Study Of Soil Aggregates And Organic Carbon Under Different Land Use Patterns In The Farming-pastoral Ecotone

In this study,the grassland and arable land in the farming-pastoral ecotone of Siziwang Banner,Inner Mongolia were experienced in different soil types(chestnut soil, gray cinnamon soil and meadow soil),based on field investigation and laboratory analysis.Distribution characteristics and stability of soil aggregates,SOC,the SOC of aggregates of various particle sizes and their contribution rate in the 0-10 cm soil layer were compared and analyzed.The results showed that comparing with chestnut soil between grassland and arable land are as follows:The content of aggregates with particle sizes>3 mm was decreased by 12.69%~59.12%,meanwhile,the content of aggregates with particle size?0.25 mm was increased by 22.88%~60.63%,aggregate stability decreased markedly.The SOC was decreased by up to 49.19%.The main body of organic carbon storage transformed from soil aggregate(>3 mm) to soil aggregate(0.25~3 mm).The contribution rate of soil non-aggregates to SOC were increased.After the grassland has been cultivated as farmland,the soil structure was degraded.The decrease of each index of gray cinnamon grassland cultivated as farmland was not significant,indicating that the soil structure degradation was not obvious.The meadow soil of grassland has poor structural structure and low organic carbon content,which is mainly caused by salinization.However,after plowing the grassland into arable land,the properties of soil were improved by the long-term cultivation and organic fertilizer fertilization.The content of aggregates with particle sizes>3 mm was increased by 141.95%,meanwhile,the content of aggregates with particle size ?0.25 mm was decreased by 43.22%,the SOC was increased by 25.82%.It is indicated that under suitable conditions,proper reclamation of grassland of salinized meadow soil is feasible.