本文聚焦公路边坡抗侵蚀生态矩阵(Erosion Control Matrix,简称ECM)的抗冲刷稳定性能展开研究。通过构建模拟秦唐高速公路秦皇岛段边坡的试验模型,选用粉土和粉质黏土,以高羊茅为草籽,设置直接植草、土工格室植草和ECM生态矩阵植草三种...本文聚焦公路边坡抗侵蚀生态矩阵(Erosion Control Matrix,简称ECM)的抗冲刷稳定性能展开研究。通过构建模拟秦唐高速公路秦皇岛段边坡的试验模型,选用粉土和粉质黏土,以高羊茅为草籽,设置直接植草、土工格室植草和ECM生态矩阵植草三种坡面处理方式,模拟小雨和大雨降雨条件进行冲刷试验。研究结果表明:小雨时各坡面植被有一定防护作用,无明显侵蚀;大雨时,直接植草坡面侵蚀量大,而ECM处理坡面侵蚀量始终为0,土工格室处理坡面侵蚀量介于两者之间。ECM处理坡面在不同降雨强度下抗冲刷稳定性优异,其ECM处理能提高种子发芽率、促进植物生长,提升边坡生态稳定性。本研究为公路边坡生态修复技术的选择提供了数据支持和理论依据。展开更多
Vegetable runoff nitrogen(N)loss is a serious environmental issue.However,whether the volume or N content of runoff determines the final N losses has not been clarified,which limited the optimal N managements in veget...Vegetable runoff nitrogen(N)loss is a serious environmental issue.However,whether the volume or N content of runoff determines the final N losses has not been clarified,which limited the optimal N managements in vegetable production.Here,we conducted a simulated rainfall experiment to study the runoff N loss flux pattern and the accumulation rate as well as the main influencing factors.The results showed that at 20 to 30 min,the volume of runoff water with a high N content reaches a critical inflection point of increase.Under 55 mm/h rainfall intensity,the N concentration decreased continuously.Under 75 mm/h,the soluble N concentration decreased during the first 25 min;thereafter,it stabilized.However,the total and particulate N decreased significantly after 30 min.Nitrogen losses via runoff from vegetable fields were from 18.5 to 26.0 kg/ha under two rainfall intensities.Runoff soluble N losses were mainly attributed to applied fertilizers(79.7%-95.5%),while particulate N losses were primarily originated from soil-retained N.Our data indicates that there was a significant difference in N losses pattern and influencing factors under varied fertilizer N inputs and rainfall intensities,which can help to optimize water and N fertilizer managements to mitigate non-point source N pollutants.In the future,long-term multi-site and-crop studies should be conducted to comprehensively clarify the N runoff losses in vegetable soils.展开更多
All characteristics of vegetation,runoff and sediment from 1960 to 2010 in the Xiliu Gully Watershed,which is a representative watershed in wind-water erosion crisscross region in the upper reaches of the Yellow River...All characteristics of vegetation,runoff and sediment from 1960 to 2010 in the Xiliu Gully Watershed,which is a representative watershed in wind-water erosion crisscross region in the upper reaches of the Yellow River of China,have been analyzed in this study.Based on the remote sensing image data,and used multi-spectral interpretation method,the characteristics of vegetation variation in the Xiliu Gully Watershed have been analyzed.And the rules of precipitation,runoff and sediment's changes have been illuminated by using mathematical statistics method.What′s more,the influence mechanism of vegetation on runoff and sediment has been discussed by using the data obtained from artificial rainfall simulation test.The results showed that the main vegetation type was given priority to low coverage,and the area of the low vegetation coverage type was reducing year by year.On the country,the area of the high vegetation coverage type was gradually increasing.In a word,vegetation conditions had got better improved since 2000 when the watershed management project started.The average annual precipitation of the river basin also got slightly increase in 2000–2010.The average annual runoff reduced by 37.5%,and the average annual sediment reduced by 73.9% in the same period.The results of artificial rainfall simulation tests showed that the improvement of vegetation coverage could increase not only soil infiltration but also vegetation evapotranspiration,and then made the rainfall-induced runoff production decrease.Vegetation root system could increases the resistance ability of soil to erosion,and vegetation aboveground part could reduce raindrop kinetic energy and splash soil erosion.Therefore,with the increase of vegetation coverage,the rainfall-induced sediment could decrease.展开更多
