EFFECTS OF SALINITY AND DROUGHT STRESSES ON ROOT WATER UPTAKE

Authors: Skaggs, Todd; Poss, James; Shouse, Peter

Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 8/20/2004
Publication Date: 10/1/2004
Citation: Skaggs, T.H., Poss, J.A., Shouse, P.J. 2004. Effects of salinity and drought stresses on root water uptake. American Geophysical Union, Eos Trans., Fall Meeting Supplement, AGU, CD-ROM.

Interpretive Summary:

Technical Abstract: 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.