Grassland ecosystems are highly sensitive to N deposition and landusechange , as well as t
heir interactions, with potentialimpacts on ecosystem C cycling and sequestration . Soil r
espiration is the main pathwayof C flux from terrestrial ecosystems to the atmosphere. Th
us, quantification of it’s the temporal pattern of SR andwhat factors determine this patte
rn are prerequisites for the estimationof ecosystem C dynamics and sequestration with glob
al change.Anthropogenic N deposition has substantially increased in manyregions across the
globe , which strongly influencesplant productivity and SR. In addition to global change
factors , grassland ecosystem structure and functioning are alsolikely to be altered by ma
nagement practices such as grazing, leading tochanged SR. N addition and grazing can inter
act witheach other in influencing SR, a nonlinear process that is still poorlyunderstood.
For example, in a semi-arid typical steppe of InnerMongolia, N addition decreased SR durin
g the growing season irrespectiveof grazing intensity . However, our previousstudy reporte
d that grazing and N addition have antagonistic effects onspatial variability of SR in Ley
mus chinensis meadow steppe