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Influence of Freeze‐Thaw and Flooding on the Loss of Soluble Organic Carbon and Carbon Dioxide from Soil
Author(s) -
Wang F. L.,
Bettany J. R.
Publication year - 1993
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1993.00472425002200040011x
Subject(s) - udic moisture regime , chemistry , leaching (pedology) , carbon dioxide , incubation , soil water , soil carbon , total organic carbon , zoology , leachate , environmental chemistry , soil science , environmental science , biochemistry , loam , biology , organic chemistry
Freeze‐thaw and flooding significantly affected the loss of water soluble organic carbon (SOC) and carbon dioxide carbon (C‐CO 2 ) from a well‐drained Black Chernozemic soil (Udic Boroll) in a leaching‐incubation study. At the end of 12 wk, the total loss of SOC was 90, 107, 399, and 224 mg kg −1 for soils with normal (incubated at field capacity moisture), freeze‐thaw, flooding and flooding‐freeze‐thaw treatments, respectively. The E4/E6 values of the leachates obtained from the four treatments ranged from 10 to 32, suggesting that SOC in the leachates was mainly low molecular weight in nature. The rate of the SOC leaching changed over time and the amount of SOC leached from the flooded treatments reached a maximum in the middle of the incubation period. In contrast, the rate of SOC leaching for unflooded treatments appeared little changed with no distinctive rate maximum. The cumulative loss of C‐CO 2 and total C (sum of SOC and C‐CO 2 ) from the treatments decreased in the order of flooding > normal > flooding‐freeze‐thaw > freeze‐thaw. The rates of C‐CO 2 evolution decreased with time for the freeze‐thaw treated soils whereas the rate of C‐CO 2 evolved from the normal treatment initially decreased and then increased after 8 wk of incubation, suggesting transient kinetics for the system. For the flooding treatment, the rate of C‐CO 2 evolution showed a similar pattern to that of SOC leaching. There was a high linear correlation between the cumulative C‐CO 2 evolved and SOC leached from the soil.