The initial rate of C substrate utilization and longer-term soil C storage |
| |
Authors: | J L Smith J M Bell Jr" target="_blank">H BoltonJr V L Bailey |
| |
Institution: | (1) USDA-ARS, 215 Johnson Hall, Washington State University, Pullman, WA 99164, USA;(2) Pacific Northwest National Laboratory, 902 Battelle Boulevard, Mail Stop P7-50, Richland, WA 99352, USA |
| |
Abstract: | The initial reaction of microbial transformation and turnover of soil carbon inputs may influence the magnitude of longer-term
net soil C storage. The objective of this study was to test the merit of the hypothesis that the more rapid substrates are
initially utilized, the longer the residual products remain in the soil. We used simple model C compounds to determine their
decomposition rates and persistence over time. Pure 14C compounds of glucose, acetate, arginine, oxalate, phenylalanine, and urea were incubated in soil for 125 days at 24°C. Total
respired CO2 and 14CO2 was quantitatively measured every day for 15 days and residual soil 14C after 125 days. The percent 14C remaining in the soil after 125 days of incubation was positively and significantly correlated with the percent substrate
utilized in the first day of incubation. The 14C in the microbial biomass ranged from 4–15% after 15 days and declined through day 125, contributing significantly to the
14C that evolved over the longer time period. Priming of 12C soil organic matter (SOM) was negative at day 3 but became positive, reaching a maximum on day 12; the total increase in
soil C from added substrates was greater than the primed C. The primed C came from 12C SOM rather than the microbial biomass. This data supports the concept that the more rapidly a substrate is initially mineralized,
the more persistent it will be in the soil over time. |
| |
Keywords: | C storage 14C C priming Substrate utilization C sequestration |
本文献已被 SpringerLink 等数据库收录! |
|