Changes in Infiltration Under Alfalfa as Influenced by Time and Wheel Traffic

Abstract

Infiltration rates were measured for alfalfa, (Medicago sativa L., cv. WL514) subjected to treatments where wheel traffic was varied in terms of area covered and time of application on a Wasco sandy loam (coarse‐loamy, mixed, nonacid thermic Xeric Torriorthent). Traffic treatments were (i) No‐traffic, (ii) Preplant, (iii) Repeated, and (iv) traffic similar to what a grower would apply. Infiltration rates increased for all treatments, with increases being 240% for treatments without harvest traffic and 140% for treatments with harvest traffic. Increases in infiltration were related to decreases in stand density. Slight packing (traffic) applied before the soil was flood‐irrigated in 1983 increased infiltration rates 20% compared to flooding loosened soil (no traffic). Harvest traffic resulted in slower water movement in the soil.