Journal of Integrative Agriculture

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长期紫云英还田通过影响土壤矿物和有机碳提升土壤团聚体稳定性

  

  • 修回日期:2024-10-11
  • 基金资助:


Long-term Chinese milk vetch incorporation promotes soil aggregate stability by affecting mineralogy and organic carbon

Yulu Chen1, Li Huang1#, Jusheng Gao2#, Zhen Zhou1, Muhammad Mehran1, Mingjian Geng1, Yangbo He1, Huimin Zhang2, Jing Huang2   

  1. 1 Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China

    2 Hengyang Red Soil Experimental Station, Chinese Academy of Agricultural Sciences, Hengyang 421001, China

  • Revised:2024-10-11
  • About author:Yulu Chen, Mobile: +86-18703617312, E-mail: yuluchenlz@163.com; #Correspondence Li Huang, Mobile: +86-13036165770, E-mail: daisyh@mail.hzau.edu.cn; Jusheng Gao, E-mail: gaojusheng@caas.cn

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摘要：

土壤团聚体受土壤矿物与有机组分之间复杂相互作用调节，对土壤可持续性和作物生产力有深远影响。为探讨绿肥施用后土壤矿物和有机组分的变化及其对土壤团聚体的影响，本研究基于5年和36年的田间试验，采集了稻-稻-冬休（CK）和稻-稻-紫云英（MV）处理的淋溶土和铁铝土表层（0-20 cm）土壤样品，分析土壤团聚体稳定性、土壤矿物、有机碳组分及团聚体微观结构特征。结果显示，黏粒含量高的铁铝土比黏粒含量低的淋溶土具有更高的团聚体稳定性。淋溶土团聚体中的层状硅酸盐矿物主要为伊利石和蛭石，而铁铝土团聚体中的层状硅酸盐矿物以高岭石为主，并含有大量游离铁。此外，铁铝土黏粒组分中的芳香族碳丰度显著高于淋溶土。经过36年紫云英还田，铁铝土大团聚体的稳定性显著提高了9.57%-13.37%。紫云英还田还促进了蛭石向高岭石的转化，并显著提高了铁铝土中黏粒、游离铁和芳香族碳的含量。背散射电子（BSE）-扫描电镜（SEM）-能谱（EDS）分析结果表明，铁铝土团聚体结构紧密，铁氧化物与高岭石共定位。此外，偏最小二乘路径模型（PLS-PM）表明，黏粒含量对大团聚体稳定性具有直接的正向效应，而高岭石和游离铁通过直接影响芳香族碳，间接调节了黏粒的形成。综上所述，长期紫云英还田通过影响土壤矿物转化，生成更多的高岭石和铁氧化物，并通过保留芳香族碳促进了黏粒的形成，最终提升团聚体稳定性。

Abstract:

Soil aggregates profoundly impact soil sustainability and crop productivity, and they are influenced by complex interactions between minerals and organics. This study aimed to elucidate the alterations in mineralogy and soil organic carbon (SOC) following long-term green manure incorporation and the effect on soil aggregates. Based on 5- and 36-year field experiments, surface soil samples (0-20 cm) were collected from Alfisol and Ferrisol soils subjected to rice-rice-winter fallow (CK) and rice-rice-Chinese milk vetch (MV) treatments to investigate aggregate stability, mineralogy, SOC composition, and soil microstructural characteristics. The results showed that high clay-content Ferrisol exhibited greater aggregate stability than low clay-content Alfisol. The phyllosilicates in Alfisol primarily comprised illite and vermiculite, whereas those in Ferrisol with high-content free-form Fe oxides (Fed) were dominated by kaolinite. Additionally, the clay fraction in Ferrisol contained more aromatic-C than the clay fraction in Alfisol. The 36-year MV incorporation significantly increased the Ferrisol macroaggregate stability (9.57-13.37%), and it also facilitated the transformation of vermiculite into kaolinite and significantly increased the clay, Fed, and aromatic-C contents in Ferrisol. Backscattered electron (BSE)-scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) revealed a compact aggregate structure in Ferrisol with co-localization of Fe oxides and kaolinite. Moreover, the partial least path model (PLS-PM) revealed that clay content directly improved macroaggregate stability, and that kaolinite and Fed positively and directly affected clay or indirectly modulated clay formation by increasing the aromatic-C levels. Overall, long-term MV incorporation promotes clay aggregation by affecting mineral transformation to produce more kaolinite and Fe oxides and retain aromatic-C, and it ultimately improves aggregate stability. 

Key words: aggregate stability , clay , milk vetch , mineralogy , soil organic carbon