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本文旨在将毛乌素沙地植被建设的水分平衡与半固定沙丘持续发展原则应用于治沙造林的实践中。毛乌素沙地是一个灌木“王国”，然而沙地灌丛植被的发育常常受到水分亏缺的严重制约。为此，根据水分平衡的原则与方法确立适宜的植物种植密度，对沙地植被的经营管理具有重要的指导意义。在水分平衡研究中，蒸散是最难估计的一项。本文提供了一种根据叶面积指数的季节变化与蒸腾速率的观测资料计算蒸腾耗水量的方法，并根据沙地水分平衡的要求估算了几种优势灌木的适宜种植密度。结果表明，毛乌素沙地灌丛生态系统的蒸发散主要来自植物蒸腾作用；在所研究的植物当中，除沙地柏（Ｓａｂｉｎａｖｕｌｇａｒｉｓ）可以形成很大的密度外（因其强的蒸腾控制能力），其它灌木的适宜种植密度应控制在使沙丘处于半固定状态的水平上。
The purpose of this paper is to apply the principle of water balance and sustainable development of semi-fixed sand dunes in the vegetation construction of Mu Us sandy land to the practice of sandification and afforestation. The Mu Us Desert is a “kingdom” of shrubs, yet the development of sandy shrub vegetation is often severely restricted by water deficits. Therefore, according to the principles and methods of water balance, establishing appropriate planting density has an important guiding significance for the management of sandy vegetation. In the study of water balance, evapotranspiration is the most difficult to estimate. This paper provides a method for calculating transpiration water consumption based on the data of seasonal variation and transpiration rate of leaf area index. The suitable planting densities of several dominant shrubs were estimated according to the requirements of water balance in sandy land. The results showed that the evapotranspiration of the shrub ecosystem in Mu Us desert mainly came from plant transpiration. Among the plants studied, Sabina vulgaris could form very large density (due to its strong transpiration control ability) The suitable planting densities of other shrubs should be controlled at the level of semi-fixed sand dunes.