Optimizing nitrogen management on organic and biologically-intensive farms

2015 Annual Report for OW15-008

Project Type: Professional + Producer
Funds awarded in 2015: $49,997.00
Projected End Date: 12/31/2017
Region: Western
State: Washington
Principal Investigator:

Optimizing nitrogen management on organic and biologically-intensive farms


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.


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.


Rob Peterson

Plum Forest Farm
20020 107th Avenue SW
Vashon Island, WA 98070
Office Phone: 2064633518
Jim Baird

Cloudview Ecofarm
14054 Road 11 SW
Royal City, WA 99375
Office Phone: 5093984624
Colin Barricklow

Kirsop Farm
6136 Kirsop Road SW
Tumwater, WA 98512
Office Phone: 3604021318
Adam McCurdy

Farm Manager
Oxbow Farm
10819 Carnation-Duvall Rd NE
Carnation, WA 98014
Office Phone: 2069093299
Kole Tonnemaker

Tonnemaker Hill Farm
9098 Dodson Rd S
Royal City, WA 99357
Office Phone: 5093469706