EFFECT OF SOIL MANAGEMENT ON THEIR THERMAL PROPERTIES

Abstract

In order to determine the effect of soil management on its thermal properties, undisturbed soil samples were taken from two tillage treatments (conventional and conservation treatment) at two depths (0-30cm and 30-60cm) of a Stagnic Luvisol (silt loam) before and after directly wheeling. The experimental field, located in Harste/Goettingen, Germany, was cultivated with sugar beet (Beta vulgaris). To calculate thermal properties of the soil, the volumetric water content (TDR needles) and temperature (pT 100 thermistors) during the simulation of the daily fluctuation of temperature were registered in laboratory and then the thermal conductivity, volumetric heat capacity and heat diffusivity were calculated following the damping depth method and the statistical-physical model. The results showed that different tillage systems as well as compaction influenced soil thermal properties. Conservational tillage treatment with more stable and better developed soil structure at a depth of 0-30cm (which represents ploughing depth and decides differences between soil management) presented higher water content as the main factor deciding soil thermal properties. According to this, values of thermal conductivity and volumetric heat capacity under this treatment were greater than under conventional. Thermal diffusivity, however, was lower. From the latter we can conclude that under conservation tillage treatment the soil can store more heat, but at the same time and as a result of the lower thermal diffusivity, the atmospheric variations do not affect the soil thermal regime strongly.