sole Chinese milk vetch treatment, nutrients that in the soil surface solution, and NC2--N, NH4+-N in the soil were higher. While there were no significant difference among the different green manure treatments in the value or content of pH, organic matter, TN, available P and available K in the soil. The EC improved quickly in the first20days, and remained stable in20-52days, then decreased quickly. In the initial period, the TN and TK in the surface solution decreased quickly, and remained stable after52days,12days, respectively. The TP of all the treatments in the surface solution was low, ranged from0.01mg/L to0.06mg/L, and fluctuated largely in different days. In the initial stage, the NO3*-N in the soil decreased quickly, while the NH4+-N improved as the incubation continued. 3. Fertilization significantly improved the rice yield and nutrient accumulation. Especially, the grail yield, grain nutrients accumulation and the contribution rate of fertilizer of the80%Chinese milk vetch mixed with20%rape treatment were higher than other treatments. The grail yield increased due to the effective panicle number and number of grains per panicle. The grain yield of the80%Chinese milk vetch mixed with20%rape treatment in the two sites arrived at8465kg/hm2-9373kg/hm2, and the N, P, K accumulation of grain and the fertilizer contribute rate were97.5kg/hm2-123.1kg/hm2,24.9kg/hm2-25.7kg/hm2,23.5kg/hm2-23.8kg/hm2,34.1%-37.2%, respectively.4. By potting under no chemical fertilizer condition, the application of green manure significantly improved the dry matter and N, P, K accumulation of various organs, except the sole ryegrass treatment. Especially, the yield the sole Chinese milk vetch treatment was the highest among all the treatments and promoted the distribution of N, P, K in grain. The grail yield increased due to the effective panicle number and number of grains per panicle. Compared with other treatments that applied with green manure, the sole Chinese milk vetch treatment increased the grain seed and straw biomass by12.16g/pot-41.27g/pot,4.40g/pot-28.41g/pot. The effective panicle number and number of grains per panicle were47.0and142.9, respectively. The N, P, K distribution rate in the grain seed were65.18%,70.02%,15.86%.