Composition Of Humus In Soils Research Articles

The effects of long-term rice straw and biochar return on soil humus composition and structure in paddy soil

The effects of long-term rice straw and biochar return on soil humus composition and structure in paddy soil

Effects of different types of vegetation cover on soil microorganisms and humus characteristics of soda-saline land in the Songnen Plain.

In the soda-saline grasslands of the Songnen Plain, Jilin Province, China, the prohibition of grazing has led to significant changes in plant communities and soil properties. However, the intricate interplay between soil physical and chemical attributes, the soil microbial community, and their combined influence on soil humus composition remains poorly understood. Our study aimed to evaluate the impact of natural vegetation restoration on soil properties, microbial community diversity, and composition in the soda-saline soil region of the Songnen Plain. We conducted assessments of soil physical and chemical properties, analyzed community diversity, and composition at a soil depth range of 0-20 cm. The study covered soils with dominant soda-saline vegetation species, including Suaeda glauca Bunge, Puccinellia chinampoensis Ohwi, Chloris virgata Swarta, Phragmites australis (Clay.), Leymus chinensis (Trin.), and Tzvelev. We compared these vegetated soils to bare land devoid of any plants. We found that soil organic content (SOC) in vegetation restoration areas was higher than in bare land, with SOC content varying between 3.64 and 11.15 g/kg in different vegetated areas. Notably, soil pH emerged as a pivotal factor, explaining 11.4% and 12.2% of the variance in soil bacteria and fungi, respectively. There were correlations between SOC content and the relative abundance of specific microbial groups, with Acidobacteria and Mortierella showing a positive correlation, while Actinobacteria, Gemmatimonadetes, and Ascomycota exhibited significant negative correlations with SOC. The disparities in SOC composition and content among the soda-saline vegetation types were primarily attributed to variations in pH. Consequently, reducing soil pH is identified as a critical step in the process of vegetation restoration in soda-saline land. Prohibiting grazing has the potential to increase soda-saline SOC content and enhance microbial diversity, with Leymus chinensis and Phragmites australis showing particularly promising results in terms of higher SOC carbon content and microbial diversity.

Responses of Soil Humus Composition and Humic Acid Structural Characteristics to the Addition of Different Types of Biochar in Phaeozems

Responses of Soil Humus Composition and Humic Acid Structural Characteristics to the Addition of Different Types of Biochar in Phaeozems

Organization of sustainable management of meadows in the Nonchernozem belt of the Russian Federation

Relevance and methodology. Meadow communities forming in various ecological regimes, participate in the biogeochemical carbon cycle, accumulating and retaining it, removing it from the atmospheric air. A significant part of the natural meadows in the old-developed region is intensively exploited and loses carbondepositing functions. The sustainable management of meadows under intensive exploitation provides for the organization of their restoration and optimal exploitation. In field and office work, the method of trial plots, ecological analytical methods with the determination of organic carbon in the composition of soil humus, the method of phytocenotic analogs, the weight method, and a number of statistical methods were used.Results. The research of the dynamics of the carbon content of above- and underground biomass, soil of three meadows types, showed a favourable effect of restoration processes on the organic carbon content of soils, the growth of biomass and productivity. The long-flooded meadows turned out to be the most responsive to restoration processes. However, the increase in the amount of aboveground and underground biomass in meadows, the productivity of meadows also increased for all types of meadows by the age of 5 years, and then decreased. The following monitoring indicators to diagnose the progress of recovery processes in meadow ecosystems are recommended: root biomass, leaf area index and content of labile organic matter. Therefore, when planning the management of meadows during restoration successions, it is necessary to provide for a moderate pasture load with 4–5 years of restoration processes. Planning the use of meadows, it is necessary to provide for a combination of sequestration and deposit processes of organic carbon, which is a way to increase or preserve the humus content of soils, preserve crop yields, and reduce CO2 emissions into the atmospheric air.

