The main prevention and control area for wind-blown sand hazards in northern China is about 320000 km2 in size and includes sandlands to the east of the Helan Mountain and sandy deserts and desert-steppe transitional ...The main prevention and control area for wind-blown sand hazards in northern China is about 320000 km2 in size and includes sandlands to the east of the Helan Mountain and sandy deserts and desert-steppe transitional regions to the west of the Helan Mountain.Vegetation recovery and restoration is an important and effective approach for constraining wind-blown sand hazards in these areas.After more than 50 years of long-term ecological studies in the Shapotou region of the Tengger Desert,we found that revegetation changed the hydrological processes of the original sand dune system through the utilization and space-time redistribution of soil water.The spatiotemporal dynamics of soil water was significantly related to the dynamics of the replanted vegetation for a given regional precipitation condition.The long-term changes in hydrological processes in desert areas also drive replanted vegetation succession.The soil water carrying capacity of vegetation and the model for sand fixation by revegetation in aeolian desert areas where precipitation levels are less than 200 mm are also discussed.展开更多
[目的]客观分析灌区农业水土资源匹配状况和承载力水平,进而促进灌区农业高质量发展和保障国家粮食安全。[方法]以江苏典型灌区为研究对象,通过计算基尼系数与农业水土资源匹配系数进行水土资源匹配现状分析,通过构建涵盖水土资源、经...[目的]客观分析灌区农业水土资源匹配状况和承载力水平,进而促进灌区农业高质量发展和保障国家粮食安全。[方法]以江苏典型灌区为研究对象,通过计算基尼系数与农业水土资源匹配系数进行水土资源匹配现状分析,通过构建涵盖水土资源、经济、生态和社会子系统的灌区农业水土资源承载力评价体系,运用熵权法TOPSIS(technique for order preference by similarity to ideal solution)、障碍度和耦合协调度模型,对典型灌区农业水土资源承载力系统健康度、影响因子和耦合协调度开展了研究。[结果](1)典型灌区基尼系数G=0.26,优于同期全国水土资源匹配水平,各灌区水土资源匹配系数为2800~11500 m^(3)/hm^(2),水土资源匹配水平差异显著;(2)各灌区水土资源承载力系统处在中低等水平,现状条件下开发潜力有限,社会子系统为影响承载力系统健康度的关键因素;(3)各灌区水土资源承载力系统处在基本协调发展状态,耦合协调度与承载力系统健康度呈正相关关系,系统耦合协调性很大程度地限制了农业水土资源承载力的发展。[结论]江苏典型灌区整体水土资源均衡,各灌区之间水土资源匹配水平和承载力健康度差异显著,灌区各子系统之间存在不均衡发展,社会子系统成为限制承载力系统健康度发展的关键因素。展开更多
确定土壤水分的植被承载力是我国北方半干旱地区合理调控土壤水分和植被生长关系、科学恢复林草植被的核心问题。我国北方半干旱地区的土壤水分主要来自大气降水,作为土壤水分限制型生态系统的坡面植被,植物种类和植被密度等结构特征与...确定土壤水分的植被承载力是我国北方半干旱地区合理调控土壤水分和植被生长关系、科学恢复林草植被的核心问题。我国北方半干旱地区的土壤水分主要来自大气降水,作为土壤水分限制型生态系统的坡面植被,植物种类和植被密度等结构特征与降水量紧密相关。根据六盘山石质山区的特点,基于水量平衡原理,建立了阴坡华北落叶松(Larix principis-rupprechti)和阳坡草地的土壤水分植被承载力数学模型,即由4～10月的生长季降雨量(P)计算得到可承载的叶面积指数(Leaf area index,LAI)公式:LAItree=exp((0.7731×P–186.12)/146.46)和LAIgrass=exp((0.5112×P–345.93)/227.89),并提出了考虑坡面水分再分配影响的不同坡位的土壤水分植被承载力计算方法。阴坡华北落叶松的植被承载力(用LAI表示)从坡顶的1.45升高到坡中的4.83,然后稳定在3.0～3.3。对于阳坡草地,土壤水分可承载的LAI从坡顶的0.37上升到坡中的0.46,然后在0.41～0.47之间变动,LAI的计算值与实测值较为接近,计算结果比较合理。展开更多
