Article

Changes in the chemical composition of water-extractable organic matter during composting: Distribution between stable and labile organic matter pools

March 2007
Chemosphere 66(11):2166-2176

March 2007
66(11):2166-2176

DOI:10.1016/j.chemosphere.2006.09.010

Source
PubMed

Authors:

Daniel Said-Pullicino

Università degli Studi di Torino

Klaus Kaiser

Martin Luther University Halle-Wittenberg

Georg Guggenberger

Leibniz Universität Hannover

Giovanni Gigliotti

Università degli Studi di Perugia

Aerobic decomposition and stabilization of organic matter during the composting of waste materials is primarily due to the biochemical transformation of water-soluble compounds in the liquid phase by the microbial biomass. For this reason water-soluble organic matter represents the most active fraction of compost, both biologically and chemically, and thus should directly reflect the biochemical alteration of organic matter. This work aims to elucidate the microbial-mediated processes responsible for the distribution of soluble organic matter between stable and labile pools with composting time. Accordingly, chemical analysis as well as UV absorption, and 1H and 13C-NMR spectroscopy of samples collected during the industrial composting of urban waste revealed microbial induced transformation of water-extractable organic matter over time. The chemical composition changed from labile, hydrophilic, plant-derived organic compounds in the beginning to predominately stable, hydrophobic moieties comprising lignin-derived phenols and microbially-derived carbohydrates at later stages of composting.

Effect of Upstream Bioactivation of Plant Residues to Accelerate the Composting Process and Improve Product Quality

Article

Full-text available

Jun 2023

Composting is considered an efficient and environmentally friendly alternative for plant waste management, resulting in compost, a high value-added product. During the process, microorganisms play a crucial role as organic matter-degrading agents. However, the highly recalcitrant nature of the lignocellulose present in plant residues sets a challenge to the microorganisms involved in the process. Therefore, the objective of this study was to evaluate the effect of a lignocellulolytic microbial consortium, previously selected in composting processes, to promote and improve the biodegradability of plant residues. For this purpose, a laboratory-scale inoculation strategy was optimized by applying different strains and doses of Bacillus spp., as well as different incubation times. Subsequently, the impact of the application of the consortium on the waste material as a pretreatment of a real composting process was evaluated. Samples from both experiments were subjected to the evaluation of parameters related to the biodegradation of the lignocellulosic fraction, in addition to those related to the stability and maturity of a compost. The inoculum proved to be effective in promoting the bioactivation of the material, favoring a higher respirometric rate and biodegradability during laboratory-scale pretreatment. In this case, inoculation with B. safensis at high doses resulted in AT4 values higher than those observed for the rest of the treatments after ten days of incubation, while B. licheniformis inoculated at lower doses was able to maintain higher AT4 values after ten days, compared to those observed in the rest of the samples analyzed. Additionally, inoculation with both strains resulted in a continuous decrease in the percentage of hemicellulose that could be detected until the end of the incubation period (thirty days), reaching biodegradation rates close to 40%. On the other hand, although the inoculation did not significantly affect the basic conditioning parameters at the beginning of the composting process (organic matter, C/N ratio, and moisture), a change in the dynamics of the lignocellulosic fractions was observed during the process, as well as in the evolution of other stability and maturity parameters, in particular the AT4 index and the lignin/holocellulose ratio, revealing an acceleration of the bio-oxidative phase during the full-scale composting process. Therefore, the treatment of plant waste with lignocellulolytic microorganisms is proposed as an effective alternative to activate the biodegradability of organic waste at the beginning of a composting process, resulting in better-quality products.

