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Determination of the Concentration and Isotopic Composition of Soil Carbon in Arid Soils
Author(s) -
Ketchian Elana,
Trimble Brittany,
Poulson Simon R.,
Verburg Paul S. J.
Publication year - 2018
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/sssaj2017.07.0250
Subject(s) - soil water , loss on ignition , arid , environmental chemistry , total organic carbon , carbonate , dissolution , chemistry , composition (language) , isotope analysis , soil carbon , carbon fibers , environmental science , soil science , geology , materials science , composite number , composite material , paleontology , linguistics , philosophy , oceanography , organic chemistry
Core Ideas Measurement of inorganic and organic C in arid soils can be challenging. Acid dissolution does not affect amount and isotopic composition of organic C. Loss on ignition is unreliable when measuring isotopic composition of inorganic C upon heating. Accurate quantification of organic C (OC) and inorganic C (IC) in arid soils is critical given that arid lands make up a substantial part of the terrestrial surface and IC is often the dominant C pool. Two methods were tested to quantify the percent OC and IC and the 13 C isotopic composition on soils prepared by mixing a carbonate‐free surface soil with a ground marble tile achieving varying ratios of OC versus. IC. The loss on ignition percent C and δ 13 C data showed that at 400°C not all organic C was volatilized making this method unreliable at higher OC fractions. Additions of 1M HCl did not alter the amount and isotopic composition of the OC regardless of the relative amounts of OC versus IC present. Overall, the best method for measuring soil C concentration and δ 13 C depends on the relative concentrations of OC versus IC that are present in the soil.