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Fig. 5. Carbon isotopic values (
13C) of CO2 emissions after correction using fractionation factors. Each point is the mean of n = 12 (i.e., four replications in each plot times three plots per soil type). Range of atmospheric CO2 from Clark and Fritz (1997). Range of C4 black grama and C3 mesquite, shown with black boxes, are from Connin et al. (1997a) and Monger (2003). Values for pedogenic carbonates shown in upper left of top figure are from the following areas in the Jornada Basin: (1) Stressor site; (2) Mayfield well; (3), (4), and (5) Liu (2002); (6) Connin et al. (1997a, 1997b). Open circles are Stage I pedogenic carbonates formed in coppice dunes.
