New Mexico Geological Society Annual Spring Meeting — Abstracts

Soil properties have a major influence on the partitioning of rainfall onto infiltration and runoff. Hence, they determine the water available for aquifer recharge, stream flow, and ecosystem processes. Quantifying hydraulic properties for soils required the use of pedotransfer functions; however no previous functions have taken into account calcium carbonate accumulation at depth and how the calcium carbonate accumulation affects the rate of water movement into the soil. The accumulation of calcium carbonate in semiarid soils increases with age and produces systematic morphological changes in calcic horizons. Studies have recognized six stages of calcic horizon development recording the gradual accumulation of calcium carbonate cementing the matrix soils until eventually producing an impermeable layer within the soil profile. Two semiarid sites in the Sevilleta National Wildfire Refuge, New Mexico and on semiarid site at Fite Ranch, hydrologically using a tension infiltrometer. Carbonate concentration and bulk density was also measured for each horizon. Preliminary results indicate that as the calcium carbonate accumulates with depth and fills in the pore spaces of the soil substrate, the water flow decreases as reflected by a reduction in hydraulic conductivity. To determine the changes on soil hydraulic properties due to calcium carbonate alone, we use pedotransfer functions based on the measured soil texture assuming that the measured hydrologic properties deviate from that indicated by the pedotransfer functions. This difference represents the changes due to calcium carbonate accumulation.