Integration of anaerobic digestion and composting allows safety recovery of energy and nutrients from AFB1 contaminated corn

Article

Jul 2022

Occurrence of human carcinogen aflatoxin B1 (AFB1) in feed and foodstuffs is expected to increase in the next years due to climate change. This work aimed to assess the possible recovery of energy and nutrients from AFB1 contaminated corn through the integration of anaerobic digestion and composting. Pilot scale anaerobic digestion and composting of the digestate were carried out using AFB1 contaminated corn (100 µg g⁻¹) and pig slurry. Biomethane yields, compost quality and AFB1 degradation were evaluated during the trials. Results of this research showed that anaerobic digestion and composting integration can represent a suitable solution for the safe valorisation of a hazardous waste like AFB1 contaminated corn. Neither biomethane yields (214 NL kg⁻¹ VS) nor compost quality were affected from AFB1 contamination (i.e., C/N ratio and germination index of the compost were 10.8 and 100.9%, respectively). In addition, the mycotoxin was completely removed at the end of the process (the concentration was under the detection limit already after the active phase of composting). This confirms that AFB1 contaminated feed and foodstuffs might be safely treated in conventional anaerobic and composting facilities, without negative effects on process stability and products quality.

Anaerobic co-digestion of a lignocellulosic residue with different organic wastes: Relationship between biomethane yield, soluble organic matter and process stability

Article

Oct 2021
BIOMASS BIOENERG

The aim of this paper was to deepen the knowledge of anaerobic co-digestion of lignocellulosic residues and evaluate the role of soluble organic matter during co-digestion. Buckwheat milling residue (buckwheat hull) was co-digested with different organic wastes to evaluate the effect of co-digestion on biomethane yield, process stability, and their relationship with soluble organic matter. Results showed that co-digestion increased the biomethane yields of buckwheat hull and the best result was achieved from the co-digestion with slaughterhouse wastes (+254% of cumulative biomethane production). Kinetic analysis showed that fruit wastes and brewery trub affected positively anaerobic digestion of lignocellulosic residues, enhancing biomethane potential (+84% and +166%, respectively) and reducing lag phase duration. A positive correlation was found between the soluble organic matter and the biomethane yields during co-digestion experiments. Nevertheless, co-digestion with fruit wastes was affected by an excessive acidification in the early stage of AD (pH 5.7) caused by the rapid conversion of sugars into volatile fatty acids (7 g L⁻¹ at day 15). Although all the digestates showed high concentrations of plant nutrients (the average content of total N was 7.8% dry weight), they were also characterized by residual phytotoxicity (germination index was always 0.0%). results. Increasing the amount of easy biodegradable organic matter during lignocellulosic residues treatment should be the main goal when selecting co-digestion substrates. Chemical composition of co-digestion substrates should be carefully considered, with particular regard to soluble organic matter, to ensure the optimal development of anaerobic digestion with lignocellulosic residues.

Bulk and water-extractable organic matter from compost: evaluation of the selective dissolution in water using infrared absorbance ratios

Article

Full-text available

Dec 2020
ENVIRON SCI POLLUT R

Land application of composts affects concentration and composition of dissolved organic matter (OM) which plays important roles in soil functioning and may have effects on spreading of environmental pollution. Linking between the composition of bulk compost OM and its water-soluble fraction may, therefore, allow better understanding and prediction of the environmental impact of compost added to soil. The objectives of this study were to (i) examine composition-based links between bulk compost OM and water-extractable OM (WEOM), and (ii) evaluate and quantify selectivity of bulk compost OM dissolution, based on infrared (IR) absorbing functional groups. For that, 8 different composts and their freeze-dried WEOMs were characterized by mid-IR transmission spectroscopy. Compositions of compost OM and of WEOM were characterized in terms of ratios (R) defined on the basis of both areas and heights of specific IR absorbance bands in relation to absorbance by aliphatic CH groups. A simple novel approach is suggested, whereby selective dissolution of compost OM components is quantified by relating the R values determined for WEOM to those associated with compost OM. Significant similarities of IR spectra found in a series of WEOMs (and, to a lesser extent, in a series of compost OMs) suggest significant contributions of OM carboxylic groups to various bands. IR absorbance of compost OM contributed by hydrophilic and, specifically, carboxyl and carboxylate groups, when related to absorbance by aliphatic CH groups, can be used for predicting the indices characterizing WEOM composition, such as IR absorbance-based R values and aromaticity estimated from specific UV absorbance.

