The use of total luminescence spectroscopy in the investigation of the effects of different rice management practices on humic substances of a planosol

Olendzki, Rodrigo Nogueira; Ignácio, Andréia Christina; Mangrich, Antônio S.

doi:10.1590/s0100-06832009000500008

Cited by 2 publications

(2 citation statements)

References 17 publications

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“…The experiment was carried out in a rice field in Capão do Leão RS, Brazil (Lat: −31.8209; Lon: −52.4588°), during the cropping seasons 2013/14 and 2014/15, under sprinkler irrigation, in soil classified as Planosol (Planossolo in the Brazilian Soil Classification System) (Olendzki et al ., 2009). The experimental design was in completely randomized blocks with four replications.…”

Section: Methodsmentioning

confidence: 99%

Phytosociological Characterization of Weeds as a Function of Residual Herbicides Applied to Rice Grown Under Sprinkler Irrigation

et al. 2017

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SUMMARYWe aimed to characterize the weed community in sprinkler irrigated rice, previously applied with residual herbicides for two years, as well as to infer about sustainability of the management applied to the fields based on an ecological approach. The experiment was conducted during the cropping seasons 2013/14 and 2014/15, under sprinkler irrigation. Rice was planted in the second-half of October, using the cultivar PUITA INTA CL. Herbicides were applied in pre- and post-emergence (sequential application) of crop and weeds. Ryegrass (Lolium multiflorum) was planted in winter. In May 2015, soil samples were collected for the soil seed bank study. Phytosociological characterization of weeds emerged from the seed bank was conducted from May 2015 to January 2016, until soil seed bank depletion. Echinochloa crusgalli, Fimbristyllis sp., Cyperus esculentus and Killinga brevifolia were the weeds to which most concern should be directed when growing rice under sprinkler irrigation in lowland areas of Southern Brazil. Their competition strategies are based on density. Herbicides used should be efficient in controlling at least these four weed species. A selecting action of herbicides on weed species was botanically characterized, as the weed species reported after two cropping seasons depended on the herbicide treatment applied.

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Section: Methodsmentioning

confidence: 99%

Phytosociological Characterization of Weeds as a Function of Residual Herbicides Applied to Rice Grown Under Sprinkler Irrigation

et al. 2017

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“…The highest intensities of A-and B-peaks were reported for FA1, whereas the lowest for FA3, independently on pH. This indicates the highest number of bearing electron-donating substituents e.g., hydroxyl, metoxyl and amino groups in FA1 [45,46] and the highest number of bearing electron-withdrawing substituents, such as carbonyl and carboxyl groups, in FA3 [47]. For most of the studied FAs, A fluorophores exhibited a higher fluorescence intensity as compared to the B ones.…”

Section: Fluorescence Properties Of Fasmentioning

confidence: 87%

Zinc Binding to Fulvic acids: Assessing the Impact of pH, Metal Concentrations and Chemical Properties of Fulvic Acids on the Mechanism and Stability of Formed Soluble Complexes

Boguta

Sokołowska

2020

Molecules

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The aim of the study was defined as a complementary analysis of molecular interactions between zinc (Zn) and fulvic acids (FAs) at a broad pH range (3–7), different metal concentrations (0–50 mg dm−3) and chemical properties of FAs and their impact on the Zn binding mechanism, stability, and efficiency. The results showed that the complexation reaction prevailed at pH 6 and 7, whereas protons exchange dominated interactions at pH 3. Stability constant of the complexes increased along with pH (logK increased from ~3.8 to 4.2). Complexation was preferred by less-humidified structures of lower molecular mass containing more oxygen groups. The number of fluorophores available for Zn(II) increased from pH 3 to 7 by ~44%. Depending on the pH, complexation involved a bidentate chelate, monodentate and bidentate bridging mode. Zn(II) binding was insufficiently modeled by the classic Stern–Volmer equation and well described by the double logarithmic equation (R > 0.94) as well as by a modified Stern–Volmer formula assuming the existence of available and unavailable fluorophore populations (R > 0.98). The fluorescence ratio of different fluorophores was proposed as an indicator of the binding affinity of various structures. A positive relationship was found between the fraction of accessible fluorophores and Zn(II) binding at pH 7 determined based on proton release (R = 0.91–0.97). The obtained results can find application in controlling the mobility and bioavailability of Zn in different conditions.

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The use of total luminescence spectroscopy in the investigation of the effects of different rice management practices on humic substances of a planosol

Cited by 2 publications

References 17 publications

Phytosociological Characterization of Weeds as a Function of Residual Herbicides Applied to Rice Grown Under Sprinkler Irrigation

Phytosociological Characterization of Weeds as a Function of Residual Herbicides Applied to Rice Grown Under Sprinkler Irrigation

Zinc Binding to Fulvic acids: Assessing the Impact of pH, Metal Concentrations and Chemical Properties of Fulvic Acids on the Mechanism and Stability of Formed Soluble Complexes

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