Comparing soil thermal properties under different plant canopies

Soil thermal properties have a significant control on soil processes and plant growth. This study was conducted to model diurnal and seasonal change of soil temperature in soil profiles under corn, sugar beets, and no crops in Kumar township of Konya (Dry-subhumid/Semiarid Continental Central Anatolian climate). Soil temperature was modeled at 0, 5, 10, 20, 30, 40, and 60 cm soil depths with layer, point1, and point2 methods. Point1 and point2 methods gave similar results compared to that given by layer method and one point1 and point2 methods outperformed layer method in all the cases. The layer method over predicted soil temperature in majority of the cases. The success of all three methods to predict soil temperature decreased consistently with depth. This decrease was more drastic beyond duping depth. Diurnal and seasonal soil temperature changes across the soil depths under corn were highly different from those of sugar beets and bare soils. Irrigation had a drastic influence on soil heat diffusivity and diurnal change of soil temperature in studied soil depths. The results suggested that that analytical solution and initial conditions used in models were important factors determining the performance of modeling. In this regard, the point2 method can be preferred to point1 and layer methods in modeling soil thermal properties. The results further showed that predications made in bare soil conditions cannot be applicable to cropped soils and that different canopies may affect soil thermal properties differently due to differences in canopy structure and in plant influence on soil water.