Moisture content as one of the main factors in modeling the features of heat accumulation in podzolic soil profiles

Abstract

Moisture plays a primary and most dynamic role among the many factors influencing the heat accumulating properties of soils (particle size distribution, density, organic matter content). The research goal was to quantitatively evaluate the influence of moisture gradients and dynamics on heat accumulation characteristics in the genetic horizons of podzolic soil by constructing and verifying a detailed physical model. All key soil properties of genetic and agricultural significance are formed as a result of numerous elementary soil processes. Quantitative assessment methods are required to determine the contribution of each of these processes. We used information-logical analysis which involved evaluating the strength of the relationship between the features by comparing the a priori probability of the entire sampling with the conditional probabilities of each factor. The degree and nature of the relationship between the volumetric thermal capacity of sod-podzolic soil and moisture content were determined. An increase of the moisture content of the humus-accumulative horizons in the study areas leads to an increase of the volumetric thermal capacity values by one rank. It is noteworthy that at moisture content of 15-20%, the rank of the heat accumulation coefficient does not change. The overall informational value for the considered variants is quite high and amounts to T = 1.1997 and T = 1.1269, respectively. The obtained informational content values allowed estimating the share of the influence of moisture content on the volumetric thermal capacity. In the grass pine forest, it was 25.3%, and in the fresh pine forest - 24.8%. The conducted study allowed determining quantitative dependence of the heat-accumulating capacity of podzolic soil profiles on the spatiotemporal moisture dynamics. The key role of moisture content as a dominant factor modulating the thermophysical properties of the genetic horizons of podzolic soil was confirmed. A mathematical model of heat accumulation was developed and verified. It was determined that seasonal moisture dynamics was the main regulator of the soil thermal regime. The mechanism of formation of a contrasting thermal regime in the sod-podzolic soil profile was revealed.