【作者】 倪文进；

【导师】 王浩；

【作者基本信息】 中国水利水电科学研究院 ， 水文水资源， 2004， 博士

【摘要】 黄土高原地区总面积达62.38万km²，涉及我国中西部的7个省（自治区）。该区沟壑密布、干旱少雨、植被稀少、暴雨集中、降雨时空分布不均，是我国生态环境最为脆弱的地区，也是我国乃至世界水土流失最为严重的地区之一。控制水土流失，改善生态环境是实现区域人与自然协调发展的根本出路，恢复或重建持续、稳定、高效的植被生态系统是区域生态环境建设的重要内容，区域水资源承载能力和水环境容量是关系植被建设成败的关键因素。在黄土高原南部地区，从时间序列和空间配置出发，在植被的组织、器官、个体、群体和系统五个水平上，应用水量平衡场、径流观测场及原状土柱法等技术和方法，全面系统地研究SPAC系统油松、侧柏、剌槐、苹果、杏等人工植被生态系统以及农田、草地的“五水”（大气水、地表水、土壤水、地下水和植物水）转化或循环、水分平衡要素及相互关系、土壤水分含量时空动态、水资源利用模式及其效率，区域植被建设的水资源承载能力和水环境容量等。该论文的主要研究结果如下： 黄土高原南部油松、侧柏、刺槐、苹果和杏人工林的大气降水量在0.8～1.0mm时，降水被林冠全部吸收，之后大气降水量与林冠穿透降水量呈显著的正相关关系；4～9月生长季节油松、侧柏和刺槐林树冠的透过降水率分别为73.8％、76.9％和79.5％，而杏林和苹果林的分别为78.9％和79.3％；密度和郁闭度小的林分透过率高，阔叶林的比针叶林的高，阔叶林透过率的变化幅度也比针叶林的高。油松、侧柏、刺槐、杏林和苹果林对大气降水的平均截留率分别为20.0％、16.9％、15.5％、14.1％和15.6％，其大小排序为油松＞侧柏＞苹果＞剌槐＞杏林，且针叶人工林林冠截留率比阔叶人工林林冠的高，变化幅度比阔叶林的小。大气降水量在1.0～1.2mm，树木不产生干流，之后随着大气降水量的增加，干流呈明显的增加趋势，油松、侧柏、刺槐、杏林和苹果林分平均干流率分别为6.1％、6.2％、4.9％、6.9％和5.0％，不同林型、前期降水及水强，干流率差异较大；干流量虽小，但在补充林地干旱月份增加土壤水分作用重大。油松、侧柏、刺槐、杏林和苹果林枯枝落叶层的最大持水率分别为309.28％、321.34％、392.37％、352.78％和345.53％，最大持水量分别为1.34、1.21、1.73、1.23和0.25 mm，上述5种林分枯枝落叶层积累现存量分别为4.234、3.885、4.924、3.581和0.563 t·hm^-2，枯枝落叶层平均蓄留率分别为4.90％、4.90％、6.02％、5.55％和0.84％，林地积累的枯枝落叶愈多，拦蓄的大气降水量愈大，阔叶比针叶林拦蓄大气降水量大。油松、侧柏、刺槐、杏林和苹果林林地对大气降水的平均净接水率分别：77.3％、78.2％、78.4％、80.3％和83.5％，大小排序为苹果＞杏林＞刺槐＞侧柏＞油松，阔叶林具有较高的净降水率。 在土壤质地、含水率以及浑水泥沙组成一定的情况下，随着浑水含沙量的增大，浑水累积入渗量相应减小。在入渗土体、含沙量相同的条件下，随着＜0.01mm物理性粘粒含量的增加，浑水累积入渗量逐渐减小，且减小的幅度随着入渗历时延长而增大。人工林林地中壤土浑水入渗试验表明应用Kostiakov幂函数比应用复合幂函数模型模拟入渗相关系数更高，土壤入渗性能的高低与土壤性质、湿度状况以及入渗水流的水头梯度有关。含沙水流可显著削弱人工林林地土壤浑水径流的入渗能力，降低人工林林地的水源涵养功能。立地条件基本相同条件下，刺槐林地浑水累积入渗量远大于侧柏林地。人工植被土壤浑水入渗过程与清水入渗相比更为复杂，可以表示为多元非线性模型，其入渗量不仅与浑水特性、土壤质地有关，而且与林分类型和林龄有关。相同土壤含水率条件下，随土壤质地加重，土壤水吸力增大；相同含水率情况下，侧W七niin Ni(( A Study on Water Cvclin只and Water Use Effieienev of the Plantation SPAC in the Southern Loess Plateau》柏人工林地土壤水吸力略高于刺槐人工林地的;对同一林分相同含水率条件下，上层（0一60cm）土壤水吸力大于下层（60一1 20cm）。人工植被土壤与相同质地农田土壤相比，饱和进气值轻壤和中壤土分别降低13.7%一74.5%和44.6%一56.0%;土壤水分达到田间持水量时，轻壤带林地主要根系分布层及其下层的土壤吸力分别为0.0412⁰ .0540和0.0436一0.0839MPa，而中壤带的分别为0.0598一0.0700和0.072一0.080MPa之间。土壤水容度主要受土壤质地和土壤层位的强烈影响，轻壤带土壤水容随着土壤容积含水率的增大而迅速增加，在0一60cm的主要根系分布层土壤含水率由1 0.0%增加到45.0%时，轻壤带林地土壤水容增加了41 5.4一474.1倍，而中壤带的增加犯3.0一436.0倍。对轻壤带来说，减少土壤水分无效蒸发的保墒措施，将比增加土壤供水量的集水措施更为有效。 黄土高原南部土壤水分含量年内季节变化呈现出三峰三谷，即大气降水补偿期而植被消耗缓慢峰、大气降水集中期和植被耗水高峰叠加峰以及植被生长发育进入休眠期的降水补偿期峰。土壤水分含量的季节变化主要发生在表土层（0一20cm）和根系分布层（2o一60cm），随着土层的加深变化逐渐趋于缓慢至到相对稳定，但森林植被和农作物对土壤水分变化有滞后作用。人?更多还原

