黄土高原“林分自创性”有效水分供给体系的研究

A study on the available water potentialities“Brought by the stand itself ”in the loess plateau forest land——A new hypothesis developed

在黄土高原半湿润区,对无林沟坡(荒坡)与林地土壤分水储量变化的多年定点测定结果表明,在蒸发潜力很大的气候条件下,在很少有植物消耗水分的荒坡近裸立地上,和在林木每年蒸腾消耗大量水分之后的林地上,若以降雨丰、欠年周期为单位计算,土壤水分的收支均保持着相对的平衡关系。表现出林地与荒坡水分收支关系有着本质的差异。提出了开展林地有效水分获取途径研究的必要性。根据对林分改造自身生存环境,为自己提供有效水分功能的定点测定结果,从系统水分收支平衡原理出发,经过对林分、荒坡各自水分小循环过程及二者水分数量关系的分析,提出了黄土高原林分“自创性”有效水分供给体系假说,建立了“自创”潜力表达方程。对“自创性”假说提出的意义、作用及应用价值,进行了阐述。提出了它在黄土高原森林水文效应及森林培育学理论研究上,具有开拓新思路的重要作用。

The amount of soil water in the bare land and forest land were compared in the subhumid climate region of the Loess Plateau for many years.The results show as follows:(1)The amount of soil water received from rainfall and evaporated from soil are nearly in balance in the bare land.The soil water is not accumulated by years.(2)There is a relative water equilibrium in the forest land where a lot of water consumed by trees.The necessity that the way of forest land available water taken needs to be studied is brought up.Based on the measured results of the forest action on the land available water and the research of the courses of water mini cycle systems in a forest land and in a nearly bare wild land,a new hypothesis,the forest land available water potentialities“brough by the stand self”,is developed.An equation is set up for estimating the potentialities.The new theory will play an important role to for studying the theory of forest hydrology and silvicuture in the Loess Plateau.