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Xinjiang University (2011)

Characteristics of Alkalinized Soil in Qitai Oasis in Xinjiang and the Investigation by Remote Sensing

张芳;Zhang Fang

Titre : Characteristics of Alkalinized Soil in Qitai Oasis in Xinjiang and the Investigation by Remote Sensing

Auteur : 张芳;Zhang Fang

Grade : Doctoral Dissertation 2011

Université : Xinjiang University

Résumé partiel
Saline-alkali soil is a general designation of a series of soil which is affected by saline-alkali components and includes all kinds of saline soil, sodic soil and soil with different degrees of alkalization and Salinization. Xinjiang has the largest area of saline-alkali soil hence is called as“the saline-alkali soil museum in the world”. Soil alkalinization and salinization have already become tone of the major land degradation reasons in oasis, the only land for the people to live in Xinjiang. The problem about soil alkalinization and salinization is also an issue related to the regional sustainable development and the environment improvement in Xinjiang’s arid areas. Hence soil alkalinization and salinization have always been a focused research field. Alkali soil and salty soil have different chemical and physical properties, land surface symptoms, occurrence and development mechanism, therefore they belong to different soil types. So far, in Xinjiang, studies on the soil salinization and alkalinization mostly focuson southern areas where salt is significantly accumulated in topsoil but very few on larger areas of alkalinized soil in the Northern Slope Area of Tianshan Mountain in XinjiangBased on a large number of field investigations and soil, spectrum and vegetation samples collected from given spots, as well as the application of geography, agrology, environmentology, ecology and remote sensing theory, this thesis systematically discusses the physical and chemical characteristics of alkalinized soil, the correlations between soil alkalinization and environment factors, the subdivision of degree of soil alkalinization, the characteristic s of spectra of alkalinization soil in different scales and the investigation by remote sensing on the alkalinized soil in Qitai Oasis in Xinjiang by the 3S techniques and quantitative and qualitative method s.The first chapter mainly introduces the background and the purpose of the soil alkalinization study summarizes the domestic and international advances of soil alkalinization research, and then demonstrates author’s research concepts, research contents, research procedures and methods in detail. The second chapter primarily introduces general situations of the study area, and specifies the procedures of field investigations, data collection and sample tests. The third chapter discusses soil physical and chemical properties in the study area, investigates into the distribution of the alkali -saline soil and the correlation between this spatial pattern and the topographic factor extracted from SRTM data and analyzes the spatial variation and distribution based on the regional topographic factor using the data from monitoring the soil alkali content in Qitai oasis. The fourth part studies the relationship between halophyte coverage and soil alkalinization indices and builds the subdivision of the degree of soil alkalinization based on the restraining effect on halophyte from different levels of soil alkalinization. The fifth part focuses on the correlation between soil pH and spectrums in three different scale (field-measured spectrum,laboratory-measured spectrum and the image spectrum). A new quantitative remote sensing monitoring index pHI for soil alkalinization is built. The last chapter summarizes the whole thesis and lists the achievements, difficulties and prospect s of this study.Main conclusions and developments as follows :(1) Alkaline-earth in the study area presents a typical desalination-alkalinization feature

Mots clés : chemical and physical properties of alkalinized soil; the subdivision of the degree of soil alkalinization; characteristic of response different scale spectrum to alkalinization soil; corresponding scale transformation; quantitative remote sensing monitoring index pHI;

Présentation (CNKI)

Page publiée le 5 mai 2013, mise à jour le 16 mai 2018