Influence of animal manure application on the chemical structures of soil organic matter as investigated by advanced solid-state NMR and FT-IR spectroscopy (original) (raw)
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Journal of Molecular Structure, 2011
In this study, using DRIFT and HR MAS NMR, we analyzed the humic substances isolated from a soil treated, over 40 years, with different organic, mineral and organic plus mineral treatments and cultivated with maize as the main crop. As expected, the structure of humic substances was very complex but by combining both techniques (DRIFT and HR MAS NMR) additional information was obtained on aromatic and aliphatic components, the most recalcitrant parts of these macromolecules. In so doing we wanted to investigate the relationship between HS structure and long-term management practices. An elevated content of lignin, aminoacids, peptides and proteins was observed mainly for farmyard manure treatments with respect to mineral or liquid manure amendments; this supports how the different management practices have greatly influenced the humification process of cultivated soils.
Organic Agriculture, 2014
Very limited information is available on the impacts of organic farming practices on the chemical composition and properties of dairy manure. In this study, we found the differences in the absorptivities of dissolved organic matter between conventional and organic dairy manure samples at 254 and 280 nm, reflecting the difference in aromaticities of dissolved organic matter of the manures. The 13 C nuclear magnetic resonance (NMR) characteristics of triple peaks around 30 ppm were more evident in organic samples than in conventional dairy manure samples. This observation was presumably due to more forage feedstuff used in organic dairy farms as this spectral feature was assigned to cutin and cutan from the outer cuticle of herbaceous plants. Thus, the distinct NMR feature of manure around 30 ppm, if further confirmed, can serve as a traceable forage marker to evaluate the authenticity of organic dairy farming programs.
European Journal of Soil Science, 1995
C-nuclear magnetic resonance (NMR) spectra taken using magic-angle spinning (MAS), cross polarization (CP) and with total suppression of side bands (TOSS) are reported for soils from two long-term field experiments. One set of soils was from the Broadbalk Experiment at Rothamsted, UK (monoculture of winter wheat since 1843) and the other was from the Lermarken site of the Askov Long-Term Experiment on Animal Manure and Mineral Fertilizers (arable rotation since 1894). At both sites soil samples were taken from three fertilizer treatments: nil, inorganic fertilizers, animal manure. Spectra were obtained from whole soil samples and from the size fractions clay ( < 2 pm), silt (2-20 pm) and, in some cases, sand (20-2000 pm).
13C NMR and mass spectrometry of soil organic matter
Central European Journal of Chemistry, 2003
Liquid state, high resolution 13 C NMR spectroscopy and mass spectrometry were used to study the composition and structure of soil organic matter (SOM) using soil extracts from two long-term experiments at the Rothamsted Experimental Station. Both one-and two-dimensional NMR techniques were applied. 13 C NMR sub-spectra of the CH n (n = 0 : : : 3) groups, obtained by the Distortionless Enhancement by Polarisation Transfer (DEPT) technique, were used for the elucidation of the qualitative and quantitative composition of humic and fulvic acids in the soils. The chemical structure of SOM was further analysed at the molecular level through Fast Atom Bombardment Mass Spectrometry (FABMS) and Gas Chromatography-Mass Spectrometry (GC/MS). Humic and fulvic extract results were not only compared to each other, but also to the solid state 13 C NMR results for the complete soil sample.
Soil Science Society of America Journal, 2011
Fractions of soil organic matter (SOM) were extracted by an integrated physical-chemical procedure and their chemical natures were characterized through 13 C nuclear magnetic resonance (NMR) spectroscopy. For the 0-to 5-cm depth of a corn (Zea mays L.)-soybean [Glycine max. (L.) Merr.] soil in Iowa, we extracted in sequence the light fraction, two size fractions of particulate organic matter (POM), and two NaOH-extractable humic acid fractions based on their binding to soil Ca 2+ : the unbound mobile humic acid fraction and the calcium humate fraction. Whole SOM was obtained by dissolving the soil mineral component through HF washes. All samples were analyzed by advanced 13 C NMR techniques, including quantitative direct polarization/magic angle spinning, spectral-editing techniques, and two-dimensional 1 H-13 C heteronuclear correlation NMR. Th e NMR spectra were comparable for the light fraction and two POM fractions and were dominated by carbohydrates and to a lesser extent lignins or their residues, with appreciable proteins or peptides. By contrast, spectra of the two humic fractions were dominated by aromatic C and COO/N-C=O groups, with smaller proportions of carbohydrates and NCH/OCH 3 groups, indicative of more humifi ed material. Th is trend was yet more pronounced in the calcium humate fraction. Th e spectrum for whole SOM had signals intermediate between these two groups of SOM fractions, suggesting contributions from both groups. Our results for this soil suggest that either chemical or physical fractions alone will partially represent whole SOM, and their integrated use is likely to provide greater insight into SOM structure and possibly function, depending on the research issue.