Soil organic matter composition impacts its degradability and association with soil minerals

Thesis

Full-text available

Jan 2012

Joyce S Clemente

Soil organic matter (OM) is a complex mixture of compounds, mainly derived from plants and microbes at various states of decay. It is part of the global carbon cycle and is important for maintaining soil quality. OM protection is mainly attributed to its association with minerals. However, clay minerals preferentially sorb specific OM structures, and clay sorption sites become saturated as OM concentrations increase. Therefore, it is important to examine how OM structures influence their association with soil minerals, and to characterize other protection mechanisms. Several techniques, which provide complementary information, were combined to investigate OM composition: Biomarker (lignin phenol, cutin-OH acid, and lipid) analysis, using gas chromatography/mass spectrometry; solid-state 13C nuclear magnetic resonance (NMR) spectroscopy; and an emerging method, solution-state 1H NMR spectroscopy. OM composition of sand-, silt-, clay-size, and light fractions of Canadian soils were compared. It was found that microbial-derived and aliphatic structures accumulated in clay-size fractions, and lignin phenols in silt-size fractions may be protected from further oxidation. Therefore, OM protection through association with minerals may be structure-specific. OM in soils amended with maize leaves, stems, and roots from a biodegradation study were also examined. Over time, lignin phenol composition, and oxidation; and aliphatic structure contribution changed less in soils amended with leaves compared to soils amended with stems and roots. Compared to soils amended with leaves and stems, amendment with roots may have promoted the more efficient formation of microbial-derived OM. Therefore, plant chemistry influenced soil OM turnover. Synthetic OM-clay complexes and soil mineral fractions were used to investigate lignin protection from chemical oxidation. Coating with dodecanoic acid protected lignin from chemical oxidation, and overlying vegetation determined the relative resistance of lignin phenols in clay-size fractions from chemical oxidation. Therefore, additional protection from chemical oxidation may be attributed to OM composition and interactions between OM structures sorbed to clay minerals. Overall, these studies suggest that while association with minerals is important, OM turnover is also influenced by vegetation, and protection through association with clay minerals was modified by OM structure composition. As well, OM-OM interaction is a potential mechanism that protects soil OM from degradation.

Variability in the Chemical Composition of Spring Waters in the Postomia River Catchment (Northwest Poland)

Article

Full-text available

Dec 2022

The paper presents the results of physicochemical analyses of spring waters in the Postomia River valley (Northwest Poland). Multivariate statistical methods, i.e., cluster analysis (CA) and principal component analysis (PCA) were used to assess the spatial distribution of similarities and differences in the concentrations of individual elements. Concentrations of macro elements (MEs), trace elements (TEs) and rare-earth elements (REEs) were analysed concerning the spring's typology, land use structure and the distance from roads. The results showed that the springs waters are of the Ca 2+-HCO 3 − and Ca 2+-HCO 3 −-SO 4 2− types, medium hardness and low mineralisation. The study revealed differences between valley springs and scarp-foot springs in terms of electrical conductivity and concentrations of F − , SO 4 2− , NO 3 − , Mg 2+ , Ba, Zn, and U. Greater variability was observed between the physical and chemical conditions of the spring waters due to their location in terms of land use. Springs located in agricultural areas had lower pH values than those in other areas, and higher NO 3 − concentrations. The pH values and concentrations of Fe, Mo, Rb, and Th in urban areas were higher than in agricultural areas. Moreover, the concentrations of F − , Cl − , K + , Na + , Mo, Sb, Se, and Sr were higher in urban areas than in forested areas. The study shows that only HCO 3 − values and SO 4 2− concentrations were related to the distance from the road network. The concentrations of Cl − , SO 4 2− , and K + were higher in the waters of springs located more than 50 m from the road network. The Ca and PCA analysis did not permit the identification of a single dominant origin of pollutants, suggesting an interaction of different types of pollution sources.

