A Portable Rainfall-Simulator Infiltrometer and Physical Measurements of Soil in Place1
- John E. Adams,
- Don Kirkham and
- Donald R. Nielsen2
A portable rainfall-simulator and infiltration cylinder are described for applying artificial rainfall to soil in place for making infiltration, runoff, and soil erosion measurements. Raindrops are formed by glass capillary tubes protruding through the base of the water supply tank. Each tube has chromel wire suspended in the capillary to reduce the rate of flow. The rainfall is delivered over a circular area 5 ¾ inches in diameter delimited laterally by a cylinder 6 inches long, driven vertically into and flush with the soil surface. The soil surface area is small and replications are easy to obtain. Air permeability measurements may be made before and after rainfall application. The equipment can be carried, set up, and operated conveniently by one man and offers a fast, economical means of evaluating the soil factor in runoff and soil erosion problems. Field data, obtained on the Edina silt loam after 30 minutes of artificial rainfall, showed that the infiltration rate for corn in a corn-oat-meadow rotation (0.70 in./hr.) was nearly twice as great as for continuous corn (0.36 in./hr.) Wash erosion, or sediment in suspension, reached a maximum value for both systems between 5 and 10 minutes after the start of rainfall. During the next 5 minutes, wash erosion decreased rapidly although runoff continued to increase.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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