Nitrous Oxide

Low nitrous oxide plants

Aim: Develop plants and planting strategies that result in reduced emissions from soil

What does success look like?

Low nitrous oxide plants and strategies adopted on farm

How will we get there?

  1. Understand the differences in nitrification between species, between cultivars and between endophyte-grass combinations
  2. Confirm lab results are repeatable in plot and field trials
  3. Undertake paddock scale trials to quantify effect
  4. Develop commercial pipeline for new pant breeds to be taken up on farm

What input is needed?

Science is needed to identify and understand plant effects on soil processes related to nitrous oxide emissions.

Commercial input will be needed, if plant varieties/breeding are agronomically sensible, to gather data to support incorporation into New Zealand farming practice. 

Commercial input will also be needed if natural nitrous oxide inhibitors are identified to evaluate and breed 

What's the timeline?  


  • Report: Desk-top review of GHG components of OVERSEER

    Report prepared for the New Zealand Agricultural Greenhouse Gas Research Centre

    August 2015 

  • PhD opportunity: University of Waikato

    NOT LONGER AVAILABLE PhD in Greenhouse Gas Emissions from Grazed Pastures
    University of Waikato, New Zealand

    We have an opening for a PhD candidate to make measurements of nitrous oxide and carbon dioxide fluxes from grazed pastures using eddy covariance and chamber techniques. Our team is currently measuring fluxes of carbon dioxide at four eddy covariance tower sites over grazed pastures. We have recently installed a quantum cascade laser system to measure nitrous oxide fluxes. The successful candidate will initially test whether chamber measurements of nitrous oxide match those of the eddy covariance tower. Our ultimate aim is to identify farm management strategies that decrease nitrous oxide emissions while increasing soil carbon and maintaining pasture production.

    Ideally, you will have experience or strong understanding of measurement of greenhouse gases, such as nitrous oxide, and the ability and motivation to learn eddy covariance techniques. A background in Matlab or similar scripting computer language is desired.

    This PhD is co-funded for three years by the University of Waikato and the NZ Agricultural Greenhouse Gas Research Centre (NZAGRC). Expressions of Interest must be submitted via the online form by 1 December 2016 at If no applicant is appointed the scholarship will remain open until a suitable applicant is found.

    You will be part of a motivated team of researchers and students at the University of Waikato with considerable experience in flux measurements. The PhD candidate will be supervised by Drs Louis Schipper, Dave Campbell and Liyin Liang. Our research team can be viewed:

  • Camilla Gardiner

    Camilla Gardiner moved to Canterbury from the USA at the end of July 2015. Originally from Seattle, Camilla has had a passion for agriculture since high school. "I spent a term at a farm school in rural Vermont in my third year of high school", Camilla says. "Four months with forty-five other sixteen year olds, spending three hours a day on the farm plus learning about the land-based environmental sciences. I was hooked". This interest in farming led Camilla to UC Berkeley to study Environmental Sciences with honours in Soil Biogeochemistry. It was a mentor at Berkeley that encouraged her to investigate PhD options in New Zealand and provided some key contacts. Fortuitously Dr Tim Clough was looking for a student at the time and the rest is now history.

    Camilla's previous research work at Berkeley primarily focused on the use of compost to sequester soil carbon, so the move to focus on nitrous oxide and urine patches has involved a steep learning curve. Her PhD project involves studying nitrogen compounds and plant metabolites in urine and identifying those which might minimise N2O emissions. The project started with a literature review and this has produced a number of interesting leads, particularly from plantain. This review is currently being revised for publication, with an aim to publish by mid-2016.

    Preferring to be out in the field, rather than at the lab bench, Camilla is looking forward to her first field trial. She is currently running a lab-scale study, whilst gearing up to a larger on-farm trial. "Planning a big trial is a huge learning experience", she says. "I've previously only worked with established trials". Camilla is surrounded by a wealth of knowledge though. "I'm the youngest member in the team by quite a long way", says Camilla. "There is a lot of expertise around here to tap into!"

    Moving to New Zealand has turned out to be everything that Camilla thought it would be, and more. As a keen skier and tramper, Camilla has been out exploring the scenic South Island as much as she can. The relaxed kiwi lifestyle is also growing on her. "Up until now I've lived in busy big cities. I love the laid back approach to life here in New Zealand".

  • Sheree Balvert

    Providing funding to students and early career scientists to increase capability in the agricultural greenhouse gas emissions mitigation research area and boost international collaboration is a key activity for the NZAGRC.

