Chin J Plan Ecolo ›› 2006, Vol. 30 ›› Issue (6): 969-975.DOI: 10.17521/cjpe.2006.0124

• Research Articles • Previous Articles     Next Articles

PARAMETER ANALYSIS AND SCALING OF PLANT ROOT HYDRAULIC REDISTRIBUTION MODEL

WANG Kun1,2,3; LIU Ying_Hui1; GAO Qiong1*; MO Xing_Guo2   

  1. 1 MOE Key Laboratory of Environmental Change and Natural Disaster, College of Resource Science & Technology, Beijing Normal University, Beijing 100875, China; 2 Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 3 Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Online:2006-11-30 Published:2006-11-30
  • Contact: GAO Qiong

Abstract:

Background and Aims Hydraulic redistribution (HR) is an extension of hydraulic lift. The simulation of hydraulic redistribution done by Ryel et al. (2002) indicated that HR is beneficial for transpiration. 
Methods Based on the Ryel Model, we first conducted a sensitivity analysis by varying critical parameters of the model. We scaled the model for time steps of 1 hour to 1 day and soil from 10 cm to greater thicknesses by adjusting the necessary parameters. The scaled model was then applied to field observations of Caragana intermedia in Huangfuchuan Watershed of Inner Mongolia to simulate transpiration with and without HR. Daily changes in transpiration were simulated from April to October in 1998 and 1999.
Key Results and Conclusions The ratio of water redistributed by root to transpiration was strongly negative to soil hydraulic conductivity. The ratio also increased when root hydraulic conductivity increased, but gradually approached a limit. Total transpiration with HR increased when root hydraulic conductivity increased <1 cm·MPa-1·h-1 and decreased when it increased >1 cm·MPa-1·h-1. The result of the scaling indicates that it provides a useful approach to incorporating HR into larger models of soil processes. Total transpiration with HR increased 4.4% more than without HR in 1998, in contrast to total transpiration without HR having increased 2.1% more than with HR. This may be related to high precipitation in 1998.