Priming of soil organic carbon decomposition induced by corn compared to soybean crops

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The rate of soil organic carbon [CS] loss via microbial respiration [decomposition rate k, y-1], and the rate of stabilization of vegetation inputs [CV] into CS [humification rate h, y-1] are usually considered independent of CV. However, short-term laboratory studies suggest that the quality and qu...

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Detalles Bibliográficos
Otros Autores: Mazzilli, Sebastián R., Kemanian, Armen R., Ernst, Oswaldo, Jackson, Robert B., Piñeiro, Gervasio
Formato: Artículo
Lenguaje:Español
Materias:
AGRICULTURAL WASTES
BIODEGRADATION
BIOGEOCHEMISTRY
BIOLOGICAL MATERIALS
CARBON FLUX
CHEMICAL COMPOSITION
COMPARATIVE STUDY
CORN
CROP RESIDUE
CROPS
DECOMPOSITION
HUMIFICATION
HUMIFICATION RATE
IN-FIELD
MAIZE
MICROBIAL ACTIVITY
ORGANIC COMPOUNDS
PARTICULATE ORGANIC MATTER
PRIMING EFFECT IN FIELD CONDITIONS
QUALITY CONTROL
SOIL CARBON
SOIL ORGANIC CARBON
SOIL ORGANIC CARBON DECOMPOSITION
SOIL ORGANIC MATTER
SOIL RESPIRATION
SOILS
SOYBEAN
STABILIZATION
TOPSOIL
ZERO TILLAGE
Acceso en línea:http://ri.agro.uba.ar/files/intranet/articulo/2014mazzilli.pdf
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Biblioteca Central (FAUBA) de Universidad de Buenos Aires
Descripción
Sumario:The rate of soil organic carbon [CS] loss via microbial respiration [decomposition rate k, y-1], and the rate of stabilization of vegetation inputs [CV] into CS [humification rate h, y-1] are usually considered independent of CV. However, short-term laboratory studies suggest that the quality and quantity of CV controls k, which is often referred to as a priming effect. We investigated how the chemical composition of different residues, [corn and soybean] controls k and h under field conditions in a no-till ecosystem. Using CV-driven shifts in ?13C, we estimated changes in carbon [C] stocks, k and h of both the labile particulate organic matter fraction [CPOM] and the stabilized mineral associated organic matter fraction [CMAOM]. After two years of high C inputs [corn: 4.4Mgha-1y-1 aboveground and C:N=78; soybean: 3.5Mgha-1y-1, C:N=17], we found no changes in CPOM and CMAOM stocks in the top 5-cm of soil or in deeper layers. However, CMAOM in corn had higher k [0.06y-1] and C output fluxes [0.67Mgha-1y-1] than in soybean [0.03y-1 and 0.32Mgha-1y-1], but similar rates and fluxes in CPOM in the top 5-cm of soil. In addition, while C inputs to CPOM were also similar for both crops, C inputs from CV to CMAOM were higher in corn [0.51Mgha-1y-1] than in soybean [0.19Mgha-1y-1]. Overall, corn plots had higher k and C inputs into CMAOM and therefore higher C cycling in this fraction. Our data suggests that the type of crop residue strongly influences C cycling in the topsoil of no-till cropping systems by affecting both the stabilization and the decomposition of soil organic matter.
ISSN:0038-0717

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