Selecting management practices and cover crops for reducing tillage, enhancing soil quality, and managing weeds in western WA

View the project final report

• 2012 annual report
• 2013 annual report

Commodities

• Vegetables: broccoli, cucurbits

Practices

• Crop Production: conservation tillage
• Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research, participatory research, workshop
• Energy: energy use
• Farm Business Management: budgets/cost and returns
• Natural Resources/Environment: carbon sequestration
• Pest Management: cultural control, mulches - killed, weed ecology
• Production Systems: agroecosystems, organic agriculture
• Soil Management: earthworms, organic matter, soil analysis, soil microbiology, soil chemistry, soil physics

Organic vegetable growers in western Washington pass over their fields 10 to 20 times annually with tillage equipment, ranging from spring tooth harrows to mold board plows. Tillage decimates large-bodied soil organisms, reduces soil carbon storage and weakens the stability of aggregates. In response to organic growers' desire to improve soil quality through tillage reduction, while maintaining adequate weed control, we formed a research and producer group to plan research and extension activities matched to the unique climate, soil properties and topography of western Washington. Our syndicate of growers, researchers and extension educators identified innovative technologies and cover cropping systems with promise for adoption.

This project will:

1) Identify production methods that effectively integrate cover crops and reduced tillage technologies to improve soil quality while reducing in-season weed pressure and seed bank populations on western WA organic farms;

2) Evaluate profitability and greenhouse gas impacts of reduced tillage cropping systems on these farms;

3) Facilitate adoption of reduced tillage technologies and ideas by a wide audience and identify tools and strategies most effective at encouraging behavior change.

The long-term goal of this integrated research and extension project is to increase organic farmer economic and environmental sustainability in western Washington through soil conservation in reduced tillage systems. Specific objectives and performance targets over the three-year grant period are to:

Objective 1: Identify production methods that effectively integrate cover crops and reduced tillage technologies to improve soil quality while reducing in-season weed pressure and seed bank populations on western WA organic farms.

Performance targets:

a. Through rigorous evaluation, we will identify reduced organic no-till systems that are the most practical, economical and beneficial to soil quality for Pacific NW vegetable producers.

b. Weeds are a challenge when tillage and cultivation - the most common weed control tools for organic farmers – are removed or reduced. An important performance target will be to find cover crop species, cover crop management techniques and cover crop termination strategies that combine to suppress weeds to the same degree as cultivation and tillage.

c. Find cover crop varieties that mature early enough to be terminated and still plant or transplant a variety of cash crops. They must also produce sufficient biomass to cover the soil with a weed-suppressive mulch.

d. Introduce leguminous cover crops into organic no-till rotation, either alone or in combination with a grain cover crop, to provide a nitrogen source while still serving a weed-suppressive function.

Objective 2: Evaluate profitability and greenhouse gas impacts of reduced tillage cropping systems on these farms.

Performance targets:

a. Farm businesses that adapt new techniques must remain profitable to remain viable. To provide farmers with a broad analysis of reduced tillage cropping systems, we will compare relative profitability of these systems to their conventional counterparts. This will allow us to more fully address the viability of systems, and and it will also be extremely important in outreach.

b. Provide regionally relevant information to growers for reduced-till organic vegetable production.

c. Consumers are increasingly aware of the environmental impacts of agriculture. Another performance target for our project will be to increase our understanding of greenhouse gas impacts from potential increased carbon storage and reduced fuel use and convey this information to growers and the public.

Objective 3: Facilitate adoption of reduced tillage technologies and ideas by a wide audience and identify tools and strategies most effective at encouraging behavior change.

Performance targets:

a. Since our 2009 symposium and planning meeting, we have seen increased interest in reduced tillage in organic vegetable production. One of our “light house” farmers and cooperators, who already uses cover crops extensively, experimented this year with strip tillage (imposed with a walk-behind tiller) to grow winter squash surrounded by a mat of cover crop. Enabling, enhancing and learning from and broadcasting this kind of experimentation and behavior change is an important performance target for our project.

b. We will survey farmers throughout our field days and workshops to monitor their interest in adopting and willingness to try new soil conservation strategies such as reduced tillage. We will also survey and interview farmers to see what challenges they perceive for changing behavior around soil tillage. Identifying the top three or four strategies likely to result in behavior change will be another performance target.

c. Facilitating farmers to overcome the obstacles to adopting reduced tillage is another performance target. Equipment is likely to be one of these challenges, and working with local agencies such as conservation districts and NRCS to help acquire appropriate technologies for use by interested farmers will be another performance target.

Research objectives 1 and 2 will be addressed by project researchers and producers by evaluating reduced-till cropping systems and cover crop varieties in the maritime NW through experiment station and on-farm trials. Outreach objective 3 will be addressed through evaluations and surveys of producers that participate in research and outreach events.