Wisconsin study shows decisions on pasture use and feed management affect GHG emissions

American researchers have created a study to compare the effects of feeding strategies and the associated crop hectares on the greenhouse  gas emissions from certified organic dairy farms in Wisconsin.

According to a Science Daily report on the work (HERE) consumer demand for organic milk in the US recently surpassed the available supply. Sales of organic products reached US$35 billion in 2014 and continue to rise.

As farms convert  to organic production to meet demand, feeding strategies will need to be adapted to meet USDA National Organic Programme requirements.

Agriculture accounts for around 9% of total US greenhouse gas (GHG) emissions.

The US dairy industry has committed to a 25% reduction of GHG by 2020 relative to 2009. By varying diet formulation and the associated crop production to supply the diet, farmers can affect the quantity of GHG emissions of various feeding systems.

The study to compare the effects of feeding strategies and the associated crop hectares on GHG emissions of certified organic dairy farms was developed by researchers from the University of Wisconsin-Madison.

“Herd feeding strategies and grazing practices influence on-farm GHG emissions not only through crop production, but also by substantially changing the productivity of the herd,” lead author Di Liang said.

“Managing more land as pasture, and obtaining more of the herd feed requirements from pasture, can increase the GHG emissions if pasture and feed management are not optimised to maintain milk production potential.”

The authors identified four feeding strategies that typified those used on farms in Wisconsin, with varying degrees of grazing, land allocated for grazing, and diet supplementation. A 16-year study was used for robust estimates of the yield potential on organically managed crop land in southern Wisconsin as well as nitrous oxide and methane emissions and soil carbon.

Production of organic corn resulted in the greatest nitrous oxide emissions and represented about 8% of total GHG emission;. Corn also had the highest carbon dioxide emissions per hectare.

Emissions decreased as the proportion of soybeans in the diet increased, because soybeans require less nitrogen fertilization than corn grain.

More intensive grazing practices led to higher GHG emission per metric tonne. But  allowing cows more time on pasture resulted in lower emissions associated with cropland. Manure management and replacement heifers accounted for 26.3% and 20.1% of GHG emissions.

Based on their findings, the authors determined that a holistic approach to farm production is necessary. Organic dairy farms with well-managed grazing practices and adequate levels of concentrate in diet can both increase farm profitability and reduce GHG emission per kilogram of milk.

“Consumers often equate more dependence on pasture with environmentally friendly farming, but this study demonstrated that low milk production per cow is a major factor associated with high GHG emission,” said Journal of Dairy Science Editor-in-Chief Matt Lucy.

“Managing both pasture and supplementation to increase milk production per cow will substantially reduce GHG emissions.”

Factors such as dairy cow breed and non-production variables may also have an effect on GHG emissions on organic dairy farms. Thus, future studies are needed in this area to elucidate the effects of grazing management and feeding systems.

With more research, however, crop and milk production, GHG emissions, and farm profitability can be optimised on organic dairy farms.

 

NZ agricultural greenhouse gas mitigation conference next week

The New Zealand Agricultural Green House Gas Mitigation Conference will provide the full breadth of updates from policy, science and industry when it comes to agricultural greenhouse gases in New Zealand.

The focus is on how the agricultural sector will contribute to New Zealand’s commitments under the Paris Agreement of the United Nations Framework Convention on Climate Change, which seeks to hold the rise in global average temperatures to well below 2 degrees above pre-industrial levels and has been ratified by more than 130 countries.

Presentations will cover the role played by agricultural emissions in climate change, industry perspectives, life cycle analysis, the role of land use change in emissions levels, projections to 2030, technology updates (myths and realities!) from methane and nitrous oxide programmes, and the role of soil carbon in on-farm solutions.

Registration is free and includes a networking lunch and a post-conference drinks function.

Pre-registration is required at www.nzagrc.org.nz/registration

Details: 9am – 4.20pm Tuesday 28 March, Palmerston North Convention Centre, 354 Main St, Palmerston North.

Experts comment on Parliamentary Commissioner’s report on agricultural emissions

The Science Media Centre has gathered expert reaction on the latest report from the Parliamentary Commissioner for the Environment, Dr Jan Wright, on the issue of agricultural greenhouse gases, methane and nitrous oxide, which form about half of New Zealand’s greenhouse gas emissions.

The debate around agricultural emissions and the emissions trading scheme has been polarised for too long, the commissioner says.

“But the ETS is not the only way forward – there are other things that can be done.”

Dr Wright says reducing biological emissions will not be easy, but a common understanding of the science is a good place to start.

