The purpose of this experiment is to measure the effect of NH4NO3 addition and light shading on vegetation under herbivore pressure. This experiment is located in field B. The plots of this experiment are those of E011 (UNFMC). Two factors are tested in this experiment. A nitrogen addition factor with two levels and a light penetration factor with two levels. Nitrogen addition levels are I and G (see fertilization details). The light penetration levels are: 1 and 2 (1 corresponds to 100 % light penetration and 2 corresponds to 20% light penetration ). The light penetration levels are achieved by using a black shade reducing light penetration by 80%. The support for the shades is made of steel T posts and 2in by 4in lumber. There are 12 replicates of the 4 treatments. Each plot is 2m by 2m. There are 4 subplots per plot each being 1m X 1m in size. If a plot has a shading treatment (treatment 2), then there is light shade covering one of the subplots in that plot. The treatments were laid out in a randomized block arranged in a split plot design where nitrogen was assigned to the main plot and light penetration assigned to subplots. For a list of treatments, see the treatment layouts in file trmte36.