Cedar Creek Natural History Area: Literature   Up   Home

Abstract



Citation. Zak, D. R.; Grigal, D. F.; Gleeson, S.; Tilman, D. 1990. Carbon and nitrogen cycling during old-field succession: constraints on plant and microbial biomass. Biogeochemistry 11:111-129.   [1220  E014  LTER]

Abstract. Soil C and N dynamics were studied in a sequence of old fields of increasing age to determine how these biogeochemical cycles change during secondary succession. In addition, three different late-successional forests were studied to represent possible "steady state" conditions. Surface soil samples collected from the fields and forests were analyzed for total C, H2O-soluble C, total N, potential net N mineralization, potential net nitrification, and microbial biomass. Above- and belowground plant biomass was estimated within each of the old field sites. - - Temporal changes in soil organic C, total N and total plant biomass were best described by a gamma function [y = at^b e^ctd + f] whereas a simple exponential model [y = a(1-e^bt) + c] provided the best fit to changes in H2O-soluble C, C:N ratio, microbial C, and microbial N. Potential N mineralization and nitrification linearly increased with field age; however, rates were variable among the fields. Microbial biomass was highly correlated to soil C and N pools and well correlated to the standing crop of plant biomass. In turn, plant biomass was highly correlated to pools and rates of N cycling. Patterns of C and N cycling within the old field sites were different from those in a northern hardwood forest and a xeric oak forest; however, nutrient dynamics within an oak savanna were similar to those found in a 60 yr old field. Results suggest that patterns in C and N cycling within the old-field chronosequence were predictable and highly correlated to the accrual of plant and microbial biomass.

Keywords. Carbon cycling, nitrogen cycling, microbial biomass, plant biomass, secondary succession, soil organic matter


For reprints or technical issues, please correspond with the author of the paper. For comments on the format or contents of the web site, please contact webmaster@cedarcreek.umn.edu