Predicting Dynamic Soil Properties by Characterizing the Influence of Land Use on Soil Hydrology.

Soil properties that effect water movement are dynamic and can be highly influenced by land use. Particularly, we expect surface soil properties such as infiltration to be dependent upon land use. Because infiltration rates are usually log-normally distributed across an area; changes in land use have the potential to dramatically alter infiltration and redistribution within a catena. The question of how to account for this change based on land use is very challenging. In particular, Vertisol infiltration is temporally dynamic under one land use, because soil shrinking with drying creates large cracks at the soil surface. The extent and depth of the cracking is dependent on current and prior soil moisture status and soil properties that vary upon landscape position.  With all these complications in quantifying Vertisol infiltration rates, it is important to develop a strategy for understanding how landscape position, and current land use alter infiltration so that measurements and documentation are consistent in describing actual soil behavior. This presentation will focus on how we have addressed this question in a Texas Vertisol under three land uses, pastureland, row crop and native prairie.