The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. ...The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. To improve the accuracy of soil-erosion estimates, a new C-factor estimation model was developed based on land cover and time series normalized difference vegetation index （NDVI） datasets. The new C-factor was then applied in the RUSLE to integrate rainfall, soil, vegetation, and topography data of different periods, and thus monitor the distribution of soil erosion patterns and their dynamics during a 3o-year period of the upstream watershed of Miynn Reservoir （UWMR）, China. The results showed that the new C-factor estimation method, which considers land cover status and dynamics, and explicitly incorporates within-land cover variability, was more rational, quantitative, and reliable. An average annual soil loss in UWMR of 25.68, 21.04, and 16.8o t ha-1 a-1 was estimated for 1990, 2000 and 2010, respectively, corroborated by comparing spatial and temporal variation in sediment yield. Between 2000 and 2010, a 1.38% average annual increase was observed in the area of lands that lost less than 5 t ha-1 a^-1, while during 1990-2000 such lands only increased on average by o.46%. Areas that classified as severe, very severe and extremely severe accounted for 5.68% of the total UWMR in 2010, and primarily occurred in dry areas or grasslands of sloping fields. The reason for the change in rate of soil loss is explained by an increased appreciation of soil conservation by developers and planners. Moreover,we recommend that UWMR watershed adopt further conservation measures such as terraced plowing of dry land, afforestation, or grassland enclosures as part of a concerted effort to reduce on-going soil erosion.展开更多
Natural wetland is one of the most important ecosystems on the earth. However, the natural wetlands in China suffered great loss and degradation due to the rapid growth of human population and economy, together with t...Natural wetland is one of the most important ecosystems on the earth. However, the natural wetlands in China suffered great loss and degradation due to the rapid growth of human population and economy, together with the long-term over-exploitation. Therefore, improving and restoring wetlands＇ various functions, such as slowing the runoff, flood control and drought prevention, water purification and restoring and rebuilding wetlands in the appropriate geographical places are the pressing issues human face today. Based on the fundamental concepts of the wetland restoration, this article expounded its principles and guidelines, illustrated three basic modes, and summarized the main goal and basic strategy in China. Finally the assessment and future trends of the wetland restoration were discussed.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.41101399)the open fund of State Key Laboratory of Remote Sensing ScienceJointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University,China
文摘The Revised Universal Soil Loss Equation （RUSLE） was applied to assess the spatial distribution and dynamic properties of soil loss with geographic information system （GIS） and remote sensing （RS） technologies. To improve the accuracy of soil-erosion estimates, a new C-factor estimation model was developed based on land cover and time series normalized difference vegetation index （NDVI） datasets. The new C-factor was then applied in the RUSLE to integrate rainfall, soil, vegetation, and topography data of different periods, and thus monitor the distribution of soil erosion patterns and their dynamics during a 3o-year period of the upstream watershed of Miynn Reservoir （UWMR）, China. The results showed that the new C-factor estimation method, which considers land cover status and dynamics, and explicitly incorporates within-land cover variability, was more rational, quantitative, and reliable. An average annual soil loss in UWMR of 25.68, 21.04, and 16.8o t ha-1 a-1 was estimated for 1990, 2000 and 2010, respectively, corroborated by comparing spatial and temporal variation in sediment yield. Between 2000 and 2010, a 1.38% average annual increase was observed in the area of lands that lost less than 5 t ha-1 a^-1, while during 1990-2000 such lands only increased on average by o.46%. Areas that classified as severe, very severe and extremely severe accounted for 5.68% of the total UWMR in 2010, and primarily occurred in dry areas or grasslands of sloping fields. The reason for the change in rate of soil loss is explained by an increased appreciation of soil conservation by developers and planners. Moreover,we recommend that UWMR watershed adopt further conservation measures such as terraced plowing of dry land, afforestation, or grassland enclosures as part of a concerted effort to reduce on-going soil erosion.
基金supported by the Key Project of Control and Treatment of Water Pollution of China (2012ZX07204-004 and 2012ZX07204-001-004)
文摘Natural wetland is one of the most important ecosystems on the earth. However, the natural wetlands in China suffered great loss and degradation due to the rapid growth of human population and economy, together with the long-term over-exploitation. Therefore, improving and restoring wetlands＇ various functions, such as slowing the runoff, flood control and drought prevention, water purification and restoring and rebuilding wetlands in the appropriate geographical places are the pressing issues human face today. Based on the fundamental concepts of the wetland restoration, this article expounded its principles and guidelines, illustrated three basic modes, and summarized the main goal and basic strategy in China. Finally the assessment and future trends of the wetland restoration were discussed.
