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干旱区影响天然植被生长的土壤水分和盐分,都和地下水埋深密切相关。地下水埋藏浅,在强烈的蒸发作用下,溶解于地下水中的盐分沿毛管上升水流于地表聚集,使土壤发生盐渍化,产生盐胁迫。地下水埋深过低,毛管上升水流不能到达植物根系层,植物生长受到水分胁迫,发生荒漠化。因此,确定既不会使土壤发生盐渍化和荒漠化的地下水埋深十分重要。本文根据地下水、土壤水及植物生长状况综合研究,把适宜的地下水埋深界定为在温带荒漠区1.5—4m,暖温带荒漠区2.0~4.0(4.5)m,即在潜水的强烈蒸发深度以下和蒸发极限深度之上的区间,为防治土地盐渍化、荒漠化和估算生态用水提供了科学依据。
Soil moisture and salinity affecting the growth of natural vegetation in arid areas are closely related to groundwater depth. Groundwater buried shallow, under the strong evaporation, dissolved in the groundwater salt along the capillary rise in surface water accumulation, the soil salinization, resulting in salt stress. Groundwater depth is too low, capillary water flow can not reach the plant root layer, plant growth by water stress, the occurrence of desertification. Therefore, it is important to identify the depth of groundwater that will not cause soil salinization and desertification. Based on a comprehensive study of groundwater, soil water and plant growth, the appropriate groundwater depth is defined as 1.5-4 m in the temperate desert and 2.0-4.0 m (4.5) m in the warm temperate desert, ie below the intense evaporation depth The range above the evaporation limit depth provides a scientific basis for preventing and controlling land salinization, desertification and estimating ecological water use.