Evaluation of big scale agriculture in grassland ecosystems in Eurasian Continent

从2003年到2006年，我们在乌克兰、哈萨克斯坦、蒙古和中国（内蒙古）四个国家进行了欧亚草原生态调查。通过植物群调查、植被调查、生物量调查和土壤剖面调查，获得了以下新的认识：1）哈萨克斯坦-蒙古边境欧亚草原东西部植物区系差异较大;那里有阿尔泰山和天山。2）欧亚草原东部与日本的植物区系在草地上差异较大，而在湿地上相似; 3）欧亚草原东部与西部在哈萨克斯坦与蒙古交界处的植物群落在物种组成上也存在差异; 4）可以估算出弃耕后的演替序列。通过样方调查发现，蒙古草原生物多样性在弃耕后10年左右达到最大值，土壤碳积累量为450- 1000 g/ha。5）欧亚草原东部和西部土壤也存在差异。（6）人类活动对东部草原的影响主要是放牧，而对西部草原的影响主要是耕作;（7）欧亚草原东半部和西部的土壤性质存在差异。

From 2003 to 2006, we conducted ecological survey of the Eurasian steppe in four countries, Ukraine, Kaza-khstan, Mongolia and China (Inner Mongolia). Our survey was made up by 1) flora survey, 2) vegetation survey, 3) biomass survey and 4) soil profile survey.We could gain, as a result, some new knowledge as follows;1) The floras between eastern part and western part of Eurasian steppe differed much at the border of Kazakhstan and Mongolia. There are Altay Mountains and Tenshan Mountains there. Plants can't exceed high mountains, freely.2) The floras between eastern part of Eurasian steppe and Japan quite differ each other in grassland, but are similar in wetland.3) Plant communities based on species composition also differed between eastern and western part of Eurasian steppe at the border of Kazakhstan and Mongolia.4) We could estimate a sere of succession after abandon plowing. It became clear that the biodiversity grew maximum at about ten years after abandon plowing and that 450-1000g/ha of carbon accumulated in Mongolian grassland, as a result of quadrat method of survey.5) Soils of eastern and western part of Eurasian steppe are also different. Eastern soil is Kastanozem, while western one is Chernozem.6) Main human impact in eastern steppe is grazing, while that of western steppe is plowing.and7) Consequently, many properties are different between eastern half of Eurasian steppe and western one.