Changes in mineral element concentrations in peat soils drained for forestry in Finland

The concentrations of Ca, Mg, K, Fe, Mn, Al, Cu, Zn, Mo, Pb, Cr and Cd were determined for surface peat samples for 80 sites on both undrained and drained pine mires in Finland. The oldest areas had been drained 55 years earlier. Although the gravimetric concentrations of many elements tend to decrease with increasing drainage age, the stores in the 0–50 cm peat layer do not change much along the drainage age gradient. This is possible because compaction of peat takes place after drainage, and, consequently, the 0–50 cm layer in the drained plots includes peat that was below the 50 cm limit before the sites were drained. The fact that elements are removed from soil by uptake by tree stands and by leaching is thus indicated by the decreasing, or unchanging, gravimetric concentrations only.