Major Biogeochemical Processes in Soils-A Microcosm Incubation from Reducing to Oxidizing Conditions

Six soils used for rice (Oryza sativa L.) production were incubated using an automatic microcosm system. Production of trace gases (CO2, CH4, and N2O) and transformation of N, S, and metals (Fe and Mn) were studied in soil suspensions incubated from reducing to oxidizing conditions. Results show tha...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Soil Science Society of America journal 2007-07, Vol.71 (4), p.1406-1417
Hauptverfasser: Yu, K, Bohme, F, Rinklebe, J, Neue, H.U, DeLaune, R.D
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Six soils used for rice (Oryza sativa L.) production were incubated using an automatic microcosm system. Production of trace gases (CO2, CH4, and N2O) and transformation of N, S, and metals (Fe and Mn) were studied in soil suspensions incubated from reducing to oxidizing conditions. Results show that soil pH variation was inversely correlated to soil redox potential (EH) change (P < 0.01). Soil CO2 production exponentially increased with soil EH increase. In contrast, soil CH4 production and DOC showed an exponential decrease with soil EH increase. Without the presence of soil oxidants, methanogenesis occurred across the entire EH range, with probable H2-supported methanogenesis at higher soil EH conditions constituting up to 200f total CH4 production. The CH4 compensation point, where CH4 concentration became constant due to equilibrium between CH4 production and consumption, exponentially decreased with soil EH increase. At pH 7, the critical EH above which soils consumed atmospheric CH4 varied among the soils, but was generally >400 mV. Significant N2O production was observed between 200 and 500 mV. Nitrification could also contribute to N2O production when EH is >500 mV, a possible critical EH for the initiation of nitrification. The critical EH for substantial immobilization of Fe and Mn was estimated to be around 50 and 250 mV, respectively. The intermediate EH range (approximately -150 to 180 mV) provided optimum conditions for minimizing cumulative global warming potential resulting from CO2, CH4, and N2O production in soils. Our results have implications in interpreting the overall benefits of soil C sequestration efforts.
ISSN:0361-5995
1435-0661
DOI:10.2136/sssaj2006.0155