Hysteresis response of daytime net ecosystem CO2 exchange during a drought

Continuous measurements of net ecosystem CO2 exchange (NEE) using the eddy-covariance method were made over an agricultural ecosystem in the southeastern US. During optimum environmental conditions, photosynthetically active radiation (PAR) was the primary climatic factor controlling daytime NEE, ac...

全面介紹

Saved in:
書目詳細資料
Main Authors: Pingintha N., Leclerc M.Y., Beasley Jr. J.P., Zhang G., Senthong C., Rowland D.
格式: Article
語言:English
出版: 2014
在線閱讀:http://www.scopus.com/inward/record.url?eid=2-s2.0-70849112141&partnerID=40&md5=deb3b95509f9c3350933df62de2818e3
http://cmuir.cmu.ac.th/handle/6653943832/360
標簽: 添加標簽
沒有標簽, 成為第一個標記此記錄!
機構: Chiang Mai University
語言: English
實物特徵
總結:Continuous measurements of net ecosystem CO2 exchange (NEE) using the eddy-covariance method were made over an agricultural ecosystem in the southeastern US. During optimum environmental conditions, photosynthetically active radiation (PAR) was the primary climatic factor controlling daytime NEE, accounting for 67 to 89% of variations in NEE. However, soil water content (SWC) was the dominant factor limiting the NEE-PAR response during the peak growth stage, as NEE was significantly depressed when PAR exceeding 1300 α1/4mol photons m-2 s-1 coincided with a very low soil water content (SWClt;0.04 m3 m-3). Hysteresis was observed between daytime NEE and PAR during periods of water-stress resulting from high vapor pressure deficit (VPD). This is significant since it limits the range of applicability of the Michaelis-Menten equation, and the likes, to determine daytime NEE as a function of PAR. The systematic presence of hysteresis in the response of NEE to PAR suggests that the gap-filling technique based on a non-linear regression approach should take into account the presence of water-limiting field conditions. Including this step is therefore likely to improve current evaluations of ecosystem response to climate change.