Monitoring Of Improving Saline-alkali Soil Effect With Pipe Drain And Optimizing Of Project Design In Yinbei Irrigation District

In order to promptly understand the results of saline effect on pipe drainage in Yellow River irrigation area in Ningxia and to optimize the design of pipe drainage,takes 220 hectares submerged tube drainage project of Ma Tai Gou Village,Tao Le Town,Pinghio County,Ningxia Hui Autonomous Region as the study area.There are 10 groundwater wells in the first-level drainage area and the second-level strong drainage area.Taking solid samples regularly,observation groundwater level,monitoring dynamic of pipe drainage and changes of soil salinity as well as pH variations are because the design of pipe drainage locally where the calculation method of suction pimple spacing is single and research of the calculation procedure is limit.We analyze the different ways to calculate spacing of pipes and find the better procedures of Yinbei irrigate area in Ningxia.Furthermore,by using Excel to write VBA program and based on database via Yinbei pipe drainage design.The main results indicated that:(1)Through 10 observation wells observe the variation of groundwater depth in the test area,the results show that during irrigation the depth of groundwater the maximum is 2.05m,the minimum is 0.59m,the average is 1.68m,the depth of groundwater in the irrigation period can be controlled between 0.6?1.6m,the groundwater depth in the non-irrigation period normally can be between 1.7?2.0m;Soil moisture content increased with the increase of soil depth,and the water content of surface soil was controlled between 7.34%and 19.85%;The water content oftillage layer was between 9.90%and 23.68%;The moisture content of the lower layer was controlled between 24.62%and 28.48%.(2)Under the condition ofpipe drainage,the totalsalt content of soil decreased with groundwater dqepth decreasing,and the change of total salt content in the first-level drainage area was between 0.20 and 0.88 g/kg,and the pH was between 8.52 and 9.44.The total salt content in topsoil of the second-level drainage area was from 0.38 to 2.61 g/kg,and the pH was controlled between 8.35 and 9.43.Compared with the buried tube,the soil in the test area was improved from alkaline soil to weak base soil.(3)According to the factors such as the climate of Yinbei Irrigation Area,PE pipe is more suitable for Yinbei irrigation area,and 68g/m2 non-woven filter material can be used to achieve the optimal choice by comparing the drainage capacity of different outsourcing materials.Under steady flow condition,VBA program is used to analyze the different spacing calculation method.The results show that the simplified formula of Hooghoudt>Qu)Xingye formula>Ernst Formula>Hooghoudt Formula.Therefore,it is recommended to use the Ernst formula and the Hooghoudt formula in the steady flow condition.It is recommended to use Qu Xingye formula under unsteady flow conditions.