Modellerade och uppmätta kväveflöden i energiskog som bevattnas med avloppsvatten
PedologyCartographyGeomorphologyPhysical geographySouthern SwedenDenitrificationModellingNitrogen flowClimatologyNaturgeografiGeomorfologiMarkläraKartografiKlimatologiEarth and Environmental Sciences
The aim of this essay was to study the nitrogen flow in two willowplantations, at different locations in the south of Sweden, that wereirrigated with sewage. The study was also performed to compare thedifferences in nitrogen flows between two years, 1998 and 1999. The studywas made in three parts. First, the denitrification activity was measuredusing the acetylen inhibition method. Second the nitrogen flow, as well asthe water- and heat flows, were modeled through the SOIL-SOILN-modelThird; the nitrogen flow was calculated to compare with the results fromthe model.The results from the measurements were then compared with the resultsfrom the SOILN-simulations to detect differences in the denitrificationrate. There was zero denitrification activity for both years and bothlocation in the results from the simulation. The measurements showed onlyone sampling occasion at one location with significant denitrificationrates. The reason for this seemed to be that Salix is effective in its abilityto incorporate nitrogen. One of the plantations was not irrigated at thetime of the measurements why the soil might have been aerobic. Theresults from the model are surprising, considering the fact that the soilswhich were irrigated had fine texture and therefore ought to becomeanaerobic. Anaerobic environment together with a supply of carbon andnitrate, are the prerequisites for denitrification, and all this seems to havebeen available in the model.The nitrogen flow was modeled and calculated. The calculation was madefrom figures given by literature, for example plant growth. The resultsfrom the model showed that there were no nitrogen leakage. In the resultsfrom the calculation, there were some remaining nitrogen on bothlocations in 1999, but none in 1998. The amounts of remaining nitrogenwere rather small. Besides a possible leakage of nitrogen to the saturationlevel there might have been a denitrification activity, and weeds ought tohave incorporated some of the remaining nitrogen for their growth.