    The NZAGRC nitrous oxide team was joined by two new PhD students in 2015 and they are both now well underway with their studies.

    Sheree Balvert has been fascinated by farming from a very young age. She was raised on a dairy farm in the Lake Rotorua catchment area and this led her into the study of fresh water ecology for her Honours and Master's degrees. A realisation that research earlier in the farming process may have more of an impact overall led her to a change of direction after completing her study. "Looking at water sometimes felt like being the ambulance at the bottom of the cliff", says Sheree. "The damage had already been done. By moving to research which focussed on on-farm processes, I felt I could be more effective".

    About 10 years ago, Sheree took up a technician role at AgResearch's Ruakura campus. Her focus was soil science and nitrogen loss mitigation. Interested in developing her career further, when an NZAGRC PhD project became available in 2015, she decided to resign from her job and move back to study. Sheree feels that she's initially had it easier than some PhD students. "I'm continuing to study in the area that I worked in", she says. "However, I've still had to learn a whole lot more in a very short space of time".

    Sheree's PhD project involves studying a diverse range of forages, their influence on the nitrogen cycle and the loss of N from farm systems. She has a particular interest in brassicas. "My goal is that by understanding the effects of different forages, I can provide farmers with another tool to help them to reduce their environmental impact", says Sheree. She has just completed a laboratory study assessing the impacts of selected compounds from brassicas on the soil nitrogen cycle and their potential for reducing nitrogen leaching. The next step is to take the promising compounds forward into a field trial.

    Outside of her study, Sheree has a love of getting active in the great NZ outdoors. Whilst she's reluctant to call them "adventure" sports, she is a keen scuba-diver, white water kayaker and snow-boarder. One impact of the move back to student life is that, for the foreseeable future, skiing trips will be confined to the North Island. "New Zealand is a fantastic place to work and play", says Sheree. "I guess that's what keeps me here".

  • KuDos to Jiafa Luo of AgResearch

    "Humbled and surprised” is how AgResearch Senior Scientist and NZAGRC Project Leader Dr Jiafa Luo describes his reaction to hearing his name read out as the winner of the Gallagher Agricultural Science Award at this year’s KuDos Hamilton Science Excellence Awards.


    He says he didn’t think he would be the winner, as he was up against strong competition from the other finalist, LIC (Livestock Improvement Corporation), in the awards, which are held annually, celebrating Waikato scientists and their world-leading research and innovation. As well as agricultural science, the categories include environmental science, medical science, science educator and lab technician.


    Jiafa is a key player in the New Zealand nitrous oxide research space and his work is having impacts both nationally and internationally. For the past 10 years Jiafa has been planning and leading many large-scale research programmes investigating country-specific nitrous oxide emission factors for deposited excreta in grazed pasture systems. His work has included investigations into nitrous oxide emissions from sheep, beef and dairy cow excreta on a range of soil types, land topographies and farming systems throughout New Zealand. Results from his work have directly impacted the NZ GHG inventory calculations, making them significantly more accurate.


    Jiafa has also led several research projects investigating N2O emissions from applied nitrogen fertilisers and farm dairy effluents. The data from these projects is the first of this kind in New Zealand and has also been used as scientific evidence to support the country-specific N2O emission factors for nitrogen fertilisers and farm dairy effluent in grazed pasture systems.


    Jiafa has led several research programme objectives examining mitigation technologies and practices for reducing N2O emissions from grazed pasture systems. The NZAGRC, GPLER and MPI funded programmes have tested and quantified the economic and environmental benefits from adopting N2O mitigation strategies (such as restricting grazing, nitrification inhibitors, novel plant species, and timing of dairy farm effluent and nitrogen fertiliser application) into New Zealand dairy farming systems. Results have been widely used by the pastoral sector and published in a number of refereed journal and conference papers.


    Well done Jiafa!


    See Jiafa in action here:

  • Reducing New Zealand's Agricultural Emissions: Gibberellins

    This publication provides an overview of the impact of gibberellins on grazed grasslands and the potential for gibberellins to mitigate farm nitrous oxide emissions.

    More information

  • 1430 Cecile de Klein, Principal Scientist (AgResearch)

    Cecile provided an overview of the nitrous oxide research being conducted in New Zealand, with a focus on plant and animal interventions.

    Cecile reminded the audience that animal urine is by far the largest source of nitrogen in the New Zealand farming system and that there are a number of key intervention points in the nitrogen cycle to target when trying to reduce nitrous oxide.

