Some sensitivity results for corn canopy temperature and its spatial variation induced by soil hydraulic heterogeneity

Abstract

The canopy temperature and its variation across an agricultural field may provide indices for scheduling irrigation. Combining the Monteith transpiration equation with both uptake from a single-layered root zone and change in internal storage of the plant, we have explicitly solved the continuity equation for water flux in the soil—plant—atmosphere system. The canopy temperatures are obtained from the energy balance equation. The scaling theory is used to model the spatial variability of soil hydraulic properties, and dynamic equations for plant storage water and root-zone soil water are used to simulate soil drying and resulting spatial variation of canopy temperatures. The canopy temperature and its spatial variation are simulated for progressive soil drying using four different sets of mostly clear sky atmospheric parameters. For one set of clear sky atmospheric parameters, the sensitivity results are obtained for uncertainties in the root distribution and in defining a unique function for the leaf stomatal control of water loss by plants.