Study On The Fuzzy Optimization Model Of Irrigation Technical Parameters Of Border Irrigation Based On The Soil Conventional Physical And Chemical Parameters

In order to improve the border irrigation performance effectively, reaching the purpose of water-saving and yield increasing, it is a great significance trying to optimize the border irrigation technical parameters,including the length of border field, irrigation flow and irrigation time. Determination of soil moisture infiltration capacity, description of border irrigation water movement process, selection and balance of border irrigation effect index were involved in border irrigation technical parameters optimization process. However, it was time-consuming, laborious that soil moisture infiltration parameters determinate, and border irrigation water movement process was more complex, border irrigation performance indicators, which are always in different irrigation evaluation perspective, were difficult to select. To solve these problems and to realize the border irrigation technical parameters optimization effectively, this paper on the basis of previous research, the following studies were carried out:(1) Aiming at the problems of difficult acquire to soil moisture infiltration parameters, a large number of field infiltration tests in Shanxi region and the corresponding soil physicochemical parameters test as the basis, according to the soil transfer function theory, using linear, nonlinear and BP artificial neural network prediction method respectively, the modified Kostiakov soil moisture infiltration model parameters prediction models about k, α and f0 were established, and the prediction results was verified. The prediction of soil moisture infiltration parameters, the soil bulk density, texture, water content and organic matter content of soil physical parameters as the input variables, were realized effectively;(2) For the realization of numerical simulation of border irrigation water movement process, the border irrigation water flow movement characteristics analysis as the foundation, by the simplification of border irrigation process and assumption of irrigation conditions, the momentum equation of hydrodynamic model was simplified, the selection and establishment of kinematic wave model of the field surface water movement was realize, and the establishment of kinematic wave model was verified by the use of Fenhe Irrigation District second branch of border irrigation experiment data. Results show that the kinematic wave model can achieve border irrigation water flow advance and recession process simulation;(3) In order to realize the evaluation of border irrigation quality scientifically, based on the analysis of distribution of soil moisture spatial after irrigation, the relationship among the evaluation index irrigation of efficiency Ea, water storage efficiency Es and irrigation uniformity Ed were studied, Ea, Ed as the optimization goal through the introduction of empirical coefficient k. And combined with the analysis of factors affecting the effect of irrigation effect index, the border length L, unit-width discharge q and irrigation time t were selected as the optimization objects, a multi-objective optimization model was established for border irrigation technical parameters. Aiming at the fuzziness of the objective function of the optimization model, using of the fuzzy optimization theory, the linear membership function of fuzzy set was introduced, according to the principle of maximum membership, multi-objective optimization problem transformed into single target optimization, the technical parameters of border irrigation were selected by the fuzzy optimum way;(4) Based on the coupling relationship analysis among the model of soil moisture infiltration parameters prediction, the model of surface water movement of border irrigation and the model of border irrigation technical parameters objective fuzzy optimization, the construction of border irrigation technical parameters integration fuzzy optimization model based on soil conventional physicochemical parameters using FORTRAN language was realized. And North Changshou in Fenhe Irrigation District optimization test for border irrigation process as an example, the process of input about soil conventional physicochemical parameters, filed basic specifications, irrigation and others, and the process of output about border irrigation technical parameters optimization, optimization process of irrigation and the soil moisture spatial distribution after irrigation on the model of integration were showed;(5) Based on the reliability of integration of fuzzy optimization model for border irrigation effect simulation, the Fenhe irrigation area optimization experimental as background, the influence factors for border irrigation effect border length L, per unit width discharge q, irrigation time t, field slope i, roughness n and soil infiltration parameters k, α and f0 were selected, using the method of orthogonal test, the fluctuation contribution rates of border irrigation effect were calculated on the deviation of influencing factors, and draw the sensitive degree of irrigation effect index as to each influencing factor, provided the basis for border irrigation process control and irrigation efficiency improvement. And made attention to the analysis in-depth of the sensitivity of border irrigation effect on soil moisture infiltration parameters specially, the soil moisture infiltration parameters prediction accuracy control range were established based on border irrigation effect, which were provided the reference for the corrective selection of the prediction model of soil moisture infiltration parameters and the analysis of the prediction results.