Growing the GHG research community through NZAGRC scholarships

During 2020 and 2021, the NZAGRC’s investment in building specialist science capability focused on funding six students across the three universities. All have produced excellent study results while preparing a pathway for their career or further study.

Lincoln University

At Lincoln University, scholarship funding was provided to PhD student Chris Chisholm for research into the abundance and activity of comammox bacteria in New Zealand soils. Comammox are a group of newly-discovered bacteria that have the ability to completely oxidise ammonia to nitrate. However, their relative abundance and activity in managed and natural terrestrial ecosystems remains relatively unknown.

By investigating comammox, Chris’s research will generate a greater understanding of a key biochemical process in the soil that contributes to two environmentally important processes -- nitrous oxide emissions and nitrate leaching. Armed with this new knowledge, future researchers may find ways to manipulate the nitrification process to reduce the number of harmful products produced.

Massey University

At Massey University, NZAGRC Student Scholarships went to Chi Vi and Pelle Slothouwer.

Chi was a Master’s student who investigated the effects of dairy pasture swards of varying plantain levels on nitrous oxide emissions. This was a complex experiment that involved the capture of urine from cows grazing swards with different plantain compositions. Chi quantified the ability of mixed swards containing 30% and 50% plantain to reduce nitrous oxide emissions.

She received an A grade for her Master’s thesis, with very favourable reviews by the examiners.

Pelle is an Undergraduate Honours student who worked on Massey University’s ‘novel drainage’ research programme investigating techniques for reducing nitrogen leaching losses in artificial drainage. As part of this study, the university built a woodchip bioreactor at Waitatapia Station near Bulls.

Bioreactors intercept artificial drainage and strip nitrate before the water enters the receiving streams. The question that Pelle set out to answer was – ‘does full-denitrification occur in the bioreactor or are there significant losses of nitrous oxide, which would be an unfortunate case of pollution swapping?’.

He is currently analysing the data collected but results to date suggest that very little nitrous oxide is produced in woodchip bioreactors and they are a very effective mitigation measure. Pelle is now working towards his Master’s degree.

Waikato University

At Waikato, NZAGRC funding enabled three summer scholarships to be awarded.

Seager Ray examined methods for measuring the temperature dependence of respiration from fungi and bacteria along a geothermal gradient. He completed his BSc and Master’s papers and is to undertake an MSc research thesis.

Tania Ng provided support for the development of material for a new first-year climate change course and worked on the growth of mosses. She completed her BSc and MSc courses and plans to undertake a Masterate thesis on mosses along a geothermal gradient.

Robert Brodnax worked at Manaaki Whenua - Landcare Research supporting the implementation of a national soil carbon sampling strategy. He is in the final year of a BSc in earth sciences and is exploring opportunities for a Masterate thesis.

Impacts

Hong Di, Professor of Soil and Environmental Science at Lincoln University, said these scholarships are keenly sought after.

“The main criteria for selecting the people who are chosen are their academic record and areas of research. It is extremely valuable for attracting top-grade students to study in the areas of greenhouse gas emissions and mitigation.”

David Horne, Associate Professor in Soil Science at Massey University, agrees the scholarships are valued by students who qualify for consideration.

“The first criterion is relevance to the interests of the NZAGRC i.e. related to greenhouse gas emissions, whether it be measurement (quantification) or mitigation. We endeavour to share the scholarships around and so try to award each student working in this area some support.

“Some studies and students may get a larger award. This may be due to greater need (large and more expensive research) or student ability.”

Professor Horne says this work is very important. “Over the past two years we have awarded support to students researching the ability of plantain to mitigate nitrous oxide emissions. Plantain is likely to be an important tool for pastoral famers seeking to reduce losses of nitrogen to the environment.

“This year Chi Vi produced some very interesting results related to the ability of plantain to mitigate nitrous oxide emissions. This was a well-executed study.”

He adds that without the NZAGRC’s support, this research would not have been possible.

Professor Louis Schipper of Waikato University uses the scholarships to support summer placements at the university and Crown Research Institutes.

“Generally, these are short-term three-month projects to collect initial information for potential future projects or to collect some additional information aligned with ongoing work, for example someone’s PhD. In that way, they add a great deal of value.”

As an example, Professor Schipper points to Anne Wecking, who received a partial stipend to support her PhD thesis on testing eddy covariance as a method for determining nitrous oxide emissions from pasture and during pasture renewal.

“The thesis was successfully defended in January 2021. Anne is currently working at Tasman District Council and has published two excellent papers out of her thesis (see footnote).”

Looking at the career paths taken by past students, Professor Schipper says the scholarship programme has produced really talented graduates who have gone into a variety of positions.

“They take to their new positions an in-depth understanding of the importance of greenhouse gas emissions and agriculture in New Zealand. This is critical -- all communities and industries need people who understand the challenge of climate change and potential solutions.”

Footnote: Anne Wecking’s two papers are:

Wecking, A.R.; Cave, V.M.; Liáng, L.L.; Wall, A.M.; Luo, J.; Campbell, D.I.; Schipper, L.A. (2021) Novel injection technique: using a field-based quantum cascade laser for the analysis of gas samples derived from static chambers. Atmospheric Measurement Techniques. 13(11):5763-5777.

Wecking, A.R.; Campbell, D.I.; Wall, A.M. Liang, L.L.; Lindsey, S.: Luo, J.; Schipper, L.A. (2020). Reconciling annual nitrous oxide emissions of an intensively grazed dairy pasture determined by eddy covariance and emission factors. Agriculture, Ecosystems and Environment. 287: 106646.

She also contributed to:

Goodrich, J.P.; Wall, A.M.; Campbell, D.I.; Fletcher, D.; Wecking, A.R.; Schipper, L.A. (2021) Improved gap filling approach for N₂O fluxes allows determination of separate annual budgets and uncertainties for two adjacent grazed pastures from one flux tower. Agriculture and Forest Meteorology. 297: 108280.