The Impact of Biochar Addition on the Water Quality of a Lowland Peat Ecosystem

The addition of biochar has been proposed as a mechanism for enhancing carbon storage in soils, but the consequences of this approach for water quality have not been assessed for peat soils. In this study we considered the impact of biochar treatment on the soil water of a raised bog in northern England. Biochar application rate was up to 64 t/ha equivalent to 2 cm depth of peat. Over the 2 years of the study we found that biochar addition brought about a statistically significant increase in soil water pH, electrical conductivity, dissolved organic carbon concentration, absorbance, inorganic nitrate and sulphate concentrations; although in most cases changes were small in magnitude and hence expected to have little ecological impact. Biochar addition made no significant difference to iron and phosphate concentrations. The lack of increase in phosphate concentration may mean that increase in inorganic N could not be utilised by biota. The study found no evidence of detrimental impact of biochar addition on water quality in and from these peat soils. Therefore, changing water quality would not be an impediment to using biochar as a nature‐based solution to anthropogenic climate change.