Project title: Linking carbon and nitrogen dynamics to mitigate nitrogen losses and greenhouse gas emissions in grazed pastures
Supervisors: Prof Tim Clough, Lincoln University, New Zealand, Dr Beckie Phillips (Landcare Research), Dr David Whitehead (Landcare Research).
Conversion of dryland, grazed pasture to high-intensity farm systems with irrigation and the addition of nitrogen fertiliser is a major land-use change in New Zealand. Research is needed urgently to understand the drivers and linkages between soil carbon, water and nitrogen dynamics to determine the impacts of changing farm systems on soil carbon storage and losses of nitrogen as nitrate in drainage water and as nitrous oxide emissions. We have established a new experimental platform at a field site near Lincoln where we intend to construct carbon, water and nitrogen budgets pre- and post-irrigation starting in spring (September, 2015). We will use paddock scale and chamber techniques to estimate gross primary productivity, carbon balances and water use efficiency, and large lysimeters to collect drainage water for analysis of nitrogen.
As a major contribution to this project, the PhD programme will investigate functional changes to determine if differences in carbon balance can be explained by changes in autotrophic/heterotrophic respiration and/or change in microbial biomass/activity. The aim of the project will be to investigate if potential differences in denitrification can best be attributed to physical factors, or substrate dynamics. Ultimately, the research will contribute to developing optimal management practices to determine if greater carbon inputs below-ground under irrigation enhance denitrification and nitrogen turnover.
Requirements: Applicants should have a primary degree and/or a MSc in an appropriate discipline. A knowledge of soil science, carbon and nitrogen dynamics and the use of stable isotopes will be advantageous.
Funding: The position is funded by Landcare Research and covers a postgraduate PhD stipend and tuition fees.
Starting date: The project will start as soon as possible and run for three years.
Location: The student will be hosted and receive supervision from within the Lincoln Hub, comprising the university, research organisations and industry partners.
Application procedure: Send applications, including statements from two referees to:
Departmental Secretary, Department of Soil & Physical Sciences
Faculty of Agriculture & Life Sciences
PO Box 85084
p +64 3 4230793 | f+64 3 325 3607