European Journal of Soil Science, 1997
The small organic matter content of mineral soils makes it difficult to obtain I3C and 15N nuclear magnetic resonance (NMR) spectra with acceptable signal-to-noise ratios. Subjecting such samples to hydrofluoric acid removes mineral matter and leads to a relative increase in organic material. The effect of treatment with 10% hydrofluoric acid on bulk chemical composition and resolution of solid-state 13C NMR spectra was investigated with six soils, some associated particle size fractions, plant litter and compost. The treatment enhanced the signal-to-noise ratio of the solid-state I3C NMR spectra. The improvement in spectrum quality was greatest in the clay fraction of soil contaminated with coal ash. The removal of paramagnetic compounds associated with the ash may be the main reason for the improvement. Based on total C, total N, C/N ratio and intensity distribution of the solid-state I3C NMR spectra, no changes in organic matter composition could be detected, except for a possible loss of carbohydrates. After treatment with HF, solid-state I5N NMR spectra of particle size fractions were obtained and indicated that the observable nitrogen is present mostly as peptides and free amino groups. Extraction with hydrofluoric acid is recommended as a routine treatment prior to solid-state I3C and "N NMR on soil containing little C or N and soil samples containing paramagnetic compounds from natural or anthropogenic sources.
13C NMR studies of organic matter in whole soils: H. A case study of some Rothamsted soils
European Journal of Soil Science, 1995
Nuclear magnetic resonance (NMR) spectra were obtained for solid samples of whole soils from three long-term field sites at Rothamsted Experimental Station, UK. In all sites, soil organic matter content was either increasing or decreasing due to contrasted long-continued treatments. Two soils were from Highfield, one from under old grassland (47 g organic C kg-') and one from an area kept as bare fallow following ploughing of grass 21 years previously (14 g organic C kg-l). Three soils were taken from Broadbalk, two from plots within the Broadbalk Continuous Wheat Experiment which had received no fertilizer or animal manure annually for 148 years (7 and 27 g organic C kg-', respectively) and one from Broadbalk Wilderness, wooded section (38 g organic C kg-l). Broadbalk Wilderness was arable until 1881 and has reverted to deciduous woodland in the subsequent 110 years. Two soils were from Geescroft, one from an arable field (9 g organic C kg-') and one from Geescroft Wilderness (35 g organic C kg-') which began reversion to deciduous woodland at the same time as Broadbalk Wilderness but is now acid (pH = 4.2) in contrast to Broadbalk which is calcareous (pH = 7.3).
Application of 1H HR/MAS NMR to Soil Organic Matter Studies
NMR is a powerful technique that allows the characterization of organic matter (OM) components directly in whole soils, providing important information on those complex materials with irregular structures and strong physical and chemical links to mineral matter. The aim of the present work is to evaluate the application of proton high-resolution magic angle spinning nuclear magnetic resonance (
Geoderma, 2004
The importance of soil organic matter functions is well known, but structural information, chemical composition and changes induced by anthropogenic factors such as tillage practices are still being researched. In the present paper were characterized Brazilian humic acids (HAs) from an Oxisol under different treatments: conventional tillage/maize-bare fallow (CT1); conventional tillage/maize rotation with soybean-bare fallow (CT2); no-till/maize-bare fallow (NT1); no-till/maize rotation with soybean-bare fallow (NT2); no-till/maize-cajanus (NT3) and no cultivated soil under natural vegetation (NC). Soil HA samples were analyzed by electron paramagnetic resonance (EPR), solid-state 13 C nuclear magnetic resonance ( 13 C NMR), Fourier transform infra-red (FTIR) and UV-Vis fluorescence spectroscopies and elemental analysis (CHNS). The FTIR spectra of the HAs were similar for all treatments. The level of semiquinone-type free radical determined from the EPR spectra was lower for treatments no-till/maize-cajanus (NT3) and noncultivated soil (1.74 Â 10 17 and 1.02 Â 10 17 spins g À 1 HA, respectively), compared with 2.3 Â 10 17 spins g À 1 HA for other soils under cultivation. The percentage of aromatic carbons determined by 13 C NMR also decreases for noncultivated soil to 24%, being around 30% for samples of the other treatments. The solid-state 13 C NMR and EPR spectroscopies showed small differences in chemical composition of the HA from soils where incorporation of vegetal residues was higher, showing that organic matter (OM) formed in this cases is less aromatic. The fluorescence intensities were in agreement with the percentage of aromatic carbons, determined by NMR (r = 0.97 P < 0.01) and with semiquinone content, determined by EPR (r = 0.97 P < 0.01). No important effect due 0016-7061/$ -see front matter D (M. González Pérez), martin@cnpdia.embrapa.br (L. Martin-Neto).