Effects of returning corn straw and fermented corn straw to fields on the soil organic carbon pools and humus composition

Abstract. In our previous studies, we filtered out fungus (Trichoderma reesei) to have the best ability to transform corn straw into a humic-acid-like substance through laboratory incubation experiments. In order to further verify our former findings, we set up a 360 d field experiment that included three treatments applied under equal carbon (C) mass: (i) corn straw returned to the field (CS), (ii) fermented corn straw treated with Trichoderma reesei returned to the field (FCS-T), and (iii) blank control treatment (CK). Soil organic carbon (SOC), soil labile organic C components, soil humus composition, and the management levels of SOC pools under the three treatments were analyzed and compared. The results showed that the SOC content of CS and FCS-T treatments increased by 12.71 % and 18.81 %, respectively, compared with CK at 360 d. The humic acid carbon (HA-C) content of the FCS-T treatment was 0.77 g kg−1 higher than in the CS treatment. Applying FCS-T appeared to promote a significant increase in SOC content, carbon pool activity index, and carbon pool management index through the accumulation of HA-C, humin carbon, and easily oxidizable organic carbon. Applying fermented corn straw treated with Trichoderma reesei (FCS-T) is more valuable and conducive to increasing soil easily oxidizable organic C (EOC) and humus C content than direct application of corn straw.

Effects of returning varying amounts of vegetable waste to fields and combined application of decomposing agents on soil humus composition

Effects of returning varying amounts of vegetable waste to fields and combined application of decomposing agents on soil humus composition

Complementary ESI and APPI high resolution mass spectrometry unravel the molecular complexity of a soil humeome

High resolution mass spectrometry (HRMS) can resolve thousands of compounds in complex mixtures such as natural organic matter. However, HRMS is seldom sufficient to fully resolve the molecular heterogeneity of Humus in the soil matrix, especially if no preliminary simplification of Humus complexity is applied and if a single ionization technique is used. Here we show that HRMS, when applied with both photoionization (APPI) and electrospray ionization (ESI) and combined with the extensive molecular simplification provided by a humeomic fractionation, significantly increases identification of the molecular composition of soil Humus. Different sequential extractions separate the soil Humeome in three organosoluble fractions (ORG1-3) and two hydrosoluble fractions (AQU2 and RESOM), which showed distinct molecular characteristics. The ORG fractions were particularly homogeneous and rich in alkyl compounds including unsaturated hydrocarbons and lipid compounds found mainly in ORG 1 and ORG 3, but also aromatic compounds comprising lignin-like molecules and condensed structures mainly detected in ORG2. The AQU2 fractions revealed greater complexity and heterogeneity due to the simultaneous detection of sugars, amino sugars, tannins and N-containing compounds not detectable in appreciable concentrations in other fractions. The most recalcitrant RESOM fraction contained highly reduced molecules and condensed structures. The combined use of APPI and ESI showed a marked selectivity in the detection of chemically different molecules separated in each fraction, thereby enhancing their molecular characterization. Specifically, APPI tended to ionize less oxidized and N-containing molecules, and compounds with high concentrations of unsaturation or aromatics, while ESI was more prone to detect highly oxidized compounds consisting of large O/C ratios. Our findings indicate that the combination of a soil Humeome fractionation with a detailed high resolution characterization of differently ionized molecules in the separated fractions enables a far deeper understanding of the molecular composition of soil Humus and the comprehension of its environmental reactivity.

Tillage effects on humus composition and humic acid structural characteristics in soil aggregate-size fractions

