Arable Layer Status And Profile Distribution Characteristics Of Different Components Organic Carbon In Liaoning Coastal Saline Paddy Soil

This paper analyzes the arable layer status and profile distribution characteristics of organic carbon and its active components through field soil investigation, sampling, and the indoor test, based on the Liaoning Panjin coastal saline paddy soil. The results have shown that as follows:(1).In Liaoning inshore saline high-yield paddy soil, thickness of top layer distributed in 18～20 cm, with an average of 18.29 cm, in low yield paddy soil, the arable layer thickness distributed with range of 14～16 cm and an average thickness of 15.02 cm; Plough layer thickness in high yield field are concentrated on 6～8 cm range, and an average thickness of 8.26 cm, but on 9～11 cm thickness distribution, the average thickness of 11.02 cm of the those in low yield field; Soil bulk density for top layer in high-yield field ranged from 0.73 to 1.38 g·cm-3, and the averaged soil bulk density of 1.22 g·cm-3, but that of low production soil ranged of 0.86～1.46 g·cm-3, the averaged soil bulk density of 1.31 g·cm-3. Top layer thickness of high yield field is greater than that of middle-and-low-yielding fields, plough layer thickness is less than the middle-and-low-yielding fields, bulk density is less than the middle-and-low-yielding fields, all significant analysis is very significant.(2). Profile distribution of soil organic carbon, readily oxidation of organic carbon (ROC) and microbial biomass carbon (MBC) all have a declining trend step by step, the changing pattern for soluble organic carbon (DOC) is not obvious; Between high and low production paddy soil, differences among components in the same layers are not obvious.(3).The correlation analysis showed that, in both overall layer and every sub layer, they have extremely significant positive correlation between the easy oxidation of organic carbons and soil organic carbons; It has an extremely significant positive correlation between soil microbial biomass carbon content and soil organic matter content in the top layer, but in the other three sub layer, the correlation is not obvious, and with the soil layer deepen, the correlation coefficient declined step by step; It has no relevance between soluble organic carbon and soil organic carbon in the profile distribution.(4) The contents of three active components of organic carbon content are characterized by ROC>DOC>MBC in both overall or sub layers.