Optimizing nitrogen management on organic and biologically-intensive farms

Optimizing nitrogen management on organic and biologically-intensive farms

Summary

The long-term goal of this project is to improve nitrogen fertilizer management on farms implementing biologically-intensive soil-building practices to grow diverse crops. Cover cropping and organic amendments contribute to the soil’s fertility beyond the year they were incorporated by building active organic matter. Through this participatory research we will be able to place dollar values on the importance of optimizing soil fertility. Growers will be able to more accurately estimate nitrogen mineralization from soil organic matter and adjust fertilizer applications up or down accordingly. Extensive outreach efforts will be used to directly reach over 200 growers in Washington and Oregon.

Objectives/Performance Targets

1. Assist producers with fertilizer applications through pre-season soil tests that predict nitrogen mineralization.
2. Evaluate the net economic return of increasing amounts of organic fertilizer applied before planting across geographically dispersed farms with differing soil quality parameters.
3. Assist producers with in-season soil tests that allow adjustment to fertility during the growing season.
4. Assist producers in developing nitrogen management plans to increase profitability while protecting water quality.

Accomplishments/Milestones

During this project reporting period we primarily worked with farmers to identify experimental plot locations on their farms, determine a suitable broccoli variety, and determine the fertilizer type and rates for the trial. We did make one change with our cooperating farms. Through planning discussions we found that Tonnemaker Farm does not grow broccoli. While they were willing to grow it for our trial, we felt it would be less risky to have another cooperator that was more experienced with this crop instead. We decided to implement two different sites at Cloudview Eco Farm. Cloudview is near Tonnemaker Farm and has similar soil types. Cloudview also has two distinct farm locations that are located about 5 miles apart, so the two Cloudview sites are distinct in their management history. Importantly, we still have two sites in Eastern Washington and a total of 5 sites. We will continue to engage Tonnemaker Farm and other organic farms in our outreach and education efforts.

Impacts and Contributions/Outcomes

We are continuing to prepare for the work ahead and look forward to a successful research and growing season.

Collaborators: