This digital document is a journal article from Soil Biology and Biochemistry, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The effects of elevated CO"2 supply on N"2O and CH"4 fluxes and biomass production of Phleum pratense were studied in a greenhouse experiment. Three sets of 12 farmed peat soil mesocosms (10cm dia, 47cm long) sown with P. pratense and equally distributed in four thermo-controlled greenhouses were fertilised with a commercial fertiliser in order to add 2, 6 or 10gNm^-^2. In two of the greenhouses, CO"2 concentration was kept at atmospheric concentration (360@mmolmol^-^1) and in the other two at doubled concentration (720@mmolmol^-^1). Soil temperature was kept at 15^oC and air temperature at 20^oC. Natural lighting was supported by artificial light and deionized water was used to regulate soil moisture. Forage was harvested and the plants fertilised three times during the basic experiment, followed by an extra fertilisations and harvests. At the end of the experiment CH"4 production and CH"4 oxidation potentials were determined; roots were collected and the biomass was determined. From the three first harvests the amount of total N in the aboveground biomass was determined. N"2O and CH"4 exchange was monitored using a closed chamber technique and a gas chromatograph. The highest N"2O fluxes (on average, 255@mgN"2Om^-^2h^-^1 during period IV) occurred just after fertilisation at high water contents, and especially at the beginning of the growing season (on average, 490@mgN"2Om^-^2h^-^1 during period I) when the competition of vegetation for N was low. CH"4 fluxes were negligible throughout the experiment, and for all treatments the production and oxidation potentials of CH"4 were inconsequential. Especially at the highest rates of fertilisation, the elevated supply of CO"2 increased above- and below-ground biomass production, but both at the highest and lowest rates of fertilisation, decreased the total amount of N in the aboveground dry biomass. N"2O fluxes tended to be higher under doubled CO"2 concentrations, indicating that increasing atmospheric CO"2 concentration may affect N and C dynamics in farmed peat soil.