『Abstract
Plant diversity was shown to influence the N cycle, but plant
diversity effects on other nutrients remain unclear. We tested
whether plant species richness or the presence/absence of particular
functional plant groups influences P partitioning among differently
extractable pools in soil, P concentrations in soil solution,
and exploitation of P resources (i.e. the proportion of total
bioavailable P in plants and soil that was stored in aboveground
biomass) by the plant community in a 5-year biodiversity experiment
in grassland.
The experimental grassland site established in 2002 had 82 plots
with different combinations of numbers of species (1, 2, 4, 8,
16, 60) and functional groups (grasses, small non-leguminous herbs,
tall non-leguminous herbs, legumes). In 2007, we determined P
partitioning (Hedley) in soil of all experimental plots. We sampled
plant community biomass and continuously extracted soil solution
with suction plates from March 2003 to February 2007 and determined
PO4-P concentrations in all samples.
The presence of legumes increased aboveground P storage in plants
and decreased labile Pi concentrations in
soil because of their higher demands for P associated with N2 fixation.During cold periods, readily plant-available
PO4-P concentrations in soil solution increased
in legume-containing mixtures likely caused by leaching from P-rich
residues. We found a consistently positive effect of plant species
richness on P exploitation by the plant community which was independent
of the presence of particular plant functional groups. With proceeding
time after establishment, plant species richness increasingly
contributed to the explanation of the variance in P exploitation.
Therefore, plant strategies to efficiently acquire P seem to become
increasingly important in these grasslands. We conclude that diverse
plant communities are better prepared than less diverse mixtures
to respond to P limitation induced by continuously high atmospheric
N deposition.
Keywords: Phosphorus; Plant diversity; Plant P uptake; P fractions
in soil; P in soil solution』
1. Introduction
2. Materials and methods
2.1. Study site
2.2. Sampling and chemical analyses
2.3. Calculations and statistical analyses
3. Results
3.1. Community biomass, P concentrations, and P storage
3.2. P exploitation by the plant community
3.3. Phosphorus partitioning in soil
4. Discussion
4.1. Plant species richness effects
4.2. Functional group identity effects
4.3. Temporal course of plant diversity effects
5. Conclusions
Acknowledgements
References