uid=SEV,o=LTER,dc=ecoinformatics,dc=org all public read Scott Collins SEV LTER

Department of Biology, MSC03 2020, 1 University of New Mexico Albuquerque NM 87131

scollins@sevilleta.unm.edu 12275 2010 english

The Monsoon Rainfall Manipulation Experiment (MRME) is to understand changes in ecosystem structure and function of a semiarid grassland caused by increased precipitation variability, which alters the pulses of soil moisture that drive primary productivity, community composition, and ecosystem functioning. The overarching hypothesis being tested is that changes in event size and variability will alter grassland productivity, ecosystem processes, and plant community dynamics. In particular, we predict that many small events will increase soil CO2 effluxes by stimulating microbial processes but not plant growth, whereas a small number of large events will increase aboveground NPP and soil respiration by providing sufficient deep soil moisture to sustain plant growth for longer periods of time during the summer monsoon.

primary production Core Areas precipitation rain carbon dioxide soil grasslands LTER Controlled Vocabulary Additional Study Area InformationStudy Area Name: Monsoon siteStudy Area Location: Monsoon site is located just North of the grassland Drought plotsVegetation: dominated by black grama (Bouteloua eriopoda), and other highly prevalent grasses include Sporabolus contractus, S.cryptandrus, S. lexuosus, Muhlenbergia aernicola and Bouteloua gracilis.North Coordinate:34.20143South Coordinate:34.20143East Coordinate:106.41489West Coordinate:106.41489Additional Information on the Data Collection Period Ongoing collection.

This dataset is released to the public and may be freely downloaded. Please keep the designated Contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement of the Sevilleta LTER. Datasets must be cited as in the example below. Muldavin, E. 2004. Sevilleta LTER Fertilizer NPP Study Dataset. Albuquerque, NM: Sevilleta Long Term Ecological Research Site Database: SEV155. (Date of download) A copy of any publications using these data must be supplied to the Sevilleta LTER Information Manager.

http://sev.lternet.edu/node/1773 Location: The Monsoon site is located within Five Points Black Grama, just to the north of the grassland drought plots. On August 4, 2009, a lightning-initiated fire began on the Sevilleta National Wildlife Refuge. The Monsoon site was entirely burned on this date, with all plots subjected to fire of comparable intensity.Vegetation: The Monsoon site is dominated by black grama (Bouteloua eriopoda). Other prevalent grasses include Sporobolus contractus, S. cryptandrus, S. flexuosus, Muhlenbergia arenicola, and Bouteloua gracilis., siteid: 35 -106.41489 -106.41489 34.20143 34.20143 2006-09-27 2009-07-24 Information Manager Sevilleta LTER SEV LTER

1 University of New Mexico Albuquerque 87131

(505) 277-2109 (505) 277.5355 data-use@sevilleta.unm.edu Sevilleta LTER

Experimental DesignMRME contains three ambient precipitation plots and five replicates of the following treatments: 1) ambient plus a weekly addition of 5 mm rainfall, 2) ambient plus a monthly addition of 20 mm rainfall. Rainfall is added during the monsoon season (July-Sept) by an overhead (7 m) system fitted with sprinkler heads that deliver rainfall quality droplets. At the end of the summer, each treatment has received the same total amount of added precipitation, delivered in different sized events. Each plot (9x14 m) includes subplots (2x2 m) that receive 50 kg N ha-1 y-1. Each year we measure: (1) seasonal (July, August, September, and October through June) soil N, (2) plant species composition and ANPP, (3) seasonal root and fungal dynamics in minirhizotrons, and (4) soil temperature, moisture and CO2 fluxes (using in situ solid state CO2 sensors). In addition, soil N2O  fluxes, and predawn and mid-day (10-12 AM) water potential and mid-day leaf photosynthetic gas exchange and stomatal conductance of black grama are measured prior to and up to 5 days after scheduled precipitation events.Soil MeasurementsSoil temperature and water content were measured with ECH2O soil sensors. Soil CO2 was measured with solid state CO2 sensors. For each plot, soil sensors were placed under the canopy of B. eriopoda to a depth of 2, 8, and 16 cm. Measurements were recorded every 30 minutes. Daily soil water content at each depth was calculated as the average soil water content for measurement times between the hours of 0000-06:00.

Instrument Name: Solid State Soil CO2 sensorManufacturer: VaisalaModel Number: GM222 sev224_monsoon_co2_02092012.txt Data for SEV224. sev224_monsoon_co2_02092012.txt column , http://sev.lternet.edu/sites/default/files/data/sev-224/sev224_monsoon_co2_02092012.txt 2012-01-05 timestamp timestamp time recorded by Campbell datalogger when observation was collected date YYYYMMDDhhmmss date date date and time as recorded by Campbell datalogger date MM/DD/YYThh:mm:ss plot plot Monsoon Study plot number, which ranges from 1 to 13 string Monsoon Study plot number, which ranges from 1 to 13 treatment treatment Monsoon study treatments string c ambient rainfall s weekly 5 mm rainfall l monthly 20 mm rainfall cf ambient rainfall + fertilizer sf weekly 5 mm rainfall + fertilizer lf monthly 20 mm rainfall + fertilizer depth depth depth of probe beneath soil surface centimeter real co2 co2 concentration of CO2 partsPerMillion real co2_qc co2_qc quality control flag for co2 concentration string 1 invalid data-instrument malfunction 2 invalid data-out of range 3 invalid data- human verified 20 valid data ratio of two quantities as parts per million (1:1000000)