Modelling the biophysical and economic impact of on-farm greenhouse gas abatement

95 Pages·2015·1.89 MB·English

by  Natalie Browne

Modelling the biophysical and economic impact
of on-farm greenhouse gas abatement

Natalie Doran-Browne, BSc (Hons)
March 2015

Thesis submitted in total fulfilment of the requirements of
the degree of Doctor of Philosophy

Faculty of Veterinary and Agricultural Sciences
The University of Melbourne

Produced on archival quality paper
Abstract
Climate change has resulted in a number of global challenges, such as the need to
reduce greenhouse gas emissions (GHGE) with the simultaneous challenge of feeding a
burgeoning world population. Agriculture is responsible for 10-12% of global
anthropogenic GHGE. In Australia, 15% of national emissions come from agriculture,
which is also the main source of anthropogenic nitrous oxide (N O) and methane (CH ).
2 4
Information is needed on various mitigation options and their effect on farm
profitability before GHGE can be reduced from the agricultural sector,. Determining
agricultural emissions is complicated by a number of factors such as the range of
production environments and management practices that characterise agriculture, as
well as the methods chosen to calculate farm GHGE. Understanding how farms with
different types of production manage under current climate variability is the precursor to
examining the potential for mitigation. From an industry perspective it is challenging,
especially for livestock farms, to expand the industry while attempting to reduce GHGE.
Additionally, unless mitigation options are profitable there is no incentive for farmers to
change the management of their farms to reduce emissions. Therefore, the cost-
effectiveness of mitigation options needs to be analysed against the current profitability
of farms.
The purpose of this thesis was to compare the GHGE produced by wool, prime
lamb, beef, dairy, and grain production in southwest Victoria and to compare the
profitability of these farms under different rainfall and market price scenarios. This
thesis also sought to demonstrate selected ways that farmers can mitigate GHGE
through changes in farm management or improvements in productivity, while assessing
the potential of these mitigation options to generate carbon offsets. The importance of
methods and metrics when researching farm GHGE was also explored.
This research focused on farm enterprises in the high rainfall areas of southwest
Victoria. This region was chosen because its fertile soils and climate make it suitable for
multiple types of livestock and crop production, enabling the comparison of emissions
from these different types of production within the one environment. Computer
modelling was used extensively to examine the GHGE, mitigation options, production
levels, profitability and economic feasibility of mitigation strategies in this thesis. Farms
are complex systems that consist of numerous components such as different soil types,
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pasture species and livestock. Whole-farm models allow the relationships between
components to be analysed and incorporated into a whole system that can be examined
across numerous years, including various changes to management or the environment.
In this thesis, whole-farm biophysical models were used to represent the livestock
enterprises. To calculate emissions that were compliant with Kyoto accounting, the
Australian National Inventory methodology was used, which is based on the IPCC
methodology but substitutes Australian values and algorithms where they exist and
otherwise uses the default IPCC values.
This thesis contributed a number of important findings to the body of knowledge
that exists on GHGE from agricultural enterprise and clarified key concepts on effective
ways of mitigating on-farm GHGE. The enterprise comparison showed that the
emissions intensity of grain farms was the lowest (0.04-0.15 t CO e/t grain), followed
2
by steers (6.3-6.7 t CO e/t carcase weight), dairy (8.5-9.4 t CO e/t milk fat plat protein),
2 2
prime lamb (11.4-12.0 t CO e/t carcase weight), wool (18.1-18.7 t CO e/t clean fleece)
2 2
and cow-calf enterprises (22.4-22.8 t CO e/t carcase weight). The research
2
demonstrated that the profitability of these enterprises was affected more by changes in
rainfall than commodity prices. Dairy enterprises were the more profitable ($/ha), but
the profitability of wheat, steer and prime lamb enterprises were least affected by low
rainfall scenarios. The self-replacing cow-calf beef systems, canola and dairy
enterprises were the most vulnerable to reduced rainfall.
This thesis showed that mitigation strategies that focused on emissions intensity
have more potential to be implemented by farmers because the improved productivity
often leads to increased profitability. Selected mitigation strategies were explored that
analysed the lifetime emissions of livestock and also the use of a novel legume on sheep
farms that increased productivity and profitability while simultaneously reducing
GHGE. The profitability from productivity gains was 4 to 13 times larger than likely
offset income at a carbon price of $23/t. Finally, a new metric was developed, t
CO e/unit nutrient density, that compared GHGE from food production using the
2
nutritional value of the food. Further analysis into this metric would be beneficial. Farm
emissions using the metric t CO e/unit nutrient density were compared with emissions
2
intensity, as well as against the protein (t CO e/t protein) and energy (t CO e/GJ)
2 2
content in food.
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The knowledge gained through this research will help farmers and policy makers to
more effectively reduce GHGE. Of key importance is that while carbon offsets in
Australia have been generated from a limited number of farms, the uptake by broadacre
farmers has been slow because implementation costs of mitigation options generally
exceed potential carbon offset income. However, pursuing productivity increases
profitability and using an emissions intensity metric to evaluate proposed mitigation
strategies is likely to be a more successful approach to reducing agricultural emissions,
provided that increased productivity occurs sustainably.

