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LEARN PhD researcher finds ways to
help farmers increase nutrient use
efficiency when applying farm effluent
Jie Li has finished her LEARN co-funded PhD at New Zealand’s AgResearch facilities at Ruakura. We first ‘met’
Jie in the December 2012 LRG newsletter when she was awarded a LEARN scholarship to investigate potential
technologies for reducing greenhouse gas emissions and denitrification nitrogen losses from land application
of dairy effluent.
Jie was supervised by Drs Jiafa Luo, David Houlbrooke and
Stewart Ledgard from AgResearch and undertook her research in
collaboration with Prof Yuanliang Shi’s lab at the Chinese Academy
of Sciences (CAS) where she previously trained as a researcher.
Jie’s research project focused on understanding the extent and
seasonal variation of ammonia (NH
3
) and nitrous oxide (N
2
O) losses
from the application of different types of farm effluents to pasture,
and evaluating the potential for urease (UI) and nitrification inhibitors
(NI) to reduce gaseous N losses from New Zealand pastoral soils.
Jie has found that applying different types of effluent to pasture soil
led to increased NH
3
volatilization and N
2
O emissions. Her study
illustrates that UIs and NIs can be effective in mitigating NH
3
and
N
2
O emissions from land-applied dairy effluents. Results from this
study also suggest that strategic application of effluent under dry
soil-moisture conditions could potentially reduce N
2
O emissions.
This project has identified technologies for farmers to increase
nutrient use efficiency and to reduce nutrient losses after application
of farm effluent or manure.
Through this research Jie has gained knowledge and experience
in N
2
O and NH
3
emission measurements, use of nitrogen process
inhibitors, novel fertilizer development, OVERSEER® nutrient
budget model use and other related agricultural and environmental
research. Jie has already published several papers in peer-reviewed
journals from her PhD study and made several international
conference and workshop presentations. The LEARN co-funded PhD
programme has also enabled Jie to visit other research centres and
universities in New Zealand and facilitated the interaction between
institutions.
Jie Li has a strong desire to contribute to science advancement in
agricultural greenhouse gas research and apply her knowledge to
mitigate nitrous oxide and ammonia emissions from agriculture in
China and New Zealand.
Jie Li has started a new job at CAS as a junior scientist. Her
research includes understanding N cycling in forage production and
cropping systems, evaluation of novel nitrogen process inhibitors,
development of new types of fertilizer and nitrous oxide emission
factors for effluents and fertilizers. She is taking this opportunity
to make full use of what she has learnt in her PhD research work
and she is looking forward to having more research collaboration
opportunities with other countries.