Dynamic Research On Shallow Groundwater And Soil Moisture Of Shihezi Agricultural Areas

Groundwater is an important part of water resources. In arid and semi-arid areas，it is themain available water and even only water sometimes. And soil moisture conditions hadalways been the main research content in farmland, forest, and grassland ecological system.Especially in arid and semi-arid areas, it is the most sensitive factors which limited vegetationsurvival.On the basis of predecessors’ study on groundwater and soil moisture, xinjiang shiheziagricultural areas was taken as study area, related hydrology, meteorology, soil water andgroundwater monitoring data were collected and analyzed. The main research results are asfollows:(1)As for the groundwater table dynamic change characteristics, it can be divided intothree periods during the year of study area, Ⅰperiod is slowing down period before the rainyseason, which is generally before April every year, in this period rainfall is less, andgroundwater table drops slowly, appears smaller fluctuation.Ⅱ periodis flood season, whichlasts3~4months, namely the spring and summer. During this period, snow is melting andheavy rains is hitting, so the groundwater table has risen sharply and reach a peak. After therainy season is Ⅲ period, the groundwater table is falling rapidly and last2~3months, thenturn into Ⅰ period in next year.The groundwater table interannual change, it declines year byyear.(2) Based on classical statistical methods, the spatial distribution characteristics of soilmoisture in the study area is analyzed, the results are shown that:①Soil moisture variabilityis different in north and south, east and west, and vertically,but the degree of variability inJuly is greater than that in June.②The average of soil moisture in June is more than that inJuly, which is relevant with local rainfall, temperature and agricultural irrigation.③Althoughthe variation coefficient is no uniform law, it presents negative correlation between the soilmoisture variation and the average soil water of each soil layer, that is to say, soil moisturevariability weakened with the average soil moisture.(3)Groundwater depth is divided into two sections: depth is less than2m and depth ismore than3m, the relationship between shallow groundwater depth and soil moisture(cultivated land, wasteland) is analyzed, as for wasteland, it is a power function relationshipand presents the negative correlation, which it is consistent with the actual situation. As forcultivated land, it is a quadratic function relationship, which is not in accordance with actual situation.(4) By using the grey correlation methods, correlation degree between the groundwaterdepth and the surface soil characteristics value is analyzed,The results show that: thegroundwater depth is strongest influence to the HCO3-of surface soil, followed by Mg2+、Ca2+，and the influence to the SO42-、Cl-is least.