Mineralization of pig slurry compost treated with retorted oil shale and dicyandiamide in two contrasting soils

Article

Full-text available

Aug 2021
PESQUI AGROPECU BRAS

The objective of this work was to evaluate carbon and nitrogen mineralization in the soil after the application of composts produced in an automated composting plant, using pig slurry (PS) with and without the addition of retorted oil shale (ROS) and dicyandiamide (DCD) during composting. Laboratory studies were carried out for 180 days on two soils with contrasting characteristics: sandy-loam Typic Paludalf and clay Rhodic Hapludox, which were managed for more than 10 years under a no-tillage system. The composts were thoroughly mixed with the soils. The mineralization of the C and N from the compost was evaluated by measuring continuously CO2 emissions and periodically mineral N (NH4+ + NO3-) content in the soils, respectively. The mineralization of the C from the compost without ROS and DCD was higher in the sandy-loam soil (20.5%) than in the clay soil (13.9%). Similarly, 19.4% of the total N from the compost was mineralized in the sandy-loam soil and 10.9% in the clay soil. The presence of ROS in the compost reduced C mineralization by 54%, compared with the treatment without additives, in the sandy-loam soil and caused net N immobilization in both soils during incubation. The addition of DCD during PS composting did not affect the mineralization of the C and N from the compost in both soils. The addition of ROS during the composting of PS favors the retention of the C from the compost in the soil, especially in the sandy-loam one, but results in a net N immobilization.

EFFICACY OF HERBICIDES AND THEIR TANK MIXTURES AT SUNFLOWER (HELIANTHUS ANNUUS L.)

Article

Full-text available

Dec 2019

Grozi Delchev

The research was conducted during 2012 - 2014. Under investigation were 4 sunflower hybrids (Helianthus annuus L.): hybrid Bacardy (an imitolerant hybrid by ClearField plus technology), hybrid Estiva (an imitolerant hybrid by ClearField technology), hybrid Sumico (a tribenuron-methyl tolerant hybrid by ExpessSun technology) and hybrid Arizona (a hybrid by conventional technology). Factor A included the years of investigation. Factor B, herbicides and tank mixtures, included 20 rates. It includes 3 variants by ClearField plus technology, 5 variants by ClearField technology, 5 variants by ExpessSun technology and 7 variants by conventional technology. Herbicide Pulsar plus by Clearfield plus technology and herbicide Listego by Clearfield technology, destroy completely all annual and perennial graminaceous and broadleaved weeds in sunflower crops, including Orobanche cumana Wall. Herbicide Express by ExpressSun technology, controls all perennial and annual broadleaved weeds. Tank mixture of Express with antigraminaceous herbicide Select super controlled successfully and all annual and perennial weeds. The highest seed yield is obtained at herbicide tank mixture Pulsar plus + Stomp aqua by Clearfield plus technology. Tank mixture Listego + Dash + Sharpen by Clearfield technology and Express + Trend + Select super by ExpressSun technology also lead to obtaining of high seed yields. Tank mixtures of herbicides Smerch, Pendigan, Wing, Raft, Pledge and Modown with Amalgerol premium by conventional technology have lower yields due to insufficient control of weeds as Xanthium strumarium L., Cirsium arvense Scop., Convolvulus arvensis L. in sunflower crops.

Assessment of biotransformation of organic matter during co-composting of sewage sludge-lignocelullosic waste by chemical, FTIR analyses, and phytotoxicity tests

Article

Jan 2014
INT BIODETER BIODEGR

The co-composting of activated sludge and lignocellulosic waste (palm tree waste) was monitored to study the evolution of two mixtures, referred to as A (2/3 palm waste + 1/3 sludge) and B (1/2 palm waste + 1/2 sludge) for 6 mo. The biotransformation during the co-composting process was evaluated by physicochemical and spectroscopy analyses. The final composts exhibited a higher degree of decomposition than the controls as shown by a decrease of C/N and NH4+/NO3− ratios, and a 43% decrease in total lipid content. The decrease of aliphatic absorbance bands at 2964, 2922, and 2850 cm-1 and the increase of structure aromatic absorbance bands at 1514, 1426, and 1386 cm-1 reflect the progress of the humification process, which judging by the increase in the humification index, is about 60%. This efficiency of co-composting in reducing phytotoxicity was confirmed by the germination index, which reached over 90%, and by metallic trace element concentration.

