Study On The Changes And Relationship Between Soil Organic Carbon And Enzyme Activities In Different Soil Texture Of Saline Alkali Paddy Field In Western Jilin Province

Soil organic carbon is a major carbon pool in the global carbon cycle. The organic carbon fixed by plant assimilation is stored in the soil organic carbon. This is the main carbon sink method of terrestrial ecosystem. The soil enzyme is closely related to the decomposition of organic matter and energy transfer, which has a great influence on the carbon cycle. And its activity is influenced by soil microbial activity and soil physical and chemical properties. Soil texture, as one of the soil physical properties, determines the physical and chemical properties and biological characteristics of the soil. Therefore the investigating of the soil texture’s effect on soil enzyme activity and organic carbon has important theoretical significance and application value for revealing the mechanism of soil organic carbon conversion and providing technical support for mitigation and adaptation to global climate change.Paddy field agriculture plays an important role in the field of food security in china. In the farmland soil of our country, the content of organic carbon in paddy soil is higher and the paddy soil has a great potential for carbon sequestration. Qian Gorlos(Qianguo) irrigation is located in the west of Jilin Province. It is one of the four major irrigation districts in Northeast China. It belongs to the Northeast China Transect in the study of global climate change. It is the concentrated distribution area of the three saline alkali land in the world and it’s an important area in the global carbon cycle research. This paper takes the soil texture of typical paddy soil in the Qianguo irrigation area as the research object. And is based on the National Natural Science Fund Project” Changes of soil organic carbon and warming potential in saline alkali paddy fields for the whole year in Jilin” and the projects of Doctor Foundation” Study on the mechanism of the change of organic carbon content caused by the Soil carbonate and microorganisms in the soil of saline alkali paddy soil”. By this dissertation, the changes of SOC and soil enzyme activities in paddy soils with different textures were deeply studied, the effects of soil texture and rice growth on soil enzymes and SOC were analyzed, the response model of SOC and soil enzyme was established, and it provided basic support for the research of carbon cycle in saline alkali soil area.The study found that in various stages of rice growth, the content of loam SOC is higher than sandy loam then the silty loam. This is due to the large salt alkalinity of silty loam. Soil organic carbon content in different stages of rice growth will change. Change regulation of soil SOC in different soil texture is as the follow: heading period > fructicative period > no rice period > seedling stage > tillering stage. The change of soil organic carbon in the bottom layer is consistent with the surface layer. Depth had significant effects on SOC in different soil textures and different rice growth stages.During each period of rice growth, the activity of invertase in loam soil is significantly higher than that in silty loam and sandy loam, and the activity of invertase in silt loam is significantly higher than that of sandy loam. Invertase activity of the heading stage is higher than that of grain filling stage, and the grain filling stage is higher than that in the not growing rice stage and the rice seedling stage. Invertase activity is significantly lower in rice tillering stage than in other stages. The change law of soil invertase activity in the bottom layer was basically consistent with the surface layer, but the difference was decreased. Soil depth can affect the activity of invertase in soil. The change law of soil amylase activity is basically consistent with soil invertase.Cellulase activity in the three types of soil is small, it means less effect paddy soil texture does on cellulase activity. The change law of soil cellulase activity is basically consistent with the soil invertase and amylase. In the three types of soil, cellulase activity is highest during the heading stage, the lowest during the tillering stage. The effect of soil depth on cellulose is less than that on invertase and amylase.Growth stage and soil texture has little influence on topsoil catalase activity. The catalase activity in underlying soil is loam> sandy loam> silty loam. The main influence of soil depth on catalase is in the seedling stage and tillering.SOC respond most strongly to the change of invertase and amylase. Soil invertase and amylase presents a significant positive correlation with SOC. Cellulase activity in loam associated with SOC reaches a highly significant level, reach significant levels in sandy loam. There is no significant correlation between cellulase activity and SOC in silty loam. The relevance of Catalase activity and SOC in sandy loam and silty loam has reached a very significant level, in loam as the significance level. The greatest impact of enzyme on SOC in loam is invertase, in silty soil is catalase, in sandy loam is amylase.The results of this study is to reveal the SOC conversion mechanism of saline soil area, improve technical methodology to study terrestrial ecosystem carbon cycle, consummate and soil carbon / sink underlying database, mitigate and adapt to global climate change.