Monsoon Rainfall Manipulation Experiment (MRME): Soil Nitrogen Data from the Sevilleta National Wildlife Refuge, New Mexico (2007 - 2020)

The Monsoon Rainfall Manipulation Experiment (MRME) is designed to
understand changes in ecosystem structure and function of a semiarid
grassland caused by increased precipitation variability, by altering
rainfall pulses, and thus soil moisture, that drive primary
productivity, community composition, and ecosystem functioning. The
overarching hypothesis being tested is that changes in event size and
frequency will alter grassland productivity, ecosystem processes, and
plant community dynamics. Treatments include (1) a monthly addition of
20 mm of rain in addition to ambient, and a weekly addition of 5 mm of
rain in addition to ambient during the months of July, August and
September. We predict that soil N availability with interact with
rainfall event size to alter net primary productivity during the
summer monsoon. Specifically, productivity will be higher on
fertilized relative to control plots, and productivity will be highest
on N addition plots in treatments with a small number of large events
because these events infiltrate deeper and soil moisture is available
longer following large compared to small events.