The Effects of Flue Gas Desulphurization Gypsum on the Properties of Dissolved Organic Matter and Bacterial Community During Composting

Article

Full-text available

May 2020

Composting is a process that converts organic materials including solid wastes into humus-like substances. Additives play an important role in regulating composting performances. This work investigated the influences of flue gas desulphurization gypsum (FGDG) on the properties and evolution of dissolved organic matter (DOM) during the co-composting of dairy manure, sugarcane leaf and pressmud (the sludge from sugar factory effluent) with the combination techniques of elemental analysis, particle size, zeta potential, UV–Vis spectroscopy and FT-IR technology. The results revealed that FGDG amendment reduced carbon loss and facilitated nitrogen emission in compost DOM, increased the aromaticity of DOM and compost maturity, enhanced the absorbance of –OH, –CHO, –COOH and C–O in polysaccharides. Additionally, the adding of FGDG was an inhibitive factor to the whole bacterial diversity during composting. These findings provided new insights into the evolution and properties of DOM and the microbial community during the composting process with FGDG amendment.

UV–Visible and Fluorescence Green Waste Composts Monitoring: Material Dependency

Article

Full-text available

Jun 2018

The most frequent way to survey green waste composts is to monitor the temperature during the composting process. However, if the temperature is a good index for global biological processes, it is not for the chemical stability. In order to identify a reliable index, this work investigates water extraction coupled to spectroscopic indexes such as E2/E3, E4/E6, and SUVA254 ratios, and fluorescence indexes such as Kalbitz, Milori, CP/PARAFAC, and Fluorescence Region Integration. The measurements of these indexes are carried out with six samples from different sites with different green waste material composition. The results show that most indexes depend on the green waste origin more than the composting time; some depend mostly on the material origin while others on compost age. A comparison of these results indicates that the biochemical process occurs more rapidly than expected by the compost producers. The combination of these indicators gives useful information on the processes that take place during composting.

Molecular characterization of digestates from Solid-State Anaerobic Digestion of pig slurry and straw using analytical pyrolysis

Article

May 2018
J ANAL APPL PYROL

Straw and pig slurry Solid-State Anaerobic Digestion (SS-AD) was carried out in a pilot-scale apparatus using percolate recirculation technology. The digestion experiments were performed using 1, 2 and 4 recirculations per day; an additional experiment without percolate recirculation was used as control. The initial mixture and the digestates were analysed by means of chemical analyses and Pyrolysis–Gas Chromatography/Mass Spectrometry (Py–GC/MS), a direct analytical technique that allows investigating the changes in the organic matter (OM) composition of digestates and the effect of percolate recirculation frequency. Chemical analyses suggested a positive effect of percolate recirculation on OM degradation. The highest values of OM loss were found with 2 (26%) and 4 (31%) recirculation cycles per day, that also corresponded with the lowest values of the hydrophilic water extractable organic matter fraction (5.5 and 6.3% respectively). Py-GC/MS showed that the anaerobic digestion proceeded with progressive polysaccharide degradation (from c. 19% in the initial mixture to 10–8% with 2–4 recirculation cycles) and selective enrichment of lignin derived compounds (from c. 58% in the initial mixture to 67–69% with 2–4 recirculation cycles). In addition, a shift in the fatty acids distribution was observed with a decrease in the long/short chain ratio of fatty acid methyl esters. These results indicate that under our experimental conditions, percolate recirculation had a positive effect on the OM degradation. Also OM stabilization is observed with relative increases in recalcitrant lignin at the expense of the more liable polysaccharide fraction. This paper represents the first attempt to apply Py-GC/MS to evaluate the OM quality in digestates obtained by SS-AD of pig slurry and straw optimized by percolate recirculation.

Determination of compost maturity using the Hot Water Percolation (HWP) method

Article

Full-text available

Dec 2017

Maturity is one of the parameters that needs to be examined when producing composts. The present paper aims to evaluate whether the Hot Water Percolation (HWP) method elaborated for soil analysis can be used to determine the maturity of composts. The methods involves percolating boiling water through dry, ground compost samples, followed by the measurement of the dissolved carbon and mineral nitrogen contents and the spectral properties of the solution. Two groups of compost samples were examined. In one group the above parameters were recorded throughout the 42-day maturing process, while in the other group these parameters were measured on 7 samples judged to be mature and 5 judged to be fresh. The HWP-soluble NH4-N/NO3-N ratio was less than 0.16 in mature composts; for both compost groups the HWP-C value was less than 100 mg L-1, absorbance at 254 nm was 1.0-2.0 cm-1, the E4/E6 ratio was generally less than 2.0 and the SUVA (specific UV absorption) value at least 1.4 but generally higher, depending on the initial materials. The extracts obtained using the HWP method provide a good demonstration of the maturity stages in the composting process in spite of the speed of extraction.

