Study On The Effect Of Intercropping Of Rape/Chinese Milk Vetch And Decomposing Of Their Mixture

In order to establish reasonable rape/Chinese milk vetch intercropping system without affecting yields of oil crops, to solve the contradiction between the expansion of green manure and rape, to provide a reasonable basis for rational use of planting technology and straw resources for crop diversity, we studied the effects of intercropping of Chinese milk vetch and rape in different planting densities on growth and nutrient uptake of rape, Chinese milk vetch in different growth periods and the effects of root separation on growth and nutrient uptake of rape and Chinese milk vetch using pot experiment and field experiment, the decomposition characteristics of the returned straw of rape, Chinese milk vetch and their mixture with different proportions. The main results were showed as follows.(1) When the intercropping mode of rape and Chinese milk vetch was2:1, and the planting density of rape was200～400thousand plants per hectare, the agronomic traits and yield of rape were significantly higher than or similar to those of monocropping rape. Compared with monocropping rape, extra green manures were harvested, the land productivity was improved.(2) Chinese milk vetch and rape could absorb more nutrients in intercropping system than in monocropping. The content of N, P and K in intercropped rape at different period was higher than or similar to those in monocropped rape. The accumulation of N, P and K of the intercropped rape in proper density was also not lower than the monocropped rape. In most cases, the content of nutrients in Chinese milk vetch was in intercropping systems.(3)Compared with monocropped rape mode, the soil fertility was improved in intercropping of Chinese milk vetch and rape in the reasonable planting density, pH, the content of organic matter, available nitrogen and available phosphorus in the soil were increased.(4) According to the root separation experiments, the intercropping of rape and Chinese milk vetch is beneficial to their growth and development through rhizosphere interaction, the content of N in rape and Chinese milk vetch was improved. (5)The decomposition rate of rape straw, Chinese milk vetch and their mixtures in soil is fast in the first10-20days, then slow.The nutrient release rate was K>P>N>C. Chinese milk vetch decomposed faster than rape straw, the decomposition rate of rape straw was improved when Chinese milk vetch was mixed, and the rape straw decomposition rate increased with the increasing amount of Chinese milk vetch.