Experimental design
This study was conducted in a Bouteloua eripoda grassland in
Pasture 13 of the Jornada Experimental Range in Dona Ana County,
New Mexico, USA. In 2006, 36 2.5m x 2.5m plots were established in
each of three blocks on a level upland with flat slopes protected
from livestock grazing since 1996. The experiment was implemented
as a randomized complete block design with 2 factors:
precipitation manipulation (3 levels) and nitrogen fertilization
(2 levels).
The 3 levels of precipitation manipulation were 1) 80% reduced
precipitation, 2) ambient precipitation, and 3) 80% increased
precipitation. Reduction of 80% precipitation was achieved with
rainout shelters with transparent acrylic troughs that acted like
shingles. An irrigation system was used to implement the water
addition treatments.
The two levels of nitrogen fertilization consisted of 1) liquid
Ammonium nitrate fertilizer applied twice each growing season in
mid- and late July from 2006 to 2008 (treatment), and 2)
application of the same amount of water, equivalent to a 2mm rain
event (controls). The ammonium nitrate fertilizer consisted of 10
grams of ammonium nitrate dissolved in water per meter per year.
Treatments began in 2007.
Treatment combinations were randomly assigned to plots within each
block. Six replicates were used for each treatment combination
yielding total 36 plots per block.
Data collection and biomass calculation
Perennial grass tillers and stolons were counted in each plot in
2012, 2013 and 2014.
Related data and publications
For further information and results, see:
Reichmann, L.G., Sala, O.E. and Peters, D.P.C. (2013b),
"Precipitation legacies in desert grassland primary
production occur through previous‐year tiller density."
Ecology, 94: 435-443. https://doi.org/10.1890/12-1237.1