Valorization of a pharmaceutical organic sludge through different composting treatments

Article

Dec 2017
WASTE MANAGE

Nowadays, the agricultural reuse of pharmaceutical sludge is still limited due to environmental and agronomic issues (e.g. low stabilization of the organic matter, phytotoxicity). The aim of the present study was to evaluate the characteristics of a pharmaceutical sludge derived from the daptomycin production and to study the possibility of improving its quality through composting. The pharmaceutical sludge showed high content of macronutrients (e.g. total Kjeldahl N content was 38 g kg-1), but it was also characterized by high salinity (7.9 dS m-1), phytotoxicity (germination index was 36.7%) and a low organic matter stabilization. Two different mixtures were prepared (mixture A: 70% sludge + 30% wood chips w/w, mixture B: 45% sludge + 45% wood chips + 10% cereal straw w/w) and treated through static composting using two different aeration systems: active and passive aeration. The mixtures resulted in the production of two different compost, and the evolution of process management parameters was different. The low total solids and organic matter content of mixture A led to the failure of the process. The addition of cereal straw in mixture B resulted in increased porosity and C/N ratio and, consequently, in an optimal development of the composting process (e.g. the final organic matter loss was 54.1% and 63.1% for the passively and actively aerated treatment, respectively). Both passively and actively aerated composting of mixture B improved the quality of the pharmaceutical sludge, by increasing its organic matter stabilization and removing phytotoxicity.

Effects of returning corn straw incorporated with fungi, and fermented corn straw on soil humic acid structural characteristics

Article

Full-text available

Mar 2023
J SOIL SEDIMENT

AimsDuring our previous laboratory incubation experiments, we found that the fungus (Trichoderma reesei (T. reesei)) has the best ability to transform corn straw into humic acid-like (HAL) substance. To further investigate whether the direct application of corn straw incorporated with T. reesei is as effective as the application of corn straw fermented with T. reesei in promoting the transformation and accumulation of stable soil organic matter components, a 720-day field experiment was established.Methods The field experiment involved four treatments applied to the soil at equal carbon mass: corn straw incorporated with T. reesei (CS-T), corn straw (CS), fermented corn straw treated by T. reesei (FCS-T), and blank control treatment (CK). The elemental analyzer, fluorescence and Fourier transform infrared spectroscopy, and thermogravimetric were used to comprehensively characterize the soil humic acid (HA) structure of the above treatments.ResultsThe results showed that the CS-T treatment encouraged the decomposition of unstable components of soil HA at 30 days, and formed a relatively younger HA at 180 days. The FCS-T treatment directly formed soil HA with more aliphatic compounds between 30 and 360 days. After a long transformation and accumulation, the FCS-T treatment at 720 days increased the relative HA content to 29.3% and formed more aromatic and stable HA with the H/C ratio and fluorescence index of 1.257 and 0.618, respectively.Conclusions The application of FCS-T could be a more suitable practice than the direct application of corn straw to increase soil HA content and aromaticity, as well as to improve soil HA stability.

Recovery of Energy and Nutrients from Mycotoxin-Contaminated Food Products through Biological Treatments in a Circular Economy Perspective: A Review

