Effects of Disturbance on Seed Germination in Some Annual Plants

Herbage removal, fire, and soil disturbance significantly reduced the numbers of germinating seedlings of Bromus mollis, B. tectorum, and Trifolium microcephalum the first season following alteration. Burining and soil disturbance caused the largest reduction in numbers of grass seedlings; clipping reduced the numbers to half that found on the undisturbed plots. Soil disturbance caused the greatest reduction in numbers of germinating clover seedlings. Burning and clipping reduced the clovers significantly below the undisturbed plots, but the reduction was much less than that caused by soil disturbance. Differences between the test conditions were not significant in subsequent years.