关键词: 无灌溉, 宜林极限, 降水量, 地下水位, 地下水矿化度

Abstract:

In arid and semi aird region of China, precipitation between irrigation plantation region and non-irrigation plantation region is 150-200mm in the monsoon climatic region and 100-150mm in the Mediterranean climatic region. In the area where precipiation is less than their limit precipitation, non-irrigation plantation should be carried out; where the groundwater table is lower than 4-6m it suits to plant trees and lower than 5-10m for xeric shrubs(dwarf trees). Mineral content of groundwater is less than 3g/l. for salt-avoiding trees and 3-8g/l. for salt-avoiding shrubs.