Insights into the composition of recalcitrant organic matter from estuarine sediments using NMR spectroscopy

Mylotte, Rosaleen; Sutrisno, Andre; Farooq, Hashim; Masoom, Hussain; Soong, Ronald; Hayes, M.H.B.; Simpson, André J.

doi:10.1016/j.orggeochem.2016.05.011

Cited by 26 publications

(12 citation statements)

References 40 publications

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“…3). The absorption peaks at 30 ppm is usually assigned to the amorphous (CH 2 ) n long chain C, which belongs to the category of alkyl C. The absorptions in the range of 55 to 60 ppm are associated with the Cs in the polypeptide and the methoxy group, and the absorption around 70 ppm is caused by the carbohydrate C 19 . The absorptions in the range of 128 to 132 ppm are mainly designated to the aromatic C with the substitutions of carboxyl group or the carboxyl group and the aromatic group C that is attached to H and is located in the ortho position to the O and N substituted groups.…”

Section: Resultsmentioning

confidence: 99%

Impacts of Long-term Fertilization on the Molecular Structure of Humic Acid and Organic Carbon Content in Soil Aggregates in Black Soil

Zhang

Fengqin

Wei

et al. 2019

Sci Rep

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Soil aggregates are the basic units of soil structure, and their composition and carbon (C) stability directly affect soil fertility. As cementing agents, humic substances play an important role in the formation and stability of soil aggregates. Long-term fertilization not only changes the structure of humic acid (HA), but also affects the content and stability of organic C in soil aggregates. In this study, based on a long-term fertilization experiment, the relationship between the molecular structure of HA and the stability of organic C in the aggregates was examined. Compared with the non-fertilization control (CK), both the application of organic manure alone (M) and organic manure combined with inorganic fertilizer application (MNPK) increased organic C content in the bulk soil and in HA. In addition, the application of organic manure (M, MNPK) favored the formation of macroaggregates (>0.25 mm) and showed a higher organic C contents of soil aggregates with different sizes than the CK. Moreover, the content of aliphatic C, the ratios of aliphatic C/aromatic C and alkyl C/O-alkyl C was increased with the application of organic fertilizer. A significant negative correlation was observed between aromatic C and organic C content of the aggregates with sizes of >2 mm, 2–0.25 mm, and 0.25–0.053 mm ( P < 0.05). The findings indicated that organic fertilization treatments (M and MNPK) increased the aliphatic C content of HA, which favored the increase in the organic C content and stability of the aggregates.

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Section: Resultsmentioning

confidence: 99%

Impacts of Long-term Fertilization on the Molecular Structure of Humic Acid and Organic Carbon Content in Soil Aggregates in Black Soil

Zhang

Fengqin

Wei

et al. 2019

Sci Rep

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“…Mylotte et al . () attributed the recalcitrance of alkyl C to its structure and hydrophobicity. Moreover, many soils with a large clay content aggregate strongly so that SOC is protected from further microbial decomposition and accumulates (Bot & Benites, ; Lützow et al ., ).…”

Section: Discussionmentioning

confidence: 99%

Evidence from nuclear magnetic resonance spectroscopy of the processes of soil organic carbon accumulation under long‐term fertilizer management

