The P cycle in grassland and forest ecosystems of different biodiversity and land-use intensity

Background

Increasingly efficient nutrient exploitation with increasing plant diversity results in lower nutrient concentrations in soil solution. This was observed for nitrogen but not for other essential nutrients such as phosphorus. In managed ecosystems, diversity is closely linked to land-use intensity and history. To understand the controls of nutrient concentrations in soil, land-use and biodiversity effects must be disentangled. Therefore, DYNPHOS studies the effect of land use and biodiversity on phosphorus cycling in grassland and forest systems of the three Biodiversity Exploratories.

Goals

Our objective is to disentangle the effect of land use and plant diversity on

Phosphorus fractions in soil
Phosphorus cycling in soil
Phosphorus storage in plants

Furthermore, we will assess the influence of land-use practices on phosphorus in soil by using novel isotope techniques, i.e. the determination of ?18O in phosphates.

Hypotheses

With these goals we plan to test the following hypotheses

Increasing land-use intensity probably associated with higher nutrient availability in soil
1. results in a less strong relationship between biodiversity and P availability (organic and inorganic) in soil and
2. will lead to a less strong relationship between biodiversity and P pools in plants.
1. Intensive land use increases the proportion of fertilizer-derived easily-soluble P minerals. The concentration of P is to a large extent chemically controlled thereby reducing the effect of diversity on P concentrations in soil.
2. At a given site fertility (within the same land use), increasing biomass production with increasing plant diversity results in an increasing size of the organic P pool and hence an increasing contribution of mineralized P to plant-available P. As a result the diversity effect on P availability will increase.
The O isotope ratio in PO4 can be used to distinguish different P sources (dissolution of mineral P, desorption, mineralization).

We will determine P pools in soil and plant biomass, P release by dissolution and mineralization, and the isotopic signature (?18O) in phosphate extracted from soil.

Publications

The role of soil chemical properties, land use and plant diversity for microbial phosphorus in forest and grassland soils

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

Land use and biodiversity effects on P-transformation in soil

Landnutzungs- und Biodviersitätseffekte auf P-Transformationen im Boden

Sorkau E. (2018): Land use and biodiversity effects on P-transformation in soil. Dissertation, University Tübingen

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

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.

Phosphate release kinetics in calcareous grassland and forest soils in response to H+ addition

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

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

Phosphorus partitioning in German grassland and forest soils as related to land-use type, management intensity, and land-use related pH.

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