    Nitrate leaching is also a big issue, so any technology or intervention to reduce nitrous oxide emissions needs to be win:win with respect to leaching.

    Cecile outlined three options for reducing nitrous oxide:

    1) reduce nitrogen excretion;
    2) increase nitrogen uptake by plants; and
    3) influence the plant effects on soil nitrogen processes.

    Starting with number three, New Zealand researchers are investigating the effects of pasture species and cultivars on nitrous oxide emissions. They have shown variability in pot trials and larger field trials are now underway. Researchers are also studying the effects of brassicas on nitrous oxide emissions and effects of diet on animal urine composition.

    For number 2, it appears that planting Italian Ryegrass, which continues to grow in the colder months of the year may have some benefits.

    When looking at reducing nitrogen excretion per urination, it appears that the quantity of nitrogen applied seems to be more important that the species that it is being applied to.

    The knowledge that we already have about "high risk" times for nitrous oxide emissions, urine being deposited under wet weather conditions with high pasture damage, is being incorporated into on-farm decision management tools. These may be helpful to farmers, but they will need to be able to assess the state of their paddocks easily.

    With respect to irrigation, it appears that if grazing is delayed until 6 days after irrigation, nitrous oxide emissions can be reduced by ~40%.

    Researchers continue to investigate win:win solutions and are working closely across organisations and programmes to achieve this.

    Download presentation

  • 1550 Keith Goulding (Rothamsted Research, UK)

    Keith provided an international perspective on nitrous oxide and soil carbon research. With respect to N2O, he highlighted work on investigating the genes related to nitrous oxide emissions and noted that there is one clear message for reducing nitrous oxide, avoid excess nitrogen.

    The IPCC has recently indicated that biochar may have a part to play in reducing agricultural GHGs and a number of research groups are searching for natural nitrification inhibitors.

    Keith indicated that soil carbon needs to be considered carefully. Data were published that could be interpreted to imply that grasslands could continue to sequester carbon indefinitely. However, this has been refuted and there is agreement that for a specific system there is an upper limit for carbon, and he noted the interesting work in New Zealand in this area. t been proven yet, but it appears that the deeper roots also reduce run off significantly and thus could offer multiple benefits.

    Keith concluded with a warning that too much emphasis on soil carbon sequestration could risk taking our eyes off more important climate change threats, such as land clearance and wetland drainage. He also stressed that our priorities should be promotion of good land stewardship and integrated solutions that consider the whole system and do not merely “pollution swap”.

    Download presentation 

  • Introducing Dr Jha

    The NZAGRC would like to take this opportunity to congratulate Dr Neha Jha on recently completing her PhD and thank her for her contribution to date to the NZAGRC's nitrous oxide research programme.

    Neha's PhD study involved steep learning curves on a number of different levels. Originally from Bihar in India, before her arrival in NZ she had never seen such big pastures, let alone cows and sheep grazing outside all day and night. Neha has a Master's degree in soil science and microbiology and these studies focused on Indian agriculture, which is much more diverse than the NZ pastoral system. "Dairying is also big in India", states Neha," but it is very different and the key issues that farmers face are not the same".

    After completing her Master's degree, Neha was interested in developing her soil and microbiology skills further and sent through a proposal relating to nitrous oxide emissions from soil to Professor Surinder Saggar (LCR/Massey) and Dr Donna Giltrap (LCR). This proposal resulted in the offer of a PhD position at Massey University and involvement in the NZAGRC-funded denitrification research programme.

    Neha's PhD focussed on understanding denitrification processes in different types of soils. During her PhD study, Neha spent a significant amount of time out in those rolling NZ pastures collecting soil samples of differing types from different geographical locations, then investigating their chemical and physical properties and the microbial communities present back in the lab. Key findings were that different soils have differing denitrification potentials, primarily due to the microbes present and soil management history. The end goal of this research is to recognise the soil and environmental factors that have potential to enhance the activity of denitrifiers in reducing nitrous oxide to nitrogen gas. This is vital for the development of novel and effective nitrous oxide mitigation technologies.

    Dr Jha is currently completing a one-year postdoctoral position at Landcare Research, still working alongside Surinder Saggar. Her interests in soil, microbiology and greenhouse gases remain high and she is keen to continue publishing and working towards becoming a renowned and respected scientist. Her PhD has led to a number of presentations and she currently has two journal articles submitted for publication. Neha has enjoyed her time in NZ so far and, now that she feels she has conquered the kiwi accent and understands the culture, she is keen to remain here for the foreseeable future.

