Simulation of soil temperature in crops

This paper presents a model that simulates soil temperature realistically with variable crop cover and soil water content and is also sufficiently small and fast to be included in a crop simulator. The model is developed according to principles of energy balance and soil heat transfer. Net radiation, sensible, latent, and ground-conductive heat fluxes are modified by foliage cover and cumulative evaporation as a basis for calculating the energy balance at the soil surface. Soil temperature at various depths is estimated with Fourier's heat transfer equation. One experiment measuring relative humidity at the soil surface was conducted to develop an equation for predicting vapor pressure at the soil surface. Two other field experiments measuring air and soil temperatures and energy balance components were carried out for model validation. The model well predicts energy fluxes at the soil surface, soil surface temperature, and soil temperature at various depths in crops. Canopy cover and soil surface wetness strongly influence energy balance and soil temperature whereas variation in soil porosity and soil thermal conductivity have little effect on soil temperature.