Immediate opportunities for reducing New Zealand’s emissions lie in new native and plantation forests, and urges real progress in this area.

“It might not be the whole solution, but a million hectares of trees would make a big difference – not to mention the added benefits for erosion and water quality.”

The Government has recently set up working groups to look at these issues. Dr Wright says this is encouraging but she warns that change is now inevitable.

“Our farmers have shown time and again their ability to adapt to new challenges,” she said. “The world will continue to need food. But in the long term the way in which food is grown, and the types of food grown, will have to change if biological emissions are to be reduced.”

The Commissioner’s report Climate change and agriculture: Understanding the biological greenhouse gases is available here. A set of frequently asked questions can be found here.

The Science Media Centre’s roundup of reactions can be found here. 

Professor Louis Schipper, University of Waikato, comments:

“As usual for PCE reports, the problem and the science are eloquently described and the text remains rigorous and accessible. This report clearly lays out the case that New Zealand’s rather unique greenhouse gas emissions require bespoke solutions. The report argues that even if we reduced much of CO2 emissions from fossil fuels, we still would have relatively high emissions due to nitrous oxide and methane primarily derived from agriculture. To deliver solutions to this problem we need tailored research on New Zealand farms with New Zealand farmers.

“The overview of the production of methane and nitrous oxide demonstrates that the emissions of both these gases are inefficiencies of the soil and animal systems and so reduction has the potential to capture these valuable resources. Over the last few decades, we have improved our farming practices and this lowered the amount of greenhouse gas produced for every kg of milk or meat. And yet we still need to decrease our total greenhouse gas emissions.

“Before describing some New Zealand examples of mitigation strategies being developed, the report describes the critical characteristics of what might be considered successful mitigation strategies. These characteristics include the need to be practical, cost effective and nationally-applicable while avoiding risks – either perceived or real. It is recognised that finding a silver bullet mitigation strategies and continuous incremental gains are equally important.

“This report does a nice job highlighting some specific New Zealand studies at different stages of development that are making good progress on finding solutions. These case studies are also a realistic assessment of success and failure. Use of case studies draws people in with practical solutions rather than dense scientific explanations. This approach allows the discussion to move beyond ‘it’s all too hard, so why bother’ to considering interesting leads. Some of these case studies nicely describe the tradeoffs that need to be considered where a management practice may lead to reduction in say, methane but lead to an increase in nitrous oxide emissions. Scientists will need to continue to look to resolve these frustrating trade-offs. The case studies clearly demonstrate that we will be faced with many good ideas that fail but we only need a few successes to make real progress.

“Table 9.1 is fascinating: an estimate of the number of hectare of native forest to offset emissions from animals. I had wondered about this but never done the calculations. Must remember this is newly planted native forest and not existing native forest. The key here is that this planting could buy us time to get other strategies in place.”Absent perhaps is a greater discussion of the role of soils in storing carbon and removing carbon dioxide from the atmosphere, briefly touched on in section 9.4 (less than a page). Ultimately, we must remove a large amount of carbon dioxide already in the atmosphere and still increasing, even if we stop methane and nitrous oxide emissions. As the PCE states: “it is not possible to stop temperatures from continuing to rise with stopping net carbon dioxide emissions”. [section 3.4] “Net” means either reducing losses of carbon or getting some gains. Conversion of this carbon dioxide to soil organic matter is one way and a focus globally in the international “4 per mille initiative”. The research is in its early days in New Zealand and very challenging work.”

Note: Professor Schipper leads a team investigating the potential for soil organic carbon to capture atmospheric CO2 as a means to reduce overall greenhouse gas emissions.

Dr Suzi Kerr, senior fellow, Motu Economic and Public Policy Research, comments:

“It is excellent to have a clear careful presentation of the different aspects of the science in this complex area which is one of the things that the PCE does so well. I agree with all the actions she suggests.

“For the sake of farmers and rural communities as well as for the climate, we need to start making a gradual transition now toward new land uses – including new types of food. On land where sheep and cows continue to be grazed, we need to move toward low emission practices including new technologies as they become available. Our long term goal on that land is to produce ultra low emission dairy and red meat.

“Many farmers are aware of these issues and deeply concerned about the resilience of their sectors. Including biological emissions in the ETS, even if it only slightly increased the cost of dairy and red meat production, would send a signal to the wider farming community and those who support them in education, research and industry that it is time to move their attention, energy and creativity toward transition.

