Soil solution and extractable soil nitrogen response to climate change in two boreal forest ecosystems

• Published in: Biology and fertility of soils 2005-05, Vol.41 (4), p.257-261
• Main Author: Verburg, P.S.J
• Format: Article
• Language: English
• Subjects: adsorption; Agronomy. Soil science and plant productions; Air temperature; Biological and medical sciences; Boreal forests; Calluna; carbon-dioxide; catchment; Catchments; chemistry; Climate change; climex project; Forest ecosystems; Fundamental and applied biological sciences. Psychology; Leaching; Mineralization; net nitrogen; nitrogen content; nutrient uptake; Physical properties; Physics, chemistry, biochemistry and biology of agricultural and forest soils; release; respiration; Soil science; Soil solution; Soil temperature; Soils; southern norway; Summer; temperature; Vaccinium; Water and solute dynamics; Winter
• ISSN: 0178-2762; 1432-0789
• DOI: 10.1007/s00374-005-0831-1

Several studies show that increases in soil temperature result in higher N mineralization rates in soils. It is, however, unclear if additional N is taken up by the vegetation or accumulates in the soil. To address this question two small, forested catchments in southern Norway were experimentally manipulated by increasing air temperature (+3°C in summer to +5°C in winter) and CO^sub 2^ concentrations (+200 ppmv) in one catchment (CO^sub 2^T-T) and soil temperature (+3°C in summer to +5°C in winter) using heating cables in a second catchment (T-T). During the first treatment year, the climate treatments caused significant increases in soil extractable NH^sub 4^ under Vaccinium in CO^sub 2^T-T. In the second treatment year extractable NH^sub 4^ in CO^sub 2^T-T and NO^sub 3^ in T-T significantly increased. Soil solution NH^sub 4^ concentrations did not follow patterns in extractable NH^sub 4^ but changes in soil NO^sub 3^ pools were reflected by changes in dissolved NO^sub 3^. The anomalous behavior of soil solution NH^sub 4^ compared to NO^sub 3^ was most likely due to the higher NH^sub 4^ adsorption capacity of the soil. The data from this study showed that after 2 years of treatment soil inorganic N pools increased indicating that increases in mineralization, as observed in previous studies, exceeded plant demand and leaching losses.[PUBLICATION ABSTRACT]