The Establishment And Evaluation Of Soil Fractal Characteristics And Pedo-transfer Functions In Hetao Irrigation District

Inner Mongolia Hetao Irrigation District is located in drought and salinization area of north-west China. Today, with the decrease and water use planning of Yellow River resources, there is an urgent question that how to allocate rationally and utilize effectively water resource for the sustainable developmental of the irrigation district. When the water-saving reconstruction project is completed, it is very urgent to study the various effect of water-saving project on the matter transfer (water, salt and fertilizer) and change mechanism in irrigation district farmland. However, the research on the rule of region water's consume, forecast of dynamic change of soil and salt, groundwater table and water quality in the irrigation district must involved with determination and spatial distribution of regional soil and hydrological features and parameters. The usual method not only spends time and effort, but also it is difficult to ensure accuracy. This paper based on the test and analysis of soil basic physical and chemical character which were sampled from different locations of Hetao Irrigation district to establish time and spatial distribution rules of soil features. Furthermore, the multi-regress models and artificial neural networks models of the soil Pedo- transfer functions were established. In addition, using different method calculated the fractal dimension of soil, and the relation of different fractal dimension was established. It makes calculation of the value of soil water characteristic parameter become simplicity. The result has important effect for the research and modeling of soil water and salt movement. It also provides a space soil characteristic module and estimate method for the lately study of farmland water and salt change mechanism in whole Hetao irrigation district. The result has important academic and applied value in the aspect of teaching, scientific research, and management of the irrigation district.The main results as below:(1)The regional soil texture and features parameters were tested and analyzed in the laboratory in Jiefangzha irrigation area. And the regional distribution of soil features and soil texture classification were systematically analyzed.(2)Based on the Artificial Neural Networks models, the connection between soil physical-chemic character and soil water characteristic curve parameter were established. The results are superior to the traditional regression method.(3)Applying for Fractal theory to disclose the change regulation of soil Fractal dimension and soil structure in Hetao irrigation district at the same time, the relations between Fractal dimension and soil water characteristic curve parameter were established. It also gets a good fitting outcome in using the fractal dimension to ascertain the percent soil-water content.(4) According to the field experimental results of soil permeability, tthe soil saturation hydraulic conductivity was fitted by the basic physics and chemistry of soil.The main innovations in this paper are: the regional soil features and water retention curve were systematically studied which is first time in the Hetao irrigation district. The artificial neural network model, fractal model and multi-aggression model were applied in the research. The soil texture classification and spatial distribution were determined which has important applied value for the study of water and salt movement and management. It offers a space soil characteristic parameter module and estimate method for region soil water-salt simulation and offers reference for predigesting calculation of soil characteristic parameter and simulation of water-salt movement.