Project
Investigating the interactions between enhanced silicate weathering and growth of legumes
Weathering of silicate minerals stabilises climate on geologic time scales by consuming CO2. Artificially enhancing weathering rates by mining, crushing and spreading rocks containing silicate minerals has been suggested as a tool to mitigate climate change. Elements released in the weathering process may overcome nutrient deficiencies, but may also lead to toxicity. At the same time, soil chemical changes resulting from the weathering process may impact the bioavailability of nutrients as well as nutrient plant uptake.
Background
Silicate weathering rates are highest at low pH, but the consumption of acid during the weathering process raises pH. Additional acid production through e.g. root exudates might therefore stimulate weathering. Leguminous plants, i.e. plants that form a symbiosis with nitrogen (N) fixing bacteria, produce more protons in the rhizosphere, potentially further stimulating weathering.
In this MSc thesis project, you will grow a N-fixing crop (Glycine max) in a greenhouse experiment on soils amended with and without crushed silicate minerals. By adding ammonium (NH4+), nitrate (NO3-), or no nitrogen (i.e. stimulating N fixation), the effect of uptake of various N sources on pH and weathering will be determined. You will chemically characterise the soils; determine the bioavailability of nutrients in the soil; and analyse the plant uptake of these elements. Weathering rates will be inferred from changes in total Mg and/or changes in total alkalinity.
Research themes
Soil Carbon, Soil Fertility.
Used skills
- Literature review;
- Proposal and thesis writing;
- Laboratory work (greenhouse experiment, plant and soil sampling and analyses);
- Data analysis.
Requirements
- Required courses for the MSc Thesis Soil Chemistry and Chemical Soil Quality (SOC81336);
- For this topic, some laboratory experience is required.