HR: 0800h
AN: H31D-0424    [Abstracts]
TI: Effects of Salinity and Drought Stresses on Root Water Uptake
AU: * Skaggs, T H
EM: tskaggs@ussl.ars.usda.gov
AF: USDA-ARS, Geroge E. Brown Salinity Lab 450 W. Big Springs Rd., Riverside, CA 92507 United States
AU: Poss, J A
EM: jposs@ussl.ars.usda.gov
AF: USDA-ARS, Geroge E. Brown Salinity Lab 450 W. Big Springs Rd., Riverside, CA 92507 United States
AU: Shouse, P J
EM: phsouse@ussl.ars.usda.gov
AF: USDA-ARS, Geroge E. Brown Salinity Lab 450 W. Big Springs Rd., Riverside, CA 92507 United States
AB: In vadose zone numerical simulation models, root water extraction is typically accounted for by introducing a sink term into the Richards equation. Various forms of the sink term have been proposed to simulate the reduction in water extraction that occurs when soil salinity and/or drought conditions exist in the root zone. While this representation of root water uptake is a fixture of modern simulation models, there has been relatively little work demonstrating agreement between the models and measured water uptake data. In this work, we compare HYDURS-1D model simulations with drainage and root water uptake data collected for forage crops grown in lysimeters using a range of salinity and drought treatments. We found good agreement between the model and the data using a single set of salinity and water stress parameters, a noteworthy result given the broad range of experimental conditions considered (irrigation waters with electrical conductivities as high as 28 dS/m). On the other hand, the required salinity and water stress parameters did not correspond to published salt tolerance data for these crops, suggesting that the near term prospects for using this model in a purely predictive capacity (i.e., without detailed crop- and site-specific calibration) are limited.
DE: 1818 Evapotranspiration
DE: 1842 Irrigation
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting