CHANGES IN THE CARBON AND NITROGEN STATUS OF FOREST SOIL ORGANIC HORIZONS BETWEEN 1949/50 AND 1987

Forest soil organic horizons from 15 profiles in NE Scotland originally sampled in 1949/50, were resampled in 1987. Analyses of both sets of soils for organic C and N show that although concentrations of the two elements have decreased with time, there has been a large increase in storage due to an increase in O horizon thickness. In most cases surface organic horizons have become more acid between 1949/50 and 1987. Calculated mean accumulation rates for C and N are 353.4 kg ha-1 year-1 and 21.2 kg ha-1 year-1 respectively. Changes in the C/N ratio with time give no indication of progressive N saturation and suggest sudden breakthrough of N in drainage water is not imminent. © 1990.