Journal of Integrative Agriculture ›› 2022, Vol. 21 ›› Issue (12): 3611-3625.DOI: 10.1016/j.jia.2022.08.072

所属专题： 农业生态环境-有机碳与农业废弃物还田合辑Agro-ecosystem & Environment—SOC

• • 上一篇    下一篇

长期耕作和秸秆管理对石灰性土壤有机碳组分的影响

  

  • 收稿日期:2019-10-27 接受日期:2022-01-05 出版日期:2022-12-01 发布日期:2022-01-05

Fractionation of soil organic carbon in a calcareous soil after long-term tillage and straw residue management

LI Teng-teng1, 2, ZHANG Jiang-zhou3, 2*, ZHANG Hong-yan2, Chrisite PHRISITE2, ZHANG Jun-ling2   

  1. 1 Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems & CAS Engineering Laboratory for Vegetation Ecosystem Restoration on Islands and Coastal Zones, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, P.R.China

    2 College of Resources and Environmental Sciences/National Academy of Agriculture Green Development/Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural University, Beijing 100193, P.R.China

    3 College of Resources and Environment/International Magnesium Institute, Fujian Agriculture and Forestry University, Fuzhou 350002, P.R.China

  • Received:2019-10-27 Accepted:2022-01-05 Online:2022-12-01 Published:2022-01-05
  • About author:Correspondence ZHANG Jiang-zhou, Tel: +86-591-86396189, E-mail: zjzky2010@163.com
  • Supported by:

    The authors gratefully acknowledge funding from the National Basic Research Program of China (2015CB150500).


PDF

摘要：

免耕和秸秆还田均影响土壤有机碳含量和组分。然而，免耕和秸秆还田对土壤有机碳库变化的影响有待进一步研究。本研究选择华北平原11年长期定位试验，试验主处理为免耕(NT)和常规耕作(CT)，副处理为秸秆不还田(S0)、仅小麦秸秆还田(S1)和小麦玉米秸秆均还田(S2)，揭示耕作和秸秆还田对土壤有机碳数量和质量的影响。分析不同管理模式下土壤有机碳及其不稳定性组分（颗粒有机碳、高锰酸钾氧化性有机碳、微生物量碳和可溶性有机碳）含量，利用荧光光谱结合平行因子分析可溶性有机碳组成，采用13C核磁共振技术分析土壤有机碳化学结构。结果表明，秸秆还田显著增加了0-20 cm土层土壤有机碳含量和储量，但免耕对其仅起到层化作用，即与常规耕作相比，免耕增加了0-10 cm土层有机碳含量和储量，却降低了10-20 cm土层有机碳含量和储量，这种现象在小麦玉米秸秆均还田条件下(S2)条件下更加明显。不稳定性有机碳组分变化趋势与土壤有机碳相似，其中颗粒有机碳和高锰酸钾氧化性有机碳对秸秆还田较为敏感，而前者对耕作更为敏感。可溶性有机碳的六个荧光组分主要包括腐殖质类物质和少量的富里酸类物质和色氨酸。秸秆还田显著降低了荧光指数(FI)和自生源指数(BIX)，但增加了腐殖化指数(HIX)。在小麦玉米均还田条件下(S2)，免耕显著增加了上层HIX和下层BIX及FI。土壤有机碳化学结构表现为氧烷基碳>烷基碳>芳香碳>羧基碳。综上所述，在小麦和玉米秸秆均还田条件下，免耕增加了上层土壤有机碳含量及其不稳定性有机碳组分、可溶性有机碳的腐殖化程度和下层微生物驱动的可溶性有机碳。小麦玉米秸秆均还田是增加耕层土壤有机碳有效管理措施，免耕对上层和下层土壤有机碳层的差异变化可能对碳固持具有长期的影响。

Abstract:

No tillage (NT) and straw return (S) collectively affect soil organic carbon (SOC).  However, changes in the organic carbon pool have been under-investigated.  Here, we assessed the quantity and quality of SOC after 11 years of tillage and straw return on the North China Plain.  Concentrations of SOC and its labile fractions (particulate organic carbon (POC), potassium permanganate-oxidizable organic carbon (POXC), microbial biomass carbon (MBC) and dissolved organic carbon (DOC)), components of DOC by fluorescence spectroscopy combined with parallel factor analysis (PARAFAC) and the chemical composition of SOC by 13C NMR spectroscopy were explored.  Treatments comprised conventional tillage (CT) and NT under no straw return (S0), return of wheat straw only (S1) or return of both wheat straw and maize residue (S2).  Straw return significantly increased the concentrations and stocks of SOC at 0-20 cm depth but no tillage stratified them with enrichment at 0-10 cm and a decrease at 10-20 cm in comparison to CT, especially under S2.  Labile C fractions showed similar patterns of variation to that of SOC, with POC and POXC more sensitive to straw return and the former more sensitive to tillage.  Six fluorescence components of DOC were identified comprising mostly humic-like substances with smaller amounts of fulvic acid-like substances and tryptophan. Straw return significantly decreased the fluorescence index (FI) and autochthonous index (BIX) and increased the humification index (HIX).  No tillage generally increased HIX in topsoil but decreased it and increased the FI and BIX below the topsoil.  The chemical composition of SOC was: O-alkyl C>alkyl-C>aromatic-C>carbonyl-C.  Overall, NT under S2 effectively increased SOC and its labile C forms and DOC humification in topsoil and microbially-derived DOC below the topsoil.  Return of both wheat and maize straw was a particularly strong factor for promoting soil organic carbon in the plough layer, and the stratification of SOC under no tillage may confer long-term influence on carbon sequestration.

Key words: soil organic carbon ,  labile C fractions , EEM fluorescence , PARAFAC analysis , 13C NMR spectrometry