Soil Water Infiltration Characteristics And Infiltration Model Parameters Prediction In The Border Of Hetao Irrigation District

Inner Mongolia Hetao Irrigation District is the largest irrigation district in China.Surface irrigation is the main irrigation method in the region.In recent years,with the implementation of water-saving renovation and irrigation system in irrigation districts,laser flat-ground technology has been widely recognized by local farmers,but The large amount of irigated sediment in the wide field,the Datian block and the Yellow River is still the characteristics of the irrigation area,which affects the improvement of irrigation water utilization coefficient in the irrigation area.At present,under the shortage of water resources in the Yellow River,it is urgent to improve the ground lmgation technology to increase the irrigation water utilization coefficient.Therefore,it is necessary to conduct in-depth research on soil water infiltration characteristics and infiltration model parameters in this area,and provide basic theoretical basis for the improvement of ground irrigation technology.In this paper,field experiment and model simulation were used to study the effects of different factors on soil infiltration,reveal the relationship between soil infiltration parameters and basic physical and chemical properties of soil,and analyze the soil moisture during the growth period of dagger,sorghum and iris.Changes in infiltration capacity and infiltration parameters,as well as dynamic trends of main soil characteristics(volume density,water content and sediment concentration in irrigation water)with time and space,using grey correlation method to study spatial and temporal variability of soil water infiltration characteristics The dominant factor.On this basis,the support vector machine regression algorithm was used to predict the soil infiltration model parameters of the first and middle growth stages of Putian.The main research results are as follows:(1)The conductivity is at a high level in the initial stage of planting,reaching 1.43ms/mrm?2.21ms/mm,and with the irrigation of spring irrigation water,the soil conductivity decreases,and the conductivity content only reaches the maturity stage.It is 0.51 ms/mm?0.82ms/mm.The soil bulk density continued to increase from the seedling stage(1.28g/cm3)to the filling stage(1.45g/m3),and decreased rapidly at the maturity stage.(2)The soil infiltration capacity accumulated the maximum infiltration at 90min during the mature period,which was 48.9cm?52.2cm,but the infiltration process was the most disordered.The infiltration capacity at jointing stage is the smallest,ranging from 9.8cm to 12.3cm.However,the infiltration rate reaches the steady phase.The infiltration parameters of the dagger,sputurri and appendix in the early stage of growth(in seedling stage and jointing stage)are relatively close.According to the analysis of variance,the infiltration capacity of the dagger was much higher than that of the middle and the tail.The initial infiltration rate was 1.42 and 1.81 times of the middle and the tail.(3)The main factors causing soil infiltration variability were analyzed by grey correlation degree.The influence degree of each influencing factor on cumulative infiltration amount ho,infiltration coefficient K,infiltration index a and infiltration rate S during the growth period was analyzed.The ordering is consistent,from large to small for soil texture(material clay)>soil initial moistlre content>soil bulk density>irrigation water sediment concentration;(4)When predicting the infiltration parameters during the growth period,the calculated value of the Kostiakov-Lewis model and the simulated infiltration amount are the best,and the fitting coefficient reaches 0.85.When predicting the infiltration parameters of the dagger,the middle and the tail,the calculated value of the Philip model and the simulated infiltration amount have the best correlation,and the fitting coefficient reaches 0.92.