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In situ Mineralization of Dairy Cattle Manures as Determined using Soil‐Surface Carbon Dioxide Fluxes
Author(s) -
Rochette Philippe,
Angers Denis A.,
Chantigny Martin H.,
Gag Bernard,
Bertrand Normand
Publication year - 2006
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/sssaj2005.0242
Subject(s) - mineralization (soil science) , loam , manure , agronomy , soil water , environmental science , fertilizer , total organic carbon , chemistry , soil organic matter , environmental chemistry , soil science , biology
Decomposition rates of organic amendments in agricultural soils provide information on nutrient release and on changes in soil C stocks. They are usually determined using incubation of soil samples under controlled conditions. Our objective was to study decomposition of liquid and solid dairy cattle manures under field conditions following application to a loamy and a clay soil. Manures were applied in two consecutive years to silage corn at rates equivalent to 150 kg ha −1 total N providing 119 to 202 kg C ha −1 Soil‐surface CO 2 fluxes, temperature and water content were monitored weekly in manured and control (mineral fertilizer) plots. Initial decomposition rates following manure application were much slower in the first than in the second year. This lag phase was attributed to cool soil temperatures and to the time required by the soil microflora to adapt to a first addition of this exogenous organic substrate. During the first year, mineralization of manure organic C was lower in the clay (52% of manure C) than in the loamy (75%) soil, presumably as a result of less favorable aeration conditions and greater physical protection of organic substrates in the clay. Equal mineralization rates of liquid and solid manures during both years in the loamy soil indicated that the two manure types had similar decomposability. Slower decomposition of the solid than the liquid manure in the clay soil was attributed to poorer mixing with the soil (presence of clods) resulting in reduced access to the solid manure for soil decomposers. The results of this study evidenced that under field conditions manure C decomposition is not determined solely by manure characteristics but also by interactions between the manure type and soil physical properties such as texture.