基金supported by the National Basic Research Program of China(2013CB429906)
文摘The main prevention and control area for wind-blown sand hazards in northern China is about 320000 km2 in size and includes sandlands to the east of the Helan Mountain and sandy deserts and desert-steppe transitional regions to the west of the Helan Mountain.Vegetation recovery and restoration is an important and effective approach for constraining wind-blown sand hazards in these areas.After more than 50 years of long-term ecological studies in the Shapotou region of the Tengger Desert,we found that revegetation changed the hydrological processes of the original sand dune system through the utilization and space-time redistribution of soil water.The spatiotemporal dynamics of soil water was significantly related to the dynamics of the replanted vegetation for a given regional precipitation condition.The long-term changes in hydrological processes in desert areas also drive replanted vegetation succession.The soil water carrying capacity of vegetation and the model for sand fixation by revegetation in aeolian desert areas where precipitation levels are less than 200 mm are also discussed.
文摘[目的]客观分析灌区农业水土资源匹配状况和承载力水平,进而促进灌区农业高质量发展和保障国家粮食安全。[方法]以江苏典型灌区为研究对象,通过计算基尼系数与农业水土资源匹配系数进行水土资源匹配现状分析,通过构建涵盖水土资源、经济、生态和社会子系统的灌区农业水土资源承载力评价体系,运用熵权法TOPSIS(technique for order preference by similarity to ideal solution)、障碍度和耦合协调度模型,对典型灌区农业水土资源承载力系统健康度、影响因子和耦合协调度开展了研究。[结果](1)典型灌区基尼系数G=0.26,优于同期全国水土资源匹配水平,各灌区水土资源匹配系数为2800~11500 m^(3)/hm^(2),水土资源匹配水平差异显著;(2)各灌区水土资源承载力系统处在中低等水平,现状条件下开发潜力有限,社会子系统为影响承载力系统健康度的关键因素;(3)各灌区水土资源承载力系统处在基本协调发展状态,耦合协调度与承载力系统健康度呈正相关关系,系统耦合协调性很大程度地限制了农业水土资源承载力的发展。[结论]江苏典型灌区整体水土资源均衡,各灌区之间水土资源匹配水平和承载力健康度差异显著,灌区各子系统之间存在不均衡发展,社会子系统成为限制承载力系统健康度发展的关键因素。
文摘确定土壤水分的植被承载力是我国北方半干旱地区合理调控土壤水分和植被生长关系、科学恢复林草植被的核心问题。我国北方半干旱地区的土壤水分主要来自大气降水,作为土壤水分限制型生态系统的坡面植被,植物种类和植被密度等结构特征与降水量紧密相关。根据六盘山石质山区的特点,基于水量平衡原理,建立了阴坡华北落叶松(Larix principis-rupprechti)和阳坡草地的土壤水分植被承载力数学模型,即由4～10月的生长季降雨量(P)计算得到可承载的叶面积指数(Leaf area index,LAI)公式:LAItree=exp((0.7731×P–186.12)/146.46)和LAIgrass=exp((0.5112×P–345.93)/227.89),并提出了考虑坡面水分再分配影响的不同坡位的土壤水分植被承载力计算方法。阴坡华北落叶松的植被承载力(用LAI表示)从坡顶的1.45升高到坡中的4.83,然后稳定在3.0～3.3。对于阳坡草地,土壤水分可承载的LAI从坡顶的0.37上升到坡中的0.46,然后在0.41～0.47之间变动,LAI的计算值与实测值较为接近,计算结果比较合理。
