Transformation of humic substances and functional groups of soil organic carbon after wildfire

2019 ◽  
Vol 67 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Xin Yue ◽  
Shimei Li ◽  
Qaiser Hussain ◽  
Shengai Jin ◽  
Qinghua Liu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Humic Substances ◽  
Functional Groups

scholarly journals The influence of organic and inorganic nutrient inputs on soil organic carbon functional groups content and maize yields

Heliyon ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. e07881
Author(s):  
M. Ndung'u ◽  
L.W. Ngatia ◽  
R.N. Onwonga ◽  
M.W. Mucheru-Muna ◽  
R. Fu ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Functional Groups ◽  
Inorganic Nutrient ◽  
Nutrient Inputs ◽  
Maize Yields

scholarly journals Effect of Mineral and Humic Substances on Tailing Soil Properties and Nutrient Uptake by Pennisetum purpureum Schumach

2016 ◽  
Vol 20 (2) ◽  
pp. 101
Author(s):  
Adhe Phoppy Wira Etika ◽  
Rahmat Hasan
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Humic Substances ◽  
Chemical Properties ◽  
Pennisetum Purpureum ◽  
Mineral Matter ◽  
Organic Carbon Content ◽  
Humic Material ◽  
Humic Materials

Tin mining produces a by-product sand tailing from soil leaching with characteristic low pH and total organic carbon, and can be reclaimed by providing a suitable ameliorant.  When available in situ, ameliorant materials can be economically used as they are required in large amounts. Fortunately, Bangka Belitung has sample stock of such kaolinite-rich minerals that can be utilized for improving soil chemical properties. Extracted organic materials, such as humic substances, can also be utilized as they influence the complex soil reactions, and promote plant growth. Thus, this study aimed to assess the effects of mineral, humic materials and interaction of both material on soil chemical properties and nutrient uptake of Pennisetum purpureum Schumach. A completely randomized design with 2 factors and 3 replications each was employed. Factor 1 was mineral matter is 0; 420; 840; 1.260 Mg ha-1 while Factor 2 was humic material is 0; 0.46; 0.92; 1.38 kg C ha-1. Air-dried samples of tailing were applied with oil palm compost then mixed evenly with mineral and humic materials.  Penissetum purpureum Schumach was planted after 4 weeks incubation, and maintained for another 4 weeks. The results demonstrated that the addition of mineral matter significantly increased soil organic carbon content, total N, exchangeable K, Fe, Mn and boosted nutrient - total Ca, Mg and Mn – uptake of the plant. But the application of humic material increased only soil organic carbon content. The interaction of both materials only lowered soil pH.

scholarly journals New possibility for characterization of dissociation behaviour of supramolecular electrolytes: results obtained for the International Humic Substances Society standard and reference samples by coulometry

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Martina Klučáková
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Humic Substances ◽  
Functional Groups ◽  
Dissociation Constants ◽  
Fulvic Acids ◽  
Molecular Organization ◽  
Humic And Fulvic Acids ◽  
Acid Base ◽  
Reference Samples

Abstract Background Humic substances can be considered as polyelectrolytes with supramolecular character and complicated behaviour in water environment. The fractions of humic substances dissolved in water are the most active ones and determinative for their functioning in nature, where the proton-binding and dissociation ability play a crucial role. The dissociation behaviour of humic and fulvic acids can be affected by different circumstances including their concentration which is directly connected with the molecular organization of humic particles in solution and the accessibility of their ionizable functional groups. This study is focused just on these active fractions and their dissociation behaviour in the dependence on their content in studied system. Results Standards and reference samples of International Humic Substances Society were used. Flow-through coulometry was used to determine the total content of acidic functional groups in fulvic solutions and humic leachates. The amount of dissociated acidic groups was determined on the basis of potentiometry. Several differences between the behaviour of humic and fulvic acids were found. While whole samples of fulvic acids including the weakest functional groups were analysed, only the active dissolved humic fractions containing stronger acidic functional groups were characterized. The fractions containing higher amounts of the weakest functional groups remained insoluble. The dissociation degree of fulvic acids decreased with their increasing content, but a maximum on its concentration dependence obtained for humic acids was observed. Conclusions Two different values of dissociation constants were determined for each sample. The first was determined on the basis of the extrapolation of infinite dilution, second was determined as their average value in the region of high concentrations in which it was constant. Obtained values characterize the functioning of dissolved humic substances from point of view of their dissociation ability. The results obtained by this approach can help to predict the acid–base behaviour of dissolved organic carbon in soil and generally in nature. The acid–base behaviour of dissolved organic carbon depends on its ratio to water. It behaves differently in soil which is dry and in soil which is wet or saturated by water.

scholarly journals Carbon Accumulation in Arable Soils: Mechanisms and the Effect of Cultivation Practices and Organic Fertilizers

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1079
Author(s):  
Jörg Gerke
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Carbon ◽  
Humic Substances ◽  
Saturation Index ◽  
Farmyard Manure ◽  
Carbon Accumulation ◽  
Organic Fertilizers ◽  
Organic Carbon Content ◽  
Arable Soils

The organic carbon content of soils is a key parameter of soil fertility. Moreover, carbon accumulation in soils may mitigate the increase in atmospheric CO2 concentration. The principles of carbon accumulation in arable soils are well known. The inclusion of clover/alfalfa/grass within the rotation is a central instrument to increase soil organic carbon. In addition, the regular application of rotted or composted farmyard manure within the rotation can increase soil organic carbon contents much more than the separate application of straw and cattle slurry. Humic substances, as a main stable part of soil organic carbon, play a central role in the accumulation of soil carbon. A major effect of compost application on soil carbon may be the introduction of stable humic substances which may bind and stabilize labile organic carbon compounds such as amino acids, peptides, or sugars. From this point of view, a definite soil carbon saturation index may be misleading. Besides stable composts, commercially available humic substances such as Leonardite may increase soil organic carbon contents by stabilization of labile C sources in soil.

