Based On EM38 Salinization Soil Profile Salt Monitoring Research

Soil salinization is in under the joint action of natural factors and human factors, enrichment of salt ions in the soil and cause soil degradation phenomenon, is also one of the main reason for the limit agricultural development in arid areas. Xinjiang saline soil with a total area of 8.476 x 106 hm2, of which31.1% arable land by the dangers of salinization. Master degree of soil salinization, and its development process is the dynamic observation of scientific management and rational use of salinization of soil improvement and the necessary premise.Due to the spatial variation of soil properties on the big, climate and human activities, such as the complexity of the unstable condition, compared with the study of controlled laboratory conditions, water and salt movement research on macro regional scale is more difficult. At present, the traditional sampling methods, due to the manpower, material resources and other factors limit, difficult to accurate analysis was carried out on the spatial distribution of soil salt. Earth conductivity meter is a kind of EM38 electromagnetic induction type won’t destroy the soil measurement technology, simple, efficient and can be used to measure enough soil salinity data. EM38 technology has become the most advanced and most commonly used to measure the space changing rule of soil salt method.The objectives of this paper were(i) to use an EM38 meter and field sampling to measure soil salinity in soil profiles which differed in land use and texture and(ii) to develop predictive models describing the relationship between ECameasured with the EM38 meter and the electrical conductivity(EC1:5) of the field samples. The soil salinity in the study area was determined by EM38,the spatial variation characteristics of soil salinity in five layers of soil profile in spring and autumn were quantitatively studied by using GIS technique and geo statistics method, and the main reasons for the spatial distribution characteristics of salinity were analyzed,Some satisfied results were obtained as follows:(1)Soil salt content gradually decreased with soil depth. The coefficients of variation were moderate,ranging from 0.67 to 0.93. In wasteland soil, the coefficients of variation were greater at the bottom of the profile than at the top. In cotton fields, the coefficients of variation were lowest in the middle of the profile.(2)The determination of soil laboratory conductivity EC1:5 with EM38 measuring the apparent conductivity(EMH and EMV) there is a better fitting relationship, different soil texture, sand 0-20, 20 to 40,40-- 60 cm soil layer is suitable for the binary function model is better than other fitting precision equation,R2 of 0.79, 0.90, 0.79, respectively. Sand 60-80 and 80-100 cm soil layer with apparent conductivity EMv index equation and linear equation model, the fitting accuracy is higher, R2 of 0.89 and 0.86 respectively. In the loam, loam soil with loam in 0 ~ 20 cm soil layer using exponential equation model accuracy is higher,R2 is 0.82, the other layers are applied to binary regression model. 20-40 different land use types, wasteland,40-60, 60-80 cm soil layer is suitable for the apparent conductivity of EMH logarithmic equation model, R2 were 0.85, 0.89, 0.8, 0-20 and 80-100 cm soil layer respectively applied to binary function and the apparent conductivity EMH linear function model, the determination coefficient were 0.89 and 0.86; Cotton 0-20,20-40, 40-60, 80-100 cm soil layer high fitting precision model function is a linear function, R2 were 0.85,0.84, 0.87, 0.85, 60-80 cm soil layer is suitable for the exponential equation model, the R2 of 0.86. Theaccuracy of the overall model fitting precision of wasteland is slightly better than the cotton fields, the heavy loam > loam > sand; Level of apparent conductivity of EMHfor the interpretation precision of surface soil electrical conductivity is higher, while vertical apparent conductivity EMVthe interpretation accuracy of soil electrical conductivity of the lower than EMH.(3)The salt content of study area showed the southeast is higher than the northwest, the spring of 2015 is higher than the autumn of 2015,Because the temperature is higher than in spring and autumn irrigation and snow melt caused by rising groundwater levels in some areas, making a strong move to the topsoil surface evaporation of salt on the bottom. Salt content of the soil profile is increased with soil depth increases, the performance of the bottom coalescence.The results reflect the Mosuowan irrigation partition soil salinization, improvement and utilization provides a theoretical basis.