Characterization of Nitrogen Cycling in Cultivated Cranberry Beds to Improve Efficiency and Sustainability of Fertilizer Application

Characterization of Nitrogen Cycling in Cultivated Cranberry Beds to Improve Efficiency and Sustainability of Fertilizer Application

Summary

This agroecosystem study will measure extractable soil nitrogen pools as well as nitrogen stored in above and belowground biomass. This study will also measure ericoid mycorrhizal colonization. This is important, as ericoid mycorrhizal fungi may be able to access forms of nitrogen that are otherwise unavailable to the plant, particularly dissolved organic nitrogen. A better understanding of the pattern of nitrogen use by cranberries may increase profitability and sustainability of crop production.

Objectives/Performance Targets

1. Measure soil nitrogen pools (ammonium, nitrate, and dissolved organic nitrogen).

2. Measure plant nitrogen pools from plant biomass samples.

3. Measure ericoid mycorrhizal fungi colonization in the field.

4. Integrate results from this study with a related study focusing on links between nitrogen cycling and hydrology in cranberry beds (P.I.s : Dr. Kevin Kosola, University of Wisconsin – Madison, and Bryant Browne, University of Wisconsin- Stevens Point, Graduate Student: Davinder Randhawa, University of Wisconsin – Madison).

5. Share results with growers and researchers at meetings: Wisconsin Cranberry School Meetings and the National Association of Cranberry and Extension Workers Meetings.

Accomplishments/Milestones

1. I have analyzed soil samples for ammonium, nitrate, and dissolved organic nitrogen across sand and peat-based cranberry beds. Dissolved organic nitrogen dominates extractable nitrogen pools in these beds. Levels of ammonium and nitrate are low.

2. Ericoid mycorrhizal colonization occurs in all beds, on average 37% of the total root length is colonized by ericoid mycorrhizal fungi.

3. I have collected biomass samples to measure above and belowground biomass, as well as tissue nitrogen content.

4. I collected hydrologic samples, measuring nitrogen in groundwater, irrigation, and precipitation, so that I can integrate this information with data on patterns in soil and plant nitrogen content.

Impacts and Contributions/Outcomes

1. This research will give growers a better understanding of nutrient inputs to their crop including organic as well as inorganic nitrogen. This has utility in supporting nitrogen management decisions and as background information as growers develop nutrient management plans. This research will also illustrate the major inputs of nitrogen into the cranberry agroecosystem, and the influences of these inputs on plant and soil nitrogen pools.

2. Submit journal article to The Journal of the American Society for Horticultural Science. Share results with the cranberry farming community at the annual growers meetings (Cranberry School, Wisconsin Dells).

Collaborators: