Influence of Irrigation Water Properties on Furrow Infiltration: Temperature Effects

*R. D. Lentz and D.L. Bjorneberg, USDA-ARS, Northwest Irrigation and Soils Research Lab., 3793 N. 3600 E., Kimberly, ID 83341 USA. *Corresponding author: [email protected] ABSTRACT For surface irrigation, the rate and spatial characteristics of infiltration processes influence crop productivity, water use efficiency, and erosion potential of stream flows. A change in infiltration rate alters furrow stream flow velocity and shear, and hence irrigation-induced erosion. Furrow irrigation models may be improved if they can account for the influence of water properties on these processes. Water temperature may influence furrow infiltration by altering fluid viscosity. We conducted laboratory soil column intake (constant head), and field recirculating furrow infiltrometer experiments, to determine whether irrigation water temperature significantly altered infiltration. The soil was Portneuf silt loam (coarse-silty, mixed superactive, mesic, Durinodic Xeric Haplocalcids). Soil column intake increased by 0.8 to 3.0 percent per degree C. This increase was not significantly different from that observed for furrows, 2.0 to 2.9% deg.. While more field studies are needed, these data show that diurnal and seasonal changes in irrigation water temperature can significantly alter furrow infiltration and stream flow. These effects may help explain observed field-infiltration variability. Inclusion of temperature algorithms in furrow irrigations models may increase their predictive accuracy.