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Declaration

This is to certify that:
(i) the thesis comprises only my original work towards the PhD except
where indicated in the Preface,
(ii) due acknowledgement has been made in the text to all other material
used,
(iii) the thesis is fewer than 100,000 words in length, exclusive of tables,
maps, bibliographies and appendices

Natalie Doran-Browne
March 2015

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Preface
The majority of this thesis consists of original published works by Natalie Doran-
Browne as the primary researcher and author, as follows:

1. Full title: A comparative analysis of on-farm greenhouse gas
emissions from agricultural enterprises in south
eastern Australia
Authors: Browne, NA, Eckard, RJ, Behrendt, R, Kingwell, RS
Candidate’s contribution: 85%
Journal: Animal Feed Science and Technology
Volume and pages: 166-67, 641-652

2. Full title: The relative profitability of dairy, sheep, beef and
grain farm enterprises in southeast Australia under
selected rainfall and price scenarios
Authors: Browne, N, Kingwell, R, Behrendt, R, Eckard, R
Candidate’s contribution: 80%
Journal: Agricultural Systems
Volume and pages: 117, 35-44

3. Full title: Does producing more product over a lifetime reduce
greenhouse gas emissions and increase profitability
in dairy and wool enterprises?
Authors: Browne, NA, Behrendt, R, Kingwell, RS, Eckard, RJ
Candidate’s contribution: 85
Journal: Animal Production Science
Volume and pages: 55, 49-55

4. Full title: Modelling the potential of birdsfoot trefoil (Lotus
corniculatus) to reduce methane emissions and
increase production on wool and prime lamb farm
enterprises
Authors: Doran-Browne, N, Behrendt, R, Kingwell, R, Eckard,
R
Candidate’s contribution: 85
Journal: Animal Production Science
Volume and pages: Published online, awaiting assignment to an edition

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5. Full title: Nutrient density as a metric for comparing
greenhouse gas emissions from food production
Authors: Doran-Browne, N, Eckard, R, Behrendt, R, Kingwell,
R
Candidate’s contribution: 85
Journal: Climatic Change
Volume and pages: 129, 73-87

The co-authors of each published paper have consented to the inclusion of these
works in this thesis and signed The University of Melbourne co-author declaration form
accordingly. The co-authors have certified that the primary author, Natalie Doran-
Browne, contributed greater than 50% to these papers and as was responsible for the
planning and execution of the research, as well as the writing and preparation of each
paper for publication.
The inclusion of the abovementioned published works in this thesis has been
approved by the candidate’s advisory committee. The University of Melbourne’s
Declaration for a thesis with publication has been certified by the candidate’s principal
supervisor, Associate Professor Richard Eckard.

