Arid Zone Research ›› 2024, Vol. 41 ›› Issue (9): 1435-1445.doi: 10.13866/j.azr.2024.09.01

• The Third Xinjiang Scientific Expedition • Previous Articles     Next Articles

Changes in the salt content of the plow layer soil during cultivation from 1990 to 2022 on the northern slope of the Tianshan Mountains

ZHANG Bin1,2,3(), ZHENG Xinjun1,2, WANG Yugang1,2, TANG Lisong1,2(), LI Yan1,2,3, DU Lan1,2,3, TIAN Shengchuan1,2,3   

  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. Fukang Station of Desert Ecology, Chinese Academy of Sciences, Fukang 831505, Xinjiang, China
    3. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2024-03-26 Revised:2024-04-28 Online:2024-09-15 Published:2024-09-25
  • Contact: TANG Lisong E-mail:zhangbin211@mails.ucas.ac.cn;tangls@ms.xjb.ac.cn

Abstract:

In recent years, with frequent changes in land use and extensive reclamation of farmlands, soil salinization has become an environmental factor leading to the degradation of cultivated land quality and hindering the development of oasis-based agriculture on the northern slopes of the Tianshan Mountains. However, an objective understanding of the current status of soil salinization in cultivated lands and its evolution is lacking. This study, based on detailed survey data, actual soil measurements, and the China Land Cover Dataset, compares the advantages and disadvantages of traditional interpolation models and random forest interpolation models for estimating the salt content in the topsoil layer (0-30 cm). The most accurate quantitative prediction model was selected to quantitatively predict as well as obtain the distribution and change characteristics of the salt content in the plow layer soil of the northern slope of the Tianshan Mountains. By using space for time, the salt content in the plow layer soil of newly reclaimed farmland over 30 years was compared to understand the impact of cultivation duration. The results showed that: (1) Compared to traditional interpolation methods, the random forest algorithm could more accurately predict the soil salt distribution of salinized land. (2) In the northern Tianshan region, there was significant spatial heterogeneity in the salt content of the topsoil, with salt concentrations in the higher altitude areas leaching with runoff and accumulating in the lower altitude areas near rivers or in depressions close to the deserts. (3) With the extension of cultivation years, the overall salt content in the plow layer soil of the northern slope of the Tianshan Mountains decreased, and the degree of soil salinization converged at a moderate level, trending toward equilibrium or “centralization.” This study has enhanced the understanding of the current salinization status of cultivated land and the alterations in soil salinity from the reclamation of virgin wastelands to cultivated lands. It provides theoretical support for the development, management, and effective use of reserve land resources in arid areas, and offers a scientific basis for the sustainable development of agriculture.

Key words: Random Forest, salinization of plow layer soil, years of cultivation, spatio-temporal variation, northern slope of the Tianshan Mountains