Effect Of Long-term Fertilization And Parentmaterials On Organic Carbon Stabilization In Red Soil

In this paper, soil samples are collections from filed and analyzed in the laboratory to study the typical red soil at Yingtan in Jiangxi Province, China. The objectives of the current study were to measure soil aggregate stability and soil organic carbon from both the nature condition and the human activities, which is critical for revealing the process and regulatory mechanism of soil carbon cycle. The main results are summarized as follows.(1)Soil aggregates stability is sensitive to the response of plant growing and the human activities, which can influence the crop root exudates and rhizosphere micro-environment. Fertilization to some extent improved the content of large aggregates, organic fertilizer and co-application of manure and chemical fertilizers treatments were best.(2)Contents of aggregates are significantly related to soil organic carbon. Long term application of fertilizer, especially in treatment NPKM, increased the content of soil aggregate in 0.25～2 mm particle size and soil organic carbon.(3)The results indicated that compared with non-rhizosphere soil, DOC content in rhizosphere soil reduced at tillering stage, increased at heading, decreased at grain-filling and increased at maturity stage. Besides, comparing with the transplanting stage of rice, the content of DOC in rice harvest time was markedly increased. The results indicated that grow crops could cause the change of soil active organic carbon sensitively.(4) Different parent materials had variable amounts of water-stable aggregates which affected amount of soil organic carbon, and dissolved organic carbon greatly. The result has showed that soil aggregate structure developed by quaternary red earth is better than other three parent materials, and the last one is granite.The content of TOC and DOC have the same feature. Based on field investigation and laboratory analysis, the characteristics of soil aggregates, soil organic carbon, and dissolved organic carbon were discussed in this paper. The dynamics of carbon sequestration by rice plants and soil organic carbon components were understood during the short term scale of rice growth stage. Those studies would accumulate the data for soil carbon management in rice fields in China. It's of important significance for mitigating greenhouse effects and agricultural sustainability.