Article

Full-text available

Dec 2022

Mycotoxins’ contamination of food products is a well-known issue that is gaining interest nowadays due to increasing contaminations that are also related to climate change. In this context, and considering the principles of Circular Economy, finding robust and reliable strategies for the decontamination and valorisation of mycotoxin-contaminated products becomes mandatory. Anaerobic digestion (AD) and composting appear as promising biological treatments to degrade mycotoxins and allow for recovering energy (i.e., biogas production) and materials (i.e., nutrients from digestate and/or compost). The aim of the present paper was to carry out an organic revision of the state of the art of energy and materials recovery from mycotoxin-contaminated food products through biological treatments, highlighting results and research gaps. Both processes considered were not generally affected by the contamination of the feedstocks, proving that these compounds do not affect process stability. Mycotoxins were highly removed due to the concurrence of microbiological and physical agents in AD and composting. From the literature review, emerged the points that still need to be addressed before considering large scale application of these processes, which are (i) to deepen the knowledge of biochemical transformations of mycotoxins during the processes, (ii) to assess the fate of mycotoxins’ residues and metabolites in soil once digestate/compost are applied, (iii) to evaluate and optimize the integration of AD and composting in order to increase the environmental and economical sustainability of the processes, and (iv) to update legislation and regulations to allow the agricultural reuse of organic fertilizers obtained from contaminated feedstocks.

Linking soil aggregation to organic matter chemistry in a Calcic Cambisol: evidence from a 33-year field experiment

Article

Full-text available

Nov 2022
BIOL FERT SOILS

Soil aggregation contributes to soil organic C (SOC) sequestration, but it is still unclear how the organic functional groups and microbial necromass operate to influence soil aggregation. This issue was explored after 33 years of manure (i.e. farmyard manure at agronomic and elevated rates) and chemical fertilizer application in a Calcic Cambisol on the Loess Plateau. The application of manure increased SOC and the mass proportion of macroaggregates by 1.1- to 1.8-fold and 1.5- to 2.3-fold, respectively, compared with the unfertilized control. The aliphaticity, aromaticity and hydrophobicity indices of SOC as characterized by ¹³C nuclear magnetic resonance spectroscopy were higher in the manure-amended soils than in the chemical fertilizer-treated soils. The application of manure increased the microbial necromass by 1.3- to 2.6-fold compared with the control. Fungal necromass was enriched in the macroaggregates, while bacterial necromass was enriched in the microaggregates. Compared with the control, manure application increased (P < 0.05) the relative contribution of fungal necromass to SOC, which was positively correlated with the chemical recalcitrance of the SOC (i.e. aliphaticity, aromaticity and hydrophobicity) (P < 0.05). Furthermore, the chemical recalcitrance and relative contribution of microbial necromass, particularly that of fungal necromass, in the bulk soil (P < 0.05) and soil aggregates (P < 0.01) were positively correlated with the mass proportion of macroaggregates. Therefore, the accumulation of recalcitrant C components and fungal necromass contributes to soil aggregation in the Calcic Cambisols of the Loess Plateau.

Revealing the Inner Changes of Component Composition Derived from DOM PARAFAC Based on Two-Dimensional Correlation Spectroscopy

Article

Full-text available

Oct 2022
MOLECULES

Plenty of humic acid components compositions are contained in dissolved organic matter (DOM) derived from composting. Fluorescence signals were employed to characterize the changes in DOM components in the component process. In the composting process, five individual DOM fluorescence parallel factor analysis (PARAFAC) components were identified. At the end of the composting, PARAFAC component C5, which represented high humification and complex structure compounds, was detected, but the simple structure DOM PARAFAC component C1 was absent. In this study, a technique combining EEM-PARAFAC with two-dimensional correlation spectroscopy (2DCOS) further supplied detailed information about the dynamics of DOM peaks in PARAFAC components. 2DCOS results showed that the variation of the peaks in PARAFAC components was different in the composting process. The formation of a complex DOM fluorescence substance was attributed to the residues from the simple fluorescence peak degradation. The evolution of the DOM fluorescence peaks in each PARAFAC component indicated that simple structure compounds helped the formation of the complex DOM fluorescence substance in the composting process. These results revealed that EEM/PARAFAC combined with 2DCOS could be used to track the evolution of DOM PARAFAC components during the composting process.

