University of Minnesota
University of Minnesota
College of Biological Sciences


Experiment 172 - Herbivory by Nitrogen Interactive Effects on Community and Ecosystem Processes and Dynamics

E172 is an herbivory experiment established by Dave Tilman in fall 2004 by enclosing in deer fences three randomly selected plots from the six replicates of each control and each treatment in the N addition E001 experiment in field C. These plots still receive the nutrient treatments prescribed in the Experiment 001 protocols. From 1982-2004 a fence containing all of e001 plots in Field C was designed to exclude deer and all small mammals, including mice, voles and pocket gophers. This fence was removed in Fall of 2004 and individual plots designated for e172 were enclosed in deer fences.

The purpose of E001 was to measure how adding nitrogen over a long time would affect the number of species, the type of species present, the amount of annual growth, and the change from year to year in the growth of each species in a plant community which is also relieved of grazing by large and small mammals. There are 8 different levels of nitrogen addition with other nutrients added to ensure that nitrogen remains the limiting nutrient, and a control which receives no nutrients. The plots are in a 6 by 9 grid and are 4 by 4 meters in size with 1 meter aisles between plots. Nitrogen fertilizer (NH4NO3) is applied twice per year, once in early May and once in late June.

Methods for e172


Dataset IDTitleRange of Years (# years with data)
lpe172Percent light penetration1982-2004 (11 years)
nbe172Plant aboveground biomass carbon and nitrogen2009-2009 (1 year)
ple172Plant aboveground biomass data1982-2011 (30 years)
rbe172Root biomass data1987-2002 (13 years)
nre172Root carbon/nitrogen data2009-2009 (1 year)
mse172Small mammal abundance1982-1984 (3 years)
cae172Soil Calcium1982-1982 (1 year)
care172Soil carbon1982-2009 (4 years)
mge172Soil magnesium1982-1982 (1 year)
nohe172Soil nitrate and ammonium1985-2004 (13 years)
ne172Soil nitrogen1982-2009 (5 years)
pe172Soil phosphorous1982-1982 (1 year)
ke172Soil potassium1982-1982 (1 year)