Document Type

Article

Source Publication Title

Vadose Zone Journal

DOI

http://dx.doi.org/10.1002/vzj2.20049

Abstract

Understanding the effect of the top soil layer on surface evaporation and water distribution is critical to modeling hydrological systems. However, the dependency of near-surface soil moisture and fluxes on layering characteristics remains unclear. To address this uncertainty, we investigate how the arrangement of soil horizons affects the evaporation and soil moisture, specifically, the near-surface soil moisture, through the combination of numerical simulations and evaporation experiments. The characteristics of fluxes and moisture from different soil profiles are then used to understand the soil layering conditions. Results show that the top soil layer can significantly affect the evolution of soil moisture profiles and evaporation dynamics, the extent of which depends on the layering sequence, thickness, and properties of each layer. The soil systems consisting of a thick coarse (C) layer overlying a fine (F) layer, or a very thin F layer overlying a C layer exhibit near-surface moisture, temperature and fluxes nearly identical to that of a homogeneous C system; in these cases, a homogeneous C soil could be used to represent the above two layered systems. However, some soil profiles cannot be described by a single set of soil properties, nevertheless, they show distinct characteristics that can serve as indicators for soil layering conditions, e.g., “first slowly then rapidly” decreasing dynamics of near-surface soil moisture. As some characteristics are not unique to layered soil, the combined information including the near-surface soil moisture defined at different depths and evaporation behavior of an entire drying cycle can be used to better characterize the layering conditions.

Disciplines

Civil and Environmental Engineering | Civil Engineering | Engineering

Publication Date

6-23-2020

Language

English

Comments

© 2020 The Authors. Published by the Soil Science Society of America.

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