Modelling Crop Transpiration in Greenhouses: Different Models for Different Applications

Abstract

Models for the evapotranspiration of greenhouse crops are needed both for accurate irrigation and for the simulation or management of the greenhouse climate. For this purpose, several evapotranspiration models have been developed and presented, all based on the Penman-Monteith approach, the "big-leaf" model. So, on the one hand, relatively simple models have been developed for irrigation scheduling purposes, and on the other, "knowledge-mechanistic" models have been developed for climate control purposes. These models differ in the amount of detail about variables, such as stomatal and aerodynamic conductance. The aim of this review paper is to present the variables and parameters affecting greenhouse crop transpiration, and to analyze and discuss the existing models for its simulation. The common sub-models used for the simulation of crop transpiration in greenhouses (aerodynamic and stomatal conductances, and intercepted radiation) are evaluated. The worth of the multilayer models for the simulation of the mass and energy exchanges between crops and air are also analyzed and discussed. Following the presentation of the different models and approaches, it is obvious that the different applications for which these models have been developed entail varying requirements to the models, so that they cannot always be compared. Models developed in different locations (high-low latitudes or for closed or highly ventilated greenhouses) are discussed, and their sensitivity to different parameters is presented.Agronomy 2019, 9, 392 2 of 17 canopy. Estimations on how much energy is absorbed by the plant depends a lot on the greenhouse characteristics (cladding material), and on the ability of the climate control equipment (if present) to automatically modify/control the relevant climate factors. With the expansion of greenhouse culture all over the world, this has led to various models for ET estimation [4][5][6][7][8]. Thus, this work aims to review and discuss the available literature on the available ET models, their basic differences, and their use under different greenhouse climate conditions. The Most Common Approaches The Penman-Monteith ModelEvaporation (from soil) and transpiration (from the crop stomata) occur simultaneously, and there is no easy way of distinguishing between the two processes [5]. However, in many cases under greenhouse conditions, the soil is covered by a mulch that may considerably reduce the evaporation [9]. In the case of a non-mulched cropped soil, the evaporation is mainly determined by the water availability at the soil surface and the part of solar radiation reaching the soil surface. The solar irradiance reaching the soil is reduced during the growing period, as the plants develop and their canopy shades an increasing fraction of the ground area. When the crop is small, water is mainly lost by soil evaporation, but once plants are well developed and completely cover the soil, transpiration becomes the main process.Crop transpiration in greenhouses could be estimated based on the crop ene...

A Canopy Transpiration Model Based on Scaling Up Stomatal Conductance and Radiation Interception as Affected by Leaf Area Index

“…Different models maybe required for different applications, but the Penman-Monteith approach that merges the physical processes of energy, mass and heat transfer, remains at the core of all models and is of use in both greenhouse conditions and in field applications [32][33][34][35].…”

Crop Evapotranspiration

“…They found that using an ensemble of models could help identify outliers and areas for future ground validation. Katsoulas and Stanghellini [10] reviewed different ET models and their application to greenhouse environments.…”

Energy saving by LED lighting in greenhouses : A process-based modelling approach

“…LAI was excluded (9 of 24 cases) or assumed constant (8 cases) by a majority of the models. Approaches to modelling transpiration varied considerably, as previously noted by Katsoulas & Stanghellini (2019). Relatively few models considered photosynthesis (9 of 24) and yield (8 of 24), and approaches varied between those that did.…”

“…A wide range of approaches can be used for modelling crop transpiration, as outlined in detail by Katsoulas & Stanghellini (2019). These approaches range from an empirically fitted function where transpiration depends only on solar radiation, through aerodynamic models that include the influence of wind, to detailed models that include the response of stomata to environmental attributes including total radiation intercepted by the crop, vapor pressure deficit (VPD), air temperature and CO2 concentration.…”

“…On the one hand this may be expected, as many models do not include a CO2 balance (Table 2.3). But even when the CO2 balance is absent, many process-based transpiration models are based on a prediction of stomatal behavior (Katsoulas & Stanghellini, 2019). For these models, it would be informative to test how the modelled stomatal behavior influences photosynthesis and crop growth, especially in models that have detailed descriptions of both transpiration and photosynthesis (e.g., (Golzar et al, 2018;.…”