Subproject 05: Soil nutrient dynamics (1 PhD position)
Principle Investigators: Yvonne Oelmann, University of Tübingen
Summary: Extreme events such as floods or droughts affect the availability of water and, thus, inevitably impact nutrient cycling in soils. The majority of grassland studies reported a nutrient flush in soil upon rewetting after drought which is eventually followed by nutrient leaching losses compromising water quality after droughts. The nutrient flush is linked to nutrient dynamics of plants and soil microorganisms and is determined by opposing processes during the drought (= resistance) and after the subsequent rewetting (= recovery).
The objectives of our subproject SP05 are (i) to assess the resistance and recovery of soil microbial nutrient dynamics during and after a drought, respectively, (ii) to test the effect of plant diversity on the resistance and recovery of microbial nutrient dynamics in soil and link this to other organisms (plants, soil fauna), and (iii) to test the long-term effect of plant diversity on soil nutrient dynamics under extreme events. We hypothesize that the soil microbial community reduces nutrient uptake and is prone to nutrient release during drought but rapidly takes up nutrients after a drought. In other words, microbial nutrient pools in soil quickly recover after drought and furthermore, faster at high as compared to low plant diversity. At high plant diversity, the nutrient dynamics of soil microorganisms and other organisms are complementary, i.e. temporally asynchronous. Consequently, plant diversity stabilizes nutrient dynamics in spite of frequent extreme events in the long run.
To test these hypotheses, our research will be based on the common research platforms (ResCUE Experiment; Main Experiment). We will rely on data of different temporal resolutions to assess nutrient dynamics related to resistance, recovery and stability. We will use state-of-the-art methods (soil microbial nutrient concentrations), stable isotope labeling and natural abundance levels of stable isotopes.
Available positions: 1 PhD student
Contact: Prof. Dr. Yvonne Oelmann (email@example.com)