Review On Mechanisms Of SOM Stabilization Of Paddy Soils In The Subtropical Zone Under Long-term Fertilizations

Paddy soil is cultivated soil in China with Chinese characteristics. Its potentialcapacity of soil carbon sequestration was great and carbon sequestration effect wasobvious. So discussing the stability of soil organic matters (SOM) under differentfertilizer management patterns was very important for understanding the soil carbonpool. Based on this, Fourier transform infrared spectroscopy (FTIR) was directlyapplied to study the structure of SOM of paddy soils under long-term differentfertilization treatments in Hunan province. From fertilizer treatments as well as man-made factors such as soil parent material and soil profile and other natural factors onSOM content changes of structure and its components were analyzed, enrich the ricepaddy soil organic carbon fixation mechanism of understanding, Which demonstratesthe protection mechanism of paddy soil stability of SOM. This also indicated a chemicalstabilization mechanism of SOM in the paddy soils. The main results are as follows:1. Paddy field under long-term different fertilizer measures of soil organic matter isbasically consistent with the functional structure, but various functional groups ofabsorption intensity were different. As compared with no fertilization (CK), differentfertilization treatments increased the functional group absorbing intensity of chemicalresistance compounds (aliphatic, aromaticity), carbohydrate and organo-siliconcompounds, which was the most distinctive under treatments of HOM, LOM and STW.For example, the absorbing intensity of alkyl was0.30,0.25and0.29under HOM,LOM and STW, respectively. These values were increased by87%,56%and81%ascompared with that under CK treatment. Straw returned and organic-inorganic fertilizer can significantly increase aliphatic, aromatic, carbohydrates, and the content oforganic silicon compounds in soils that contribute to the high organic content, whichincreased the chemical stability of soils.2. The organic functional group structures in soils from different parent materialsunder long-term fertilization measures were basic unanimously, but the componentcontent was different. The content of aliphatic, aromaticity, carbohydrate and organo-silicon compounds in soils from the shale was higher than those from the river alluvium.The absorption intensity of hydroxide radical and alkyl radical in soils under HOM fromshale was0.75and0.34, which were increased by53%and55%as compared with thatfrom river alluvium (0.49and0.22). This indicated the ability of carbon sequestration inpaddy soils from shale was better than that from river alluvium.3. Under the long-term fertilization measures, paddy soil organic functional groupsin different depth of1m deep structure basic were consistent, but the content of theSOM generally decreased with the increase of soil depth, and in0-20cm deep place fellsharply,20cm below the decline gradually slowing down, and it was minimized in90-100cm. The absorption intensity of alkyl radical in surface soils under HOM and CKwas increased by120%and78%as compared with that in deep soils.