Modelling Canopy Stomatal Conductance of Hedysarum scoparium and Long-term Prediction in Semiarid Region in China

• Published in: Nature environment and pollution technology Vol. 15; no. 3; p. 847
• Main Authors: Li, Jinghao, Deng, Jifeng, Zhou, Yongbin, Ding, Guodong, Zhang, Ruohan
• Format: Journal Article
• Language: English
• Published: Karad Technoscience Publications 01.09.2016
• Subjects: Hedysarum scoparium; China, People's Rep
• ISSN: 0972-6268; 2395-3454

Hedysarum scoparium (H. scoparium) is a fast-growing and drought-resistant shrub species that has been extensively used for grassland restoration and agricultural landscapes protection such as farmland protection and wind shelterbelts in semiarid regions of Northwestern China. To date knowledge about the water consumption characteristics and physiological response to environmental factors of H. scoparium is quite limited. Thus, the primary objective of this study was to create a Jarvis-type model of canopy stomatal conductance (g^sub s^) in H. scoparium shrubs and use the model to predict long-term trend variations. During the research, the sap flow rate (J^sub S^) of four shrubs with diameters of 29, 21, 15, and 11 mm was monitored under natural conditions. Meteorological factors were obtained at a flux tower on site. Results indicate that the meteorological variables are significantly correlated with g^sub s^, which increases exponentially with the increase in vapour pressure deficit (VPD) after controlling for the additional effects of air temperature (T^sub a^) and solar radiation (R^sub n^). The Jarvis model was set up to express the variation observed in g^sub s^, and the sequence affecting the accuracy of the model is R^sub n^ > VPD > T^sub a^. This study attempts to probe g^sub s^ of H. scoparium by using J^sub S^ and applying Jarvis-type model, the proposed Jarvis-type model offers a solution to the above-specified problems, which also solves the time lag issue in g^sub s^ prediction. The conclusions obtained in the study can provide the intentionality reference and conservation management guidance for environment protection and desertification combating.