Effects Of Adding Straw And Aluminum Sulfate On The Fertility Betterment Improvement Effect Of Soil In Light Chernozems

Chernozem was one of main cultivated soils in China. In Jilin province, light chernozems and saline-sodic chernozems had the largest area(respectively 44.94% and 19.11%), which was the main middle and low yielding soil. According to soil survey results in Jilin province, light chernozems was generally light texture, heavy sandy, less clay content, strong permeability, declined soil organic matter content, low fertility, weakly water and nutrient retention capacity, and alkalescence. Drought, soil infertility, extensive management were the main obstacle factors of Chernozem region of grain yield promotion. The objective of the experiment was to build new light chernozem soil fertility improvement technology system,which was matching straw returned to field. Test soil was the light chernozem in Western Jilin Province, this paper used the incubation method to study the effect of adding the straw and aluminum sulfate to soil to improve soil fertility. The main results are as follows:1. Adding straw and aluminum sulfate to the soil was good for increasing the carbon content. After 135 days culturing, in adding an equal amount of aluminum sulfate conditions, soil organic carbon content was higher with more straw added; In adding an equal amount of straw conditions, soil organic carbon content was higher with more aluminum sulfate added. If the amount of straw was greater than or equal to 1.0%, we can make sure that the soil organic carbon content was increasing.2. During the cultivation period, in adding an equal amount of aluminum sulfate conditions, the release rate of CO2 and cumulative release amount of CO2 increased substantially with more straw added; In adding an equal amount of straw conditions, in prophase of cultivation the release rate of CO2 increased with more aluminum sulfate added,and in late stage of cultivation the release rate of CO2 reduced with more aluminum sulfate added. After 135 days culturing, in adding an equal amount of straw conditions, cumulative release amount of CO2 reduced with more aluminum sulfate added.3. Adding straw and aluminum sulfate to the soil can reduce the soil pH. Adding aluminum sulfate to the soil can reduce the soil carbonate content, but adding straw had not obvious effect on the carbonate content in soil. Soil carbonate content and soil pH was positive correlation.4. Adding straw and aluminum sulfate to the soil was good for increasing the soil cation exchange capacity. In adding an equal amount of straw conditions, soil cation exchange capacity was higher with more aluminum sulfate added; In adding an equal amount of aluminum sulfate conditions, soil cation exchange capacity was higher with more straw added.5. Adding straw and aluminum sulfate had no obvious impact to the total quantity of soil organo-mineral complex and in this research all treatments were G1>G0>G2. Adding straw was good for increasing the carbon content of each group of organo-mineral complex, increasing the content of G2 complex, and reducing the content of G0 complex. Adding aluminum sulfate was good for improving the carbon content of G0 complex to some extent, but reduced the carbon content of G2 complex. Meanwhile, adding aluminum sulfate was good for improving the content of G2 complex but reduced the content of G0 complex. Adding straw and aluminum sulfate had no obvious effect on the content of G1 complex and its carbon content.6. Adding straw and aluminum sulfate to the soil was good for increasing the micro-aggregate content of >0.25 mm size, and reducing the micro-aggregate content of <0.01 mm size. However, the micro-aggregate content of <0.01 mm size showed no special rules with straw and aluminum sulfate added.