Soil pCO2, soil respiration, and root activity in CO2 - fumigated and nitrogen-fertilized ponderosa pine
The purpose of this paper is to describe the effects of C0 2 and N treatments on soil pC0 2 , calculated CO 2 efflux, root biomass and soil carbon in open-top chambers planted with Pinus ponderosa seedlings. Based upon the literature, it was hypothesized that both elevated CO 2 and N would cause increased root biomass which would in turn cause increases in both total soil CO 2 efflux and microbial respiration. This hypothesis was only supported in part: both C0 2 and N treatments caused significant increases in root biomass, soil pCO 2 , and calculated CO 2 efflux, but there were no differences in soil microbial respiration measured in the laboratory. Both correlative and quantitative comparisons of CO 2 efflux rates indicated that microbial respiration contributes little to total soil CO 2 efflux in the field. Measurements of soil pC0 2 and calculated CO 2 efflux provided inexpensive, non-invasive, and relatively sensitive indices of belowground response to CO 2 and N treatments.
Plant and Soil 165: 129 -138
Johnson, Dale; Geisinger, Donn; Walker, Roger; Newman, John; Vose, James; Elliott, Katherine; Ball, Timothy 1994. Soil pCO 2 , soil respiration, and root activity in CO 2 - fumigated and nitrogen-fertilized ponderosa pine. Plant and Soil 165: 129 -138