基于EM38的玛纳斯县土壤剖面盐分的解译模型构建

大地电导率仪(EM38)是快速无损测定土壤盐分的有效方法。为建立新疆农田土壤EM38测试值与土壤盐分关系模型，以新疆玛纳斯县农田土壤为研究对象，利用EM38在野外实地测定土壤表观电导率，并挖掘土壤剖面进行分层采样，室内测定土壤盐分含量，据此构建基于EM38的土壤盐分解译模型。结果表明：（1）利用土壤实测盐分和EM38电导率数据，分别建立不同土壤深度下EM38垂直模式和水平模式以及两者联用的二元线性回归土壤盐分解译模型。（2）3种EM38盐分解译模型的R2随着土壤深度增加而增加，并且在土壤深度小于20 cm时，垂直模式的解译精度大于水平模式，深度大于20 cm后，解译精度则刚好与之相反。（3）二元线性回归模型的解译精度明显优于一元线性回归模型。本研究所构建的EM38土壤盐分解译模型，将为绿洲农田土壤盐分快速调查和动态监测提供可靠的反演参数和模型。

Modeling of Soil Salinity Interpretation in Manas County Based on EM38

Geodetic conductivity meter (EM38) is an effective method for rapid and nondestructive determination of soil salinity. To establish the relationship model between soil salinity and EM38 test value of farmland in Xinjiang, farmland soil in Manas County of Xinjiang was taken as the research object, EM38 was used to measure soil apparent conductivity in the field, and soil profile was excavated for stratified sampling, then the soil salinity content was measured in the laboratory. Based on this, a soil salinity interpretation model based on EM38 was constructed. The results showed that: (1) based on the measured soil salinity and EM38 conductivity data, the EM38 vertical model and horizontal model and their combined binary linear regression soil salinity interpretation model at different soil depths were established; (2) the R² of the three EM38 salinity interpretation models increased with the increase of soil depth, and the accuracy of the vertical model was higher than that of the horizontal model when the soil depth was less than 20 cm, but the accuracy was conversed when the soil depth was greater than 20 cm; (3) the interpretation accuracy of binary linear regression model was obviously better than that of unitary linear regression model. The EM38 soil salinity interpretation model constructed in this study could provide reliable inversion parameters and models for the rapid investigation and dynamic monitoring of soil salinity in oasis farmland.