Arid Zone Research ›› 2024, Vol. 41 ›› Issue (7): 1120-1130.doi: 10.13866/j.azr.2024.07.04

• Land and Water Resources • Previous Articles     Next Articles

Evaluation of multimodel inversion effects on soil salinity in oasis basin

LONG Weiyi1,2,3(), SHI Jianfei1,2,3, LI Shuangyuan1,2,3, SUN Jinjin1,2,3, WANG Yugang1,2,3()   

  1. 1. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, Xinjiang, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China
    3. Fukang Station of Desert Ecology, Chinese Academy of Sciences, Fukang 831505, Xinjiang, China
  • Received:2024-03-12 Revised:2024-04-05 Online:2024-07-15 Published:2024-08-01

Abstract:

A case study was conducted on the plain oasis in the Sangong River Basin of Xinjiang, China, to monitor and control soil salinity to improve the sustainable development of oases. Based on the climate, topography, vegetation, groundwater, and salinity of the soil survey data, many model methods, such as the Random Forest model, Support Vector Machine, Decision Tree, and Ordinary Kriging, were applied to estimate the inversion accuracy and the spatial distribution of soil salinity in the topsoil. The results revealed that the range of soil salinity values was 0.29-30.18 g·kg-1 and an average of 4.06 g·kg-1 for the sample sites. The value of the coefficients of variation was 149.73%, indicating a robust spatial variability. Among the four models, the Random Forest model showed a higher simulation precision compared to the others, with a coefficient of determination value of 0.73, a root-mean-square error value of 1.89 g·kg-1, and an absolute mean error value of 1.49 g·kg-1. The results of the Random Forest model inversion revealed that areas of higher soil salinity were concentrated in the northwest and the midbasin. Among the nine environmental covariates, elevation and groundwater salinity had a significant impact on the accuracy of identifying spatial distribution characteristics of soil salinity. In general, the Random Forest model as a machine learning method can not only avoid the smoothing effect and abrupt changes on both sides of the map boundary but also identify the local spatial distribution of soil salinity in the basin. The results of this study can provide technical and methodological applications for the long-term monitoring of soil salinization in arid areas.

Key words: machine learning, soil salinity, spatial distribution, Sangong River Basin, arid area