Interaction between soil aggregates and humic substances directly determine soil carbon (C) sequestration and stabilization dynamics. This study investigated the influence of different tillage systems on soil humus composition and humic acid (HA) structural characteristics in water stable soil aggregates in the 0−20 and 20−40 cm soil depths. Tillage systems included no-tillage (NTS) and conventional tillage (CTS) both with corn straw returned, and conventional tillage without corn straw returned (CT). Fluorescence, Fourier transform infrared (FTIR) and 13C nuclear magnetic resonance (13C NMR) spectroscopies were employed to comprehensively characterize soil HA structure in soil aggregate fractions. The results showed that large quantities of humus C was stored in the large macro-aggregates (> 2 mm) and silt/clay (< 0.053 mm) fractions across all tillage systems, highlighting the importance of these aggregate fractions in C sequestration and stabilization. Among all tillage systems, NTS was more conducive in improving humus C content within soil aggregates. The fluorescence and FTIR spectra demonstrated that < 0.053 mm aggregate fractions of all tillage systems were characterized by greater aromatic and phenolic C, and lower carboxyl C groups, indicating complex molecules in HA structures. The> 2 mm aggregates were dominated by aliphatic, methoxyl, hydrophobic and carboxyl C groups, and this result was more evident in NTS indicating improved soil C stability. Comparing all tillage systems, NTS enhanced aliphatic, methoxyl and hydrophobic C in > 2 mm aggregates, which indicate improved soil C stability. The 13C NMR results of bulk soil demonstrated that NTS enhanced alkyl, O-alkyl and methoxyl/N-alkyl C in the 0−20 cm. We therefore concluded that NTS is the better system to effectively improve soil C sequestration and stability.

Changes in quantity and quality of organic matter in soil after application of poultry litter and poultry litter biochar—5-year field experiment

Changes of the addition of poultry litter (PL) and poultry litter biochar (PLB) on quantitative and qualitative humus parameters in loamy sand were estimated during the 5-year study period. The following properties were determined in soil: pH, total carbon (Ctotal), total nitrogen (Ntotal), humic and fulvic acids, extracted carbon, and non-hydrolysing carbon. Additionally, light absorbance in the solutions of humic acids was computed at the wavelength of 280, 465, and 665 nm. It was demonstrated that organic matter mineralisation was most intense in soil with the addition of PL, causing significant quantitative and qualitative changes in humus compounds in soil. A slower rate of organic matter mineralisation was observed in soil amended with PLB, especially in a dose of 5.0 t ha−1, which indicated the long-term effect of this material on improving soil properties. Spectrophotometric indexes for the solution of humic acids also showed that PLB had a more favourable effect on the structure durability and lower mobility of humic acid carbon compared with PL. The application of PL and PLB significantly increased the non-hydrolysing carbon content in soil, indicating greater stabilisation of humus compounds and, at the same time, lower CO2 emissions. It was found that the addition of organic materials to soil significantly increased the soil organic carbon contents. Our study has shown that the identification of changes that may occur in the quantitative and qualitative composition of soil humus after the application of PLB may be helpful in determining the appropriate biochar dose.Graphical abstract

Effect of ravined forest biogeocenoses on soil humus status in a steppe environment

A detailed study of the relationships between all components of each biogeocenosis is needed for its in-depth investigation. According to the concept of biogeocenoses developed by V. M. Sukachev, soil is one of the five components of biogeocenosis being its resulting unit. Soil is a bioinert component body of biogeocenosis. Playing the role of a subsystem, it is characterized by self-regulation, stability, direct and feedback mechanisms, self-restoring fertility, a specific biological cycle of substances and energy flow against the background of a specific natural geographical area. When the soil testing, its chemical, physical, water, micromorphological properties should be determined, and, above all, a total humus content and quality. Humus affects all important soil properties. In fertility, its essential role consists in a nutrient source as a factor that has a physiological effect on plants. A role of humus in improving the physical, thermal and water properties of soils is well-known. The total content and group composition of humus are also determined during the diagnosis and classification of soils. For a more detailed description of humus, Grishina and Orlov proposed a system of indicators of soils humus condition. This is a level of humus content and reserves, its profile distribution, type of humus, degree of humification, etc. In this work, we made an attempt to diagnose the soils of ravined biogeocenoses and steppe virgin lands in Dnipropetrovsk region on the basis of a number of the above parameters. To compare, the common steppe virgin chernozem and forest chernozems of the northern and southern variants of the ravines were used. The study was carried out in the fresh linden-ash oakery (the Kapitanovsky Bayrak) and in the fresh maple oakery (the Viyskovoy Bayrak) occured in the middle part of the slopes of the northern exposition. The paper presents data on the study of the ravined forest biogeocenoses influence on the total content and qualitative composition of soil humus in the northern and southern variants of Dnipropetrovsk region in comparison with the steppe virgin soil. It was established that the total humus content and reserves in the layer of 0–20 cm increased and varied from moderate to high under the influence of ravined forest vegetation; the type of humus turns from humate to fulvate-humate, which has a positive effect on plant growth and development, as it makes nutrients more mobile and available to plants. Under the influence of forest vegetation in the ravines, the soil humus condition improved, namely, the total humus content and reserves in the 20 cm layer varied from moderate to high, and the type of humus turned from humate to fulvate-humate. Our data confirmed O. L. Belgard and A. P. Travleev provisions that forests in the steppe zone effect positively on soil properties, in particular their humus condition, in contrast to the forest zone.

