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Radiocarbon Signatures of Turnover Rates in Active Soil Organic Carbon Pools
Author(s) -
Hsieh YuchPing
Publication year - 1993
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1993.03615995005700040023x
Subject(s) - radiocarbon dating , accelerator mass spectrometry , soil carbon , tracer , environmental science , soil water , carbon cycle , environmental chemistry , soil science , geology , chemistry , ecology , ecosystem , paleontology , biology , physics , nuclear physics
Identifying turnover rates in active soil organic carbon (SOC) pools is a critical step toward the understanding of soil nutrient cycling and global C cycles. The mean residence times (MRT) of the dominating active SOC pools in surface soils are usually less than a few decades. This range of MRT is difficult to determine because it is too short for radiocarbon dating and too long for most tracer techniques. I developed a procedure to construct radiocarbon signatures for identifying MRT in active SOC pools based on the residue bomb 14 C in the atmosphere. The radiocarbon signature is specific to the year when a soil sample is taken. The sensitivity of the radiocarbon signatures is a function of MRT and the time when a soil sample is taken. This method is sensitive to MRT of active SOC pools in a range from 1 to 80 yr at the present time. Using those radiocarbon signatures, the MRT of active SOC pools in the Morrow Plots (Urbana, IL) and Sanborn Field (Columbia, MO) were estimated at 67 and 34 yr, respectively.