作者机构:
College of Resources and Environment, Hunan Agricultural University, Changsha, 410128, China;Institute of Soil and Water Conservation, NWUAF,Chinese Academy of Sciences & Ministry of Water Reso
会议名称:
2010 International Conference on Combating Land Degradation in Agricultral Areas(土地退化防治国际学术研讨会 LandCon2010)
会议时间:
2010-10-11
会议地点:
西安
会议论文集名称:
2010 International Conference on Combating Land Degradation in Agricultral Areas(土地退化防治国际学术研讨会 LandCon2010)论文集
关键词:
impacts on environment by soil and water conservation;value of ecological service;Yanhe River Basin
摘要:
Soil erosion is one of the important causes of land degradation. Many soil and water conservation practices have been implemented in order to decrease soil erosion and prevent land degradation for a long period in Yanhe River Basin which is characteristic of serious soil erosion for concentrated rainfall, erodible soil and hilly and gully terrain. Soil and water conservation practices can not only reduce soil and water loss but also change the situation of the land surface and influence the structure and functions of the eco-system. This study tried to put forward of the index of impacts by soil and water conservation on environment to quantitatively assess the impacts. The index was equal to 100 multiplied by percentage of ecological service value of the basin eco-system in the end state to the initial state of soil and water conservation and it was 100 if keeping the initial state. The larger the index was, the more the environment quality improved if not considering other factors. It could be calculated using the data of precipitation, soil, terrain and soil and water conservation practice with the guidance of the theory of soil and water conservation science and science of ecological economics based on GIS. For the study area the ecological service value of eco-system was 13.693 billion and 24.464 billion RMB respectively in 1997 and 2006 in the initial state of soil and water conservation while was 14.264 and 25.620 billion RMB in the end state. The index of impacts on environment was 106.55 and 110.24 in 1997 and 2006 and soil and water conservation improved the quality of environment.
摘要:
In the process of urban agglomeration development, space distribution and form structure develop ceaselessly. The space patterns of urban agglomeration are related to city production, living standards and a series of important issues such as developing and reforming rationally. In December, 2007, Changsha, Zhuzhou, and Xiangtan have been became one Megalopolis of "two-oriented" society. It indicated that our urban agglomeration development has entered the new stage. In this paper, Changsha-Zhuzhou-Xiangtan Megalopolis was study as an important object. The technology of the study is RS and GIS while the basic data are multitemporal RS image. Used by the information of multitemporal RS image. The space patterns change of the Chang-zhu-tan Megalopolis such as spatial framework, Space center and development model was discovered. Furthermore, the development tendency of the Megalopolis was analyzed in this paper.
摘要:
Rare earth elements (REEs) are widely used to increase crop production in China. However, little attention has been paid to their impacts on aquatic ecology. Batch cultivation was used here to study the effects of lanthanum (La) and EDTA on the growth and competition of the cyanobacteriurn Microcystis aeruginosa and the green alga Scenedesmus quadricauda. When EDTA was present at a very low concentration (0.269 mu mol L(-1)), low lanthanum concentrations (<= 7.2 mu mol L(-1)) had little stimulative effect oil the growth of M. aeruginosa and S. quadricauda, whereas a high lanthanum concentration (72 mu mol L(-1)) had significant inhibitory effect oil both of them. The results of cultivation experiments suggested that the inhibitory effect on M. aeruginosa was higher than that oil S. quadricauda and S. quadricauda could become dominant in mixed cultures. When lanthanum was not added to the culture medium, high EDTA concentrations (> 13.4 mu mol L(-1)) had a great inhibitory effect on the growth of M. aeruginosa but little effect on the growth of S. quadricauda, which could become dominant in the mixed cultures. Lanthanum and EDTA had complex effects on the growth and competition of M. aeruginosa and S. quadricauda. EDTA did not change the stimulation of low lanthanum concentrations on both, but at intermediated concentrations (2.69-13.4 mu mol L(-1)) it could greatly alleviate lanthanum inhibition on M. aeruginosa; thus, M. aeruginosa would dominate S. quadricauda in these mixed cultures. Lanthanum at low concentration (7.2 mu mol L(-1)) could also alleviate the inhibition of high EDTA oil M. aeruginosa, but did not alter the outcome of the competition. (C) 2008 Elsevier GmbH. All rights reserved.