期刊
GEODERMA
卷 189, 期 -, 页码 397-403出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.geoderma.2012.06.001
关键词
Black soil; Carbon associated with aggregates; CPMAS C-13 NMR; Functional group
类别
资金
- country's 12th Five-Year Plan project [201103001]
This study aimed to reveal the impacts of tillage systems on the fractions (active, slow, and passive carbon) and chemical compositions of soil organic carbon (SOC). A long-term (26 years) tillage experiment in northeast China examined no-tillage (NT), plowing tillage (PT) and deep loosing (DL). The soil samples (from a depth of 0-20 cm) were wet-sieved into five aggregate classes (1000-2000 mu m, 500-1000 mu m, 250-500 mu m, 50-250 mu m, and <50 mu m). The active carbon (C) and passive C were detected in the 500-1000 mu m, 250-500 mu m, and 50-250 mu m aggregates, and the chemical compositions of SOC in micro-aggregates (<250 mu m) and macro-aggregates (>250 mu m) were assessed by CPMAS C-13 NMR. Macro-aggregates contained more SOC concentration than micro-aggregates. However, PT resulted in a greater SOC concentration in 50-500 mu m aggregates. NT and DL increased the active C and decreased the slow C in 500-1000 mu m aggregates, whereas PT showed the inverse. The C-13 NMR spectrum demonstrated that NT increased alkyl-C content, PT obtained a higher carbonyl-C concentration, and DL gained a greater O-alkyl-C concentration. Moreover, evaluating the impacts of tillage systems on the complexity revealed that the most complicated structure was presented in NT, the least in PT, whereas DL had an intermediate effect. Active C contains C2-C6 carbohydrate and anomeric C (Cl) polysaccharides, slow c consists of aldehyde-C, ketonic-C and quinone-C, and the passive C is enriched in aromatic-C. In conclusion, long-term tillage systems significantly affected the fractions and compositions of SOC. with NT stabilizing the SOC. (C) 2012 Elsevier B.V All rights reserved.
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