Study On Balance Of Water And Salt On Yellow River Irrigation Areas In Kenli

The study on balance of water and salt is the key point of Agricultural Planting inirrigation district. It has important significance for Yellow River Irrigation Area in YellowRiver delta, which is special effected by geological environment and climate condition. Uponon this, this paper based on the soil salinization problems in Yellow River irrigation area,Summarized research trends of Yellow River delta and theory and practice of water and salttransport at home and abroad. Meanwhile, it researched and analysis the characteristics ofsalinity, constructs water and salt transport model and simulated by HYDRUS-1D, which issoftware used on unsaturated solute movement. All of these combined the saline land featuresand actual situation, and the model constructer relied on the basic hypothesis onhydrodynamic theories of unsaturated soil. Besides this, this paper settled five kinds ofirrigation schemes according to geographical position, distribution features of local waterresources and requirement on irrigation, and simulated the water and salt movement of thefive schemes by the validated program relying on HYDRUS-1D. By this, process on waterand salt movement were predicting and based on them, irrigation system suitable for the localwas determined.The main contents are as follows:(1)By means of field work and chemical analysis on saline soil in study area todetermine soil features. Choosing and measuring the groundwater regime and variation ofwater-salt between summer-autumn and studying them according to the requirement on soilobstacle Through studying, it is between the moderate (total salt content is0.4%~0.6%) andthe severe (total salt content is0.6%-1.0%) soil salinization degrees. The average of PH indifferent seasons and depth is7.64. The sources of salt are NaCl and Na2SO4Solutions fromseawater.(2)Relied on the basic hypothesis on hydrodynamic theories of unsaturated soil, thispaper constructed the numerical model on water-salt movement through HYDRUS-1D. Ageneral analysis was made of water-salt movement on this region, parameter values wereassessed according to the previous research and hydro-geologic information, boundary conditions were determined according to the actual, and finite-difference method were usedfor numerical solution.(3)One-dimensional Mathematical model suitable for the region was made by combingmeasured data on water-salt, debugging the parameter and comparing the measured data andsoftware HYDRUS-1D to simulate unsaturated soil.(4)In accordance with the irrigation region position, water resources distribution andplanting requirements, five kinds of irrigation program of the water saving were made, and bysimulation of water-salt movement in these situation, finally an economical irrigationschedules to save water resources was determined. Among these, general irrigation principlesfor soil salinization and technical index of brackish water irrigation were concerned,prediction of five kinds of schedule was made by HYDRUS-1D and finally deficit irrigationscheduling was made concerning about crop growth and soil fertility, which provides atheoretical guidance to saline water utilization and irrigation methods.