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Accueil du site → Doctorat → Chine → 2017 → Overgrazing and Light Grazing Effect on Vegetation,Soil and Socio-Economy of Pasture in the Mongolian Steppe

Chinese Academy of Agricultural (2017)

Overgrazing and Light Grazing Effect on Vegetation,Soil and Socio-Economy of Pasture in the Mongolian Steppe

格日勒玛(Gerelmaa Khurlee)

Titre : Overgrazing and Light Grazing Effect on Vegetation,Soil and Socio-Economy of Pasture in the Mongolian Steppe

Auteur : 格日勒玛(Gerelmaa Khurlee)

Grade : Doctoral Dissertation 2017

Université : Chinese Academy of Agricultural

Résumé
Grassland animal husbandry,which is highly adaptive to natural ecosystem,is a dominant industry of Mongolian.Vegetation characteristics of pastoralist households’pastures at different economic levels were quantified to compare the grassland conditions in overgrazing and light grazing in Khentii and Sukhbaatar province Mongolian eastern region in 2015-2016.During the experiment,we had collected 300 field notes,7050 plant samples and 1000 soil samples.The changes of plant and soil of overgrazing grassland and light grazing grassland social-economic status in the degradation grassland are as follows :(1)Comparing with light grazing grassland,the plant species number,vegetation cover,and biomass accumulation of the community and canopy cover of perennial grass plant species on the overgrazing grassland significantly decreased.The canopy covers of sedge,annual and biennials plants on the overgrazing grassland significantly increased.The community height is 20-50 cm and5-25 cm in light grazed and overgrazed grassland,respectively.Affected by overgrazing,leaf size and stem diameter of Leymus chinensis and Stipa grandis significantly decreased.(2)With the decreasing of geographical latitudes from north to south along transects Mongolia grasslands,the effects of overgrazing on canopy cover and biomass of perennial grasses have the decreasing trend.(3)In addition,our results in the Mongolia and Inner Mongolia of China showed that the percentages of perennial grasses significantly decreased induced by overgrazing.Affected by livestock overgrazing,the plant species with low nutritional value dramatically increased.The aboveground biomass,below ground biomass and total biomass of grassland of Mongolia are all higher than grassland of Inner Mongolia of China,which means Xiliin River Inner Mongolia of China has heavier grassland degradation.(4)The humus level in the brown soil rarely exceed 3%in the light clay soil the levels about at 2-3%,in the sandy soil 1.5-2%.Affected by overgrazing,soil sand composition content increased by 3%in layer of 0-30 cm and soil total carbon content overgrazed pasture in depth 0-10 cm Inner Mongolia of China Xiliin River province 9.0±0.03(kg/m 3),Mongolia Sukhbaatar province15.4±0.19(kg/m 3)and Mongolia Kentii province 9.9±0.01(kg/m 3),and light grazed pasture 0-10cm 19.4±0.01(kg/m 3),19.7±0.25(kg/m 3),11.8±0.19(kg/m 3).The soil total nitrogen content overgrazed pasture in depth 0-10 cm in Inner Mongolia of China Xiliin River province was 0.84±0.08(kg/m 3),in Mongolian Sukhbaatar province was 1.24±0.14(kg/m 3)and in Mongolia Kentii province was 0.92±0.01(kg/m 3),and in light grazed pasture was0-10 cm 2.31±0.45(kg/m 3),1.69±0.55(kg/m 3),1.2±0.12(kg/m 3).The phosphorous content in depth of 0-10 in Inner Mongolia of China Xiliin River province was3.1±0.06(kg/m 3),in Mongolian Sukhbaatar province was 0.3±0.01(kg/m 3)and in Mongolian Kentii province was 0.18±0.77(kg/m 3)and in light grazed pasture of 0-10 cm was 0.32±0.04(kg/m 3),0.33±0.07(kg/m 3),and 0.03±0.12(kg/m 3).(5)Grassland animal husbandry is the foundation and main industry of social and economic development in Mongolian.Similar to Inner Mongolia of China,households are independent grazing units.With the marketization and livestock husbandry development,the land desertification and ecological degradation is intensified,and the frequency of grassland catastrophes increased,which caused household sheep units decreased,monthly income decreased,45%of the total interviewed households were living below poverty line,72.6-80.5%of the household’s income is only sufficient for food and clothing expenses

Mots clés : grazing; plant canopy cover; biomass; perennial grasses; annual and biennials; soil; social and economic;

Présentation (CNKI)

Page publiée le 12 juin 2019