Climate-Sustaining Agriculture: Carbon Footprints of Organic and Conventional Onions and Wheat

View the project final report

• 2016 annual report

Commodities

• Agronomic: wheat
• Vegetables: onions

Practices

• Crop Production: cover crops, organic fertilizers
• Education and Training: decision support system
• Energy: energy use
• Farm Business Management: whole farm planning
• Natural Resources/Environment: carbon sequestration
• Production Systems: agroecosystems, organic agriculture
• Soil Management: nutrient mineralization, organic matter

Agriculture can be both a source and a sink of greenhouse gas (GHG) emissions, whether conventional, organic, or other alternative systems are used. More sustainable agriculture must be resilient in the face of climate change and reduce GHG on both per-acre and per-unit product bases. Despite a willingness to make personal and professional changes to reduce their climate impacts, farmers may lack the knowledge and tools to make effective choices. Carbon footprint calculators (CFC) based on farm practices, inputs, infrastructure, and processes can address these knowledge gaps. A new CFC “OFoot” is the first user-friendly model capable of integrating the annual and embodied footprints of complex organic and sustainable farms. This tool will be used and improved through this study to assess the per-acre, per-farm, and per-unit carbon footprints (CF) of organic onion, organic wheat, and conventional wheat. Specifically, studies will be carried out on four organic onion producing farms in the state of Washington to determine their primary sources or “hotspots” of GHG and to assess the effect of farm size on carbon footprint estimation. In addition, a comparative study will be carried out on three organic wheat producing farms and three neighboring (paired) non-organic (conventional) wheat producing farms. A process-based Partial Life Cycle Assessment (PCLA) will be used to generate a Life Cycle Inventory (LCI) for each farm. The PLCA computations will utilize the international EcoInvent database, outputs of the Intergovernmental Panel on Climate Change (IPCC, 2007) and the operational guide to the ISO Standards (Guinée, 2002). Soil dynamics as a source or sink of GHG emissions will be analyzed with the CropSyst model; a multi-year, multi-crop, and process-oriented cropping systems simulation model (Stockle, 1996; 2003). The results of these analyses will be integrated to estimate total CF of onion and wheat production in the selected farms. Factors that may affect the model, such as farm size and farming system practices, will also be analyzed. This project will also provide educational opportunities for growers, farmer-to-farmer learning, and networking events. Education and discussion will focus on identifying GHG hotspots in any farm, potential on-farm solutions to reduce GHG, and the costs and benefits of those options. The outreach will be organized in collaboration with both the cooperating farmers and Tilth Producers of Washington. The development and the use of models for CF estimation on complex systems are expected to enhance the adoption of more sustainable practices by both conventional and organic farmers in the PNW. The models will also benefit both organic certifying agencies and the carbon credit trade industry to achieve and document environmental sustainability goals. Overall, these tools will enable consumers to make more informed decisions in reducing their CF.

The two primary goals of this study are:

1) to identify opportunities to reduce farm greenhouse gas emissions in wheat and onion production, and

2) further improve the carbon footprint calculator (CFC) OFoot.

These goals will be accomplished through the following objectives:

1. Estimate the carbon footprint of organic onion production on four farms,

2. Estimate the carbon footprint of organic and conventional wheat production on three sets of paired farms,

3. Assess individual and grouped farms for hotspots and trends in GHG production,

4. Expand the OFoot calculator to utilize information from the study farms,

5. Provide outreach and networking to farmers, consumers, extension agencies, and organic certifiers on ways to reduce GHG emissions.

The basic hypotheses in this study are:

• Farm size is not proportional to the carbon footprint of organic onion production when examined per unit mass of onion produced.

• Indirect GHG emission of the total CF of wheat is greater in conventional farming systems than organic farming systems.

• There is a significant difference between the carbon footprint of conventional and organic wheat production when examined per unit mass of wheat produced.

• There is no significant difference between the carbon footprint of conventional and organic wheat production when examined per unit area.