Influence of liming and sward management on soil carbon storage by semi-improved upland grasslands

Soils in less favoured areas (LFAs), defined as areas where unfavourable environmental conditions allow only extensive farming systems such as livestock rearing, are relatively stable, being rarely ploughed or disturbed, and cover extensive upland regions of the UK and Europe. Under low intensity management these soils have the potential to act as long-term carbon stores, mitigating the effects of climate change and potentially acting as a source of income for rural economies. However, upland grasslands are sensitive to management decisions, and careful planning is needed to ensure that they continue to provide a range of ecosystem services. Using the long-term grassland experimental plots at Brignant, Wales, management and liming effects on soil organic carbon and related soil parameters under long-term permanent pastures were explored. Results showed that interactions between management and liming could significantly influence carbon storage potential, making a difference of up to0.45 kg C m-2 in Hay-cut swards. The greatest reductions were found under pastures that had been cut (rather than grazed) and limed, probably due to a combination of enhanced soil microbial activity, increased root production and a lack of fresh biomass. These results indicate that while the potential to further increase soil organic carbon may be limited, grazing for all or part of the year can reduce losses by providing regular organic matter inputs.