Intercropping And Fertilization Of Forage Rape With Sorghum In Feed Rapeseed Effect Of Yield Quality And Soil Organic Carbon Composition

In view of the low utilization rate of wheat land after harvest and the lack of forage grass in Hetao irrigated area,this study took two kinds of forage grass,rapeseed and sorghum,as experimental materials,and selected conventional fertilizer applied farmland in Hetao irrigated area and organic fertilizer applied farmland for 5 consecutive years as the research subjects for field experiment.The experiment was carried out in three planting modes:forage rape monoculture,sorghum monoculture,and Forage rape intercropped with sorghum.The relationship between forage yield and soil nutrient,soil organic carbon component and soil enzyme activity was systematically studied under the monoculture and intercropping modes.The main findings are as follows:(1)Intercropping combined with fertilization can significantly increase forage yield.In conventional farmland and organic farmland,the highest yield treatments were intercropping combined with chemical fertilizer treatment and intercropping combined with organic fertilizer treatment,indicating that both intercropping and fertilization could increase forage yield.The yield of fresh grass was increased by 12.06%-71.06%and that of hay was increased by 12.92%-56.30%.The yield of fresh grass was increased by 16.06%-23.41%and that of hay was increased by 10.49%-21.40%.(2)Intercropping can significantly improve forage quality.The crude fat content and crude protein content of forage grass were increased by 10.44%-50.53%and 24.06%-65.28%,and the content of acid and neutral washing fiber were reduced.Intercropping combined with organic manure significantly improved the quality of forage grass,and combined with chemical fertilizer reduced the quality of forage grass.The content of crude fat and crude protein in conventional farmland without fertilization was significantly higher than that in chemical fertilizer treatment,and the difference of relative forage value was not significant.In organic farmland,crude fat content was higher without fertilization,while crude protein content and relative feeding value were significantly higher with organic fertilizer than without fertilization.(3)Intercropping combined with fertilization can significantly increase soil nutrient content.The contents of alklytic nitrogen,available phosphorus,available potassium,total phosphorus and available phosphorus in the soil layer of 0-20cm were significantly increased under the intercropping mode of conventional farmland and organic farmland.The contents of alkali-hydrolyzed nitrogen,available phosphorus,available potassium,total nitrogen and total phosphorus in soil were increased by applying chemical fertilizer in conventional farmland,while the contents of alkali-hydrolyzed nitrogen,available phosphorus,total phosphorus,total potassium and available phosphorus and total phosphorus in soil layer 0-20cm deep were significantly increased by applying organic fertilizer in organic farmland.(4)Intercropping combined fertilizer significantly improved the soil total organic carbon,soluble organic carbon,microbial biomass carbon content,including microbial biomass carbon content increase significantly,as high as 52.21%,and intercropping combined with fertilization can significantly enhance the soil enzyme activity,including intercropping combined with chemical fertilizer treatment of alkaline phosphatase activity increased significantly,growth of 37.07%to 77.19%.The content of total organic carbon,soluble organic carbon and the activities of cellulase,sucrase,protease and alkaline phosphatase in the soil layer of 0-20cm were significantly increased by applying chemical fertilizer in the conventional farmland,and the content of soluble organic carbon and easily oxidized organic carbon in the soil layer of 20-40cm was also significantly increased.Compared with no fertilization,the application of organic fertilizer in organic farmland only increased the content of soil soluble organic carbon and microbial biomass carbon.Intercropping combined with organic fertilizer treatment significantly improved the activities of soil cellulase,sucrase and alkaline phosphatase,among which the cellulase activity increased by 11.83-22.74%.(5)In the case of intercropping of replanted feed rapeseed,the treatment with the highest conventional farmland benefit was intercropping combined with chemical fertilizer treatment,while the treatment with the highest organic farmland benefit was intercropping combined with organic fertilizer treatment.