Soil Respiration at the Amargosa Desert Research Site
By Alan C. Riggs, Robert G. Striegl, and Florentino B. Maestas
Abstract
Automated opaque flux-chamber measurements of soil carbon dioxide
(CO2) flux (soil respiration) into the atmosphere at
the Amargosa Desert Research Site show seasonal and diel cycles of soil
respiration that are closely linked with soil temperature and soil
moisture. During 1998, soil respiration increased with soil warming
through spring, reaching a maximum rate (not counting anomalously high
values scattered through the record) of about 0.055 moles CO2
m-2 day-1 around Julian Day 120. Respiration rates
then declined along with volumetric soil moisture content, tending to
stay at or below about 0.02 moles CO2 per square meter per
day (m-2 day -1) for the rest of the year, except
after summer rainfalls when respiration sharply increased for short
periods. The diel respiration pattern during dry spells is marked by a
sharp rise in CO2 flux coincident with steeply rising soil
temperatures in the morning, then dropping back to low levels about the
time of maximum soil temperature. The reason for this pattern in unclear.