Zhao

Chu

et al. 2017

European J Soil Science

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Summary Long‐term application of fertilizers has a considerable effect on the accumulation of soil organic carbon (SOC), but the underlying processes remain unclear. We have examined the effects in the soil of two long‐term (> 20 years) field experiments of a double‐cropped maize (Zea mays L.)–wheat (Triticum aestivum L.) rotation on a Calcaric Fluvisol and paddy rice (Oryza sativa L) on a Hydragric Anthrosol. The chemical structures of the SOC were characterized with multiple cross‐polarization magic‐angle spinning 13C nuclear magnetic resonance spectroscopy. The treatments included organic fertilizer (OF) only, combined NPK (nitrogen, phosphorus and potassium) fertilizer with OF (NPKOF), mineral fertilizer pairings of NPK, NP and NK, and an unamended control. The continuous fertilizer treatments did not change the chemical composition of the Anthrosol SOC greatly except that the NPKOF treatment slightly enriched aromatic C and depleted O–alkyl C compared with the Control. All the treatments on the Anthrosol soil resulted in SOC accumulation, but to different extents. Principal component analysis of the Anthrosol and Fluvisol showed different relationships between the soil properties and functional groups. The Fluvisol SOC decreased in the order balanced fertilizer treatments (OF, NPKOF and NPK), NP, Control and NK treatments. The main structural changes of the Fluvisol SOC followed the same order with a decrease in the abundance of aromatic CO, aromatic C, anomeric C, O–alkyl C and OCH3/NCH, and an increase in COO/NCO and alkyl C, which led to an increase in alkyl–C/O–alkyl–C ratios and a decrease in aromaticity values. These results suggest that SOC accumulation with balanced fertilization on the Fluvisol can be attributed to less decomposition and more humification of the organic materials, whereas the smallest SOC content associated with P omission can be ascribed to more complete decomposition to gaseous end products. We consider that the chemical compositions of SOC may be altered by long‐term fertilizer treatments, depending on the soil type. Highlights How does soil organic carbon (SOC) change in response to long‐term fertilizer management? Improved understanding of SOC accumulation in Fluvisol and Anthrosol agricultural soils. Phosphorus omission in the Fluvisol retarded the accumulation and stimulated the decomposition of SOC. Fertilizer treatments affected chemical composition of SOC of the Fluvisol, but not the Anthrosol.

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“…Because Black Soil in the study area is free of carbonate, soil total C accurately represents soil organic carbon (SOC). Total P and total K concentrations were determined by digesting samples in sodium hydroxide and then measuring, respectively, by ascorbic acid colorimetry and by atomic absorption [ 18 ].…”

Section: Methodsmentioning

confidence: 99%

Effects of long-term fertilization on soil humic acid composition and structure in Black Soil

Zhang

Wang

et al. 2017

PLoS ONE

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The composition and structure of humic acid (HA) can be affected by fertilization, but the short-term effects are difficult to detect using traditional analysis methods. Using a 35-year long-term experiment in Black Soil, the molecular structure of HA was analyzed with Fourier transform infrared spectroscopy (FTIR), 13C nuclear magnetic resonance spectroscopy (NMR), and fluorescence spectroscopy. Variation in HA was analyzed after long-term fertilization, including fertilization with manure (M), inorganic N, P and K fertilizer (NPK), manure combined with inorganic N, P, and K fertilizer (MNPK), and a no-fertilizer control (CK). The application of each fertilizer treatment increased crop yields compared with the CK treatment, and the MNPK treatment increased crop yield the most. The ratio of main IR absorption peak of HA at 2,920 cm−1 compared with the peak at 2,850 cm−1 (2920/2850) was higher in the NPK and MNPK treatments compared with the CK treatment. The application of manure (MNPK and M treatments) increased the ratio of hydrogen to carbon (H/C) in HA, and raised the ratio of the main IR absorption peak of HA at 2920 cm−1 to that at 1720 cm−1 (2920/1720). Manure treatments also raised the ratio of aliphatic carbon (C) to aromatic C, alkyl C to alkoxy C and hydrophobic C to hydrophilic C and the fluorescence index (f 450/500), but decreased the degree of aromatization of HA, when compared with the CK treatment. The ratio between each type of C in HA was similar among all the fertilizer treatments, but NPK had a lower ratio of H/C and a lower content of aliphatic C compared with the CK treatment. These results indicated that the molecular structure of HA in Black Soil tends to be aliphatic, simpler, and younger after the application of manure. While the application of inorganic fertilizers increased in the degree of condensation of HA and made HA structure complicated. The application of manure alone or combined with inorganic fertilizers may be an effective way to increase crop yield and improve the structure of soil organic matter.

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Insights into the composition of recalcitrant organic matter from estuarine sediments using NMR spectroscopy

Cited by 26 publications

References 40 publications

Impacts of Long-term Fertilization on the Molecular Structure of Humic Acid and Organic Carbon Content in Soil Aggregates in Black Soil

Impacts of Long-term Fertilization on the Molecular Structure of Humic Acid and Organic Carbon Content in Soil Aggregates in Black Soil

Evidence from nuclear magnetic resonance spectroscopy of the processes of soil organic carbon accumulation under long‐term fertilizer management

Effects of long-term fertilization on soil humic acid composition and structure in Black Soil

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