Computational fluid dynamics modelling of crop-microclimate interactions for plants under water restriction inside a greenhouse compartment

摘要

Increasing water-use efficiency in greenhouses is a way of reducing water inputs. To this end, better understanding and quantifying the crop sensible and latent heat exchanges in response to water restriction conditions could be helpful. This may be reached by using predictive models of water transfers in the soil-plant-atmosphere continuum. To date, most models for plants grown in greenhouses have been established for well-watered conditions. Following previous work undertaken on a scale restrictedto the canopy and its close environment, the aim of this work was to simulate transpiration and microclimate for plants grown in pots on the scale of a greenhouse compartment for different irrigation regimes. To this end, a two-dimensional transient computational fluid dynamics (CFD) model was implemented. A specific routine was developed to include the resistance to air flow exerted by the crop, together with the sensible and latent heat exchanges with the ambient air. The routine uses the stomatal resistance, which depends on the substrate matric potential. This last parameter was inferred from the water content calculated from a water balance over the pot. Boundary conditions were established from experimental data collected inside a greenhouse compartment equipped with ornamental plants (New Guinea impatiens) grown in containers on shelves. Both well-watered and restriction conditions were analyzed. The results of the CFD simulations showed the ability of the model to correctly predict transpiration and air and leaf temperatures as well as air humidity inside the greenhouse for both water conditions. The CFD model could therefore be useful to test different irrigation scenarios and better manage water inputs.