Study On The Transport Of Soil Water And Salt Based On Remote Sensing Technology And Hydrus-1D Model In Hetao Irrigation District

Located in the arid and semi-arid area of Inner Mongolia hetao irrigation, soil salt organic content at large, underground water level higher, introduced large quantities of salt each year, soil secondary salinization in serious trouble, is the typical area of soil salinization development of typical also without irrigation, no agriculture area.With the shortage of water resource of the Yellow River, and Huang Wei unified dispatching to the Yellow River water resources, in the case of the Yellow River irrigation water continued to decline, the balance between agricultural production and soil salinization to the healthy development of the situation, for the soil water in saline area movement and salt transport in soil factors and complex processes to the local main types of land salinized wasteland of salt as the research object, a field experiment with a combination of laboratory test methods, salinization of irrigated land and irrigation in remote sensing of salt wasteland of water movement and salt transport in the complex mechanism of this goal.Research mainly include:1. Studies based on remote sensing technology, the United States LandSat5 the TM sensor data, irrigation of salt wasteland of the Loop has been studied, statistical analysis of controlled salt wasteland area and land use survey.Using remote sensing and image ENVI4.7 software LandSat5 1986, 1999, 2005, 2009 TM data were processed, select the TM5, 4, 3 simulated true color band combination is the best combination of the classification, accuracy evaluation, and extract relevant information and analysis.Studies have shown that continued occupation of agricultural land, other land areas. From 1986 to 2009, the average annual increase of irrigated vegetation 1.805%; water, sand, salt wasteland and settlements, roads and bare land in an average reduction of 1.137%, 0.925%, 1.208%, 1.738%. At the same time in 2005 and 2009 classification accuracy assessment conducted, the overall accuracy reached 76.82%, respectively, and 78.12%; Kappa coefficients were 0.7033 and 0.7091. Multi-spectral remote sensing image information can be moderate to severe salt wasteland for better classification, but the mild salt wasteland by the images of vegetation and other factors, classification performance is poorer. 2. By HYDRUS-1D model and model calibration and testing of simulation studies have shown that simulated and observed values better fitting. Inner Loop model for crop growth period and the autumn irrigation water on salt and water movement during irrigation change is reasonable and credible simulation of the model could simulate a more objective representation of crop growth period and during the autumn irrigation on soil water irrigation salt transport rule, reveal the distribution of land clearance wasteland of salt water and salt transport in the law when irrigation.Model studies have shown that salt and water movement, crop growth period is the period of salt wasteland of salt storage, irrigated land to become "temporary salt Library" for the land provided favorable conditions for crop growth. Autumn irrigation on crop growth and irrigation of salt-standing conducted a large-scale irrigation, discharge of salt, so that irrigation salinization has been some relief, save for the following year brought irrigation water salinity vacated the "Salt Library."3. Research shows that the annual input of salt wasteland and loss of salt is basically equal, irrigation in the upper reaches of the study area decreasing salt wasteland area, the annual average reduction of 1.208%, salt wasteland ability to adjust the salt dropped substantially, the average decline in volume of salt 2.161%, an increase of salinity of deep accumulation of soil and groundwater quantity, increases the difficulty of irrigation water leaching salts.In 2009, the total area of 11520 km~2 irrigation salt wasteland, total year input irrigation salt is 1.896×10~8 kg, total loss 1.818×10~8 kg, total annual volume of salt is 0.078×10~8 kg.The main innovation is take the He Tao irrigation area salt wasteland as the research background, based on HYDRUS-1D model by using remote sensing, a hierarchical analysis in the irrigation area in the upper reaches of the wilderness area of salt water and salt distribution and migration law, for the first time by using remote sensing the wasteland of salt for irrigation area of the statistical distribution area, the use of models to simulate the migration of salt water and salt wasteland law and quantitative estimate of the wasteland of salt accumulation and loss of salt.Research further exploring and utilizing the model simulation emersion the salt wasteland of soil moisture and salt migration regularity, combined with remote sensing technology quantitative estimates of the irrigation area in the upper reaches of salt wasteland of salt input and loss of salt, the implementation of the irrigation water-saving irrigation and soil salinity control provides a theoretical basis, the development of agricultural economy play an important guiding role of irrigation water, on the irrigation areas of high efficiency utilization of water resources and the reasonable configuration has the important practical significance, for salt and water management and irrigation area of sustainable development and provide the scientific basis.