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Pool Size and Mean Age of Stable Soil Organic Carbon in Cropland
Author(s) -
Hsieh YuchPing
Publication year - 1992
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/sssaj1992.03615995005600020020x
Subject(s) - soil carbon , cycling , organic matter , environmental science , ecosystem , soil water , nutrient cycle , radiocarbon dating , soil organic matter , fractionation , total organic carbon , soil science , nutrient , decomposition , carbon fibers , ecology , environmental chemistry , chemistry , geology , forestry , geography , biology , mathematics , paleontology , algorithm , composite number , organic chemistry
Most modern surface soils are believed to contain a pool of very stable soil organic carbon (SOC) with a mean age (MA) that may reach several thousand years. The remaining SOC pools are much younger, perhaps no older than a few decades. The SOC can thus be divided into two major classes: very old (stable pool) and relatively young (active pool). Because active and stable SOC play very different roles in soil organic‐matter dynamics and nutrient cycling, it is desirable to know the pool size and turnover time of the two fractions in an ecosystem. Unfortunately, none of the physical or chemical fractionation methods can satisfactorily separate active from stable SOC. The pool size and MA of the stable SOC pool in the surface soil of the Morrow Plots (University of Illinois) and Sanborn Field (University of Missouri) were determined using the concept of management‐induced differential decomposition of active SOC in a pair of soil samples and the principle of radiocarbon dating. Pool size and MA of the stable SOC in the surface soil (0–20 cm) was estimated at 11.0 g/kg and 2973 yr for the Morrow Plots and 7.3 g/kg and 853 yr for Sanborn Field, respectively.