In this study, Land Surface Temperature(LST) and its lapse rate over the mountainous Kashmir Himalaya was estimated using MODIS data and correlated with the observed in-situ air temperature(Tair) data. Comparison betw...In this study, Land Surface Temperature(LST) and its lapse rate over the mountainous Kashmir Himalaya was estimated using MODIS data and correlated with the observed in-situ air temperature(Tair) data. Comparison between the MODIS LST and Tair showed a close agreement with the maximum error of the estimate ±1°C and the correlation coefficient >0.90. Analysis of the LST data from 2002-2012 showed an increasing trend at all the selected locations except at a site located in the southeastern part of Kashmir valley. Using the GTOPO30 DEM, MODIS LST data was used to estimate the actual temperature lapse rate(ATLR) along various transects across Kashmir Himalaya, which showed significant variations in space and time ranging from 0.3°C to 1.2°C per 100 m altitude change. This observation is at variance with the standard temperature lapse rate(STLR) of 0.65°C used universally in most of the hydrological and other land surface models. Snowmelt Runoff Model(SRM) was used to determine the efficacy of using the ATLR for simulating the stream flows in one of the glaciated and snow-covered watersheds in Kashmir. The use of ATLR in the SRM model improved the R2 between the observed and predicted streamflows from 0.92 to 0.97.It is hoped that the operational use of satellite-derived LST and ATLR shall improve the understanding and quantification of various processes related to climate, hydrology and ecosystem in the mountainous and data-scarce Himalaya where the use of temperature and ATLR are critical parameters for understanding various land surface and climate processes.展开更多
The runoff of some rivers in the world especially in the arid and semi-arid areas has decreased remarkably with global or regional climate change and enhanced human activities. The runoff decrease in the arid and semi...The runoff of some rivers in the world especially in the arid and semi-arid areas has decreased remarkably with global or regional climate change and enhanced human activities. The runoff decrease in the arid and semi-arid areas of northern China has brought severe problems in livelihoods and ecology. To reveal the variation characteristics, trends of runoff and their influencing factors have been important scientific issues for drainage basin man- agement. The objective of this study was to analyze the variation trends of the runoff and quantitatively assess the contributions of precipitation and human activities to the runoff change in the Huangfuchuan River Basin based on the measured data in 1960-2008. Two inflection points （turning years） of 1979 and 1998 for the accumulative runoff change, and one inflection point of 1979 for the accumulative precipitation change were identified using the methods of accumulative anomaly analysis. The linear relationships between year and ac- cumulative runoff in 1960-1979, 1980-1997 and 1998-2008 and between year and accu- mulative precipitation in 1960-1979 and 1980-2008 were fitted. A new method of slope change ratio of accumulative quantity （SCRAQ） was put forward and used in this study to calculate the contributions of different factors to the runoff change. Taking 1960-1979 as the base period, the contribution rate of the precipitation and human activities to the decreased runoff was 36.43% and 63.57% in 1980-1997, and 16.81% and 83.19% in 1998-2008, re- spectively. The results will play an important role in the drainage basin management. More- over, the new method of SCRAQ can be applied in the quantitative evaluation of runoff change and impacts by different factors in the river basin of arid and semi-arid areas.展开更多
Rainfall simulations have been conducted to study the soil erosion process of purple soil in two cultiva-tion practices—contour cultivation and downslope cultivation. Results showed that under the two cultivation pra...Rainfall simulations have been conducted to study the soil erosion process of purple soil in two cultiva-tion practices—contour cultivation and downslope cultivation. Results showed that under the two cultivation prac-tices,the surface runoff can be described by the logarithmic function formula. In the initial period of rainfall,the amount of runoff increased with the rainfall duration and 20 minutes later it became relatively constant. The chang-ing process of soil erosion rate may be described by the logarithmic function formula. The erosion rate increased with the rainfall duration and 20 minutes later it also became constant. Under downslope cultivation condition,the soil erosion rate increased more significantly than that under contour cultivation condition in the case of gentle rain-fall intensity,and there is no obvious difference in erosion rate for downslope cultivation and contour cultivation practices. However,with increasing rainfall intensity the soil erosion rate under the downslope cultivation condition could be more than 30 times that under the contour cultivation condition. But this kind of difference would be re-duced to some extent in the case of heavy rain.展开更多
