Changes in soil quality on horse paddock trails and the influence of paddock grids

Abstract Paddock trails offer horses the possibility to follow their natural urge to move and to behave interactively in a group association. To create appropriate conditions all year round, the installation of paddock grids is a common solution to avoid muddy trails and to prevent horses from injuries. The impact of horses on the soil on those trails is relatively unknown. In this study, we quantified the impact of horses kept on paddock trails on key soil quality indicators (soil bulk density, microbial biomass and soil organic carbon (SOC)) of the topsoil (0–0.3 m depth), and evaluated possible protective effects of paddock grids in an on‐farm study across 17 sites. We found significantly higher soil bulk density at 0–0.1 m depth, significantly lower soil microbial biomass in the 0–0.2 m layer, and significantly lower SOC contents at 0–0.2 m depth in paddock trails compared to ungrazed control sites. Comparing trails with and without paddock grids showed no significant difference in soil bulk density at any sampling depth, but significantly lower soil microbial biomass and a significantly higher soil organic carbon to nitrogen ratio (soil CN‐ratio) in trails with paddock grids compared to trails without grids. We could not find any impact of soil texture on the response ratio of the measured soil quality indicators, regardless of the type of trail (with or without paddock grids). Although we found overall lower mean soil bulk densities in trails with paddock grids, the difference to trails without paddock grids was not significant. A trend of an increase in bulk density over time was found for trails without paddock grids but not for trails with paddock grids, indicating that paddock grids might have a protective effect over time. In summary, our results suggest that soil quality is negatively affected by horses on paddock trails but that the effects are restricted to the top 0.2 m of soil. Furthermore, the results indicate that paddock grids were not able to prevent the negative effects of horses trampling but weakened them.