What is NOPP:
The Nitrogen Optimization Pilot Program (NOPP) is a grant program funded by the Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP) that encourages Wisconsin agricultural producers to conduct on-farm research pertaining to the use of commercial nitrogen (N) fertilizer. In addition to 19 other projects funded by the 2023 grant cycle, Cranberry Creek received a $50,000 award to study N application timing in Wisconsin cranberry marshes. The main goals of NOPP are to answer producer-specific N research questions, improve commercial nitrogen management efficiency across Wisconsin, reduce nitrates in surface- and groundwater, and improve farm profitability.
NOPP in Cranberries:
With 2023 being the first year of NOPP projects, many row-crop producers chose to research N rate questions. Because cranberry growers already match nitrogen rates to plant needs within a very tight dose-response window, doing rate research within NOPP would be redundant.
An area of nitrogen management that is less well understood, and thus would benefit from grower-led research, is nitrogen application timing.
Cranberry growers apply crop nutrients in small, spoon-fed doses—monitoring crop response and applying only what cranberry vines can uptake (and translocate to the canopy to enhance photosynthesis and, thus, fruit production). Many growers apply one small dose per week—but the starting time of nutrient application varies from grower to grower. At the earliest, some growers begin their nutrient application program at 10% in bloom, while others wait until the vines have set fruit, using 50% out of bloom as an application threshold. Many growers use other thresholds between those two points.
To evaluate the impact of N fertilization timing, Cranberry Creek tested 4 treatments based on the timings of the first N fertilization application during the growing season: 10% in bloom, 25% in bloom, 25% out of bloom, and 50% out of bloom. Each treatment received the same amount of N and the same number of application passes—the only difference is when the fertilizer application schedule started. Mullica Queen beds and Stevens beds are both hosting trials with these four start dates. (Both Mullica Queens and Stevens beds received Cranberry Creek’s Nutrient Management Plan indicated total nitrogen amount specific to the variety.) Tissue tests, soil tests, in-season observations, and final yield will be compared across these four treatments.
What We’ve Learned So Far:
Visual observations in-season suggest that the operating window (10% in bloom to 50% out of bloom) for 2023 was quite wide, and some treatments had some vegetative overgrowth at the beginning of the study, however as we approach harvest those differences are not visually distinguishable anymore. Based on visual results this year, we suggest that future research projects have a more narrow scope. Cranberry Creek’s attempt to test the total range of timings in use in Wisconsin resulted in a wide spectrum of growth patterns. We suggest that future projects evaluate a range that the trial-host grower would actually consider, on the host marsh.
Tissue test results and yield results for 2023 are being collected and will be analyzed following harvest.
Many kinds of projects will be considered. Have you been curious about using drones for fertilizer applications? Wondering how fall fertilizer applications might impact your overwintering success? The NOPP program is a great opportunity to get UW rigor and DATCP financial support to test your ideas, and share the information with Wisconsin growers.
NOPP Application and Request for Proposals (RFP) are intended to be released in October 2023 with applications being due in January 2024 and grants being awarded in February/March 2024. Some of the program criteria may not apply to perennial crops like cranberry so, we encourage interested applicants to reach out to NOPP staff to discuss your idea! More information, soon-to-be confirmed dates, and contact details can be found at