【Abstract】 The Loess Plateau, which is located at the northwest of China with the total area of 640 thousand km2 including 7 Provinces or autonomous regions, such as Qinghai, Gansu, Ningxia, Shaanxi, Inner Mongolia, Shanxi and Henan, is the one region of the most severe soil erosion and fragilest eco-environment in China and even in the World. The natural conditions in the Loess Plateau are the crashed landforms, loosening soil textures, sparse vegetations, drought climate, concentrated rainstorms, rich natural resources with frequent natural disasters. To control soil erosion and better the eco-environment in the region is the essential way to realize the sustainable development between human and nature in harmony. To restore or rehabilitate the everlasting, stabilizing and high efficient vegetation ecosystems are the importance viscera for the eco-environmental construction in the region. The regional water resources’ carrying capacity and its’ environmental capability is the limited factors related to the success or failure of vegetation construction. In the southern Loess Plateau, the ’five water’ (such as atmospheric water, surface water, soil water, ground water and botanical water) transfer or cycling, water budget elements, temporal and spatial changes of soil water contents, water resources using patterns and its’ efficiency, water resources’ carrying capacity and its’ environmental capability for the regional vegetation construction under the SPAC in the ecosystems of Chinese pine, arborvitae, black locust, apple, apricot, farming field and grassplot have being completely and systematically studied under the five levels of tissues, organs, individuals, communities and ecosystems by the water budget field, run-off observation field and original state soil column. The main results were made to draw the following conclusions:When the atmospheric rainfalls above the Chinese pine, arborvitae, black locust, apple and apricot stands in the southern Loess Plateau are among 0.8-1.0mm, its are completely absorbed by the canopies, then there markedly are positive relations between the atmospheric rainfalls and canopy penetration rainfalls. During the plant growing seasons from April to September, the canopy penetration rainfall rates of the Chinese pine, arborvitae, black locust, apple and apricot stands were 73.8%, 76.9% , 79.5%. 79.3% and 78.9% separately, its were higher with lower density and canopy density, the rates of the broad-leaves plantations were higher than the coniferous plantations, so were the change ranges of the rates. The average interception rates for the atmospheric rainfalls of the Chinese pine, arborvitae, black locust, apple and apricot stands were 20.0%, 16.9%, 15.5%, 15.6% and 14.1% separately, and its’ were higher in the coniferous plantations than in the broad-leaves plantations, so were the change ranges of the rates. When the atmospheric rainfall above the Chinese pine, arborvitae, black locust, apple and apricot stands were among 1.0-1.2mm, its were completely absorbed by the stem run-off, then the stem run-off rainfalls increase with the atmospheric rainfalls in evidence, the stem run-off rainfalls of the Chinese pine, arborvitae, black locust, apple and apricot stands were 6.1%, 6.2%, 4.9%, 5.0% and 6.9% separately, it changes with stand types, former precipitation and raining intensity. The stem run-off rainfall is very importance meaning to reinforce soil water resources in the drought region or months. The maximum litter holding water rates of the Chinese pine, arborvitae, black locust, apple and apricot stands were 309.28%, 321.34%, 392.37%, 345.53% and 352.78% separately, their maximum litter holding water amounts were 1.34, 1.21, 1.73, 0.25 and 1.23 mm separately. The standing litter biomass of the five stands were 4.234, 3.885, 4.924, 0.563 and 3.581 t hm-2 separately, and the average holding water rates were 4.90%, 4.90%, 6.02%, 0.84% and 5.55% separately. The more the litter accumulates in the stands, the more it holds back the atmospheric precipitation. The litter holds more back theatm更多还原