Shifts in pore connectivity from precipitation versus groundwater rewetting increases soil carbon loss after drought.

ABSTRACT: Droughts and other extreme precipitation events are predicted to increase in intensity, duration, and extent, with uncertain implications for terrestrial carbon (C) sequestration. Soil wetting from above (precipitation) results in a characteristically different pattern of pore-filling than wetting from below (groundwater), with larger, well-connected pores filling before finer pore spaces, unlike groundwater rise in which capillary forces saturate the finest pores first. Here we demonstrate that pore-scale wetting patterns interact with antecedent soil moisture conditions to alter pore-scale, core-scale, and field-scale C dynamics. Drought legacy and wetting direction are perhaps more important determinants of short-term C mineralization than current soil moisture content in these soils. O

SUBMITTER: Smith AP 

PROVIDER: S-EPMC5673896 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature