ISHS Acta Horticulturae 537: III International Symposium on Irrigation of Horticultural Crops
USE OF A 3D PLANT / CANOPY STRUCTURE-BASED MODEL OF MASS AND ENERGY TRANSFERS TO ASSESS THE WATER REQUIREMENTS OF TREES AND ORCHARDS |
| Authors: | F.A. Daudet, X. Le Roux, H. Sinoquet |
| Keywords: | Leaf boundary layer conductance, microclimate, stomatal conductance, decoupling factor. |
| Abstract:
Due to highly complex structure and the resulting complex 3D transfers of mass and energy, the "big leaf" analogy is not suitable for orchards. Within-crown gradients of physiological parameters that are inherent to adult trees provide additional complexity. These two reasons largely explain our poor knowledge of the water requirements of tree crops. The proposed way for overcoming these limitations is to use 3D models that take explicitly into account the spatial variation of leaf properties. Recently, the RATP (Radiation Absorption, Transpiration and Photosynthesis) model, aimed at simulating the spatial distribution of short time canopy functions, was parameterised for walnut trees in orchard conditions and validated by radiation, sap flow, and photosynthesis measurements (Sinoquet et al., 2000). RATP simulations are used in the present study to analyse the spatial distribution of variables such as leaf-to-atmosphere coupling and transpiration rate. Some examples of simulated variations of whole tree transpiration in response to variations of climate factors and of canopy structure are given. The possibility of applying this simulation approach to different combinations of tree species, climate and training conditions in order to obtain relatively quick and reliable answers to the question of water requirements of orchard-like tree crops is discussed. | |
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