Submitted to: Geoderma
Publication Type: Trade Journal
Publication Acceptance Date: 8/14/1996
Publication Date: N/A
Interpretive Summary: The Simultaneous Heat And Water (SHAW) model, developed by ARS, was used to simulate the downward movement of water in the soil under different climates, vegetation types, and soil textures to examine the impact of periods of wetter climate found during the Holocene on the development of calcium carbonate layers in soils throughout the Mojave Desert. Model predictions showed that the depth of water movement in the soil for dry and wet years strongly corresponds with two zones of carbonate accumulation found in the soil, respectively. This study suggests that the shallower zone of accumulated carbonate is a result of periods of decreased winter and spring rainfall and not due to increases in temperature during the Holocene or the development of clay horizons in the soil.
Technical Abstract: The Simultaneous Heat And Water (SHAW) model was used to simulate the downward flux of soil-water under varied conditions of climate, vegetation, and soil texture to determine the potential impact of episodic periods of wetter climate during the Holocene on calcic soils in the Mojave Desert. Modeling results indicate that the soil-water balance for dry and wet years strongly corresponds with the upper and lower zones of a bimodal accumulation of carbonate in the soil, respectively. This study suggests that the shallow zone of accumulated carbonate is a result of periods of significant decreases in winter and spring rainfall and not primarily due to increases in Holocene temperature or the development of clay horizons.