Spent mushroom substrates affect soil humus composition, microbial biomass and functional diversity in paddy fields

Spent mushroom substrate (SMS) is the residue after mushroom production. The aims of this work were to analyze the effects of continuous application of SMS for nearly 10 years on soil organic carbon (SOC), soil humus composition, microbial biomass and functional diversity in paddy fields and to provide a theoretical basis for scientific application of SMS. A continuous application of SMS from Agaricus bisporus experiment was established in paddy field of southeastern China in 2007. Soils were collected from 6 treatments in 2016. The results showed that application of SMS could significantly increase the contents of SOC, soil total alkali-soluble humic carbon (HEC), humic acid carbon (HAC), especially the treatment of with high quantity of SMS, but not significantly increase the content of fulvic acid carbon (FAC). The microbial biomass carbon and nitrogen contents of MR3 (the amounts of SMS were 9574.5 kg hm−2, converted to pure nitrogen were 180 kg hm−2) were the largest, it illustrated that the amount of SMS was not the more the better. The average well color development (AWCD), the Shannon index, Simpson index and McIntosh index of MR3 treatment were the highest. Microorganisms of MR3 treatment could make better use of carbon sources. Carboxylic acids, carbohydrates and polymers were the main carbon source types. Sufficient but not excessive application of SMS was beneficial to the carbon source utilization of fast-growing microorganisms and was considered to be a good way to improve the productivity of paddy soil.

Effects of Returning Granular Corn Straw on Soil Humus Composition and Humic Acid Structure Characteristics in Saline-Alkali Soil

Returning straw plays an important role in protecting the environment and maintaining the sustainable development of agriculture. In this research, we explored the effects of returning granular corn straw on soil humus composition and humic acid structural characteristics in a typical saline-alkali soil. This study was conducted in Jilin province. A randomized block design consisting of nine plots with three treatments in three replicates was used for this study. The treatments were granular corn straw (GS), coarse corn straw (CS), and control (CK). The results show that treatments GS and CS both increased the contents of soil humus and its components in the soil compared to CK. However, treatment GS recorded the highest significant increase in soil humus carbon (HEC), fulvic acid carbon (FAC), and humic acid carbon (HAC) by 17.59%, 8.32%, and 26.51%, respectively. Comparing the two straw treatments, it was found that the relative intensities of treatment GS at 2920 and 2850 cm−1 were higher than treatment CS by 1.58% and 72.49%, respectively. The relative intensities of treatment GS at 1720 cm−1 and 1620 cm −1 were lower than treatment CS by 52.2% and 30.43%, respectively. Moreover, an analysis of soil humic acid (HA) through an infrared spectrum, fluorescence spectrum, and principal components analysis (PCA) showed that the application of straw makes the structure of HA aliphatic, simple, and younger, and also promotes the continuous renewal of humus. In this study, the application of granular corn straw effectively improved the soil humus content and humic acid structural characteristics and is thus highly recommended.

