The Influence of Soil Compaction on Runoff Formation. A Case Study Focusing on Skid Trails at Forested Andosol Sites

Julian J Zemke,Alexander Klein,Marc Skubski,Michel Enderling

doi:10.3390/geosciences9050204

Abstract

This study discusses the influence of soil compaction on runoff generation with a special focus on forested Andosol sites. Because of their typical soil physical characteristics (low bulk density, high pore volumes) and the existent land use, these areas are expected to show low to no measurable overland flow during heavy rainfall events. However, due to heavy machinery traffic in the course of forestry actions and pumice excavations, skid trails have been established. Here, a distinct shift of soil dry bulk density (DBD) was observable, using a detailed soil mapping and data interpolation in order to generate in-depth DBD-cross profiles. Additionally, infiltration measurements and rainfall simulations (I = 45 mm·h−1, t = 30 min) were conducted to evaluate effects of observed soil compaction on infiltration rates and overland flow formation. Results show that soil compaction was increased by 21% on average in skid trail wheel ruts. As a consequence, observed runoff was 8.5-times higher on skid trails, while saturated hydraulic conductivity was diminished by 36%. These findings show, that soil compaction leads to a higher possibility of runoff formation during heavy rainfall events, especially at sites which showed initial conditions with presumably low tendencies of runoff formation.

Highlights

Wide areas of northern Rhineland-Palatinate are covered by Laacher SeeTephra (LST), originated from the last major eruption of the Laacher See volcano 12,916 yr B.P
Andosols feature soil physical properties that prevent a quick formation of overland flow during heavy rainfall events: The rather coarse pumice lapilli lead to characteristically low dry bulk densities (DBD) and high pore volumes [4,5,6,7]
Before evaluating the anthropogenic influence of machinery traffic, a view at natural site conditions, regarding soil texture, soil dry bulk density (DBD), and percentage of coarse material and sand had to be undertaken for delivering standard values

Summary

Introduction

Wide areas of northern Rhineland-Palatinate (southwest-Germany) are covered by Laacher SeeTephra (LST), originated from the last major eruption of the Laacher See volcano 12,916 yr B.P. Andosols feature soil physical properties that prevent a quick formation of overland flow during heavy rainfall events: The rather coarse pumice lapilli lead to characteristically low dry bulk densities (DBD) and high pore volumes [4,5,6,7]. This leads typically to a low tendency of runoff formation [8,9,10,11,12,13]. Pumice is being excavated leading to a total conversion of soil physical properties—which has to be discussed in future studies – and to increased heavy machinery traffic in the course of these operations

Methods

Discussion

Conclusion