“Inclusion in the ETS could be done with a focus on helping the rural community make a gradual transition, not with expectations that the relatively small group of farmers would bear a significant part of the cost of New Zealand’s Paris commitment. In the short term, trees – including natives – are the main way that the rural sector can help achieve our Paris goals but we can’t wait to start action on the longer game of reducing nitrous oxide and methane.”
Note: Motu Economic and Public Policy Research prepared two reports that informed the PCE’s report.

The New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC) provided a media release in response to the PCE’s report:

The Parliamentary Commissioner for the Environment’s report into greenhouse gas emissions from agriculture highlights the need for a suite of mitigation solutions rather than a single silver bullet.

In welcoming this report, Harry Clark, NZAGRC Director says, “The report provides a comprehensive overview of the unique challenges New Zealand faces when it comes to agricultural greenhouse gases. It emphasises that, for effective mitigation, New Zealand needs to have a suite of mitigation options available that match our diverse farming systems rather than hope for a single, one size fits all ‘silver bullet’ solution.”

The report released by the Parliamentary Commissioner for the Environment (PCE) today outlines New Zealand’s unique situation and provides an overview of the technologies and practices that could help reduce greenhouse gases from New Zealand’s pastoral sector. The report covers breeding low methane-producing animals, identifying low methane feeds, manipulating rumen microbial communities to reduce methane emissions, pathways for reducing nitrous oxide, and the use of trees to offset emissions.

The government funded NZAGRC, in partnership with industry, is coordinating and investing in research to allow these options to be developed, tested and adopted by New Zealand farmers.

Harry Clark says, “New Zealand’s agricultural emissions make up almost half of New Zealand’s total greenhouse gas emissions. The more options we have to reduce agricultural greenhouse gases, the easier it will become for New Zealand to achieve its 2030 emission target signalled under the Paris Agreement of a 30% reduction in emissions compared with 2005.”

The PCE report not only presents technical options but emphasises that any solution needs to be scrutinised for the actual reduction it can achieve on farm (and whether it reduces absolute emissions or, primarily, emissions per unit of product), its positive or negative side-effects, cost-effectiveness, ability to be integrated into existing systems, and whether it makes sense from a national perspective.

Harry Clark says “Research and technical development is only the first step in a solution. The report by the Parliamentary Commissioner for the Environment provides a highly accessible summary of potential solutions. More importantly though, it concludes by considering the next steps: how we can collectively ensure that our science can be adopted to the benefit of the country and the climate? The Paris agreement sets a new framework for addressing climate change issues and this report makes a valuable contribution to the debate New Zealand must have round the role of agriculture in meeting national emissions reduction commitments agreed under this framework.”

Note: Dr Clark was involved in the review process of the PCE’s report.

NZ farm sector and the Paris Agreement

A paper titled The Paris Agreement and its impact on cattle and food sectors of New Zealand is among the latest articles posted online by the New Zealand Journal of Agricultural Research.

The authors are M.A.Fernandex and A.Daigneult, from the Governance and Policy Team at Landcare Research in Auckland.

The absract says:

The Paris Agreement asserts that greenhouse gas emission pathways should be consistent with holding the increase in global temperature below 1.5 °C, or 2 °C above pre-industrial levels.

The purpose of this paper is to assess the economic impact of this agreement on the cattle and food product sectors of New Zealand. We used a general equilibrium approach to evaluate the economic impacts, and the Global Timber Model to estimate forestry carbon sequestration.

We simulated eight scenarios where we allow accounting/not accounting for sequestration, pricing/not pricing agricultural emissions, and linking/not linking the New Zealand Emissions Trading Scheme (ETS) with the European Union ETS.

We found that significant negative impacts occur if sequestration is not accounted, the ETS remains unlinked and agriculture is priced. Competitiveness, in turn, is not significantly affected if sequestration is accounted, regardless of the linking scheme of the ETS.

Study finds boosting farm yields to restore habitats could create greenhouse gas ‘sink’

New research has shown that emissions from the UK farming industry could be largely offset by 2050 if agricultural yields were increased and coupled with expanding the areas of natural forests and wetlands.

The study suggests these habitats would act as a carbon ‘sink’ – sucking in and storing carbon – by increasing forest cover from 12% to 30% of UK land over the next 35 years (close to that of France and Germany, but still less than the European average) and restoring 700,000 hectares of wet peatland,

This could be enough to meet government targets of 80% greenhouse gas reduction by 2050 for the farming industry. Agriculture currently produces around 10% of all the UK’s damaging greenhouse gas emissions.

The new woodlands and wetlands would be more than just a carbon sink, say researchers. They would help support declining UK wildlife – including many species of conservation concern – provide more areas for nature recreation, and help to reduce flooding.

