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With increasing diversity, the content of plant-available nutrients in the soil decreases due to more effective resource use by the plants. This relationship has already been shown several times for nitrogen. Such studies are lacking for other nutrients that may also limit plant growth, such as phosphorus. Since diversity and land-use intensity or history are closely related in managed systems, the influence of these factors on the phosphorus cycle in the grassland and forest of the biodiversity exploratories is being investigated in the DYNPHOS sub-project in order to determine the control variables for soil nutrient levels.


Our aim is to separate the effects of diversity and land-use on:

  1. the phosphorus fractions in the soil
  2. the phosphorus cycle in the soil
  3. the phosphorus stocks in plants

We also plan to determine the influence of past land-use via innovative isotope methods (?18O in PO4).


1. More intensive land-use, which is usually linked to higher nutrient availability in the soil due to fertilisation, leads to a reduction in the negative influence of plant diversity on phosphorus availability (organic and inorganic) in the soil.

  • a reduction in the negative influence of plant diversity on phosphorus availability (organic and inorganic) in the soil and correspondingly
  • a reduction in the positive influence of plant diversity on phosphorus stocks in the above-ground biomass.

2. Among the main sources of phosphate in the soil solution (dissolution of P-containing minerals, desorption, mineralisation of organic matter), the share of phosphorus in the above-ground biomass

  • is with more intensive land-use, the proportion of easily soluble, fertiliser-borne P-containing minerals is increased and thus the influence of plant diversity – according to hypothesis 1a –
  • is reduced and within a land-use intensity (with the same nutrient supply), the proportion of mineralised phosphate increases with increasing plant diversity due to the stimulation of the mineralisation of organic matter.

3. The oxygen isotope signal of phosphate can be used to distinguish between different phosphorus sources (solution of P minerals, desorption, mineralisation).

To prove these hypotheses, we determine the phosphorus stocks in soils and plants, the phosphorus release by solution, desorption and mineralisation, and ?18O in PO4 from these three sources.


Doc
The Phosphorus Cycle in Grassland and Forest Ecosystems of different Biodiversity and Management
Alt F. (2013): The Phosphorus Cycle in Grassland and Forest Ecosystems of different Biodiversity and Management. Dissertation, University Tübingen.
Doc
Wie viel Phosphor wird in Grünland- und Waldböden freigesetzt?
Alt F., Oelmann Y., Schöning I., Wilcke W. (2013): Phosphate release kinetics in calcareous grassland and forest soils in response to H+ addition. Soil Science Society of America Journal 77 (6), 2060-2070. doi: 10.2136/sssaj2013.02.0072
More information:  doi.org
Doc
Phosphor-Partitionierung in deutschen Grünland-und Waldböden in Bezug auf Landnutzungstyp, Bewirtschaftungsintensität und landnutzungsbedingtem pH-Wert.
Alt, F., Oelmann, Y., Herold, N., Schrumpf, M., Wilcke, W. (2011): Phosphorus partitioning in German grassland and forest soils as related to land-use type, management intensity, and land-use related pH. Journal of Plant Nutrition and Soil Science 174 (2), 195-209. doi: 10.1002/jpln.201000142
More information:  doi.org
Doc
Landnutzungs- und Biodviersitätseffekte auf P-Transformationen im Boden
Sorkau E. (2018): Land use and biodiversity effects on P-transformation in soil. Dissertation, University Tübingen
Doc
Die Rolle von Bodeneigenschaften, Landnutzung und Pflanzenartenvielfalt für den mikrobiellen Phosphor im Boden
Sorkau E., Boch S., Boeddinghaus R., Bonkowski M., Fischer M., Kandeler E., Klaus V., Kleinebecker T., Marhan S., Müller J., Prati D., Schöning I., Schrumpf M., Weinert J., Oelmann Y. (2018): The role of soil chemical properties, land use and plant diversity for microbial phosphorus in forest and grassland soils. Journal of Plant Nutrition and Soil Science 181 (2), 185-197. doi: 10.1002/jpln.201700082
More information:  doi.org
Doc
Phosphorus budget of German grasslands – effects of management and relation to biodiversity
Traub K. (2016): Phosphorus budget of German grasslands - effects of management and relation to biodiversity. Master thesis, University Tübingen
Doc
Effects of plant species richness on plant-available nitrogen and phosphorus concentrations in soils under grasslands of the Schwäbische Alb differing in land-use intensity
Wahl A. S. (2012): Effects of plant species richness on plant-available nitrogen and phosphorus concentrations in soils under grasslands of the Schwäbische Alb differing in land-use intensity. Thesis, University Tuebingen

Scientific assistants

Prof. Dr. Wolfgang Wilcke
Project manager
Prof. Dr. Wolfgang Wilcke
Karlsruher Institut für Technologie
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