University of Minnesota
University of Minnesota
College of Biological Sciences


Experiment 001 - Long-Term Nitrogen Deposition: Population, Community, and Ecosystem Consequences

The purpose of this experiment is to measure how adding nitrogen over a long time will 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. The experiment is being conducted within fields (A, B, C, and D) which were initially low in soil nutrients. 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. There are 6 replicates of the 9 treatments in fields A, B, and C and 5 replicates in field D. The treatments were randomly assigned to the plots. In fields A, B, and C the plots are in 6 by 9 grids and are 4 by 4 meters in size with 1 meter aisles between plots. In field D the plots are 1.5 by 4 meters and are placed in a 3 by 17 grid. The plots are enclosed by a fence to keep out mammalian herbivores. Gophers are trapped and removed as they appear. Nitrogenfertilizer (NH4NO3) is applied twice per year, once in early May and once in late June. This experiment was begun in 1982 by David Tilman.

Methods for e001


Dataset IDTitleRange of Years (# years with data)
abue001Field C Microplot Arthropod Sweepnet Sampling1995-1996 (2 years)
lpe001Percent light penetration1982-2004 (11 years)
nbe001Plant aboveground biomass carbon and nitrogen2009-2009 (1 year)
ple001Plant aboveground biomass data1982-2014 (32 years)
rcne001Root Carbon and Nitrogen2009-2009 (1 year)
rbe001Root biomass data1987-2013 (16 years)
mse001Small mammal abundance1982-1985 (4 years)
cae001Soil Calcium1982-1982 (1 year)
care001Soil carbon1982-2011 (5 years)
mge001Soil magnesium1982-1982 (1 year)
nohe001Soil nitrate and ammonium1985-2013 (14 years)
ne001Soil nitrogen1982-2011 (7 years)
phe001Soil pH1982-2010 (10 years)
pe001Soil phosphorous1982-1982 (1 year)
ke001Soil potassium1982-1982 (1 year)

Compiled data is also available in these pre-formatted files.

Compiled Biomass and Soil Data
Descriptions of Data FieldsTABJMPEXCEL