Study on Features of Soil Salt Distribution and Adjusting Method in Arid Area
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【Author in Chinese】 张江辉；
【Author's Information】 西安理工大学， 水文学及水资源， 2010， 博士
【Abstract】 According to the features of salt-effected soils in arid area, the features ofsoil salt distribution and its adjusting method were studied through the theoretical analysis and experimental research based on the review on the related research results at home and abroad. The main research resuls are as following.1、The soil water movement features were analyzed, and the relation between soil sorpitivity and diffusion coefficient was established in order to provide an approach for mutual thansformtion of hydraulic parameters. At the same time, the relatioship among parametrs in the physical basis infiltrtion models were found in order to provid a method of mutual transformtion of the infiltration models. The.According to the features of irrigation in winter and in spring, the simple mathematical models for soil water and salt content distribution were established in order to provide a new method for describing soil water and salt transfer.2、The basic features of groundwater evaporation was analyzed and the exponential funtion relation between groundwater evaporation and underground water table was found based on the soil water dynamic theory. There is a linear realtion between revised soil evaporation and water evaopration based on the revision of soil evaporation through soil temperature, and the relation between groundwater evaporation amount and monthy cumulative temperature in soil was found. The effects of groundwater table and its salt concentrtion on soil salt content in six countys, Tarum basin, and the results indicate that there is a linear relation between groundwater salt concontration and a exponential relation betweent soil salt content and groundwater table. In addtion, the comprehensive relation between soil salt content and groundwater table and salt concnetration was found. Meanwhile, a mathematical equation describing soil salt cumulation was established in order to analyze the soil salt cumulation for a long time.3、According to the features of the farmland drainage in arid area, the relation between soilsalt content and its ion component was analyzed, and the results indicate that there was a linear relation between soil salt content and its ion component. The research results indicated that the plastic film mulch can restrain the salt cumulation in soil upper layer and the restrain role descreases as the soil depth increases. According to soil salt cumulation features and crop salt tolerance, the concnept of the allowing groundwater depth was put forward, and the calculation equations for drainage ditch depth and space were established in order to provide a new method for drainage sysytem design in arid area.4、The research results indicate that the farmland irrigation in winter can leach soil salt, and the salt decreasing amount and depth increase as the irrigation water amount increases. The relation between soil salt deacring ratio and irrigation water amount was eastablished, and there are exponential relations among soil salt decreasing ratio and soil salt residual ratio with the irrigation water amount. The effects of applied amount and method of Handilong and Miaokang on soil salt content distribution and crop yields were analyzed, the results indicate that application of Handilong and Miaokang may change the soil salt content and its ion component, and the soil salt descreasing ratios were 30.3% and 22.3% for applying Handilong and Miaokang and is 10.4% without Handilong and Miaokang for growing cotton land with dripper irrigation. The effects of applied Handilong and Miaokang on soil salt content distribution, cotton growth and yield, and comprehenive effectives were analyzed, the results indicate that Handilong can greatly decrease sil salt content, improve cotton growth situation and enhance economic effectives.5、The experimental results in grape farmland indicate that the irrigation water amount affects soil salt content distribution under dripper and converging area, and the irrigation times also effects the soil salt content and decreasing rate. In addtion, the features of soil salt cumulation and leaching and soil improving approaches in arid area were analyzed, and the salt-effected soil improving styles in arid area were studied in order to find reasonble salt-effected soil improve methods.