The Test Study On Chemical Properties Of Soil And Water In Heifangtai Irrigation District

Among the loess irrigation areas on the Loess Plateau in China,Heifangtai Irrigation District is a typical loess tableland,and it is a typical landslide case caused by agricultural irrigation leading to the formation of loess landslides.Since the 1960s,Heilongtai has built a water-pumping irrigation project.Due to the long-term use of flood irrigation,it changed the original hydrogeological conditions,drastically increased the salinity in the groundwater,soil salinization,and led to soil.With reduced body strength,a large number of loess landslides have been induced around the Black Terrace.The main factor inducing landslides in the study area is the intensity of groundwater activity that has been exacerbated by irrigation.Therefore,understanding the chemical properties of soil and water in the area is an important means for studying landslides.The main purpose of this paper is to conduct experimental research on the chemical properties of landslides in the Heifangtai Irrigation District,and to conduct field observation and sampling in large numbers and periodically to determine the optimal soil water for the soil extracts in the Heifangtai Irrigation District.The use of four kinds of test methods to test the salt content of spring water,analyze the advantages and disadvantages of various test methods,and then according to the test results,discuss the temporal and spatial distribution of salt content and anion and cation in spring water in Heifangtai Irrigation District,and use Piper diagram analyzes the type of spring water chemistry.Get the following conclusions:?1?When the soil sample taken in the Heifangtai Irrigation District is the test object,the conductivity of the extract and the total amount of dissolved solids reach the equilibrium first when the ratio of soil to water is 1:10.Under this proportion of soil and water,most of the soluble salts in the soil are soluble in water,which also facilitates the determination of soil salinity to characterize the degree of soil salinization.According to the results obtained from the experiments in this paper,it is suggested that when the soil extracts are prepared from loess irrigation areas or high salinity soils,the proportion of soil to water is selected to be 1:10.?2?For the salt content test of spring water,this article uses the drying method,water quality monitor,ion chromatograph and refractometer to measure the spring water.The drying method is a routine use method,and has the characteristics of simple and quick operation;water quality monitor And ion chromatograph operation is cumbersome,need to carry on the pretreatment or follow-up correction;And refractometer can reach the required precision,the operation is simpler,practical,and the precision can reach thousand place.When testing the salt concentration in high salinity water,the experiment results show that using a refractometer to measure is also a good method.?3?The salt content in the outcropping springs of the Black-Taipei edge landslide is generally higher than that of the eastern margin of Heitai,while the salt content in the outcrop springs of the Loess basement landslide is higher than that of the Loess landslide and the spring water Clear.According to the measured results,the spatial distribution of dew-springs in the study is:gradually decreasing from north to south from east to west;the time distribution of salt content in springs is related to the local agricultural irrigation activities and seasonal freezing and thawing of groundwater.?4?In the spring water in the study area,Cl^-and SO₄^2-are the main anions in the study area.The two ions together account for more than 90%of the total anion and cation ions in the spring,and the cations are mainly Na+.In all spring water samples,the highest Cl^-content was found.In terms of time,the concentrations of anions and cations in the marginal waters of Black Taipei were highest in September,while the anions and cations in the springs of the eastern margin of Heitai were highest in October.The chemical type of spring water is Sodium-chloride type,in which the percentage of cations is almost unchanged,while the percentage of Cl^-and SO₄^2-has a certain change.