Soil organic carbon fractions and humic substances are affected by land uses of Caatinga forest in Brazil

2019 ◽  
Vol 33 (3) ◽  
pp. 255-273 ◽  
Author(s):  
Uemeson José dos Santos ◽  
Gustavo Pereira Duda ◽  
Marise Conceição Marques ◽  
Erika Valente de Medeiros ◽  
José Romualdo de Sousa Lima ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Humic Substances ◽  
Land Uses ◽  
Carbon Fractions ◽  
Organic Carbon Fractions ◽  
Soil Organic Carbon Fractions

Sorption of the Pesticide Aldicarb by Soil: Its Mobility Through a Saturated Medium in the Presence of Dissolved Organic Matter

1988 ◽  
Vol 23 (2) ◽  
pp. 253-269 ◽  
Author(s):  
P. Lafrance ◽  
L. Ait-ssi ◽  
O. Banton ◽  
P.G.C. Campbell ◽  
J.P. Villeneuve
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Humic Substances ◽  
Soil Column ◽  
Soil Samples ◽  
Saturated Soil ◽  
Organic Carbon Content ◽  
Treated Soil ◽  
Dissolved Humic Substances

Abstract Adsorption characteristics of the radiolabeled pesticide aldicarb (2-methyl-2-(methyl-14C-thio)-propionaldehyde-O-methycarbamoyO-oxime) on loamy sand and its mobility through a water-saturated soil column were studied. This study emphasizes the effect of soil organic carbon content and of dissolved humic materials on the sorption characteristics of aldicarb. Dissolved humic substances at 25 mg/L present a very small binding affinity for aldicarb (“association constant” ≈ 20 [nmol/g carbon]/[nmol/g water]) and do not significantly affect the sorption rate for this pesticide. Freundlich isotherms were determined for aldicarb sorption on the original soil (% o.c. = 2.2) and on soil samples treated to reduce the initial soil organic carbon content (% o.c. = 0.8). If linear isotherms are assumed, the adsorption coefficient KD is nearly three-fold higher for the original soil than for the treated soil samples. The ratios of the KD values obtained for adsorption in the presence and in the absence of dissolved humic substances (25 mg/L) were 1.3 and 1.4, respectively, for the original and for the treated soil samples: this indicates that humic substances could modify only slightly aldicarb transport in soil. Effluent concentration profiles for the movement of the radiolabeled pesticide through a 30-cm long saturated soil column indicate a retardation factor R = 1.4. This R value is related to hydrolysis product of aldicarb, since no detectable parent compound was found in the column effluent. Results showed 45% loss of the initial radioactivity applied on the soil column: this could be attributed to irreversible adsorption and to biodegradation of the pesticide compounds.

scholarly journals Response of the chemical structure of soil organic carbon to modes of maize straw return

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuqing Zheng ◽  
Jiuming Zhang ◽  
Fengqin Chi ◽  
Baoku Zhou ◽  
Dan Wei ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Functional Groups ◽  
Chemical Structure ◽  
Plant Residues ◽  
Straw Mulching ◽  
Soil Microbial ◽  
Straw Return ◽  
And Function

AbstractElucidating the chemical structure of soil organic matter (SOM) is important for accurately evaluating the stability and function of SOM. Aboveground vegetation directly affects the quantity and quality of exogenous organic matter input into the soil through plant residues and root exudates, which in turn affects soil microbial species, community structure, and activity, and ultimately impacts the chemical structure of SOM. In this study, a 13C nuclear magnetic resonance technique was used to analyze the chemical structure characteristics of soil organic carbon (SOC) under various rates of straw returning combined with rotary tillage and under full straw mulching. The results showed that full straw returning with rotary tillage and full straw mulching more effectively increased the SOC content than reduced rate of straw returning (1/2 and 1/3 of full straw) with rotary tillage. The contents of alkyl C and alkoxy C in the functional groups of SOC under various straw returning treatments were increased compared with those under the treatment of maize stubble remaining in soil (CK). Furthermore, the contents of aromatic C and carboxyl C were decreased, which were consistent with the chemical shift changes of SOC. Compared with CK treatment, straw returning decreased the content of aromatic C in the functional groups of SOC, but increased the content of alkoxy C, which could be associated with the change in integral areas of absorption peaks of alkyl C and alkoxy C moving toward left and right, respectively. The content of total SOC was significantly positively (P < 0.05) correlated with that of alkoxy C and significantly negatively (P < 0.01) correlated with that of aromatic C. The molecular structure of SOC tends to be simplified due to the decreasing in refractory C and the increasing in easily decomposed C after straw returning to the field.

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