Nitrogen cycling and proton fluxes in an acid forest soil

Abstract

Ironhill, near Liphook, UK, was the site of a forest fumigation experiment. Nitrogen cycling within the humoferric podzol soil was a component of the study into the impacts of sulphur dioxide and ozone on coniferous trees. Variation in total soil N and N mineralisation was too great to determine impacts from the fumigant gases. Differences in the nitrogen mineralisation potential of the soils were unrelated to the initial levels of mineral or total N, or to pH. Mineralisation potential was affected by temperature and a Q10 of approximately 3 was demonstrated. Mineralisation potential was reduced in very dry soils, but the wetting of these dry soils did not result in enhanced mineralisation, relative to fresh samples of equivalent moisture content. Nitrification potential was detected in this forest soil of pH 3 (in 0.01 m CaCl2).