PARENT SESSION
Poster Session #40: Water Relations I.
Wednesday, August 7. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC
79
Rapid soil moisture recharge to depth by roots.
Ryel, Ronald*,1, Leffler, A. Joshua1, Caldwell, Martyn1, Yoder, Carolyn2, 1 Department of Rangeland Resources and Ecology Center, Logan, Utah2 Department of Biological Sciences, Richmond, Kentucky
ABSTRACT- A previously unrecognized role of plant roots is the efficient transfer of water into soils following precipitation events. Such movement of water through soils has classically been regarded as a physical process regulated by the characteristics of the soil. We assessed the importance of water movement by roots in a stand of Artemisia tridentata in central Utah, USA during the summer (which included small periodic rainfall events) and over the winter (when most of the soil recharge occurs in this environment). The pattern of recharge after a rain event, when compared to an area cleared of aboveground vegetation, strongly indicated that the downward movement of water to 0.3-1.5 m was primarily conducted by roots, and was estimated to range from 100% for small rainfall events (< 8 mm) to 74 % for a large event (35.6 mm storm). Simulations with a model of soil water movement that compared situations with and without hydraulic redistribution by roots, indicated that during the fall-spring recharge period, 67 % of all water moved downward below 0.1 m was via roots, while 87 % of the water was moved downward by roots below 0.3 m. These results indicate that rapid downward movement of rainwater by roots can be a significant mechanism of soil water recharge to depth in arid and semiarid ecosystems, and may be functionally important in maintenance and restoration of these ecosystems.
KEY WORDS: hydraulic redistribution, soil/water relations, Artemisia tridentata, soil/water model