African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6576

Full Length Research Paper

Characteristics and modelling of canopy conductance and transpiration of Platycladus orientalis (L.) Franco in Loess Plateau of China

Lei Han1,2, Kang-ning He1*, Xing-bo Hu1, Dong Zhang1, Jing Qin1, Mei Dong1 and An-chao Li1
1College of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China. 2New Technology Application and Research Center, Ningxia University, Yinchuan 750021, China.
Email: [email protected]

  •  Accepted: 09 August 2011
  •  Published: 12 September 2011

Abstract

Estimating plant water use is an important step in assessing the effects of increasing vegetation cultivation on the hydrological cycle especially in arid and semi-arid regions. In this study, meteorological measurements combined with sap flow techniques provided a low-cost option to study the canopy physiological transpiration of Platycladus orientalis response to environmental factors on a continuous basis. Canopy transpiration (Ec) was measured by thermal dissipation method of Granier, and canopy conductance (gc) was calculated by inverting the Penman-Monteith equation. The results showed that the transpiration ofP. orientalis was strongly controlled by stomatal conductance, and gc was a comprehensive and compounded environmental variable. An improved Jarvis-type model, based on a series of environmental control functions, explained 85% of the variation observed in gc. Cross validation showed that this model provided good predictions of canopy conductance and transpiration for P. orientalis. Such a methodology offers a reasonable estimation of water use in the determination of water balance for land water resources planning, vegetation management and impact assessments of rehabilitation.

 

Key words: Sap flow, canopy transpiration, canopy conductance, model, Penman-Monteith equation, Platycladus orientalis, semi-arid region.