Nitrogen and phosphorus budgets in experimental grasslands of variable diversity.
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.
Oelmann
Yvonne
Y
Institute of Ecology, Department of Soil Science, Berlin University of Technology, Salzufer 11-12, D-10587 Berlin, Germany. yvonne.oelmann@uni-mainz.de
Kreutziger
Yvonne
Y
Temperton
Vicky M
VM
Buchmann
Nina
N
Roscher
Christiane
C
Schumacher
Jens
J
Schulze
Ernst-Detlef
ED
Weisser
Wolfgang W
WW
Wilcke
Wolfgang
W
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
D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D012987:Soil; D010758:Phosphorus; D009584:Nitrogen