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Spatiotemporal dynamics of soil water-salt and its topographic gradient effects on Alpine area over the Northeastern Tibetan Plateau, China

Authors :
Xiaoning Zhang
Lili Nian
Samuel Adingo
Quanxi Wang
Xiaodan Li
Xuelu Liu
Xingyu Y. Liu
Yingbo Yang
Caihong Hui
Miaomiao Zhang
Zixuan Mao
Quanxi Li
Li Luo
Biao Ma
Source :
Frontiers in Environmental Science, Vol 10 (2022)
Publication Year :
2022
Publisher :
Frontiers Media S.A., 2022.

Abstract

Soil water–salt variations at different spatiotemporal scales and their influencing factors are essential for regional vegetation restoration and management. However, the study of soil water–salt of the alpine area has not taken into account the effect of topography, especially in the long time series. This work investigated the spatiotemporal characteristics of water and salt in topsoil from 2000 to 2021, using regression analysis of on-site data and MODIS products. The heterogeneity and trends of soil water–salt in various topographic factors (elevation, slope, and aspect) were also explored by selecting the maximum area of each gradient factor as the constrained condition with the help of ArcGIS software. The results revealed that 1) the models applied to SWC (soil water content), EC (electrical conductivity), and pH utilizing vegetation indices were suitable for estimating the spatiotemporal variations of soil water–salt. 2) Soil water–salt exhibited local aggregation characteristics with an upward trend in SWC and a downward trend in EC and pH as a whole. 3) Mean annual SWC peaked at 3,400–3,800 m with increasing elevation and trended downward with increasing slope. The aspect of mean annual SWC was characterized by lower values in the southwest and south and higher values in the north, while the results for pH were reversed. The slope had a greater influence on EC than on SWC and pH. 4) The trend change of SWC, EC, and pH fluctuated at 2000–2,400 m and >4,600 m with a clear inflection point at 4°–8° and 20°–24°, respectively. In summary, the effects of topography responded to the distribution and trends of soil water–salt. The results have significant implications for implementing ecological improvements in regions with complicated topography and can serve as a reference for formulating future ecological policies.

Details

Language :
English
ISSN :
2296665X
Volume :
10
Database :
Directory of Open Access Journals
Journal :
Frontiers in Environmental Science
Publication Type :
Academic Journal
Accession number :
edsdoj.49ba3db6067342eab4ba7d5e288df799
Document Type :
article
Full Text :
https://doi.org/10.3389/fenvs.2022.950547