Open AccessEstimating Transpiration from Turfgrass Using Stomatal Conductance Values Derived from Infrared Thermometry
Author(s) -
Peterson K. W.,
Bremer D. J.,
Blonquist J. M.
Publication year - 2017
Publication title -
international turfgrass society research journal
Language(s) - English
Resource type - Journals
ISSN - 2573-1513
DOI - 10.2134/itsrj2016.09.0788
Subject(s) - transpiration , lysimeter , evapotranspiration , latent heat , canopy , environmental science , stomatal conductance , sensible heat , energy balance , evaporation , atmospheric sciences , flux (metallurgy) , festuca arundinacea , water balance , water content , canopy conductance , hydrology (agriculture) , soil water , vapour pressure deficit , chemistry , soil science , agronomy , meteorology , botany , photosynthesis , physics , ecology , poaceae , thermodynamics , biology , engineering , biochemistry , geotechnical engineering , organic chemistry
Infrared thermometry provides accurate measurements of plant canopy temperature, which, along with basic weather variables, allows estimation of canopy stomatal conductance to water vapor flux ( g c ) and transpiration. Our objectives were (i) to compare single‐ versus two‐source energy balance approaches for sensible and latent heat flux calculations; (ii) to use g c calculated with the method of Blonquist et al. (2009) to estimate transpiration from a dense, well‐watered sward of tall fescue ( Festuca arundinacea Schreb.) turfgrass; and (iii) to compare calculated canopy transpiration with measured lysimeter evapotranspiration (LYS ET ). The study was conducted from June to October 2012 near Manhattan, KS. Three microlysimeters containing ambient cores of turfgrass were used to measure LYS ET . Four infrared radiometers, used to measure canopy temperature, were positioned on a weather station that recorded all data necessary for calculating g c . Transpiration calculated from modeled g c averaged 1.71 mm d −1 (29.6%) less than mean LYS ET , suggesting 29.6% of LYS ET was from soil water evaporation. Nighttime LYS ET may have inadvertently contributed to the soil water evaporation component using this method (our conductance model assumed zero nighttime transpiration). Differences were negligible between the single‐ and two‐source energy balance approaches for sensible and latent heat flux calculations. Results indicate transpiration may be reliably estimated via calculation of g c in turfgrass.