North Dakota State University is trying to put together a big study of variable rate fertilizer economics.
You can enroll up to four fields in the study.
NDSU will prepare zone and fertilizer application maps and analyze the yield data at the end of the growing season.
You'll have to zone soil sample the field, apply fertilizer according to the variable rate map and send in your yield monitor data.
Contact John Nowatzki, NDSU agricultural engineer, at firstname.lastname@example.org or (701) 231-8213 for more information.