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Soil Redox and pH Effects on Methane Production in a Flooded Rice Soil
Author(s) -
Wang Z. P.,
DeLaune R. D.,
Patrick W. H.,
Masscheleyn P. H.
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/sssaj1993.03615995005700020016x
Subject(s) - chemistry , soil ph , redox , incubation , methane , environmental chemistry , soil science , soil water , agronomy , environmental science , inorganic chemistry , biochemistry , biology , organic chemistry
Methane formation in soil is a microbiological process controlled by many factors. Of them soil redox potential (Eh) and soil pH are considered critical controls. A laboratory incubation experiment was conducted to study the critical initiation soil Eh, the optimum soil pH, and the interaction of Eh and pH on CH 4 production. The critical soil Eh for initiation of CH 4 production observed was approximately from −150 to −160 mV. Between ‐230 and −150 mV, the relationship of CH 4 production and soil Eh appeared to be negatively exponential ( Y = a 10 ‐bx , where Y is the CH 4 production rate, µg g ‐1 d ‐1 ; x the soil Eh, mV; and a and b are constants). The optimum pH of CH 4 production was near neutrality. A small decrease in pH resulting from the introduction of acidic materials significantly decreased CH 4 production. A slight increase in soil pH (about 0.2 unit higher than the natural soil suspension pH), however, resulted in an enhancement of CH 4 production by 11 to 20% and 24 to 25% at controlled Eh of ‐250 and ‐200 mV, respectively. Results suggest that a decrease in CH 4 emissions could be obtained by a small reduction in soil pH in Crowley soil (fine, montmorillonitic, thermic Typic Albaqualf).