The catchment of runoff which improves the moisture content condition in tree holes isof great improtance to the development of the afforestation in arid and semi-arid regions.The crux of this technique is the soil wa...The catchment of runoff which improves the moisture content condition in tree holes isof great improtance to the development of the afforestation in arid and semi-arid regions.The crux of this technique is the soil water content which influnences the survial rates,展开更多
文摘本文聚焦公路边坡抗侵蚀生态矩阵(Erosion Control Matrix,简称ECM)的抗冲刷稳定性能展开研究。通过构建模拟秦唐高速公路秦皇岛段边坡的试验模型,选用粉土和粉质黏土,以高羊茅为草籽,设置直接植草、土工格室植草和ECM生态矩阵植草三种坡面处理方式,模拟小雨和大雨降雨条件进行冲刷试验。研究结果表明:小雨时各坡面植被有一定防护作用,无明显侵蚀;大雨时,直接植草坡面侵蚀量大,而ECM处理坡面侵蚀量始终为0,土工格室处理坡面侵蚀量介于两者之间。ECM处理坡面在不同降雨强度下抗冲刷稳定性优异,其ECM处理能提高种子发芽率、促进植物生长,提升边坡生态稳定性。本研究为公路边坡生态修复技术的选择提供了数据支持和理论依据。
基金supported by the National Key Research and Development Program of China(No.2021YFD1700801).
文摘Vegetable runoff nitrogen(N)loss is a serious environmental issue.However,whether the volume or N content of runoff determines the final N losses has not been clarified,which limited the optimal N managements in vegetable production.Here,we conducted a simulated rainfall experiment to study the runoff N loss flux pattern and the accumulation rate as well as the main influencing factors.The results showed that at 20 to 30 min,the volume of runoff water with a high N content reaches a critical inflection point of increase.Under 55 mm/h rainfall intensity,the N concentration decreased continuously.Under 75 mm/h,the soluble N concentration decreased during the first 25 min;thereafter,it stabilized.However,the total and particulate N decreased significantly after 30 min.Nitrogen losses via runoff from vegetable fields were from 18.5 to 26.0 kg/ha under two rainfall intensities.Runoff soluble N losses were mainly attributed to applied fertilizers(79.7%-95.5%),while particulate N losses were primarily originated from soil-retained N.Our data indicates that there was a significant difference in N losses pattern and influencing factors under varied fertilizer N inputs and rainfall intensities,which can help to optimize water and N fertilizer managements to mitigate non-point source N pollutants.In the future,long-term multi-site and-crop studies should be conducted to comprehensively clarify the N runoff losses in vegetable soils.
基金Under the auspices of National Basic Research Program of China(No.2011CB403303)Innovation Scientists and Technicians Troop Construction Projects of Henan Province(No.162101510004)Foundation of Yellow River Institute of Hydraulic Research of China(No.HKY-2011-15)
文摘All characteristics of vegetation,runoff and sediment from 1960 to 2010 in the Xiliu Gully Watershed,which is a representative watershed in wind-water erosion crisscross region in the upper reaches of the Yellow River of China,have been analyzed in this study.Based on the remote sensing image data,and used multi-spectral interpretation method,the characteristics of vegetation variation in the Xiliu Gully Watershed have been analyzed.And the rules of precipitation,runoff and sediment's changes have been illuminated by using mathematical statistics method.What′s more,the influence mechanism of vegetation on runoff and sediment has been discussed by using the data obtained from artificial rainfall simulation test.The results showed that the main vegetation type was given priority to low coverage,and the area of the low vegetation coverage type was reducing year by year.On the country,the area of the high vegetation coverage type was gradually increasing.In a word,vegetation conditions had got better improved since 2000 when the watershed management project started.The average annual precipitation of the river basin also got slightly increase in 2000–2010.The average annual runoff reduced by 37.5%,and the average annual sediment reduced by 73.9% in the same period.The results of artificial rainfall simulation tests showed that the improvement of vegetation coverage could increase not only soil infiltration but also vegetation evapotranspiration,and then made the rainfall-induced runoff production decrease.Vegetation root system could increases the resistance ability of soil to erosion,and vegetation aboveground part could reduce raindrop kinetic energy and splash soil erosion.Therefore,with the increase of vegetation coverage,the rainfall-induced sediment could decrease.
