| Organic carbon and nutrient varying pattern and spatial distribution of quality condition under different lift field types of paddy soil was conducted in main gain production of XiaJiang areas(Lao Qiao lift field,ShuiTian lift field,ChaTan lift field and GeShan lift field). Four lifting field types: untreated field(WT), has lifted land and cultivate for three years(YT3),for one years(YT1),and nothing to do.39 mixed sample point from four areas collected for test biological characteristics,chemical characteristics and physical properies of different parent materials. The main results were as follows:(1)Analysis of soil moisture and soil respiration rate exhibit showed that tendency: WT>YT3>YT1>YT0.bulk density,and the regularity of the opposite trend,soil PH has a even distribution.A large paddy soil of study area shows a general acid soil.The total quantity of soilmicrobial was analyzed the highest in WT,secendly,YT3.the quantity of becteria and fungi in the four types of lift field types shows:YT3>WT>YT1>YT0,and actinomycetes does not render the rule.(2)The total conents of total nitrogen(TN), total phosphorus(TP),alkli-hydrolyzable nitrogen and available postassium was significant differences in four class field types. The differece is WT YT3 was highly contents and TY0 contentsis the lowest. Total postassium contents were in the order of WT>YT3>YT0>YT1. There were certain difference in contents between different sample points collection from same type lift field. Overall,the types of WT and YT3 nutrient content is higher.(3)Study influence factors on soil nutrients by the methods of pearson relation analysis and grey relation analysis,after PH,the analysis results of the 2 kinds of methods are consistent.The analysis results showed that total phosphorus,organic carbon,alkali-hydrolyzable nitrogen,rapidly available phosphorus and bulk density,soil moisture,respiration rate were significant correlation; total nitrogen,organic carbon,alkali-hydrolyzable and microbial biomass were strong correlation.besides,total phosphorus and bacteria,total potassium and fungus,available postassium and bacteria were highly correlation.Those testing indexes has been divided to three groups to do further analyzed by canonical correlation analysis,the results was the same as the other methods.The use of cluster analysis to seven major nutrient indexes classified into five categories.(4)Based on the above analysis, used the Principal Component Analysis and Integrated Fertility Index to evaluate soil quality and fertility in the studied area.Theresults show that the overall of paddy soil quality and fertility is concentrated in medium and high grade,two method of evaluation showed that the YT3 type soil quality the highest, followed by WT,YT0 quality lowest; 39 sample evaluation results in four levels(low, medium, high, extra-high)were 18%,41%,41% and propartion of0.The result of the analysis shows that two methods have a high imitation degree and some stability, correlation coefficient R2 OF 0.6379 extremely significant correlation.(5)Combined with the technology and the characteristics of lift field carried analysis: It has a great impact on agricultural production that the soil stability and structure is destroyed early on the project, and retention of nutrient and moisture loss.Therefore, at the beginning of the lifting field to farmers to farm subsidies. Several years later,it has got a experiment andfield management of cultivated land, carry various technology and characteristics began to play to the efficiency and stability,soil quality to achieve even more than unlift field level, shows up the field of engineering can effectively solve the problem such as farmland submerged in water conservancy engineering immigrants moved. |
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