Response Of Soil Carbon Components And Microbial Functional Diversity To Intercropping System On Slope Land In The Loess Plateau

The hilly and gully areas in the Loess Plateau are the areas where Chinese rural residents live in poverty.Crop unicast and excessive tillage lead to serious soil erosion,natural precipitation variability,crop yield is low and unstable,agricultural system stability is poor.Therefore,in the Loess Plateau,the existing agricultural system to add economic value of authentic Chinese herbal medicine and leguminous grass and other crops and varieties,can be in alleviating soil erosion,repair ecological damage at the same time,so that farmers get real economic benefits,to achieve economic and eco-win goal.Therefore,in this study,2 kinds of authentic medicinal plants,Licorice,Isatis tinctoria and perennial forage Alfalfa were used as test materials in the hilly and gully region of the Loess Plateau,and the field test was laid out by using sloping farmland in typical rain-fed agricultural area.The settings include 4 different patterns for Wheat monoculture(W),Wheat/Licorice(W/L),Wheat/Isatis-indigotica(W/I)and Wheat/Alfalfa(W/A).By exploring the differences of soil carbon components and the characteristics of soil microbial functional diversity,the microbiological mechanism of soil quality change was discussed,in order to enrich the basic theory of intercropping system,and to provide theoretical reference for sustainable development of rainfed agricultural system in the Loess plateau of western China.The main conclusions are as follows:(1)Compared with Monoculture wheat(W),intercropping can increase the total organic carbon(TOC)and soil medium laible organic carbon(MLOC)in the surface(0-10cm).especiallyWheat/Isatis-indigotica(W/I)and Wheat/Alfalfa(W/A)have the most obvious effect respectively..(2)Compared with monoculture wheat,intercropping can improve the activity of 0-10 cm protease enzyme and alkaline phosphatase,and the protease and alkaline phosphatase activity of the wheat intercropping with Isatisindigotica and Alfalfa increased by 3.2%?11.4% ?240.0%?320.2% respectively,and the difference was significant.Under 10 cm soil,There was significant difference between alkaline phosphatase activity monoculture and intercropping.(3)Compared with monoculture wheat,intercropping can increase the metabolic capacity of soil microbial community and enhance the utilization ability of soil microorganism to the substrate carbon source,among which the Average well color development(AWCD)of W/I is higher than that of wheat monoculture in 0-50 cm soil.Its 96 h AWCD value is 1.3?1.4 and 4.2times that of W in 0-10 cm ? 10-30 cm ? 30-50 cm soil depth respectively.The AWCD value decreases with the depth of soil layer,which indicates that the microbial community of topsoil has strong metabolic ability.intercropping can significantly improve the McIntosh index and richness index,but the Shannon and Simpson indices are not significant.(4)Compared with monoculture wheat,intercropping can improve the intensity of soil microorganism to 6 kinds of carbon sources,enhance the stability of soil microbial community,and the principal component analysis shows that intercropping leads to the change of soil microbial Community metabolic function,in which carbohydrates?Amino acids and Carboxylic acids are the main carbon sources of soil microbial utilization.