PRECIPITATION AND DUFF FALL AS NATURAL SOURCES OF NITROGEN AND PHOSPHORUS FOR FOREST SOILS IN THE SŁOWIŃSKI NATIONAL PARK

Abstract

Every year forest soils are enriched with nitrogen and phosphorus compounds due to the fall of leaves and litter of conifer needles, mineralization of ground cover and decaying tree roots, as well as precipitation. The process has been examined in two forest ecosystems: a mixed forest (plot I) and a young wood (plot II). The overall fall of duff collected in the young wood of the Słowiński National Park (plot II) has been 3.014 t/ha·year, which constitutes 69.35% of the fall collected in the mixed forest (plot I) on this territory (4.346 t/ha·year). The maximum intensity of duff fall occurred in autumn months and constituted 62.36% and 64.20% of annual fall respectively. Totally, 46.96 kg/ha·year of N and P were supplied to the soil of the plot I and 22.04 kg/ha·year in the case of the plot II. The precipitation enriched the soils of the mixed forest by 33.66 kg/ha·year of nitrogen and 1.19 kg/ha·year of phosphorus, the soils of the young wood – by 23.06 kg/ha·year of nitrogen and 0.92 kg/ha·year of phosphorus.

Key words: nitrogen, phosphorus, duff fall, precipitation, mixed forest, young wood