Nonnative plantations can effectively conserve soil and water and improve the ecology and environment, but soil desiccation can occur and may become severe in forest and grass lands in water-limited regions, leading to soil degradation, vegetation decline, and crop failure. Therefore, it is necessary to regulate the changing relationship between plant growth and soil water. However, there is no universally accepted theory to provide guidance in the sustainable use of soil water resources, management of forests, and production of crops in such regions. The regulation of the relationship between plant growth and soil water in water-limited regions can be expressed by the soil water resources use limit by plant (SWRULP) and soil water carrying capacity for vegetation (SWCCV) indexes. The SWCCV is the population in a plant population or density of indicator plants in a plant community when the soil water supply is equal to soil water consumption in the root zone at a given time, and changes with plant community type, location, and time. For example, the SWRULP in caragana shrubland is 222.8 and the SWCCV is 71 bushes per 100 m² in the semiarid region. The degree of coverage, productivity, and benefits of a plant community when the population quantity of an indicator plant equals the SWCCV provides the theoretical basis for ensuring the sustainable use of soil water resources and sustainable development of forest land.

中文翻译：

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植被的土壤水分承载能力

外来人工林可以有效地保持水土，改善生态环境，但在缺水地区的林地和草地，可能会发生土壤干燥并可能变得严重，导致土壤退化、植被减少和农作物歉收。因此，有必要调节植物生长与土壤水分的变化关系。然而，在这些地区的土壤水资源的可持续利用、森林管理和作物生产方面，还没有普遍接受的理论提供指导。限水区植物生长与土壤水分关系的调控可以用植物土壤水资源利用极限（SWRULP）和土壤植被水分承载力（SWCCV）指标来表示。SWCCV是在给定时间土壤供水量等于根区土壤耗水量时，一个植物种群中的一个植物种群或一个植物群落中指示植物的密度，并随着植物群落类型、位置和时间的变化而变化。例如，锦鸡儿灌木丛中的 SWRULP 为 222.8，而 SWCCV 为每 100 米 71 个灌木丛²半干旱地区。指示植物种群数量等于 SWCCV 时植物群落的覆盖程度、生产力和效益，为保证土壤水资源的可持续利用和林地的可持续发展提供了理论依据。