Caracterização das frações das substâncias húmicas de diferentes tamanhos moleculares

Sanches, S. M.; Campos, Sandro Xavier de; Vieira, Eny María

doi:10.1590/s0100-46702007000100007

Cited by 14 publications

(18 citation statements)

References 23 publications

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“…These results suggest that the HA-C presents a high structural condensation (larger amount of aromatic structures than aliphatic structures) and a large molecular size [17]. The measured E4/E6 and D log K values are among the smallest values reported [4,16,18].…”

Section: Resultsmentioning

confidence: 79%

Characterization of the Coal Humic Acids From the Candiota Coalfield, Brazil

JL¹,

DM²,

VS³

et al. 2012

Int J of Agri Scie

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Abstract-Humic acid (HA) is a principal component of humic substances, which are the major organic constituents of soil, peat, coal, many upland streams, dystrophic lakes and ocean water. HA has an important impact on a variety of environment processes. This work aimed to characterize the HA extracted and purified from the Candiota coalfield (Brazil) by visible (VIS), Fourier transform infrared (FTIR), energy dispersive X-ray (EDX), inductively coupled plasma absorption emission (ICP-AES), and X-ray diffraction (XRD) spectroscopies, thermogravimetry (TG), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The results of these analyses showed that Candiota HA presents a high degree of humification, which is considered to be type A with a turbostratic structure. The elemental analysis (EDX/ ICP-AES) indicated the presence of low concentrations of heavy metals.

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Section: Resultsmentioning

confidence: 79%

Characterization of the Coal Humic Acids From the Candiota Coalfield, Brazil

JL¹,

DM²,

VS³

et al. 2012

Int J of Agri Scie

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“…(Sanches et al, 2007) point out that the E 4 :E 6 ratio is influenced by several variables including molecular size, as well as the higher condensation observed in this period. It is observed that the molecules in this period were of a larger size, as indicated by the values of E 2 : E 3 .…”

Section: Resultsmentioning

confidence: 83%

“…E 4 : E 6 corresponds to the absorbance ratio between 465 and 665 nm, which is directly related to the st and aromaticity of the humic substances. Lower values of E 4 : E 6 indicate a high degree of condensation, wh terize low structural condensation (SANCHES et al, 2007). For pasture areas, the highest averages of the ring the dry period (Figure 6), which suggests a lower degree of structural condensation.…”

Section: Resultsmentioning

confidence: 94%

Variação Sazonal Do Carbono Orgânico Dissolvido (Cod) E Propriedades Ópticas Da Matéria Orgânica Em Diferentes Sistemas De Pastagem E De Soja No Estado De Mato Grosso

Morais

Dalmagro

Pinto³

et al. 2017

CeN

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The objective of this study is to characterize the quantity and quality of dissolved organic carbon (DOC) Resumo O objetivo deste estudo é caracterizar a quantidade e a qualidade do carbono orgânico dissolvido (COD) em diferentes condições hídricas nos sistemas de produção de pastagem e soja no estado de Mato Grosso. As amostragens foram realizadas nas estações úmidas(Fevereiromarço) e nas estações secas (setembro-outubro). A concentração de COD e suas propriedades de fluorescência óptica foram medidos a partir de amostras coletadas em diferentes ecossistemas no Estado de Mato Grosso (Cerrado, Pantanal, Amazônia e ecótono Cerrado/Amazônia

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“…The C/N ratio provides an indication of the origin of organic matter in natural environments. Values below 20 are indicative of humification processes favored by microbial activity, while values greater than 20 indicate the predominance of plants in the humification process [19]. For both HS samples, the humification process was associated with the presence of plants.…”

Section: Structural Characterizationmentioning

confidence: 99%

Investigations on the Thermodynamic Stability and Availability of Nutrients for Plants by Humic Substances Extracted from Peat Samples

Melo¹,

Oliveira²,

Cunha³

et al. 2015

JESE-A

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This work evaluated the complexation capacity, exchange constants and availability of micronutrients for plants and humic substances extracted from peat samples. Samples of humic substances extracted from two tropical peats (HS-P1 and HS-P2) were enriched with the micronutrients Cu(II), Co(II), Fe(II), Mn(II), Ni(II) and Zn(II) and the parameters for formation of the complexes (HS-N) were evaluated at different pH. The Scatchard model was used to calculate the maximum complexation capacity and the nutrient availability was studied using exchange capacity experiments based on ultrafiltration procedure. The optimum pH for complexation was 4.5 and the order of affinity was: Fe(II) > Cu(II) > Co(II) > Mn(II) = Ni(II) > Zn(II). The maximum complexation capacity reached 56.8 mg·g -1 Fe of HS-P1 (the highest) and 1.7 mg·g -1 Zn of HS-P2 (the slightest). The exchange experimentsshowed that HS-P-Fe complexes were formed preferentially. The least stable complex was formed with Zn, which was therefore, more easily available. The results contribute to understand the behavior and availability of some nutrients in soils.

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Caracterização das frações das substâncias húmicas de diferentes tamanhos moleculares

Cited by 14 publications

References 23 publications

Characterization of the Coal Humic Acids From the Candiota Coalfield, Brazil

Characterization of the Coal Humic Acids From the Candiota Coalfield, Brazil

Variação Sazonal Do Carbono Orgânico Dissolvido (Cod) E Propriedades Ópticas Da Matéria Orgânica Em Diferentes Sistemas De Pastagem E De Soja No Estado De Mato Grosso

Investigations on the Thermodynamic Stability and Availability of Nutrients for Plants by Humic Substances Extracted from Peat Samples

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