The need to disaggregate podzols and peaty podzols when assessing forest soil carbon stocks.

Abstract

Inventories of forest soil carbon (C) stocks are necessary to determine spatial and temporal C stock changes and support climate change mitigation policy development. Afforested podzols and peaty podzols were sampled to measure bulk density (BD) and soil organic carbon (SOC) content with the aim of improving baseline soil C stock estimates for Irish forests. Podzols are not always distinguished from peaty podzols and both qualify as mineral soil types. Distinct differences in mean BD, SOC % and soil C stock values were found between sites with podzols and peaty podzols across the four depths sampled, i.e., 0-10, 10-20, 20-30, 30-40 cm. The estimated soil C stocks for the podzol sites ranged from 129-139 Mg C ha-1, while the peaty podzols had 229-385 Mg C ha-1. The major disparity in the soil C stocks implies the need to disaggregate podzols and peaty podzols in conducting soil C inventories, with the need for development of carbon emission factors for peaty podzols to reduce uncertainty in soil C stock estimates.