Altitudinal and Seasonal Trends in Soil Nitrogen Mineralization Rate in the Scottish Highlands

Soil nitrogen mineralization rate and nitrification rates were determined in situ and in the laboratory for a number of sites along two altitudinal transects in the scottish Highlands for four periods during the growing season. Available nitrogen, total nitrogen, ignition loss, water content and pH were determined on the same soil samples. Mineralization rates in both field and laboratory either did not change with altitude or were highest in samples from high altitudes, despite the altitudinal decline in temperature. Mineralization and nitrification rates were highest at the beginning and end of the growing season. It is suggested that the mineralization rate is influenced by the concentration or readily decomposed nitrogenous compounds and that at high altitude these are not broken down winter as much as at low altitudes, because of the incidence of freezing temperatures (...)