In order to construct stable vegetation for reducing wind and sand disasters and soil erosion in the Bashang Area of Northwest Hebei Province in China,it is very important to understand the ecological water demand of ...In order to construct stable vegetation for reducing wind and sand disasters and soil erosion in the Bashang Area of Northwest Hebei Province in China,it is very important to understand the ecological water demand of different vegetation types in this area.Based on observed data and the Irmak-Allen formula,we investigated the ecological water demand and ecological water shortage of arbor,shrub and grassland in Bashang Area of northwestern Hebei province.The results showed that the actual evapotranspiration values of the three vegetation types in the growing seasons in the study area from high to low were arbor forest(401.81 mm),shrub(358.78 mm)and grassland(346.02 mm).The minimum ecological water requirements of arbor forest,shrub and grassland in the growing season were 243.96 mm,218.35 mm and 211.36 mm,respectively,and the optimal ecological water requirements were 472.99 mm,423.34 mm and 409.77 mm,respectively.In addition,the optimal ecological water shortage values were 198.56 mm for arbor forest,148.91 mm for shrub and 135.34 mm for grassland.The ecological water shortage of vegetation has obvious seasonality,with the largest water shortage in May and June,and a lower and steady water surplus in July to October.Therefore,an artificial water supplementation in May and June would alleviate the drought stress of the vegetation.The rainfall in Bashang Area of Northwest Hebei Province can meet the requirements of minimum ecological water demand for arbor forest,but the gap between the rainfall and the optimal ecological water requirement is too large to support good growth of an arbor forest,which could explain why the degradation of poplar protective forests has occurred in Bashang Area.展开更多
切沟体积是表征切沟侵蚀量、输水输沙能力的重要参数。笔者以冀西北山盆地区典型流域切沟为研究对象,使用Riegl三维激光扫描仪获取切沟点云数据,构建高分辨率DEM,提取切沟形态参数,分析切沟断面特征,构建并验证适宜的切沟体积估算模型...切沟体积是表征切沟侵蚀量、输水输沙能力的重要参数。笔者以冀西北山盆地区典型流域切沟为研究对象,使用Riegl三维激光扫描仪获取切沟点云数据,构建高分辨率DEM,提取切沟形态参数,分析切沟断面特征,构建并验证适宜的切沟体积估算模型。结果表明:1)切沟间的发育不均衡,不同切沟沟长、面积和体积相差较大,但同一参数在各个断面位置的参数值差别较小;2)面积、沟长和沟深与体积呈显著的正相关,相关系数较高,分别为0.949、0.870和0.814;3)基于V-L关系、V-A关系和V(A,D)关系建立对应的线性回归方程,其决定系数R 2分别为0.7706、0.9159和0.9748,模型验证结果显示,V(A,D)关系模型V=0.04653 A 1.499+24.08 D 1.916-44.26在预测冀西北山盆地区切沟体积上更有优势。研究结果可为大空间尺度切沟侵蚀定量模拟及制图提供理论和技术支持,为水土保持工程提供科学理论依据。展开更多
基金The Forestry Industry Public Welfare Project(201404206-02)。
文摘In order to construct stable vegetation for reducing wind and sand disasters and soil erosion in the Bashang Area of Northwest Hebei Province in China,it is very important to understand the ecological water demand of different vegetation types in this area.Based on observed data and the Irmak-Allen formula,we investigated the ecological water demand and ecological water shortage of arbor,shrub and grassland in Bashang Area of northwestern Hebei province.The results showed that the actual evapotranspiration values of the three vegetation types in the growing seasons in the study area from high to low were arbor forest(401.81 mm),shrub(358.78 mm)and grassland(346.02 mm).The minimum ecological water requirements of arbor forest,shrub and grassland in the growing season were 243.96 mm,218.35 mm and 211.36 mm,respectively,and the optimal ecological water requirements were 472.99 mm,423.34 mm and 409.77 mm,respectively.In addition,the optimal ecological water shortage values were 198.56 mm for arbor forest,148.91 mm for shrub and 135.34 mm for grassland.The ecological water shortage of vegetation has obvious seasonality,with the largest water shortage in May and June,and a lower and steady water surplus in July to October.Therefore,an artificial water supplementation in May and June would alleviate the drought stress of the vegetation.The rainfall in Bashang Area of Northwest Hebei Province can meet the requirements of minimum ecological water demand for arbor forest,but the gap between the rainfall and the optimal ecological water requirement is too large to support good growth of an arbor forest,which could explain why the degradation of poplar protective forests has occurred in Bashang Area.
文摘切沟体积是表征切沟侵蚀量、输水输沙能力的重要参数。笔者以冀西北山盆地区典型流域切沟为研究对象,使用Riegl三维激光扫描仪获取切沟点云数据,构建高分辨率DEM,提取切沟形态参数,分析切沟断面特征,构建并验证适宜的切沟体积估算模型。结果表明:1)切沟间的发育不均衡,不同切沟沟长、面积和体积相差较大,但同一参数在各个断面位置的参数值差别较小;2)面积、沟长和沟深与体积呈显著的正相关,相关系数较高,分别为0.949、0.870和0.814;3)基于V-L关系、V-A关系和V(A,D)关系建立对应的线性回归方程,其决定系数R 2分别为0.7706、0.9159和0.9748,模型验证结果显示,V(A,D)关系模型V=0.04653 A 1.499+24.08 D 1.916-44.26在预测冀西北山盆地区切沟体积上更有优势。研究结果可为大空间尺度切沟侵蚀定量模拟及制图提供理论和技术支持,为水土保持工程提供科学理论依据。
