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Accueil du site → Doctorat → Chine → 2005 → Seeding Biology of the Plant Species Used in Air Seeding in Ordos Plateau and the Optimized Scheme for Vegetation Restoration

Beijing Forestry University (2005)

Seeding Biology of the Plant Species Used in Air Seeding in Ordos Plateau and the Optimized Scheme for Vegetation Restoration

姜联合;

Titre : Seeding Biology of the Plant Species Used in Air Seeding in Ordos Plateau and the Optimized Scheme for Vegetation Restoration

Auteur : 姜联合;

Grade : Doctoral Dissertation 2005

Université : Beijing Forestry University

Résumé
Owing to the serious effect of quick desertification on socio economy and environment, combating desertification has been more urgent work at the country level. The Ordos plateau is one of the center of desertification in China, although great efforts on desertification has been made from 1950s, a great number of man power and materials has been devoted, and thus great progress has been made. However, it is very difficult to reverse the situation of desertification that desertification improved partially and was inverse generally. The reasons lied in many aspects. Among them, the disconnection of the engineering for combating desertification and local socio economic development and ignoring holding capacity of natural environment should be the main reasons. Now, the foundation of coal and natural gas in the Ordos plateau made the combating desertification more important and urgent. Therefore, explaining the basic desertification reasons, the reasonable evaluation on ongoing engineering and technologies and pursuit for reasonable pattern for combating desertification in the Ordos plateau will make it more efficient for combating desertification, and also will set a sample for desertification combating in similar zones in China.The paper analyzed the reason of desertification in the Ordos plateau by the climatic change and socio economic development in long term and in large scale ; explained the rule of germination and seedling emergence, which may contribute to improve the technology of air seeding for combating desertification by the germination experiment of the main species related to the effect on temperature, light intensity and sand burial in growth cabinet, at last contribute to obtain suitable timing for air seeding ; found the better methodsfor sapling transplantation from nursery by the regeneration experiment of sapling treated, which promoted the quick vegetation restoration ; determined the suitable restoration vegetation coverage and suitable livestock density by the field observation and the model simulation results ; found the reasonable zonal economic orientation and the pattern by the multiple statistic analysis and socio economic development analysis, which eliminated the possibility of desertification ; finally established the optimized eco-production pattern for desertification combating based on the above analysis. The research was focused on the following aspects :(1) Climatic change of 50 years in the Ordos plateau represented by Ordos city was analyzed. Temperature increment combined with precipitation decrement in autumn and winter will reinforce the effects of drought. Moreover, autumn and winter is the season that wind is prevailing and soil surface is bared, the trend of drought in this time will reinforce the desertification. This should be one reason for desertification and ecosystem degradation in the Ordos plateau. Overgrazing and land exploitation are main reason for desertification in this region. During 1980s, although sowing cropland area changed insignificantly, land exploitation and then abandonment in short time should be the hidden reason. The number of livestock increased form 300000 in 1947 to 1.3 million recently, the overgrazing is thus very serious. Meanwhile, economic supplement by different zones was ignored, this situation further decreased the resource applicability and thus speed the desertification.(2) Germination of six species (Hedysarum laeve, Caragana korshinskii, Caragana intermedia, Glycyrrhiza uralensis, Medicago sativa and Astragalus adsurgens) was independent of light, while germination of three species (Agriophyllum squarrosum, Artemisia sphaerocephala, Artemisia ordosica) was significantly inhibited by light. Compared with the high final germination percentage (92.7%) of Agriophyllum squarrosum in the dark, even weak light intensities severely inhibited its germination and resulted in very low final germination percentage (12.9%). Strong light intensity also inhibited germination of Artemisia sphaerocephala and Artemisia ordosica,

Mots clés : Ordos plateau; Air seeding; Germination; Seeding emergence; Growth model; Optimized vegetation restoration; Socio-economic development;

Présentation (CNKI)

Page publiée le 18 avril 2018