کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4573613 | 1629493 | 2012 | 7 صفحه PDF | دانلود رایگان |
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 μm, 500–1000 μm, 250–500 μm, 50–250 μm, and < 50 μm). The active carbon (C) and passive C were detected in the 500–1000 μm, 250–500 μm, and 50–250 μm aggregates, and the chemical compositions of SOC in micro-aggregates (< 250 μm) and macro-aggregates (> 250 μm) were assessed by CPMAS 13C NMR.Macro-aggregates contained more SOC concentration than micro-aggregates. However, PT resulted in a greater SOC concentration in 50–500 μm aggregates. NT and DL increased the active C and decreased the slow C in 500–1000 μm aggregates, whereas PT showed the inverse. The 13C 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 (C1) 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.
► No-tillage increased alkyl-C content, plowing tillage increased carbonyl-C content.
► Slow C consists of aldehyde-C, ketonic-C and quinone-C is enriched in aromatic-C.
► No-tillage stabilized the composition of SOC, and reduced the decomposition of SOC.
Journal: Geoderma - Volumes 189–190, November 2012, Pages 397–403