We monitor soil carbon, nitrogen, phosphorus, other nutrients, and microtopography to link these aspects of soil structure and biogeochemistry with climate; disturbances, such as fires; ecological interactions; and major ecosystem state transitions, such as grassland to shrubland. Nitrogen (N) can limit plant productivity in drylands. Microtopography influences the rates of infiltration and run-off following rains. Soil carbon (C) data are essential to improved understanding of the global carbon cycle, particularly in drylands which contribute most to interannual variation in global land surface CO2 flux.


Assessments of terrestrial biogeochemistry are critical components of LTER monitoring across the network. Drylands contain a third of the organic carbon stored in global soils; however, the long-term dynamics of soil organic carbon and soil organic matter (SOM) in drylands remain poorly understood relative to dynamics of the vegetation carbon pool. Our data have uncovered novel patterns. Our soil N data revealed the dependence of nutrient limitation on climate. Soil N levels were greatest following a drought period in 1989, declined during wetter periods that followed, and remained relatively stable until another extended drought period. After a drought in 1995-6, both forms of soil N increased, indicating the potential for a pulse of increased plant productivity following drought that subsides during periods of normal precipitation. Our SOM data linked soil C accumulation with periods of severe drought, and revealed that soil C declined nonlinearly with precipitation. Declines in SOM during wet periods are likely caused by increased soil respiration, runoff, leaching, and soil erosion. In addition, SOM concentration decreased 14% following prescribed fire, a response that magnified over time and persisted for nearly a decade due to the slow recovery of vegetation. Short-term spatial sampling campaigns revealed key differences among ecosystem types: in grasslands, all elements were uniformly distributed, but in shrublands, plant-essential elements, nitrogen, phosphorus, and potassium, were concentrated under shrub canopies, whereas non-limiting elements were either concentrated in the intershrub spaces or were equally across the surface. These results revealed how state transitions from grassland to shrubland contribute to long-term, widespread changes in the structure and function of dryland ecosystems.


We have monitored soil biogeochemistry in short-term snapshots in several ecosystems types. The longest time series occurred in two grassland locations (1989 – 2014). Soil sample cores (4 cm diameter by 20 cm long) were taken from under vegetation cover or from non-vegetative soil surfaces (open), then composited to give a single soil sample from each sampling location for analysis of soil C and N. In addition, we maintain soil bridges that measure small changes in soil microtopography, erosion and deposition.


We have monitored soil C (loss-on-ignition, delta 13C), N (available N and potentially mineralizable N), P (Kjeldahl digestion with copper sulfate), texture (percentage of sand, silt, and clay) and microtopography in space and time with several SEV LTER monitoring campaigns. We also maintain a long-term archive of ground, dried plant leaves for chemical analysis (Moore and Baker 2016).

Supporting Documents:

Long-term dynamics of soil organic matter and aboveground net primary production in a Chihuahuan Desert Grassland at the Sevilleta National Wildlife Refuge, New Mexico (1989-2014). https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sev&identifier=326

Sevilleta LTER Vegetation Sample Catalog- Ground Samples for Chemical Analysis. https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sev&identifier=294

Soil Surface Dynamics in the Chihuahuan Desert at the Sevilleta National Wildlife Refuge, New Mexico (1994-2013). https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sev&identifier=65

Post-fire SOC and delta-13C at different types of microsite at a grassland-shrubland ecotone. https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sev&identifier=314

Precipitation Chemistry Data For the Sevilleta National Wildlife Refuge, New Mexico (1989-present). https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sev&identifier=2

Soil Nutrient Distributions in Chihuahuan Desert Grasslands and Shrublands at the Sevilleta National Wildlife Refuge, New Mexico (1989). https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sev&identifier=152

Soil Characteristics Following a Lightning-Initiated Fire at MacKenzie Flats, Sevilleta National Wildlife Refuge, New Mexico (1998). https://portal.edirepository.org/nis/mapbrowse?scope=knb-lter-sev&identifier=170