| For the arid and semi-arid areas of northwest China,the land is rich in resources and abundant in water,but the water resources are very poor,in order to solve the shortage of water resources in the arid areas of northwest China,many irrigated areas have been built,but with a lot of water transferred,causing such as the rise in the groundwater level and soil secondary salinization and many other ecological and environmental problems.Therefore,it is of great significance to study the law of field water movement and the dynamic analysis of groundwater level in the irrigated irrigated area,which is of great significance to the scientific management of water resources and the sustainable development and utilization of land resources.In this paper,Jingjing irrigation area is the research area,the methods of on-site investigation were used to collect the meteorological,irrigation,crop,soil and groundwater data,the dynamic law of field soil moisture was simulated by Hydrus-1D software,the model was validated by using the soil moisture content from the irrigation test station to determine the rationality and accuracy of the simulation,according to the model simulation results,the soil water content,evapotranspiration,leakage and water balance;And then through the years of monitoring data to obtain the regional groundwater dynamic changes,combined with M-K test and R / S analysis of the groundwater level changes in the trend,concluded as follow:(1)According to Hydrus-1D,soil water movement simulation results show that: Soil moisture content and soil depth,the deeper the higher the soil moisture content,after the irrigation,the soil water content of each layer will be greatly improved,rainfall only 50 cm and above soil layer has an impact;a source of soil water for a maize growth cycle is rainfall and irrigation,totaling 953.7mm,soil water consumption items for evapotranspiration and deep leakage,a total of 875.8mm,the evapotranspiration accounts for 50.7% of the total soil water supply,and the leakage accounts for 41.1% of the total soil water supply,soil water reserves varied by 77.9 mm,accounting for 8.2% of total soil water supply.(2)The surface water content in shallow groundwater area is consistent with that in deep buried area,the soil moisture content of subsoil is greatly affected by irrigation and ground water;groundwater supplies soil water,field evapotranspiration will increase;the soil water and groundwater in the shallow groundwater area are frequently exchanged with each other,during irrigation,irrigation water supplies groundwater by infiltration,in absence of irrigation,capillary action caused by soil evaporation and crop transpiration can cause groundwater to recharge soil water.(3)After years of water irrigation,JID irrigation area throughout the groundwater level has improved,The groundwater level of the catchment zone is the most obvious,with an increase of 13 meters over the past 20 years and has been exposed to the surface;The lower water level of the solute transport zone is also affected by the uplift of the groundwater level in the catchment zone.Although the groundwater level of the irrigation infiltration zone and the diving belt is fluctuating,the overall groundwater level is relatively stable due to the relative balance between the recharge and the excretion.The results can be used as the theoretical basis for the optimal allocation of irrigation water and the rational utilization of groundwater in Jingdian Irrigation District,which is of great significance to maintain the ecological environment stability of irrigation area. |
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