Changes in soil humus composition and humic acid structural characteristics under different corn straw returning modes

Studying changes in soil humus composition and humic acid (HA) structural characteristics caused by agronomic practices provide insights into the pathways of soil organic carbon (C) stabilisation dynamics. This five-year field study evaluated the effects of straw returning modes on humus composition and HA structure. Treatments included (i) corn straw returned on the soil surface (NTS), (ii) corn straw incorporated into soil within 0–10 cm (MTS), (iii) corn straw incorporated into soil within 0–20 cm (CTS) and (iv) no corn straw applied (CT). Soil HA was characterised by Fourier transform infrared (FTIR) and fluorescence spectroscopies. The results demonstrated that corn straw returning improved humus C fractions in this order NTS &amp;gt; MTS &amp;gt; CTS &amp;gt; CT in 0–20 cm depth. The FTIR and fluorescence results demonstrated that corn straw returning enhanced aliphatic, hydroxyl, methoxyl and carboxyl groups and simplified HA molecular structure, indicating regenerated and newly formed HA. Among all treatments, NTS was more conducive in simplifying HA molecular structure and enhancing aliphatic and hydrophobic C. Hydrophobicity in aliphatic C is the driving force in the stabilisation of soil C, which is important for sustainable agriculture. Therefore, we conclude that NTS is the better practice to turn arable lands into a sink for C.

Effects of different corn straw amendments on humus composition and structural characteristics of humic acid in black soil

ABSTRACT Straw returning to the field has become a common way to utilize crop residues. This method does not only solve the problem of rational utilization of straw but also improves soil organic carbon (SOC) quality and quantity. So far, various methods of straw return exist, but the comparison of these methods has not been sufficiently studied, especially in the black soil of Northeast China. The purpose of this study is to evaluate the effects of different corn straw amendments applied under equal carbon (C) mass on soil humus composition and structural characteristics of humic acid (HA). The pot experiment was carried out by simulating corn straw return, which included four treatments: no corn straw applied (CK), corn straw (CS), humidified corn straw (HCS) and corn straw biochar (Bc). Soil HA was characterized by Fourier transform infrared spectroscopy (FTIR), elemental analyzer and thermogravimetric analysis (TG). The results showed that CS, HSC, and Bc treatments increased SOC content by 7.51%, 31.03%, and 33.65%, respectively, compared to CK. Bc treatment showed a greater degree of humification (79.16%) and increased the C content of HA by 10.87% and 7.37% compared with CS and HCS, respectively. The FTIR spectra and elemental results revealed that CS and HCS treatments increased the aliphaticity of the HA structure, while Bc increased the aromaticity of C in HA structure, rendering HA structure complicated. It can, therefore, be inferred that the application of biochar will improve humus compositions, SOC content and enhances the stability of HA structure.

Biochar changes in soil based on quantitative and qualitative humus compounds parameters

Abstract Due to the indisputable significance of humus in many biochemical processes as well as its increasing deficit particularly in light soils, alternative sources of substrates for the reproduction of this constituent should be sought. The aim of this study was to evaluate the effect of the addition of wheat straw and wheat straw biochar (in four rates) on quantitative and qualitative humus parameters. The following properties were determined in soil: pH, organic carbon, total nitrogen, humic and fulvic acids, carbon in the extract, non-hydrolysing carbon and spectrophotometric indexes for solution of humic acids including A2/6, A2/4, A4/6. After applying 1% and 2% additions of biochar to the soil, the Corg soil content significantly increased compared to the same doses of thermally unconverted straw. After 254 days of incubation, the addition of biochar to soil at higher doses, decreased the share of humic acid carbon (CHA, CFA) in the Corg content compared to treatments without organic additions and WS treatment. The nonhydrolysing carbon soil content was significantly increased by treatments with 1% and 2% additions of WSB, which indicates greater stabilisation of humus compounds and, at the same time, lower CO2 emission. Soil humic acids amended by treatment with biochar, especially at 1% and 2% doses, were characterised by lower A2/6 and A2/4 ratios. Recognition of changes that may occur in the quantitative and qualitative composition of soil humus after the application of biochar may in the future be helpful information for determining appropriate biochar dose.

