黄土高原人工林地水分亏缺的补偿与恢复特征  

Compensation and rehabilitation characteristics of soil water deficit at a planted forest site of the drought-prone Loess Plateau

作　　者：王进鑫[1] 黄宝龙[2] 罗伟祥[1] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]南京林业大学森林资源与环境学院,南京210037

出　　处：《生态学报》2004年第11期2395-2401,共7页Acta Ecologica Sinica

基　　金：国家"九五"重点科技攻关资助项目 ( 96-0 0 7-0 1-0 1-0 2 ) ;国家重点基础研究发展规划资助项目 ( G19990 43 60 2 ) ;西北农林科技大学回国人员科研启动基金资助项目 ( 0 80 80 4)~~

摘　　要：采用单株平衡法 ,通过定位监测与对比分析 ,对黄土高原半湿润落叶阔叶林区 ,持续干旱期末人工林地土壤水分亏缺度、雨季末降雨补偿深度及土壤贮水亏缺补偿度的时空分布进行了研究。结果表明 ,在水分条件较为优越的半湿润落叶阔叶林带 ,丰水年雨季过后的土壤贮水亏缺补偿深度不超过 2 80 cm,平水年 2 4 0 cm,枯水年仅 4 0 cm,而耗水深度超过 32 0 cm。丰水年0～ 32 0 cm土层 ,土壤贮水亏缺补偿度仅 14 .5 3%。自然状况下 ,单纯依赖天然降水 ,人工林地土壤水分亏缺状况将难以恢复。人工林地土壤贮水亏缺补偿度具有极为明显的空间分布规律。其中 ,水平方向土壤贮水亏缺补偿度与距主干距离成反相关 ,垂直方向因林分类型不同而异。林木根系的存在 ,削弱了天然降雨对土壤水分亏缺的补偿作用。在黄土高原南部半湿润落叶阔叶林带 ,仅采用传统的一维垂向土壤水分观测结果 ,或以 3m以上土层的土壤水分动态监测资料为基础 ,进行有关土壤水量平衡及蒸散量的计算 。The dried soil layer at a forest plantation site of the drought-prone Loess Plateau in China has threatened the survival and sustainability of the existent plantation, and also hindered the restoration and rebuilding of artificial forest vegetation. There have been numerous studies on the location and depth of dried soil layer's, and the influence of species composition. However, studies on root functions under soil water deficit, compensation and rehabilitation characteristics after rainy seasons in different precipitation years have been sparse. In this paper, the temporal and spatial distributions of compensation degree of soil water storage deficit in a plantation site of black locust (Robinia pseudoacacia Linn.), Chinese pine (Pinus tabulaeformis Carr.), and oriental arborvitae (Platycladus orientalis Franco) were studied using the method of single-tree water balance. Field experiment plot was divided into two zones, root zone and non-root zone, and soil water measurements were made every 5 days from the beginning of June to the end of November by a soil moisture meter of neutron scattering. The monitoring period covered continental-climate wet periods in dry years, normal years and rainy years, respectively. The root zones were divided into 3 or 4 sections from the tree's root crown to 1/2 spacing in the row at an interval of 30 cm to characterize the horizontal distribution of soil water content, and 16 layers from the surface to 320 cm depth at an interval of 20 cm to characterize the vertical distribution of soil water content. The non-root zone, 1.0 m×1.0 m on the surface, was at the same site with and near the root zone, but the roots from the nearby trees were cut off by digging a ditch around their periphery, followed by wrapping the soil column of 2.5 m in depth with 4 layers plastic sheet to prevent from root penetration, water uptake and soil water transport between the root and non-root zones. The annular ditch was then re-filled and a tube was put into the central of non-root zone to determine

关 键 词：人工林 土壤水分亏缺 降雨补偿 时空分布 黄土高原 

分 类 号：S714[农业科学—林学]