Research On Distribution Of Organic Carbon And Humus Characteristics Between Different Soil In Mingshan River Watershed

Soil organic carbon and soil humus are important indexes of the soil quality evaluation. In this paper, it combined with the achievements of previous studies and then chose the Ming shan River basin’s typical soil as the research object. I selected three types of soil:the yellow soil, purple soil and paddy soil.Through field sampling and laboratory analysis,I studied the soil profile,the distribution of soil organic carbon in soil aggregate and the structural characteristics of humic coordination,to provide how to use Ming shan River watershed land In harmony and how to develope sustainable agriculture with references. The main conclusions are as follows:The basin soil organic carbon content of Ming shan River ranged from20.09g/kg to33.037g/kg, which performed as paddy soil>yellow soil>purple soil.From the way of using, the content of paddy soil organic carbon and labile organic carbon are significantly higher than those of dry land, tea gardens and orchards.The allocation proportion of active organic carbon ranged from1.78to2.49, so no significant differences between different ways of utilization.From the research, soil active organic carbon and soil organic carbon were significantly positive correlation (r=0.8350). Different soil humus carbon content ranged from12.08g/kg to20.84g/kg,meanwhile,the content of humus carbon, Hu Min acid and the HA/FA (Hu Min acid and fulvic acid ratio) performed as paddy soil>purple soil>yellow soil. The content of humus Combining form was:tight junction state>pine knot state>stable node state. From the way of using, HA/FA was positively correlated with humus content (r=0.8264), which performed as paddy field>orchard>dry field.The tea garden humus elastic was the highest, so it was the most active. Humic substances and organic matter content were significantly positive correlation (r=0.9797).The content of soil organic carbon reduced with the soil depth increased in0-40cm soil layer. The organic carbon content within the order of paddy soil>yellow soil>purple soil in the upper, and the lower is the paddy soil>purple soil>yellow soil, meanwhile,labile organic carbon has a similar rule. In different utilization modes, the surface soil organic carbon content within the order of paddy field> dry-land>tea garden, and the lower was paddy field>tea garden>dry-land. This was because the organic carbon content changed with the vegetation type and the organic carbon resulted from the tea garden’s Litter went to lower sediment.The active organic carbon in paddy field both in the upper and the lower were both significantly higher than those of dry land, orchard and tea garden. It proved again active organic carbon is one of the important characteristics of organic carbon. Humus components and carbon content was positively related to performance. They all reduced with the soil depth increased. HA/FA in the paddy soil and purple soil within the order of lower>upper. It proved that in the lower layer of high degree of polymerization of humic substances.Yellow soil was on the contrary.The content of upper ahd heavier group soil and the combination form of carbon was upper>lower,nevertheless,the different types of soil’s elastic ratio was lower>upper. In different utilization modes,the humus components showed the same trend as the soil organic carbon in the upper of soil within the order of paddy field> dry land>orchard>tea garden, and paddy field>orchard>tea garden> dry land in the lower.The HA/FA was at the range of0.26to0.53,and the maximum content was in paddy field. It means that the soil humus in the lower paddy field was indicated a good quality. The content of the heavier group soil and the combination form of humus was upper>lower.In soil profiles of different utilization modes, the soil’s elastic ratio ranged from0.66to1.37.The diameter of Ming shan River basin soil aggregate ranged from0.78mm to6.34mm,performed as paddy field dry land>orchard>tea garden, was the result of high organic matter content in paddy field and also promoted the formation of aggregates. The unit of yellow soil aggregates organic carbon content reduced when the soil profile became deeper.At the same time, the units of soil organic carbon content distributed in a wave change way in aggregates.By contrast,the content of purple soil organic carbon content in aggregates had no significant changes. The soil organic carbon were the highest,when the aggregates’particle size smaller than0.25mm in tea plantation or the aggregates’particle size bigger than5mm in orchards and dry land.The aggregates’organic matter content of paddy soil developed from purple soil Indicated that the upper was bigger than the lower. By contrast,the paddy soil developed from yellow soil had no obvious regularities.When this soil was used as paddy fields and tea garden, organic carbon content of soil aggregates increased with soil profile going deeper. But that walked in the opposite direction in purple soil.The carbon content of yellow soil aggregates’humus ranged from0.66g/kg to5.25g/kg, which distributed in aggregates’particle size bigger than5mmor smaller than0.25mm.These aggregates’PQ average values werel0.76%. The carbon content of purple soil aggregates’humus ranged from0.47g/kg to12.68g/kg. When the particle size reduced, the carbon content of humus aggregates exhibited in a wave change way. These aggregates’PQ average values were11.62%.Meanwhile, the carbon content of paddy soil aggregates’humus ranged from0.30g/kg to23.42g/kg.These aggregates’PQ average values were12.75%.