Cutting greenhouse gas emissions in agriculture

How is agriculture related to climate change and what can we do about it? Around the world, farmers, researchers and policy makers are taking these questions very seriously.

While scientists continue to analyze the details, the global community agrees greenhouse gases (GHGs) contribute to climate change that is real, damaging and already happening.

Agriculture is definitely part of the problem. The statistics show GHGs from agriculture, in the forms of carbon dioxide, nitrous oxide and methane, contribute about eight percent of Canada’s total. Every effort to reduce emissions must be made, but what does that mean for Canadian agricultural producers and the hungry world they feed?

Farming in Canada relies on fossil fuels for running tractors and field equipment, drying harvested grains, heating barns, generating electricity and shipping food products around the world.

Seeking efficiencies is an ongoing effort to ensure long-term sustainability and global competitiveness of the industry. But GHGs in agriculture are also related to biological processes that are much more difficult to manage. They involve living organisms and are tied to temperature, moisture and a host of inter-related processes that occur in soils, crops and livestock—all of which are influenced by the changing climate.

Canada’s soils for example, contain carbon-rich humus that decomposes slowly through the natural actions of bacteria and fungi. But tilling to plant crops disturbs soils and activates microbes, causing the rate of carbon dioxide releases to rise dramatically, depleting soil carbons and adding to the atmospheric load.

Farmers have responded by virtually eliminating plowing of prairie soils and by moving to direct seeding and careful crop rotations—actions the Soil Conservation Council of Canada predicts could lead to millions of tons of conserved carbon per year. Better soil management also results in better yields, moisture retention and erosion control.

Improving land stewardship

Crops require nutrients to grow and in Canada, this usually entails fertilizers or animal manures. When plants are growing vigorously, the nitrogen from these expensive inputs is rapidly taken up. But too much or the wrong timing can result in losses as nitrous oxide.

A program developed by the Canadian Fertilizer Institute (CFI) and supported by the Climate Change and Emissions Management (CCEMC) Corporation, called Farming 4R Land, is helping Albertan farmers determine optimal applications to their fields to ensure the best plant growth, improved economic return and minimal GHG impact. CFI has been sharing its findings in Alberta, across Canada and around the world in an effort to improve global land stewardship.

An estimated 40 percent of Canada’s agricultural emissions are in the form of methane emitted by livestock, including cattle and sheep. Methane is a natural emission arising from the digestion of feed. On a per-animal basis, it’s quite substantial: a single dairy cow produces about the same amount of GHG per year as a mid-sized car driven 20,000 kilometers.

New Canadian research has confirmed some cattle are more efficient in their conversion of feed to milk or meat and these traits are passed on, which will lead to more efficient herds of the future with lower GHG impacts. In the meantime, farmers are adapting their feeding strategies and herd management to minimize emissions.

But the news isn’t all bad. Plant growth to produce crops or feed for livestock relies exclusively on the ancient biological process of photosynthesis, which takes carbon dioxide out of the atmosphere and water from the soil and uses the sun’s energy to convert these to carbohydrates and ultimately biomass.

New markets for biomass feedstocks are emerging as technologies to convert these to fuels, chemicals and bio-products mature and become more economical.

Increased awareness of GHG emissions from agriculture has led to changes such as reduced tillage and the 4R nutrient management system. These changes also improve yields, economic efficiency and highlight the multiple benefits of sound land stewardship.

As global demand for food, feed, fuels and other bio-products increases, product-specific life-cycle impact assessments on the environment are likely to become the norm and agriculture will need to maintain a balance between unavoidable production emissions and the beneficial biological carbon sequestration that can offset those emissions.

Dr. Susan Wood-Bohm is executive director of the Biological GHG Management Program, which is funded by the Climate Change and Emissions Management (CCEMC) Corporation and delivered in partnership with Alberta Innovates Bio Solutions. The mandate of the program is to discover, develop and deploy technologies that will reduce biological GHG emissions or enhance biological carbon sequestration in the province of Alberta. For more information visit: www.bio.albertainnovates.ca