Stabilization by hydrophobic protection as a molecular mechanism for organic carbon sequestration in maize-amended rice paddy soils.
Stabilization by hydrophobic protection as a molecular mechanism for organic carbon sequestration in maize-amended rice paddy soils.
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DOI：
10.1016/j.scitotenv.2013.04.052
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发表时间：
2013-08
期刊：
影响因子：
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通讯作者：
Xinwei Song;R. Spaccini;Genxing Pan;A. Piccolo
中科院分区：
文献类型：
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作者：
Xinwei Song;R. Spaccini;Genxing Pan;A. Piccolo
土壤有机质（SOM）中的疏水组分对土壤有机碳（SOC）的稳定起着重要作用。通过为期6个月的水稻土培养试验，研究了疏水性物质对南方4种水稻土有机碳固定的贡献。土壤样品包括：江苏太湖平原发育良好的湖相粘土型水稻土（TP）、江西红壤丘陵区发育的酸性粘土型水稻土（RP）、重庆侏罗纪紫色页岩上发育较弱的中性水稻土（PP）和安徽沿着长江流域湿地发育的钙质潮土（MS）。培养30天和180天后的SOC分子组成通过离线热化学分解然后通过气相色谱-质谱分析来确定。木质素、脂类和碳水化合物是处理土壤中主要的热化学分解产物。选择性保存疏水性有机质，包括木质素和脂质，在玉米修订的土壤与长期培养。木质素和脂质的分解在TP和RP土壤中显着较慢，其特征在于可提取的铁氧化物（Fed）含量较大，pH值较低。玉米培养样品中疏水物质的总体增加与粘土和Fed的总含量呈正相关，与土壤pH值呈负相关。此外，木质素和脂类组分的产率与培养后SOC的增加均表现出显著的相关性。这些结果表明，有机质中脂类和木质素含量越高，有机碳的稳定性越强，表明有机质疏水组分可能在控制南方水稻土有机碳固定过程中起重要作用。
The hydrophobic components of soil organic matter (SOM) are reckoned to play an important role in the stabilization of soil organic carbon (SOC). The contribution of hydrophobic substances to SOC sequestration was evaluated in four different paddy soils in the South of China, following a 6-month incubation experiment with maize straw amendments. Soil samples included: a well developed paddy soil (TP) derived from clayey lacustrine deposits in the Tai Lake plain of Jiangsu; an acid clayey paddy soil (RP) derived from red earth in the rolling red soil area of Jiangxi; a weakly developed neutral paddy soil (PP) formed on Jurassic purple shale from Chongq; and a calcic Fluvisol (MS) derived from riverine sediments from a wetland along the Yangtze valley of Anhui, China. The SOC molecular composition after 30 and 180days of incubation, was determined by off-line thermochemolysis followed by gas chromatography-mass spectrometry analysis. Lignin, lipids and carbohydrates were the predominant thermochemolysis products released from the treated soils. A selective preservation of hydrophobic OM, including lignin and lipids, was shown in maize amended soils with prolonged incubation. The decomposition of lignin and lipids was significantly slower in the TP and RP soils characterized by a larger content of extractable iron oxyhydrates (Fed) and lower pH. The overall increase in hydrophobic substances in maize incubated samples was correlated, positively, with total content of clay and Fed, and, negatively, with soil pH. Moreover, yields of both lignin and lipid components showed a significant relationship with SOC increase after incubation. These findings showed that the larger the lipid and lignin content of SOM, the greater was the stability of SOC, thereby suggesting that OM hydrophobic components may have an essential role in controlling the processes of OC sequestration in paddy soils of South China.