Analysis of runoff‐plat experiments with varying infiltration‐capacity

Research Bulletin 280, Missouri Agricultural Experiment Station, gives the results of runoff plat experiments by Jesse I. Neal see 1 of “References” at end of paper. The same sail was used in all the experiments. This was Putnam soil, taken from the surface five to six inches, from a timothy meadow. The soil was placed in a tank 12 feet long, 3.63 feet wide, and 26 inches deep. Water was applied by an overhead sprinkling applicator. Neal states: “Before each run the soil was dried and cultivated to a depth of 4 inches … After the moisture‐content of the surface four inches of soil had been reduced to between two‐thirds and three‐fourths of the capillary capacity, the surface‐soil was leveled off and worked down to approximately the proper height… After the soil was approximately leveled off with a rake, a wooden templet was drawn the length of the box and all excess soil scraped off. Since the templet left the soil in a smooth condition, the rake was run lightly back and forth across the slope to simulate the condition of a good seed‐bed… The surface‐inch of soil was further dried to between one‐fourth and one‐half the capillary capacity before applying the rain.” The rain was applied at intensities of approximately 4 inches, 3 inches, 2 inches, 1.5 inches, and 0.9 inch per hour, and the experiments were carried out with surface‐slopes of 0, 1, 2, 4, 8, 12, and 16 per cent.