Comparative effects of different maize straw returning modes on soil humus composition and humic acid structural characteristics in Northeast China

ABSTRACTIn order to evaluate the effects of different maize straw returning modes on humus composition and humic acid (HA) structural, a field experiment was designed to have five treatments, i.e. Treatment CK (no straw returned), Treatment EIS (straw incorporated evenly into the soil using the crashing-ridging technique), Treatment SP (straw plowed into the soil), Treatment SM (straw returned as mulch) and Treatment SG (straw returned as pellets). Our results showed that Treatment EIS significantly increased the content of soil organic carbon (SOC), soil humus substances (HEC), soil humic acid carbon (HAC) and fulvic acid carbon (FAC) by 27.8%, 47.6%, 63.3% and 33.8%, respectively, as compared with CK. Among all the straw returning treatments, Treatment EIS was the most significant in effect of increasing the content of HEC, HAC and FAC. Moreover, Treatment EIS altered the composition of humus more significantly than all the other treatments, by increasing the proportion of alkyl C and the ratio of aliphatic C/aromatic C. These results suggest that straw returning accelerated the accumulation of soil organic C and various components of humus, significantly improved the structure of soil HA, with the practice of EIS in particular.

Regularities of extracting humic acids from soils using sodium pyrophosphate solutions

Regularities of extracting humic acids from different soil types (soddy-podzolic soil, gray forest soil, and all chernozem subtypes) with sodium pyrophosphate solutions at different pH values (from 5 to 13) have been studied. It is found that, regardless of soil type, the process occurs in two stages through the dissociation of carboxylic groups and phenolic hydroxyls, each of which can be described by a logistic function. Parameters of the logistic equations approximating the extraction of humic acids from soils at different pH values are independent of the content and composition of humus in soils. Changes in the optical density of humic acids extracted from soils using sodium pyrophosphate solutions with different pH values are described in the first approximation by the Gaussian function. The optically densest humic acids are extracted using sodium pyrophosphate solutions at pH 10. Therefore, it is proposed to use an extract with pH 10 for the characterization of organic matter with the maximum possible degree of humification in the given soil.

ROLE OF APORRECTODEA CALIGINOSA IN THE PROCESSES OF SOIL ORGANIC MATTER TRANSFORMATION UNDER THE CONDITION OF MONOCULTURE AND MULTISPECIES PLANT COMMUNITY

The study has been carried out in the experimental field of the Centre for Ecological Research of the Polish Academy of Sciences, PAN, located in Dziekanow Leoeny (north of Warsaw). Six hundred lysimeters were installed covering the experimental area. The surface of the experimental plots (both lysimeters and their vicinity) was sown with either one grass ( Festuca rubra ) on half of the area, or with a mixture of 8 grass species on the other half of the area. In the next year, geophagous earthworms A. caliginosa were introduced to half of the lysimeters. The content of C-org, N-total, and the fractional composition of soil humus, were first determined at the beginning; at the end of the experiment also pH and the capacity of sorption complex were identified. The empirical results were subject to statistical analyses. After two years of the study, in comparison to red fescue sodding, the grass mixture sodding caused an increase in the content of organic carbon, total nitrogen and carbon of the humus fraction. The differences between the mean values of both soddings were not statistically significant. In soils under grass mixture, A. caliginosa caused an increase in the contents of organic carbon and fulvic acids carbon in relation to the initial soil; the CHA/CFA ratio significantly decreased. A slight increase in the degree of organic matter humification was observed in both soddings in combination with earthworms.

Buried humus horizons of flooded soils of the Selenga river delta

Presented are the results derived from investigating the buried humus horizons in flooded soils of the Selenga delta. A study of the morphology, chemical properties and composition of soil humus showed that the buried horizons are the product of evolution of soil cover across the territory which serve as filtrates of substances.

Humus specificity in ordinary chernozems of the Kammennaya Steppe area

tion of organic substances in the soil profile. In fact, this is in agreement with the views of Dokuchaev, who considered both processes to be important in the genesis of chernozems [1]. Information about changes in the properties of ordinary chernozems of the Kamennaya Steppe area under the impact of artificially planted forest vegetation, anthropogenic loads, and climate changes in the past century is rather ambiguous. In particular, this concerns data on changes in the humus status of ordinary chernozems. In this context, the study of the group and fractional composition of soil humus and the content of labile organic matter attracts special attention. Data on the amphiphilic properties of humic substances of ordinary chernozems are important for the proper assessment of the character of hydromorphism in chernozemic soils developed under steppe vegetation on the abandoned fields, under cropland, and under shelterbelts.