Upland grassland management influences organo-mineral soil properties and their hydrological function

Land-use change acts as a potential moderator of flood risk, affecting vegetation and soil properties and thus influencing the storage and flow of water across landscapes. This study, conducted in northwest England, investigated physical soil properties and their hydrological function using overland flow and soil moisture sensors, for five upland grassland habitats each created through management action. Overland flow was common, occurring up to 60% of the time with longer durations in grassland excluded from grazing with higher density vegetation. Soil moisture varied significantly between grassland habitats, but there was no clear soil moisture threshold for overland flow. Surface soil properties to 5-cm depth varied significantly between grassland types, with saturated hydraulic conductivity (Ks) ranging across several orders of magnitude from 1.3 × 10−3 to 1.5 × 102 m day−1. With shallow soils and a median Ks of 2.4 m day−1, saturation-excess overland flow was determined as the main driver of flood risk. Landscape management was found to be a significant driver of soil physical and hydrological properties in upland grasslands and therefore should be strongly considered as part of flood management.