title: Nitrogen and phosphorus budgets in experimental grasslands of variable diversity.
abstract: Previous research has shown that plant diversity influences N and P cycles. However, the effect of plant diversity on complete ecosystem N and P budgets has not yet been assessed. For 20 plots of artificially established grassland mixtures differing in plant diversity, we determined N and P inputs by bulk and dry deposition and N and P losses by mowing (and subsequent removal of the biomass) and leaching from April 2003 to March 2004. Total deposition of N and P was 2.3 +/- 0.1 and 0.2 +/- 0.01 g m(-2) yr(-1), respectively. Mowing was the main N and P loss. The net N and P budgets were negative (-6.3 +/- 1.1 g N and -1.9 +/- 0.2 g P m(-2) yr(-1)). For N, this included a conservative estimate of atmospheric N(2) fixation. Nitrogen losses as N(2)O were expected to be small at our study site (<0.05 g m(-2) yr(-1)). Legumes increased the removal of N with the harvest and decreased leaching of NH(4)-N and dissolved organic nitrogen (DON) from the canopy. Reduced roughness of grass-containing mixtures decreased dry deposition of N and P. Total dissolved P and NO(3)-N leaching from the canopy increased in the presence of grasses attributable to the decreased N and P demand of grass-containing mixtures. Species richness did not have an effect on any of the studied fluxes. Our results demonstrate that the N and P fluxes in managed grassland are modified by the presence or absence of particular functional plant groups and are mainly driven by the management.
authors.affiliation: Institute of Ecology, Department of Soil Science, Berlin University of Technology, Salzufer 11-12, D-10587 Berlin, Germany. yvonne.oelmann@uni-mainz.de
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Oelmann
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Kreutziger
authors.forename: Vicky M
authors.initials: VM
authors.lastname: Temperton
authors.forename: Nina
authors.initials: N
authors.lastname: Buchmann
authors.forename: Christiane
authors.initials: C
authors.lastname: Roscher
authors.forename: Jens
authors.initials: J
authors.lastname: Schumacher
authors.forename: Ernst-Detlef
authors.initials: ED
authors.lastname: Schulze
authors.forename: Wolfgang W
authors.initials: WW
authors.lastname: Weisser
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wilcke
mesh_terms: D000383:Agriculture / Q000379:methods*; D044822:Biodiversity; D018533:Biomass; D007887:Fabaceae / Q000254:growth & development; D009566:Nitrates / Q000032:analysis; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*; D006109:Poaceae / Q000254:growth & development*; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D011891:Rain; D012987:Soil / Q000032:analysis
chemical_list: D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D012987:Soil; D010758:Phosphorus; D009584:Nitrogen