Effects Of Density Of Larix Principis-rupprechtii Plantation On Organic Carbon Mineralization Of Soil Aggregate

The Larix principis-rupprechtii Mayr forest is one of China's important plantation resources.Organic carbon in the forest soil is a key indicator for evaluating soil fertility and an important part of the global carbon cycle.The structure of aggregates in the soil has a physical protection effect on soil organic carbon,and soil organic carbon is the cement material formed by soil aggregates,and the two affect each other;soil organic carbon is the substrate of mineralization of soil organic carbon,and the Microorganisms are organisms that promote mineralization of soil organic carbon.So,in this paper,the Larix principis-rupprechtii plantations in Taiyueshan Forest Farm,Shanxi Province were used as the research object to explore the soil aggregate organic carbon content,active organic carbon content,soil microbial characteristics and soil aggregate organic carbon deposits in four different forest densities.Characteristics,and analyzed the main factors affecting the organic carbon mineralization.The results are as follows:?1?The mass distribution of soil aggregates in Larix principis-rupprechtii plantations under different density forest stands as follows:>2mm soil aggregate content is largest,0.25-1mm particle size soil aggregate content and 1-2mm particle size soil aggregate content are second,The content of soil aggregates<0.25mm is the smallest;?2?The stability of soil aggregates increases first and then decreases with the increase of forest density,and the stability of soil aggregates is the largest in the forest of density1415 plants·hm^-2,The forest aggregates with a forest density of 2100 plants·hm^-2 had the lowest stability of soil aggregates;?3?The total organic carbon content of soil aggregates and the active organic carbon content of each component as a whole increased with the increase of forest density The trend of increasing first and then decreasing is that the soil nutrient content in the forest with a density of 1415plants·hm^-2 is the highest;?4?The microbial content of soil aggregates in forests with different densities is different.The total amount of soil aggregates microbes increases first and then decreases with the increase of forest density.The total amount of microbes in 1415·hm-2 stands is the highest;?5?The accumulation of organic carbon in soil aggregates The amount of mineralization gradually increased with the incubation time.The organic carbon mineralization rate of soil aggregates in the early period of cultivation?before 29 days?decreased rapidly,and the later period?after 29 days?was relatively stable and gradually approached"0";?6?Affect the soil mass The factors of aggregate organic carbon mineralization and mineralization rate are mainly soil organic carbon content.Fungi and water-soluble organic carbon in large aggregates have the greatest influence on the cumulative mineralization of soil aggregates,while in small aggregates The bacteria contributed the most to the aggregate mineralization of soil aggregates.