Dynamic Simulation Of The Microclimate Of a Row Crop Canopy.

V.Shelia and G. Hoogenboom, Dynamic Simulation of the Microclimate of a Row Crop Canopy The microclimate of a row crop canopy is a function of weather and soil conditions, crop management, crop growth stage and canopy development and canopy architecture. It will, therefore, change dynamically at both daily and seasonal time scales. The objective of this study was to simulate light interception, air and canopy temperature, relative humidity and wind speed distribution within a row crop canopy with a specific focus on spatial and temporal variation within the row and the inter-row. These factors are important for the calculation of not only photosynthesis and evapotranspiration, but also crop development, especially under high temperatures. We considered that the geometric anisotropy of a row crop canopy in the horizontal direction influences just the horizontal convective gradient of heat and moisture fluxes, while the vertical transfer of fluxes is based on the same principals as for horizontally isotropic crops. On the assumption that the processes for of energy and mass exchange are quasi-steady, a process-based mathematical model consisting of partial differential equations for simulating heat and moisture flux gradients was developed. Different optical properties of the crop canopy for light interception, shading, and orientation were used in the model. The parameters related to canopy architecture included row distance and canopy height, vertical and spatial distribution of the leaf area, and leaf angular distribution. Following model development, the vertical and horizontal distributions of the micro weather variables were simulated. Computer experiments with different geometric canopy structures, plant density, leaf area index, leaf inclination and location were conducted. During the next phase of this project experimental data should be obtained for verification of the model simulations.