A robust assessment of crop water stress for irrigation schedule requires the estimation of both potential crop water needs and actual crop water use, defined respectively as potential and actual (evapo)transpiration.
Potential evapotranspiration (ET ) has usually been computed based on Penman-Monteith energy combination equation, which treats the land surface as a ‘big leaf’ composed of a mixture of soil and vegetation that is the single source for energy and water exchanges with the atmosphere.
Furthermore, most applications consider that ET for a given crop is proportional to a reference rate ET of a homogeneous and well irrigated short canopy such as alfalfa or grass through a crop coefficient K (i.e. ET =K- ET ).
However, vineyards show a unique vertical canopy structure and a strongly clumped plant distribution/row structure that could induce significantly different energy and aerodynamic regime compared to a homogeneous crop.
Two-source models can account for clumped canopies with significant soil/ substrate component by achieving a balance in the radiative and turbulent flux exchange with the lower atmosphere for the soil/substrate and vegetation elements, allowing hence for the partitioning between soil evaporation (E) and canopy transpiration (T).
In this work we utilized modelling tools to evaluate the utility of one- and two-source models for predicting both potential and actual (evapo)transpiration.
The paper reproduced in this video-seminar was presented at the International Congress on Grapevine and Wine Sciences - ICGWS (Logroño, Spain, November 7-9, 2018) organized by ICVV.
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VIDEO SEMINAR (Hector NIETO; streaming 15 min)
