Drought effects on soil carbon and nutrient cycling mediated by rhizosphere processes
The interactive effects of grazing (clipping), nitrogen and phosphorus addition on carbon and nutrient dynamics are examined in a grassland near the Centre for Carbon, Water and Food in Camden, NSW. This project will fill important knowledge gaps in managing grasslands for sustainable production.
Carbon costs for plant uptake of nutrients and water
This project will investigate how much carbon plants need to invest belowground in return for water and nutrients. By using economic principles of supply and demand the project quantifies carbon expenditure for water and nutrients in grasslands and crops under different climate and land management scenarios. Novel triple and quadruple isotope labelling techniques are used to explore the dependency of carbon investment on plant-microbial interactions and availability of belowground resources.
Impacts of biochar on soil nitrogen and phosphorus dynamics
Effects of phosphorus availability on nitrogen mineralisation and loss
Effects of soil phosphorus availability on nitrogen dynamics are explored for a variety of soil types. Most nitrogen transformations in soil, including gross nitrogen mineralisation, nitrification, and denitrification are mediated by microbes. All of these microbes require phosphorus, but little is known how phosphorus availability affects these microbial processes. In this project the effect phosphorus availability on nitrogen transformations and loss (e.g., nitrous oxide emission) will be explored for soil types that differ in phosphorus and carbon content, pH and texture.