scholarly journals Humic Substances Extracted by Alkali Are Invalid Proxies for the Dynamics and Functions of Organic Matter in Terrestrial and Aquatic Ecosystems

2019 ◽  
Vol 48 (2) ◽  
pp. 207-216 ◽  
Author(s):  
Markus Kleber ◽  
Johannes Lehmann
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Aquatic Ecosystems

scholarly journals Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Romualda Bejger ◽  
Guillaume Debaene ◽  
Bożena Smreczak
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Sorption Properties ◽  
Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

scholarly journals Using water hyacinth (Eichhornia crassipes) biomass and humic substances to produce urea-based multi-coated slow release fertilizer

Cellulose ◽  
2021 ◽  
Author(s):  
Iris Amanda A. Silva ◽  
Osmir Fabiano L. de Macedo ◽  
Graziele C. Cunha ◽  
Rhayza Victoria Matos Oliveira ◽  
Luciane P. C. Romão
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Natural Organic Matter ◽  
Nitrogen Fertilization ◽  
Water Hyacinth ◽  
Eichhornia Crassipes ◽  
Slow Release ◽  
Leaching Tests ◽  
Slow Release Fertilizer ◽  
Atmosphere System

AbstractUrea-based multi-coated slow release fertilizer was produced using water hyacinth, humic substances, and chitosan, with water rich in natural organic matter as a solvent. Elemental analysis showed that the nitrogen content of the fertilizer (FERT) was around 20%. Swelling tests demonstrated the effectiveness of the water hyacinth crosslinker, which reduced the water permeability of the material. Leaching tests showed that FERT released a very low concentration of ammonium (0.82 mg L−1), compared to the amount released from urea (43.1 mg L−1). No nitrate leaching was observed for FERT, while urea leached 13.1 mg L−1 of nitrate. In water and soil, FERT showed maximum releases after 30 and 40 days, respectively, while urea reached maxima in just 2 and 5 days, respectively. The results demonstrated the promising ability of FERT to reduce nitrogen losses, as well as to minimize environmental impacts in the soil–plant-atmosphere system and to improve the efficiency of nitrogen fertilization. Graphic abstract

Soil Augmentation by Humus: Replenishing lost soils and supplementing new ones

2021 ◽  
Author(s):  
Hemlata Bagla ◽  
Asma Khan
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Plant Growth ◽  
Humic Substances ◽  
Soil Degradation ◽  
Lunar Regolith ◽  
Radioactive Waste Disposal ◽  
Saline Stress ◽  
Plant Metabolites ◽  
Growth Phenomenon

<p>Earth’s regolith consists of a vital component that is lacking on other planets ­­– the pedosphere or soil body – that is rich in organic matter, soil fauna, minerals, water, gases, that together support life and is thus essential for plant growth. In stark contrast to our blue planet, Martian regolith is devoid of organic matter and contains crushed volcanic rocks, with high mineral content and toxic chemicals like perchlorates. Nevertheless, Martian and Lunar regolith simulants formulated by NASA, have been experimented for crop growth by addition of organic matter suitable to bind xenobiotics and provide ample nutrients, as an essential step towards expanding our horizon in the extensive field of soil sciences.</p><p>Soil is an ecosystem as a whole and acts as a modifier of planet Earth’s atmosphere. The organic matter present in it originates mainly from plant metabolites with the onset of senescence and humification. Humic substances thus formed in the pedosphere exhibit exceptional characteristics for soil conditioning. Besides providing nutrients and aeration to the soil, they interact and bind with toxic heavy metals, radionuclides, pesticides, industrial dyes, and other xenobiotics that may be present as pollutants in the ecosystem, thus acting as natural sieves. As top soils have maximum organic matter, essential for plant growth, phenomenon like soil erosion leave the soils devoid of humic substances. Another major reason for soil degradation is excessive salinity, leading to osmotic and ionic stress in plants, eventually reducing their growth. Addition of humic acid in soils provides protection against high saline stress and minimizes yield losses. In India, one of the leading agrarian countries, it is a common practice to enrich soils with manure, which is an inexpensive form of humus-boost for the crops. Such practices aid the cyclic flow of organic matter in the environment, against the background of widespread soil degradation.</p><p>Another global form of soil degradation is radioactive contamination of soils which occurs mainly due to nuclear accidents and improper practices of radioactive waste disposal. In order to explore such interactions with humic acid following Green technique, batch biosorption studies were performed over a range of parameters, with radionuclides Cs and Sr that are found in low level radioactive wastes. Biosorption percentages of 91±2% and 84±1% were obtained for Cs and Sr respectively. The technique is chemical-free and emphasizes the ‘nature for nature’ outlook of solving environmental problems. Humic acid and its various forms thus act as traps for radionuclides and work as excellent restorative soil stimulants that supplement depleted soils, boost plant growth, and play a vital role in sustaining life on Earth.</p>

scholarly journals Heavy-metal pollution alters dissolved organic matter released by bloom-forming Microcystis aeruginosa

RSC Advances ◽  
2017 ◽  
Vol 7 (30) ◽  
pp. 18421-18427 ◽  
Author(s):  
Haiming Wu ◽  
Li Lin ◽  
Guangzhu Shen ◽  
Ming Li
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Microcystis Aeruginosa ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Aquatic Ecosystems ◽  
Eutrophic Lakes

The risk of heavy metals to aquatic ecosystems was paid much attention in recent years, however, the knowledge on effects of heavy metals on dissolved organic matter (DOM) released byMicrocystiswas quite poor, especially in eutrophic lakes.

ORGANIC MATTER CHARACTERISTICS OF UNDISTURBED AND CULTIVATED CHERNOZEMIC AND SOLONETZIC A HORIZONS

1979 ◽  
Vol 59 (4) ◽  
pp. 349-356 ◽  
Author(s):  
J. F. DORMAAR
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Chelating Resin ◽  
Anthropogenic Pressures ◽  
Organic C ◽  
Amide Bonds ◽  
Acid Ratio ◽  
Humic Materials ◽  
Fallow System ◽  
Extractable Organic Matter

Under a wheat-fallow system of farming practised on Brown, Dark Brown, and Black Chernozemic soils, on a Black Solodized Solonetz, and on Brown and Black Solods, organic C decreased by as much as 60%; the humic acid/fulvic acid ratio decreased little for the semiarid soils but up to 38% for the Black soils; ethanol/benzene-extractable organic matter increased by as much as 330%; chelating resin-extractable C increased by 27–115%; and total acidity of the extracted humic substances increased up to 36%. The ash contents of the humic substances from the Ah horizons were all less than 12%, whereas those of the Ap horizons varied between 20 and 28%. Apparent differences between the infrared spectra of the resin-extractable humic substances of the Ah and Ap horizons existed particularly near 2920 and 1550 cm−1 suggesting less aliphatic C-H and amide bonds. Anthropogenic pressures have wrought, therefore, distinct measurable qualitative changes, i.e., the general trend with cultivation was towards humic materials with a decreased proportion of side chain components, such as C-H and NH2 groups, but increased carboxyl group content.

Sign in / Sign up

Export Citation Format

Share Document