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Sichuan Normal University (2010)

Northwest deterioration and desertification of grassland vegetation restoration

Shi Chang Guang

Titre : Northwest deterioration and desertification of grassland vegetation restoration

Auteur : Shi Chang Guang

Grade : Master’s Theses 2010

Université : Sichuan Normal University

Résumé partiel
At present, the grassland degradation and desertification has become an issue of China and the world, the plateau grassland area located in the northwestern Sichuan Province is no exception. In order to prevent further degradation of grassland and restore the degraded grassland, government has been actively engaged in grassland vegetation recovery, and carried out a lot of measures. This paper was based on the vegetation restoration measures in northwestern Sichuan, adopted the method of field researches combined with analysis in lab, by researching to the basic physical and chemical properties of soil and community characteristics of grassland with different vegetation recovery years, focused on the distribution characteristics, the dynamic changes and the relationship between vegetation and soil in the recovery process, and attempted to offer basis for the defending and recovering work for the grassland degradation and desertification of this area. The main results see below,(1) The soil content of soil moisture and bulk density has changed significantly. With the vegetation recovery years increased, the contents of soil moisture increased obviously, especially on the superficial soil layer. Compared with the CK1plot, soil moisture of 1a, 3a, 7a plots increased by 2.07%, 13.97%, 6.03% in the 0-20cm layer, while it increased by 6.93%, 17.17%, 10.25% in the 20-40cm soil layer ; soil bulk density showed a decreased trend, 0-20cm layer of soil bulk density decreased by 0.70%, 2.82% and 1.41%, and in the 20-40cm layer, they respectively decreased by 0.69%, 17.17% and 10.25%.(2) During the process of vegetation recovery, soil chemical properties showed an increased trend, especially in the soil surface. From CK1plot to 7a plot, content of organic matter in the 0-20cm soil layer were separately 2.67 g.kg-1, 3.12 g.kg-1, 3.51 g.kg-1 and 3.22 g.kg-1, compared to CK1 plot, it increased by 16.85%, 31.46% and 20.60 % ; there was a less increase in the 20-40cm soil layer. The other nutrients in the soil also changed by different degrees, including soil total nitrogen, total phosphorus, available nitrogen, available phosphorus and available potassium radiated different levels of growth trend, while the total potassium content was not obvious. Further analysis showed that the impact of vegetation recovery in the 0-20cm soil layer is greater than that in the 20-40cm soil layer.(3) The vegetation investigation reports showed that plant species were gradually increasing during the process.

Mots clés : Sichuan northwest grassland degradation soil degradation and desertification vegetation recovery physical and chemical properties

Présentation (Dissertation topics)

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