• ISSN 1008-505X
  • CN 11-3996/S
龙杰琦, 苗淑杰, 李娜, 郝翔翔, 乔云发. 施用生物炭对黑土各组分有机质结构的影响[J]. 植物营养与肥料学报, 2022, 28(5): 775-785. DOI: 10.11674/zwyf.2021290
引用本文: 龙杰琦, 苗淑杰, 李娜, 郝翔翔, 乔云发. 施用生物炭对黑土各组分有机质结构的影响[J]. 植物营养与肥料学报, 2022, 28(5): 775-785. DOI: 10.11674/zwyf.2021290
LONG Jie-qi, MIAO Shu-jie, LI Na, HAO Xiang-xiang, QIAO Yun-fa. Effects of biochar application on the structural properties of organic matter fractions in Mollisols[J]. Journal of Plant Nutrition and Fertilizers, 2022, 28(5): 775-785. DOI: 10.11674/zwyf.2021290
Citation: LONG Jie-qi, MIAO Shu-jie, LI Na, HAO Xiang-xiang, QIAO Yun-fa. Effects of biochar application on the structural properties of organic matter fractions in Mollisols[J]. Journal of Plant Nutrition and Fertilizers, 2022, 28(5): 775-785. DOI: 10.11674/zwyf.2021290

施用生物炭对黑土各组分有机质结构的影响

Effects of biochar application on the structural properties of organic matter fractions in Mollisols

  • 摘要:
    目的 生物炭还田已经成为培肥土壤的重要农艺措施之一,研究生物炭还田对黑土各粒径水稳性团聚体中有机碳的分配,以及对不同密度组分有机质化学结构的影响,以深化认识施用生物炭增加农田土壤固碳潜力的机理。
    方法 选取中国科学院海伦农业生态实验站内长期定位试验中施用化肥(−BC)和化肥配施生物炭(+BC) 的两个处理,采集土壤样品以常规方法分析了有机质总量,并将土壤样品分离为>2 mm、2~0.25 mm、0.25~0.053 mm和 <0.053 mm 4个粒级水稳性团聚体,测定其中的有机碳含量。将土壤样品中的有机质分为游离态轻组(free light fraction, LF)、闭蓄态轻组(occluded light fraction, OF)和矿物结合态组(mineral-associated fraction, MF) 3个密度组分,利用元素分析仪和傅里叶红外光谱技术分析了有机碳含量和化学结构。
    结果 与−BC处理相比,+BC处理的土壤有机质含量增加19.72%,密度组分中LF和OF有机质含量分别增加了73.50%和192.66%,团聚体>2 mm和2~0.25 mm两个粒级的有机质含量分别显著增加了12.54%和21.35%。土壤中除芳香族C=C和羰基C=O相对丰度分别减少了18.18%和21.95%以外,其他官能团均增加,−CH/C=C和−CH/C=O值分别增加66.67%和62.11%;在>2 mm团聚体中,脂肪族−CH的相对丰度增加了55.11%,芳香族C=C减少17.06%,致使>2 mm团聚体中的−CH/C=C和−CH/C=O值增加;在<0.25 mm粒级中,芳香族C=C相对丰度增加27.63%~49.83%,脂肪族−CH减少了16.58%~20.80%,致使−CH/C=C和−CH/C=O值下降。在>2 mm的团聚体中—CH/C=C和CH/C=O值的增幅最大。此外,与−BC相比,+BC处理各密度组分中脂肪族−CH和芳香族C=C相对丰度均增加,其中OF组分中增幅分别达125.74%和29.06%,−CH/C=C值增加了74.19%。
    结论 施用生物炭增加了黑土有机质含量,促使土壤特别是大团聚体中的有机质结构趋于脂肪化,促进了微团聚体中有机质的稳定性。闭蓄态轻组中脂肪族−CH的相对丰度增幅最大,有利于促进有机质活性的增强,加快土壤有机质的周转更新。

     

    Abstract:
    Objectives Biochar application has become one of the important agronomic strategies for increasing soil fertility. We studied the distribution of organic matter in various soil aggregates, and the variation of chemical structures of organic matter across density fractions, to understand the effect of biochar application on carbon sequestration potential of farmland soil.
    Methods The long-term experiment of biochar application was located in the Hailun Agricultural Ecological Experimental Station of the Chinese Academy of Sciences, which started from 2011. Soil samples were collected from the plots of applying biochar (+BC) and without biochar (−BC). Total conent of soil organic carbon was analyzed with conventional method. Subsamples were divided into four aggregate classes as > 2 mm, 2–0.25 mm, 0.25–0.053 mm and < 0.053 mm and soil organic carbon were determined in them. Moreover, subsamples were divided into free light fraction (LF), occluded light fraction (OF) and mineral-associated fraction (MF) according to their density. The concentration and characteristics of infrared spectrum of soil organic carbon in aggregates and density fraction were determined by Fourier infrared spectroscopy.
    Results Compared to –BC treatment, +BC treatment increased the concent of soil organic matter (SOM) in bulk soil, free light fraction (LF) and occluded light fraction (OF) by 19.72%, 73.50%, and 192.66%, respectively. +BC treatment increased the concent of SOM by 12.54% and 21.35% in >2 mm and 2–0.25 mm aggregates, respectively. Among the main functional groups in bulk soil, +BC treatment decreased the relative abundances of aromatic C=C and carbonyl C=O by 18.18% and 21.95%, respectively, while increased other groups, and the ratio of −CH/C=C and −CH/C=O increased by 66.67% and 62.11% respectively. In >2 mm aggregate, +BC treatment increased the relative abundance of aliphatic −CH by 55.11%, but decreased the aromatic C=C by 17.06%, leading to the increase in −CH/C=C and −CH/C=O ratios. In <0.25 mm aggregate, +BC treatment increased the relative abundance of aromatic C=C by 27.63%−49.83%, but reduced the aliphatic −CH by 16.58%−20.80%, leading to the decrease in −CH/C=C and −CH/C=O ratios. Compared to −BC treatment, +BC treatment increased the relative abundances of aliphatic —CH and aromatic −C=C in the three density fractions, and increased the —CH/C=C ratio in OF by 74.19%.
    Conclusions Biochar application increased significantly organic matter content in Mollisols, which led to more aliphatic groups in macro-aggregates and improved stability of micro-aggregates. The increment of relative abundance of aliphatic —CH in occluded fraction was the highest across density fractions, which enhanced the turnover of soil organic matter.

     

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