NITREX project - Gårdsjøn. Status report for 1988-1990

Abstract

At the NITREX site at Gårdsjøn, Sweden, nitrogen deposition will be experimentally increased to an entire forested catchment to study the potential for nitrogen saturation. Investigations include regular sampling of precipitation, thoughfall and runoff and compilation of input-output beugets. Short-term experiments of toxicity of the runoff water to fish are also underway. Studies of vegetation and soils are centered around three vegetation types characteristic of the catchments. Plots have been selected on the basis of soil and vegetation maps of the three catchments. Regular measurements include (1) volume and chemical composition of soil solution, (2) soil temperature, (3) chemical composition of needles, (4) amount and chemical composition of litterfall, and (5) soil moisture. In addition studies of mineralization, fine roots, and mycorrhiza are being conducted. Nitrogen addition will begin in April 1991. The NITREX data from Gårdsjøn will be combined with similar data from the other NITREX sites throughout Europe.