Evaiuation Model Of Irrigation Quaiity Of Border Irrigation Based On Farmiand Scale Soil Infiitration Variability

Border irrigation is the most common ground irrigation technology in northern China.After many years of research and development, the design and management of border irrigation system has been greatly improved, but the quality of irrigation is still the main problem. In the past, when the irrigation scheme was optimized, the effect of soil infiltration variation on the quality of irrigation was not taken into account, so that the optimization results could not reflect the actual situation, and the improvement of irrigation quality was limited. Based on the analysis of the spatial variability of soil infiltration characteristics on farmland scale, this paper constructs the evaluation model of border irrigation irrigation quality considering the variation of soil infiltration characteristics, and puts forward the optimization method of border irrigation irrigation scheme, Research results:(1) Based on the field double - loop infiltration test, the soil infiltration characteristics under different texture conditions were studied. The results showed that the optimal infiltration model was the modified Kostiakov model in the first stage terraces, third grade terraces and Wugong County in Yangling District. The typical soil patches selected from the first grade terraces in Wugong County and Yangling District were tested by soil infiltration The observation time should not be less than 90min, and the observation time of the typical plots in the third grade terrace should not be less than 120 min. The spatial variation of the soil infiltration characteristics under the selected soil texture can be determined by the stable infiltration rate f0 and Permeability coefficient k.(2) The normalized treatment method of modified kostiakov formula is proposed, and the spatial variation characteristics of soil infiltration characteristic parameters are analyzed. The results show that the cumulative cumulative Kostiakov formula is used to estimate the cumulative infiltration of soils in the typical soils, and compared with the measured values, the two are highly consistent, indicating that the modified kostiakov formula is normalized The results showed that the variation of the soil infiltration parameters was less than 0.50, indicating that the variation was mainly caused by the structural factors, while the random part of the role is relatively weak.(3) Based on the modified Kostiakov formula, the evaluation model of irrigation quality of border irrigation was established considering the variation of soil infiltration. The results show that the evaluation model of the border irrigation is very consistent with the measured value by using the evaluation model established in this paper. It is further verified that the method of estimating the reliability of the irrigation quality index of border irrigation shows that the estimated value of irrigation water quality and the simulated value of WinSRFR software But also has a high consistency, which shows that the use of the method to estimate the border irrigation irrigation quality indicators have a high reliability.(4) This paper puts forward the optimization method of technical factors of border irrigation irrigation under the condition of soil infiltration variation. The results showed that the comprehensive index of irrigation water quality in both borderline and homogeneous soils showed a trend of increasing first and then decreasing with the increase of single width flow rate, which was consistent with parabolic function. Based on the variation of soil conditions,The results showed that the optimal single-flow flow rate under the conditions of homogeneous soil infiltration could be used to design the border irrigation scheme under the condition of variation, which could ensure that it was high The quality of irrigation.