| Nowadays, as growing with population and diminishing with farmland, Saline alkali soil as an important part of land resources,it was an important project for exploitation and utilization in the development of our country's sustainable agriculture. Saline and alkaline was widely distributed from the northeast to the Midwest of China,and the area is about 320,000 km2. Tn Da'an of Jilin province, the area of saline soil is approximately 247680.28km2, as 50.39% of the whole city, and the alkaline area accounts for 77% of the saline soil area. In recent decades, while the deterioration of ecological environment, the area of soil salinization of Da'an is increasing rapidly.How to solve the increasingly serious problem of soil salinization has become the main task of sustainable development on agricultural economy in Da'an. The base of this thesis on abundant literatures, discussed on definition of saline-alkali soil,it discussed the actuality of saline-alkali soil in Zhenlai county,and the amelioration measures of saline-alkali soil.In this experiment,materials include gold vermiculite (VE),sharp lherzolite (LE), aluminum sulfate and calcium sulphate. The tested soil is collected from the county of Daan,the type of saline-alkali soil belong to inland Soda saline soil in this area,the alkalization is serious,the permeability is poor,the groundwater close to the surface,so the salt accumulated easily in the surface.This thesis analysed the research of physical properties,chemical properties and nutrient of soil,and humus composition of soil. Detailed analysis of the mechanical composition of soil salinization, soil aggregates, soil organic matter, soil pH, soil cation exchange capacity, soil exchangeable sodium, soil alkalization, soil nitrogen, soil phosphorus,soil salinity and soil Humus composition as the evaluation index, in addition, the physiological tested of crops were analyzed.The results showed that:(1) The application of aluminum sulfate and calcium sulfate can reduce the soil pH in the culture test, which would increased with the amount of aluminum sulfate increased, the biggest drop to 2.39, and soil pH decrease of 0.46 in the calcium sulfate test. Second, aluminum sulfate and calcium sulfate in the soil after application of the CEC also increased significantly compared with the control soil after application of aluminum sulfate increased CEC 2.51 cmol/kg, calcium sulfate increased 2.2 cmol/kg. At the same time, exchangeable Na+content and salt content decreased. Puccinellia plants tested were sensitive to soil environment of the EC> 2, Puccinellia were almost no germination in the culture experiments.(2)Through the field improved test, the soil improvement effect that comparing application aluminum sulfate with calcium sulfate:the application aluminum sulfate amount of 6kg/a and the application calcium sulfate amount of 9.0kg/a which were the greater, and the crop biomass increased significantly which determine the salt tolerance of crops improved. Simultaneous analysis inorganic elements changed of the body before and after two years,it was found itself can also improve soil properties in the follow-up of the body, the effect of improved materials and add more effective than treatment.(3) Mineral fertilizer in the culture test can improved significantly soil properties. Application of vermiculite can effectively improve soil chemical properties, especially the significantly effect of reducing soil EC compared with the control 43.02%, which can promoted the growth of Puccinellia. The application pointed lherzolite for soil pH, EC had little effect, but the effect for soil CEC increased significantly. When the tip of lherzolite application rate was 0.5%, the growth conditions geater, improvement order:LE 0.5%> LE4%> LE 2%> LE 1%> CK.(4) Combined application of modified material can improved effectively the soil's chemical properties, Content of Na+, K+ and changes of Na+/K+ values discussed plant resistance. The results proved that the higher concentration improved physical environment and fertilizer application can increased the K+content of plants, and reduced absorption of Na+, thereby reduced the Na+/K+ values, and promotedcrop growth.(5) The improvement of subsurface pipe and the application of MM powder can promoted the formation of large grain level in the composition of soil particles and soil aggregates, and improved soil permeability. The advantage size fraction of soil aggregate were 2-0.25mm and 0.25～0.053 mm. The carbon content of HA were higher than the FA, this explained this was benefit for the accumulation of HA in soil, the humification degree were higher, the PQ value change of soil particle was similar to the carbon contant change order of FA, HA, it showed that humus gradually degraded to FA,then FA transformed into HA,it made soil humification enhanced and soil fertility improved.(6) The different improvement measures effect for the alkali soil under the topsoil clay mineral characteristics of the structure analysised by XRD, IR, and DTA., The saline-alkali soil mineral types in DaAn are mainlytype 2:1 montmorillonite,also contain a certain amount of Mengyi mixed-layer minerals, illite and vermiculite by the analysis. The two group are known that the result is no effect for mineral composition of soil type which the sodic soil add in MM powder and application of underground pipe, but the different improvement measures are effected to clay mineral content by the intensity changes of diffraction peaks. |
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