| As one of significant water loss and soil erosion areas in Sichuan province and Changjiang river, the hilly areas of Sichuan Hilly Basin have Characteristics of geology loose, Rainfall is rich and concentrated. In recent years, small watershed was governanced by the agricultural technical measures, engineering measures, forest and grass measures of soil and water conservation,than,the soil physicochemical was improved.So the study of soil physicochemical properties and soil fertility quality of different governance patterns of small watershed are urgently needed.By taking the region representation into full account,the Nanya small watershed in Chuanshan County, Suining city,Sichuan province was selected as pilot. By focusing on the treatment measures of different governance patterns(Walnut Forest,Orange Forest,Conservation Forest,Leveled Cropland,Slope Cropland, Bare Land)of small watershed and on the basis of field investigation and sampling, laboratory analysis and statistical analysis, this study has analyzed the physical and chemical properties and soil quality under different treatment measures of governance patterns, In accordance with above results, governance patterns with better effect on soil fertility quality shall be selected thus provide scientific basis for vegetation restoration and for soil and water loss control in the hilly areas of Sichuan Hilly Basin. The main study achievements are as follows:(1)In the different governance patterns,the average content of the organic matter, total N, available N varies the same:the content of Conservation Forest is the highest, Conservation Forest is the highest, Bare Land is the lowest. The sequence of the organic matter for different governance patterns was Conservation forest> Orange forest> Walnut forest> Slope-terrace> Bare-land> Grading of slope land. The sequence of total N and available N for different governance patterns were Conservation forest> Orange forest> Walnut forest> Bare-land> Slope-terrace> Grading of slope land. By taking measure of afforestation, organic matter content of Bare-land and grading of slope land decreased and another governance patterns increased along with the change of the afforestation time, Walnut forest increased by 12.31%, and it is the most amplitude governance pattern. The average content of total N and available N increased along with the change of the afforestation time, total N of Walnut forest increased by36.42%,and it is the most amplitude governance pattern, total N of Orange forest increased by 13.03%,and it is the most amplitude governance pattern.(2)In the different governance patterns, the average content of total P and available P varies the same:Walnut forest> Orange forest> Conservation forest> Slope-terrace> Grading of slope land> Bare-land. By taking measure of afforestation, total P content of Bare-land and grading of slope land decreased and another governance patterns increased along with the change of the afforestation time, the average content of available P increased along with the change of the afforestation time. In the different governance patterns, the average content of total K and available K varies is different, the sequence of total K for different governance patterns was Walnut forest> Conservation forest> Slope-terrace> Orange forest> Grading of slope land> Bare-land, along with the change of the afforestation time, total K content of Bare-land and grading of slope land decreased and another governance patterns increased.the sequence of available K for different governance patterns was Slope-terrace> Walnut forest> Grading of slope land> Bare-land> Orange forest> Conservation forest, along with the change of the afforestation time, available K content of Conservation forest, Orange forest increased and another governance patterns decreased.(3)The content of soil bulk density was shown as the sequence of Bare-land> Slope-terrace> Grading of slope land> Conservation forest> Walnut forest> Orange forest. The soil bulk density content under Bare-land was 1.17 times higher than that under Orange forest. But the available porosity index varies in a contrary way, total porosity, capillary porosity and non-capillary porosity under Bare land is the highest lowest,under the Orange forest is the highest. Soil infiltration values of different governance patterns and bare land were shown as the aequence of Orange forest> Walnut forest> Conservation forest> Slope-terrace> Grading of slope land> Bare-land.Test also indicated that general empirical model was the best one to describe the soil infiltration processes of this area,Philip model was the second,but the Kostiskov model and Horton model could not describe the soil infiltration processes of this area good.Correlation analysis showed that:There had significant or extremely significant correlation between soil infiltration and soil bulk density, total porosity, capillary porosity.(4)The results showed that soil micro-aggregates of 0.01-0.05 mm size was dominant aggregates and soil micro-aggregates of 1～0.25 mm size was the lowest Significant differences were observed among different patterns of governance. The range of fractal features of soil micro-aggregates was 2.53-2.71, the sequence of fractal features of soil micro-aggregates for different governance patterns was Bare-land> Grading of slope land>Slope-terrace> Walnut forest>Conservation forest> Orange forest. Correlation analysis showed that, There had negative correlation between fractal feature and 1-0.25,0.25～0.05mm size soil micro-aggregates, There had positive correlation between fractal feature and 0.01～0.005,0.005～0.001,<0.001 mm mm size soil micro-aggregates.(5) Correlation analysis showed that:There had a positive correlation between soil bulk density and <0.01mm soil micro-aggregates, ractal features,and a negative correlation between soil bulk density and total porosity, capillary porosity, non-capillary porosity,>0.01mm soil micro-aggregates. significant or very significant positive correlation were found between the organic matter and total N, available N, total P, available P. Linear relation between fractal features and composition of soil physicochemical properties was observed. Fractal features of soil micro-aggregates showed negative correlations with total N, available N, total P, available P, total K. However, positive correlations were noted between fractal features of soil micro-aggregates and available K.The soil fertility quality integrated indexs under different governance patterns were ranked as follows:Walnut Forest (0.518) Conservation Forest (0.372)> Orange Forest (0.253)> Slope-terrace (-0.086)> rading of slope land (-0.481)> Bare-land (-0.577).the soil fertility quality integrated index in Walnut Forest is the highest and the soil fertility quality integrated index of Bare-land is the worst. |
PDF Full Text Request