Optimum nutrition and nitrogen saturation in Scots pine stands

摘要: Long-term field experiments are described, in which nitrogen and other plant nutrients were added regularly to young Scots pine stands at two sites Sweden, Lisselbo (1969-1988) Norrliden (1971-1989; some treatments still progress). A main aim was establish a range of needle concentration levels, as stable possible, study the effects these factors (other nutrients, soil acidity changes, irrigation) on tree growth nutrient status. The results confirmed previous experience that supply normally is growth-limiting factor boreal forest, but showed regular additions can induce boron magnesium deficiency, low internal concentrations trees, e.g. potassium phosphorus. Other aspects ecosystem functioning varied supply-biomass production, balances for several elements; vegetation nitrification, studied by ourselves or cooperating research groups-are reviewed. importance long-term urgent environmental problems, such saturation acidification, discussed.