The impact of hedges maturation on soil organic carbon stocks in agricultural landscapes

Hedgerows can provide a wide range of regulatory ecosystem services within improved grassland landscapes, such as soil function improvement, soil erosion reduction, biodiversity, water quality, and flood prevention and mitigation. Because of their beneficial effects, farmers are incentivised to retain their hedgerows and the planting of hedges has been encouraged in agri-environment schemes in Europe. Today, hedgerow planting it is one of the most popular practices adopted in the Countryside and Environmental Stewardships in England. The role of hedgerows in climate change mitigation has been increasingly recognized over the past decade, however, while other services have been more widely studies, less is known about hedges soil organic carbon (SOC) storage capacity. The Resilient Dairy Landscapes project aims at identifying strategies to reconcile dairy systems productivity and environment in the face of climate change, and with the Committee on Climate Change calling for a 30% - 40% increase in hedgerow length by 2050 in the UK, it is important to determine the role of hedgerows in meeting Net Zero targets. In this study, we estimate the extent of SOC stock beneath hedges and how it may vary with depth, hedge management and age, as well as how it may compare to SOC stock in adjacent agricultural fields. Thus, we measured SOC under 2-4 years old, 10 years old, 37 years old, and 40+ years old hedgerows at 10 cm intervals up to 50 cm of depth under 32 hedges located on dairy farms in Cumbria, UK. We found that the time since planting and the depth of samples play a crucial role in the amount of SOC stock stored underneath hedgerows when accounting for differences in soil type. Our results contribute measurable outcomes towards the estimate of targets for Net Zero 2050 and the extent of ecosystem services provision by hedgerow planting in agricultural landscapes.