基金Department of Science and Technology (DST), Government of India sponsored consortium project titled "Himalayan Cryosphere: Science and Society" and the financial assistance received from the Department under the project
文摘In this study, Land Surface Temperature(LST) and its lapse rate over the mountainous Kashmir Himalaya was estimated using MODIS data and correlated with the observed in-situ air temperature(Tair) data. Comparison between the MODIS LST and Tair showed a close agreement with the maximum error of the estimate ±1°C and the correlation coefficient >0.90. Analysis of the LST data from 2002-2012 showed an increasing trend at all the selected locations except at a site located in the southeastern part of Kashmir valley. Using the GTOPO30 DEM, MODIS LST data was used to estimate the actual temperature lapse rate(ATLR) along various transects across Kashmir Himalaya, which showed significant variations in space and time ranging from 0.3°C to 1.2°C per 100 m altitude change. This observation is at variance with the standard temperature lapse rate(STLR) of 0.65°C used universally in most of the hydrological and other land surface models. Snowmelt Runoff Model(SRM) was used to determine the efficacy of using the ATLR for simulating the stream flows in one of the glaciated and snow-covered watersheds in Kashmir. The use of ATLR in the SRM model improved the R2 between the observed and predicted streamflows from 0.92 to 0.97.It is hoped that the operational use of satellite-derived LST and ATLR shall improve the understanding and quantification of various processes related to climate, hydrology and ecosystem in the mountainous and data-scarce Himalaya where the use of temperature and ATLR are critical parameters for understanding various land surface and climate processes.
基金National Basic Research Program of China,No.2010CB428404
文摘The runoff of some rivers in the world especially in the arid and semi-arid areas has decreased remarkably with global or regional climate change and enhanced human activities. The runoff decrease in the arid and semi-arid areas of northern China has brought severe problems in livelihoods and ecology. To reveal the variation characteristics, trends of runoff and their influencing factors have been important scientific issues for drainage basin man- agement. The objective of this study was to analyze the variation trends of the runoff and quantitatively assess the contributions of precipitation and human activities to the runoff change in the Huangfuchuan River Basin based on the measured data in 1960-2008. Two inflection points （turning years） of 1979 and 1998 for the accumulative runoff change, and one inflection point of 1979 for the accumulative precipitation change were identified using the methods of accumulative anomaly analysis. The linear relationships between year and ac- cumulative runoff in 1960-1979, 1980-1997 and 1998-2008 and between year and accu- mulative precipitation in 1960-1979 and 1980-2008 were fitted. A new method of slope change ratio of accumulative quantity （SCRAQ） was put forward and used in this study to calculate the contributions of different factors to the runoff change. Taking 1960-1979 as the base period, the contribution rate of the precipitation and human activities to the decreased runoff was 36.43% and 63.57% in 1980-1997, and 16.81% and 83.19% in 1998-2008, re- spectively. The results will play an important role in the drainage basin management. More- over, the new method of SCRAQ can be applied in the quantitative evaluation of runoff change and impacts by different factors in the river basin of arid and semi-arid areas.
基金This research project was granted jointly by the National Program on Key Basic Research Projects "973" (2007CB407206)
文摘Rainfall simulations have been conducted to study the soil erosion process of purple soil in two cultiva-tion practices—contour cultivation and downslope cultivation. Results showed that under the two cultivation prac-tices,the surface runoff can be described by the logarithmic function formula. In the initial period of rainfall,the amount of runoff increased with the rainfall duration and 20 minutes later it became relatively constant. The chang-ing process of soil erosion rate may be described by the logarithmic function formula. The erosion rate increased with the rainfall duration and 20 minutes later it also became constant. Under downslope cultivation condition,the soil erosion rate increased more significantly than that under contour cultivation condition in the case of gentle rain-fall intensity,and there is no obvious difference in erosion rate for downslope cultivation and contour cultivation practices. However,with increasing rainfall intensity the soil erosion rate under the downslope cultivation condition could be more than 30 times that under the contour cultivation condition. But this kind of difference would be re-duced to some extent in the case of heavy rain.
文摘The catchment of runoff which improves the moisture content condition in tree holes isof great improtance to the development of the afforestation in arid and semi-arid regions.The crux of this technique is the soil water content which influnences the survial rates,
