The purpose of this experiment is to look at the effect of NH4NO3 addition in an unfenced area. The experiment is located in field E. There are 4 different treatments C, F, H, and I as defined in fertilization details in the "microplot" strategy. The plots are 4 by 4 meters and are laid out in an 8 by 8 grid with 1 meter aisles. For a list of treatments, see the treatment layouts in file trmte08. From 1989-1994 plots with fertilizer treatment 1 were treated as complete controls, receiving no nutrients at all.