GDD base 50 = 832 at http://agebb.missouri.edu/weather/reports/gddTable.asp
Phenology stages described according to the Modified E-L System http://door.uwex.edu/files/2010/10/ModifiedEichhornLorennzsystem.pdf
I am in the process of figuring out how to estimate crop given most of it is on basal and non-count shoots!