Earthworm (Metaphire guillelmi) activities increase the risk of soil erosion – a simulation experiment

Abstract

AbstractEarthworms exert a great impact on soil physical and chemical properties through feeding, burrowing, and casting activities. These activities can further affect soil erosion processes. However, we have insufficient knowledge on the effects of earthworm activities on soil erosion. In this study, we quantified the effects of earthworm activities on soil water distribution, runoff rate, and soil erosion rate under three slope gradients (5°, 10°, and 15°) through a laboratory‐simulated rainfall experiment. The uniform rainfall intensity (80 mm h−1) was set, and the rainfall duration after runoff generation was set to 60 min. Results showed that earthworm increased soil water infiltration and soil water storage (SWS). The increments in SWS were 41.2, 24.0, and 34.9 mm, respectively, in the tanks with earthworms at the slope gradients of 5°, 10°, and 15°, which were 93%, 51%, and 70% higher than the values of the control plots (21.3, 15.9, and 20.5 mm). Compared with the control plots, earthworm activities reduced the runoff rate at slope gradients of 5°, 10°, and 15° by 70%, 13%, and 39%, respectively; and increased soil erosion rate at slope gradients of 10° and 15° by 42% and 46%, respectively. Through their feeding, burrowing, and casting activities, earthworm increased soil water infiltration, reduced surface runoff, and increased soil erosion. This study provides insights into the effects of soil animals on soil erosion processes, and these data could then be incorporated into existing soil erosion simulation models or provide a basis for new models.