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Arid Land Geography ›› 2022, Vol. 45 ›› Issue (5): 1547-1558.doi: 10.12118/j.issn.1000-6060.2022.018

• Biology and Pedology • Previous Articles     Next Articles

Analysis of cultivated land salinization in Kashgar Oasis based on PSO-PNN model

XIE Conghui1,2(),WU Shixin1(),LIN Juan3,ZHUANG Qingwei4,ZHANG Zihui1,2,HOU Guanyu1,2,LUO Geping1   

  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. Xinjiang Uygur Autonomous Region Institute of Natural Resources Planning, Urumqi 830011, Xinjiang, China
    4. State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, Hubei, China
  • Received:2022-01-11 Revised:2022-02-11 Online:2022-09-25 Published:2022-10-20
  • Contact: Shixin WU E-mail:xieconghui19@mails.ucas.ac.cn;wushixin@ms.xjb.ac.cn

Abstract:

Salinization is one of the main causes of low yields in oasis agriculture and a major constraint and barrier to agricultural and sustainable development. In order to improve the productivity of saline-cultivated land and to promote the sustainable development of oasis agriculture, and taking the cultivated land of the Kashgar Oasis in Xinjiang, China, as the research object, this study used Landsat 8 OLI remote sensing image data to extract 20 remote sensing indices. It also calculated the reclamation age of cultivated land in the study area based on land use data and downscaled the vegetation net primary productivity (NPP) data simulated by the vegetation photosynthesis model using a linear-fitting method. In this analysis, soil sampling and measured data were used to obtain the relevant remote sensing characteristic variables, the probabilistic neural network (PNN) model of particle swarm optimization (PSO) optimization was used to classify the degree of salinization, and, finally, the distribution of the salinization level of cultivated land in the study area was obtained and then superimposed onto the cultivated land reclamation age and NPP in the study area. The following conclusions were reached: (1) In this paper, five remote sensing parameters: enhanced vegetation index (EVI), salinity index 2 (SI2), humidity index (WI), MSAVI-WI-SI characteristic space (MWSI), and band 6 (B6, 2.11-2.29 μm), were selected to invert the degree of salinization using the PSO-PNN model, and this method was found to be effective for salinization inversion. (2) The greater the reclamation years of cultivated land, the lower the degree of salinization in the area. The newly reclaimed cultivated land is primarily located in the eastern part of the study area. The newly reclaimed cultivated land in the western part of the study area is more sparse and is mostly comprised of oasis agricultural areas with a land age of more than 45 years. (3) Salinization of cultivated land has significantly reduced its productivity. Most of the areas with a higher NPP of cultivated land are located in the west, and most of the lower areas are in the east, which is nearly the inverse of the hierarchical distribution of salinization degrees.

Key words: remote sensing (RS), geographic information system (GIS), salinization inversion, particle swarm optimization, probabilistic neural network