Soil Carbon

Increasing the quantity of carbon stored in agricultural soils has the potential to offset emissions of greenhouse gases to the atmosphere, while soil carbon losses would further add to those emissions.

However, realising this mitigation potential is technically challenging when soil carbon stocks are already high (as they are in New Zealand), potential changes in soil carbon are small and spatial variability is high.

The current NZAGRC programme has three distinct components:

(1) testing specific management practices that may increase the long term soil carbon store in field situations;

(2) developing and using models to predict how a range of management practices may influence long and short tem soil carbon storage; and

(3) identifying those factors that influence the stability of current or newly added soil carbon.

We have also supported international work to map on farm soil carbon and will participate in the international research programme CIRCASA.

Principal Investigators

Dr David Whitehead, Manaaki Whenua - Landcare Research (2010-present)
Professor Frank Kelliher, AgResearch (2010-2017)

Research Stories

Two PhD studentships in New Zealand: Soil carbon stabilisation and resistance to loss

There are two PhD studentships available that will contribute to a wider programme of research funded by the Global Partnership for Livestock Emission Research entitled: MANAGEMENT OPTIONS FOR INCREASING SOIL CARBON UNDER GRASSLANDS. The PhD students will be based at the University of Waikato (Hamilton, North Island) and Lincoln University (near Christchurch, South Island) and will work closely together to deliver the project objectives.

Background

Intensification of pastoral farming is occurring widely throughout New Zealand (NZ) and the effects on soil processes such as soil carbon storage and stabilisation are poorly known. Some evidence suggests that species-diverse pastures and intensification with irrigation can enhance both pasture production and soil carbon storage. But how stable is this stored carbon and what are the factors that affect its resistance to loss? We have assembled an international team with specialist skills to measure and model the impact of these pasture management practices on soil carbon stabilisation and turnover using advanced stable-isotope techniques. Our findings will be used to develop and validate a process-based model (CenW) that will be used to determine management options for increasing soil carbon stabilisation and its resistance to climate change.

PhD projects

Project 1: Belowground partitioning and stabilisation of pasture-fixed carbonThis PhD project will focus on determining how species-diverse pastures and intensification with irrigation practices affect the stabilisation of C in soils. It will deploy stable isotope techniques to quantifying the C fixed by pasture species and its partitioning to aboveground and belowground components under the different management system. It will also apply physical, chemical and biological fractionation techniques to evaluate the stability of the soil organic C fixed by pastures. The appointee for project 1 will be based at Lincoln University and the nearby New Zealand Institute for Plant and Food Research, Lincoln.

Project 2: Resistance of incorporated soil carbon to lossThis PhD will examine the resistance of stored C to loss in the face of variation in temperature and moisture and physical disturbance. Physical disturbance occurs in pastures during grazing and pasture renewal, whereas temperature and moisture vary naturally and as a product of irrigation and climate change. These disturbances will be used to test and rank the resistance of stored C from different pasture management practices to loss. This project will also use stable isotopes to separate the response of different pools of carbon in soil. The appointee for project 2 will be based at the University of Waikato, within the WaiBER research group (www.waiber.com).

Award details

The appointees will each receive a PhD stipend of $27,000 (NZD) per year and have their enrolment fees paid. Funding will be for three years, with provision for a further 6 months of support if required. For more information and to apply for a position, please visit www.careers.plantandfood.co.nz (vacancy number 13948). Applications should include a cover letter with a brief statement of research interests and experience, CV, transcripts and contact information for two referees. Please indicate in your cover letter whether you have a preference for one of the PhD topics and why.

For more information contact:

Prof Louis Schipper schipper@waikato.ac.nz

Prof Tim Clough timothy.clough@lincoln.ac.nz

Dr Mike Beare mike.beare@plantandfood.co.nz

Applications open 7 October 2015 and close 6 November 2015.

  1. pdf Two PhD opportunities in New Zealand.pdf (0.30MB)

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