But to make space for habitat restoration, and to meet rising levels of food demand, land sparing would depend on increases in farm yields, so that food needs can be met from less farmland.

The study, published this week in the journal Nature Climate Change, is the first to show that land sparing has the technical potential to significantly reduce greenhouse gas emissions at a national scale.

“Land is a source of greenhouse gases if it is used to farm fertiliser-hungry crops or methane-producing cattle, or it can be a sink for greenhouse gases – through sequestration. If we increase woodland and wetland, those lands will be storing carbon in trees, photosynthesising it in reeds, and shunting it down into soils,” said senior author Prof Andrew Balmford, from Cambridge University’s Department of Zoology.

“We estimate that by actively increasing farm yields, the UK can reduce the amount of land that is a source of greenhouse gases, increase the ‘sink’, and sequester enough carbon to hit national emission reduction targets for the agriculture industry by 2050,” he said.

The study originated from a workshop run as part of the new Cambridge Conservation Initiative, which convened leading experts and asked them to “look into their crystal balls”, says Balmford.

“We wanted to know what food yield increases they reckoned were achievable in the 2050 timescale across crop and livestock sectors,” he said.

The project included researchers from the Universities of California, Bangor, Aberdeen, East Anglia, the Royal Society for the Protection of Birds, Forestry Commission, Rothamsted Research, ADAS UK Ltd and Scotland’s Rural College (SRUC).

The potential they identified included improving farm management and optimising breeding programmes to produce plants that are better at capturing soil nutrients, sunlight and water, and to produce more efficient animals that produce less methane.

The researchers then used these and other data to produce a series of modelled scenarios that projected long-term farm yields. Scenarios ranged from yield declines through to sustained yield growth that averaged 1.3% per year until 2050.

If yields rise, the area of farmland required for food production can decline – allowing countryside to be spared. By converting spared land back to natural habitats of woodland and wetland, which would have been a large portion of the UK’s native land cover in the past, a carbon sink is created that the research suggests could come close to cancelling out agricultural emissions in just a few decades.

Dr Toby Bruce, co-author from Rothamsted Research, said:

“The current findings show the value of land sparing for reducing greenhouse gases. To allow this productivity needs to increase on the remaining land, for example, by minimising crop losses to pests, weeds and diseases or by improving crop nutrition.”

Significantly,  says Balmford, the research team did not allow themselves the “get-out-of-jail-free card” of increasing food imports. Overall food consumption looks set to rise substantially – some 38% – in the UK by 2050, and the researchers locked into their future models the contribution that UK production makes to its food supply.

“We made sure we met expected production requirements in all our figures, and then explored the consequences of different ways of achieving them,” he said.

But it is not all or nothing, say the researchers, who conducted lots of sensitivity analyses around different ways of using spared land, and different levels of yield growth, consumer waste, and meat consumption – which has a disproportionate environmental footprint

“Reducing meat consumption appears to offer greater mitigation potential than reducing food waste, but more importantly, our results highlight the benefits of combining measures,” said Balmford.

“For example, coupling even moderate yield growth with land sparing and reductions in meat consumption has the technical potential to surpass an 80% reduction in net emissions,” he said.

Balmford said policy mechanisms must now be found to deliver sustainable high-yield farming that doesn’t come at the expense of animal welfare, soil and water quality, as well as safeguarding and restoring habitats.

USDA report provides uniform ways of measuring greenhouse gas emissions

The US Department of Agriculture has released a report that for the first time provides uniform scientific methods for quantifying the changes in greenhouse gas emissions and carbon storage from various land management and conservation activities.

A media statement from Colorado State University says its faculty members served as authors and external science advisors on the new report and a CSU team is leading the implementation of a new online tool that provides customized GHG reports and management plans in accordance with the new guidelines.

The report is titled Quantifying Greenhouse Gas Fluxes in Agriculture and Forestry: Methods for Entity-Scale Inventory. It is expected to help the USDA evaluate greenhouse gas mitigation programmes and develop new tools to help farmers, ranchers and forest landowners participate in emerging carbon markets.

Nitrogen pollution, climate and land use: why what we eat matters

Greenhouse gas emissions from agriculture would be cut by 25-40% if Europeans cut their meat and dairy consumption by half, according to a UN report.

Scientists from the UN Economic Commission for Europe say that as well as cutting air and water pollution, adopting a “demitarian diet” – cutting meat and dairy consumption in half – would lead to a 40% cut in Europeans’ intake of saturated fats.

An account of the findings in The Guardian says the vast majority of saturated fats come from animal products that can lead to cholesterol problems and obesity. Such a cut would bring levels to within a range recommended by the World Health Organisation.