The amount of nutrient applied (recommended nutrient application rates) are calculated based on many different factors. Crop nutrient budgeting, recent yields, soil productivity, climatic conditions, level of management, nutrient costs, expected return, and University of Minnesota Extension Service guidelines are all factors used in selecting an application rate.
http://www.eorinc.com/documents/AG-BMPHandbookforMN_09_2012.pdf pg. 49-51
UMN Nutrient Management Home Page
http://www.extension.umn.edu/agriculture/nutrient-management/index.html
Nitrogen Fertilizer Best Management Practices
http://www.mda.state.mn.us/protecting/bmps/nitrogenbmps.aspx
American Farmland Trust- Fertilizer application Research
http://www.farmland.org/resources/documents/AFT_FertilizerApplicationResearchStudy.pdf
Vermillion River Watershed
Has special N application rates, focus on UM application rates
Phyllis Bongaard, UM Extension, Dakota County - Nitrogen Fertilizer Research– Goal is to get people to adopt BMPs for N
Porosity of soil led to concern about City of Hastings
Nitrate Study, Drinking Water Supply – Jill Trescott, Dakota County -
Kevin Chamberland, organic producer
Trout Unlimited partnerships with streambank restoration