作者:Xianfeng Zhang, Xiuli Xin, Anning Zhu, Jiabao Zhang, Wenliang Yang
题目:Effects of tillage and residue managements on organic C accumulation and soil aggregation in a sandy loam soil of the North China Plain
刊物:CATENA,卷: 156 页: 176-183 DOI: 10.1016/j.catena.2017.04.012
出版年: SEP 2017
文章下载:http://www.sciencedirect.com/science/article/pii/S0341816217301340
摘要:
This paper was primarily devoted to
reveal the stock of soil organic carbon (C) as well as its lability and
to compare their differences existing among tillage and residue
practices, aiming to identify the effects on the accumulation process of
organic C and its association with macroaggregation. Arable soils
following 8-year contrasting managements were collected to determine
aggregate size distribution, organic C content and its lability. A
wet-sieving method was used to fractionate aggregate fractions
including> 2000 μm large macroaggregates, 2000–250 μm small
macroaggregates, 250–53 μm microaggregates, and< 53 μm silt + clay fractions. The C amount in physical subfractions was measured using
aggregate fractionation techniques. It was found that reduced/no-tillage
and straw returning significantly promoted soil macroaggregation and
aggregate stability at the 0–10 cm depth. The organic C stock was 20.7%
higher in 0–5 cm soil and 7.5% higher in 5–10 cm soil under
reduced/no-tillage than continual tillage, whereas straw returning
significantly increased organic C stock by 28.8%, 25.1% and 7.7%,
respectively at the 0–5, 5–10 and 10–20 cm depths. Macroaggregates made a
larger contribution to soil organic C accumulation than did other
fractions. Both reduced/no-tillage and straw returning significantly
increased the contribution of macroaggregates at the expense of
microaggregates and silt + clay fractions at the 0–10 cm depth. When
large and small macroaggregates were further separated into physical
subfractions, reduced/no-tillage coupling with straw returning
averagely increased the C amount in the intra-particulate organic matter
(iPOM) and mineral-associated C (mSOC), but decreased the oxidation
stability coefficients (Kos) of organic C in aggregates. Significant and
negative relationships were found between the mass proportion of
macroaggregates as well as aggregate stability and the Kos values of
organic C. The Kos values of macroaggregate-associated C were also
significantly negatively correlated with the C amount in subfractions.
Overall, the accumulation of organic C in physical subfractions within
macroaggregates might contribute to sequester relatively labile organic C
in soil following reduced/no-tillage and straw returning, which in turn promoted soil macroaggregation.