宏观根系吸水补偿模型研究进展

根系吸水模型是研究植被耗水规律的关键要素,尤其在干旱-半干旱地区,土壤经常出现水分胁迫状态,使得根系吸水过程更为复杂。为准确描述根系的吸水过程,吸水补偿模型在1989年被概念化并成为一个重要的研究方向,国外进行了大量的研究探索,而国内在该领域鲜有研究。虽然根系吸水补偿模型已取得一定的进展,但其模型本身仍然存在一定的物理缺陷,因此,总结并综合分析根系吸水补偿模型发展历程,指出补偿吸水模型忽视了水分胁迫抑制根系吸水的物理机制,以及植物胁迫指数判定是否进行吸水补偿有一定局限性。在此基础上,提出根系吸水补偿模型应考虑潜在蒸腾量和土壤可利用水量供需关系、植物根系生长环境,补偿模型应耦合植物胁迫函数、土壤水分分布及地下水动态特征。

A review of studies on macroscopic compensated root water uptake model

The ro ot w ater upt ake mo del is essential to the study of v eg etatio n ev apo transpirat ion. I n arid and semi2arid reg io ns, the soil of ten has w ater str ess, which makes the ro ot w ater uptake pro cess even mo re complicat ed. I n o rder to describe t he r oot water uptake mor e accurately, the compensated roo t w ater uptake mo del w as co nceptualized in 1989 and became an important research directio n. There are many ex plo ratio ns abroad, but few in China. Although certain pr og ress has been made on the com2 pensated roo t water uptake mo del, it still has some physical defects. This paper summarizes and analyzes t he dev elo pment histo2 r y o f the compensat ed r oot w ater uptake mo del. It po ints out that the compensated water uptake mo del ov erlooks the physical mechanism of water str ess restr aining the r oot w ater uptake and that using plant stress index to judge w hether there is compen2 sated water uptake has certa in limitatio ns. Based on comprehensiv e analysis, this paper pro po ses that the compensated r oot w a2 ter uptake model should consider the g r ow ing env ir onment of plant ro ots and the supply2demand relationship betw een po tential transpiratio n and available soil moist ur e. The compensated model should co uple the plant stress function, the characteristics of so il moisture distribution, and the dynamic char acteristics of gr oundwater.