期刊论文详细信息
Scientia Agricola
Carbon sequestration in clay and silt fractions of Brazilian soils under conventional and no-tillage systems
Cecília Estima Sacramento Dos Reis2  Deborah Pinheiro Dick1  Jennifer Da Silva Caldas2  Cimélio Bayer2 
[1],Federal University of Rio Grande do Sul Faculty of Agricultural and Life Sciences Soil Science Dept.Porto Alegre RS ,Brazil
关键词: carbon saturation;    mineralogy;    physical fractionation;    soil organic matter;    soil profile;   
DOI  :  10.1590/0103-9016-2013-0234
来源: SciELO
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【 摘 要 】
The capacity of soils to sequestrate carbon (C) is mainly related to the formation of organo-mineral complexes. In this study, we investigated the influence of soil management systems on the C retention capacity of soil with an emphasis on the silt and clay fractions of two subtropical soils with different mineralogy and climate. Samples from a Humic Hapludox and a Rhodic Hapludox, clayey soils cultivated for approximately 30 years under no-tillage (NT) and conventional tillage (CT) were collected from six layers distributed within 100-cm soil depth from each site and from an adjacent native forest. After the removal of particulate organic matter (POM), the suspension (<53 µm) was sonicated, the silt and clay fractions were separated in accordance with Stokes' law and the carbon content of whole soil and physical fractions was determined. In the Humic Hapludox, the clay and silt fractions under NT showed a higher maximum C retention (72 and 52 g kg-1, respectively) in comparison to those under CT (54 and 38 g kg-1, respectively). Moreover, the C concentration increase in both fractions under NT occurred mainly in the topsoil (up to 5 cm). The C retention in physical fractions of Rhodic Hapludox varied from 25 to 32 g kg-1, and no difference was observed whether under an NT or a CT management system. The predominance of goethite and gibbsite in the Humic Hapludox, as well as its exposure to a colder climate, may have contributed to its greater C retention capacity. In addition to the organo-mineral interaction, a mechanism of organic matter self-assemblage, enhanced by longer periods of soil non-disturbance, seems to have contributed to the carbon stabilization in both soils.
【 授权许可】

CC BY   
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