摘要
在冻结势作用下,包气带水重新分配,以液态和气态向冻土层迁移富集并冻结成冰。在富水带,水量比冻结前增加8%~40%;过度贫水带,比冻结前水量减少15%~30%;汽化输水带,比冻结前减少了6%~20%。春季土壤开始解冻,冻结滞水首先转化为土壤水,冻结滞水含水量为20%~40%。要把握适时造林深度、密度,树种选择要适宜,才能充分利用冻结滞水资源。
Indoors and outdoors studies show that frost water migrates into the freezing soil layer in terms of vapor and moisture, so three soil layers which have different water content were divided: one is rich in water, .it is found that its water content is increased from 8% to 40% after frost; one is deficient in water, water content of which is decreased from 15% to 30% after frost; the third is transporting water in the form of vapor, its water content is found to be decreased from 6% to 20% . Dynamic characters show timeliness and metamorphosis. Seasonal frozen stagnant water can be absorbed directly by plant and balance water metabolization in winter and spring. Temperature rises in spring, frozen soil begins to thaw. Frozen stagnant water turns to soil water at first. It is the best season for plant seeds to germinate and seedling to grow when the frozen stagnant water content is at 20% to 40% . Frozen soil which will thaw entirely would lost its water from evaporations on the surface and seepage if afforestation is too late, buts the thawing soil layer couldn't be thick enough to meet the depth needed if it is made earlier. The development of root system is in accord with enrichment of water in kremastic water zone. Frozen stagnant water content varies with the depth of soil. To make best use of the resource of frozen stagnant water, depth, density and seed for afforestation should be chosen carefully .
出处
《中国水土保持科学》
CSCD
2003年第2期52-56,共5页
Science of Soil and Water Conservation
基金
国家自然科学基金项目(39960021)