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Additional Papers: Conference Proceedings
Doran-Browne, NA, Eckard, RJ, Kingwell, RS, Behrendt, R (2014) Modelling the
methane reduction from dairy cows that are fed supplementary dietary fats.
Proceedings of the International Symposium on the Nutrition of
Herbivores/International Symposium on Ruminant Physiology, 8th to 12th
September 2014, Canberra, Australia.
Browne N, Eckard R, Kingwell R, Behrendt R (2013) An analysis of extended lactation
as a potential mitigation and carbon offset option for pasture-based dairy
enterprises in south eastern Australia. Proceedings of the 2013 Greenhouse Gases
and Animal Agriculture Conference, Dublin, Ireland.
Browne N, Eckard R, Behrendt R, Kingwell R (2012) The economic viability of
selected greenhouse gas mitigation options on sheep, beef and dairy enterprises in
southwest Victoria. Proceedings of the 2012 Climate Change Research Strategy
for Primary Industries, Melbourne, Australia.
Browne N, Behrendt R, Kingwell R, Eckard E (2012) Comparing Greenhouse Gas
Emissions and Farm Profit on Sheep, Beef, Dairy and Grain Farms in Southwest
Victoria. Joint Proceedings of the 2nd Conference of the New Zealand and
Australian Societies of Animal Production, Lincoln, New Zealand.
Browne N, Kingwell R, Behrendt R, Eckard, R (2012) Comparing the profitability of
sheep, beef, dairy and grain farms in southwest Victoria under different rainfall
scenarios. Proceedings of the 2012 Australian Agricultural and Resource
Economics Annual Conference, Fremantle, Australia.
Browne N, Eckard R, Behrendt R, Kingwell R (2010) A comparative analysis of
greenhouse gas emissions from agricultural enterprises in SE Australia.
Proceedings of the 2010 Greenhouse Gases and Animal Agriculture Conference,
Banff, Canada.

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Acknowledgements
My gratitude and thanks goes to all those who have helped throughout my PhD.
Firstly to my supervisory team, all of whom are highly esteemed in their respective
fields. Thanks to my chief supervisor, Associate Professor Richard Eckard from The
University of Melbourne, for your perspective and willingness to make time for
students. I have appreciated your patience and understanding, your expertise, readiness
to discuss research and general good advice. Thanks to Dr. Ralph Behrendt from DEPI
Hamilton for your skill as a scientist and the thorough way you analyse research which
helped throughout the PhD. Also for your calm manner that made me see that things
would work out alright, even during the hectic times. To Professor Ross Kingwell from
The University of Western Australia, thanks for your guidance, and particularly for your
prompt and valued feedback on papers. Thanks for always asking how everything was
going along this journey, which helped to make the process less isolating. I would like
to thank the many researchers that have shared their time so generously, particularly the
whole-farm system analysis of greenhouse gas abatement options for the southern
Australian grazing industries (WFSAM) team for being willing to bounce ideas off and
act as sounding board to discuss my research.
To my fellow PhD candidates, I am grateful for the many talks, the mutual support
and advice received along the way. Thanks especially to Tamara for your valued
friendship, motivation and understanding at all stages of my studies. I also appreciate
the friendship of Glenn and your four-legged children. My gratitude goes to my friends
who have been so patient and considerate, especially in those times when I withdrew
from social life to work on my research. Thanks to Stephen and Sara for your friendship
and the games nights that provided a welcome break.
Many thanks to my family, especially my parents, Therese and Roger. Thanks dad
for knowing when I needed extra support and for making it known that you are behind
me. Thanks mum for your caring and generous ways, for the many meals we’ve shared
(that you’ve cooked!) and for lending a hand through the hard times. Thanks especially
for always making time available to help out in whatever way you could.
Finally I would like to thank my husband Shane for your tireless and enduring love,
support and encouragement, your contagious happiness, positive attitude and endless
belief in my abilities and who I am. I truly don’t know where I would be today without
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you. You have experienced the highs and lows of PhD research with me and been there
at each step. And also to Pippa and Rex, our happy hounds who always greeted me with
a smile, no matter what mood I was in and who helped me to leave the desk for a walk
and to remind me of what is important in life. To Bessie, thanks for the incentive to
finish my thesis and in the end providing the motivation I needed to complete my PhD.

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