Effects of Rainfall Interception by Crop Canopy and Residue and Depression Storage on Soil Water.
(3974)
Authors:
J.A. Kozak* - USDA-ARS, Fort Collins, CO L.R. Ahuja - USDA-ARS, Fort Collins, CO T. Green - USDA-ARS, Fort Collins, CO L. Ma - USDA-ARS, Fort Collins, CO
Abstract:
Crop canopies and residues have been shown to intercept a significant amount of rainfall. Canopy interception is controlled by canopy density and rainfall intensity and duration. Residue interception is a function of crop residue type, residue density and cover, and rainfall intensity and duration. We account for these
controlling factors and present a model for both interception components based on Merriam’s (1960) approach. This model was applied and validated through
experimental studies before being input into the Root Zone Water Quality Model (RZWQM). Using this enhanced version of RZWQM, a theoretical study was performed to examine the quantitative effects of interception on the components of the soil-water mass balance in a semi-arid environment. Lower soil water storage was observed due to interception as well as decreased evapotranspiration and infiltration. The effect of depression storage was examined as well. A model based on Onstad’s (1984) approach is presented as a function of random roughness, slope, tillage, and rainfall. The model was input into RZWQM, and a theoretical study was performed to examine the effects of depression storage on the soil-water mass balance. Higher infiltration and lower runoff were observed. Accounting for these hydrologic components may improve assessment of management effects on water conservation and water quality.
Speaker Information: Joseph Kozak, USDA-ARS, Fort Collins, CO,
USDA-ARS-NPA-GPSR 2150 Centre Ave Building D Rm. 2055, Fort Collins, CO 80526-8119; Phone: 970-491-7330; E-mail: [email protected]
Session Information: Monday, November 1, 2004, 7:55 AM-2:15 PM Presentation Start: 1:05 PM
Keywords: interception; depression storage; soil water; crops