  • NZAGRC nitrous oxide programme focussing on the bigger picture

    It's been said that in order to see the whole picture, you need to step out of the frame. That's the approach that the Principal Investigators of the NZAGRC nitrous oxide (N2O) programme and their team took whilst planning the work out to mid-2017. PIs Dr Cecile de Klein (AgResearch) and Professor Hong Di (Lincoln University) have ensured that the updated NZAGRC N2O research complements and is well coordinated with the broader nitrogen cycle and water quality related work being conducted in NZ.

    "When investigating options for reducing N2O emissions, we must remember that any potential mitigation strategy is likely to have other environmental impacts", says Cecile. "Additionally, researchers that are trying to reduce nitrogen leaching, for example, need to ensure that their changes to the system aren't unintentionally increasing GHGs. Ideally, by aligning our research programmes, we can come up with win:win strategies that reduce on-farm GHGs whilst also minimising leaching and improving water quality".

    In order to investigate the effect of forage species on N2O emissions, the NZAGRC-funded team is working closely with the "Forages for Reduced Nitrate Leaching" (FRNL) programme. This will allow the effects of a range of forage species on both leaching and emissions to be measured in the same trials.

    FRNL is a six year Dairy-NZ led programme being conducted in partnership with AgResearch, Foundation for Arable Research, Landcare Research, Lincoln University and Plant & Food Research. The principal funder is the Ministry of Business, Innovation and Employment with all partners providing co-funding to the programme. The key aim is to reduce nitrate leaching losses by 20 percent by delivering proven, adoptable and profitable pasture and forage crop options. Dairy, arable (crop) and sheep and beef farms are involved in the cross-sector project which is focusing on three areas - alternative pasture species, crops and farm systems.

    Experimental work involves investigating agronomically viable feeds that have a lower N content and feeds that have the ability to change the partitioning between urine and dung, and urine composition, such that both leaching and nitrous oxide emissions are reduced. Also, research is being conducted into the presence and role of natural nitrification inhibitors produced by the plants themselves. By sharing results with FRNL and the NZAGRC-PGgRc funded methane feeds programmes, the NZAGRC N2O team can gain a comprehensive insight into the effect of NZ based feeds and forages on N partitioning, and urinary output and composition. The overall goal is to develop feed management options for mitigating N2O emissions from NZ systems, where all major intended and unintended consequences of alternative species are well quantified.

    "Working together does occasionally raise challenges, as the different groups all need to be on the same page regarding common approaches and methodologies before trials get underway", says Cecile. "On-farm trials generally need to be conducted at a specific time of year. Miss the right time, and the trial is delayed until the following year. So we don't always have as much time as we'd like to plan. However, overall there are great benefits from a scientific perspective to working collaboratively and we are much more likely to reach our goal of reducing on-farm GHGs".


  • The search for plant species to reduce nitrous oxide emissions


    Could plants be used to reduce nitrification rates in soils and hence reduce nitrate leaching and emissions of nitrous oxide? Results of screening experiments conducted by Dr Saman Bowatte and his team at AgResearch Grasslands campus in Palmerston North suggest that they could. Plus, the variability of nitrification activity detected presents an opportunity to explore alternatives to synthetic inhibitors such as DCD.

    The screening experiment measured the potential nitrification rate in soil associated with 126 cultivars of 26 species representing three functional groups used in temperate managed grassland. The team found little difference between the average nitrification values for grasses, legumes and fodder crops, but there was a 71% difference between the lowest and highest nitrification values. Fortuitously, several cases were found where a low nitrification rate was coupled with an above average biomass, suggesting that some currently available cultivars may have lower N emissions - a possibility that is now being tested out in the field.

    Over the past New Zealand winter, 18 plant species/cultivars carefully selected from the screening experiment have been quietly growing away in a paddock at Grasslands. The team sowed the experimental plot trial back in mid-April and have been busy weeding, fertilising and watering as required to ensure good growth ready for the next stage of the work. This will involve adding urine to each species/cultivar and then measuring the nitrous oxide emitted.

    The hypothesis is that the results seen in the glasshouse experiments will be repeated in the field and that some species will have lower emissions than others. Ideally, the reduction will be of a sufficient magnitude to warrant further investigation and lead on to potential options for low N emitting plant species for use in NZ pastoral settings and beyond.


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