Phosphor im Grünland – Antrieb der Leguminosen, aber Bremse der Phytodiversität?

Summary

In our study we investigated the effect of soil phosphorus (P) status on legume occurrence and on phytodiversity of organically managed permanent grassland sites. Therefore, we realized screenings on 2 m x 2 m plots with a clear spatial
differentiation between the functional groups ‘legumes’ and ‘non-legumes’ on five mown pasture sites under organic management in north-eastern Germany. We found no significant difference between the phosphorus content of aboveground biomass of legumes and the associated non-legume group. However, we detected a significant difference between the soil PDL contents of these two groups with lower contents in
soils of the legume patches whereas the different P fractions and thus different P availability on the mineral site could not explain the occurrence of legumes. Contrary
to reports by many ecologists, we could not confirm a clear relationship between soil phosphorus and species number.