Long-term partial substitution of chemical nitrogen fertilizer with organic fertilizers increased SOC stability by mediating soil C mineralization and enzyme activities in a rubber plantation of Hainan Island, China

Article

Feb 2023
APPL SOIL ECOL

The partial substitution of chemical nitrogen (N) fertilizer with organic fertilizers is widely used to maintain soil fertility and enhance crop yield, although its effects on soil organic carbon (SOC) composition, mineralization and stability are not fully understood. For this study, a 12-year field experiment was conducted in a rubber plantation field of Hainan Island, China. Three fertilizer treatments included no fertilizer application as control (CK), chemical fertilizer application (NPK), and half of the chemical N fertilizer plus manure application equivalent to half of chemical N fertilizer (NPKM). We determined the soil physicochemical properties, four labile SOC compositions (microbial biomass carbon (MBC), light fraction organic carbon (LFOC), dissolved organic carbon, dissolved organic carbon extracted by hot water (HOC), particulate organic carbon (POC)), four C-associated soil enzymes (β-1, 4-glucosidase (BG), polyphenol oxidase (POX), catalase (CAT) and cellulase), and SOC mineralization (from a 46-day aerobic incubation experiment) in two soil layers (topsoil layer (0–10 cm) and subsoil layer (10–20 cm)). Compared with NPK, NPKM significantly increased soil pH, total nitrogen, total phosphorus, available phosphorus and potassium, NH4⁺-N, and NO3⁻-N contents, and SOC, LFOC, POC, HOC, and MBC concentrations. NPKM had higher cumulative CO2 production but lower SOC mineralization potential (Cp) than NPK, although the difference was not significant. In both soil layers, NPKM significantly increased POX activity, but decreased BG and CAT activities. Soil pH can regulate enzyme activities and synthesis in acidic soil in a tropical region with a significantly positive correlation with POX activity. Compared with NPK, the relatively lower Cp/SOC and higher carbon quality index (CQI) indicated higher SOC stability (Cp/SOC) in NPKM. The redundancy analysis results revealed that the dominant factors affecting SOC stability were NH4⁺-N, pH, POC and MBC in NPK, and available phosphorus, BG, and pH in NPKM. In the three fertilization treatments, the POX was the dominant factor affecting the CQI. Conclusively, half of the chemical N fertilizer plus half of the manure application could facilitate SOC stability by mediating soil C mineralization and enzyme activities in the rubber plantation of Hainan Island, China.

Zróżnicowanie przestrzenne wybranych składników biogennych w śródpolnych oczkach w Polsce Północnej = Spatial differentiation characterising selected biogenic components in mid-field kettle ponds of northern Poland

Article

Full-text available

Apr 2021

Closed basins are important and fixed elements of a post-glacial landscape, in which they may occupy rather a large percentage of the total area. Sometimes these fill to become bodies of water known as kettle ponds. Each such basin has its own closed catchment at the surface and, owing to the limited circulation of matter in these types of depressions, biogenic components often accumulate to excess. In that context, the work detailed here had as its main objective the identification of sources of biogenic substances like nitrates, ammonium-nitrogen and phosphates, with a view to determining the range of variability characterising their presence in small mid-field ponds present in the catchments of two of northern Poland’s rivers, i.e. the Parsęta and the Borucinka. Most of the kettle ponds under study could not be said to have particularly high contents of nitrate, given an average for the bodies of water studied within the Parsęta basin equal to 2.98 mg·dm-3. There was nevertheless considerable variability in concentrations of the ion – ranging from 0 to as much as 51.30 mg·dm-3. It was the “Sadkowo” pond that might be singled out here for its extremely high concentration (the aforesaid maximum value of 51.30 mg·dm-3; along with a mean value of 13.41 mg·dm-3). In this case a local factor is likely to have been operating – i.e. areal runoff pollution from fields involving nitrogenous compounds. Ponds in the Borucinka catchment had only low concentrations of nitrate, with a mean value for all kettle ponds studied there of just 0.24 mg·dm-3 (with values in the overall range 0 to 2.17 mg·dm-3). Concentrations of the analysed component were thus lower in the Borucinka catchment than in the Parsęta basin, with a key influencing factor likely to have been the sizes of the bodies of water studied. The Parsęta-basin examples were in fact smaller kettle ponds whose catchment features and morphometric parameters are such as to ensure higher concentrations of biogenic (especially nitrogenous) compounds in any standing waters. Mean concentrations of ammonium ions obtained for the Parsęta basin were of 0‑2.41 mg·dm-3, the value averaged for the six ponds being 0.95 mg·dm-3. However, four other Parsęta-basin ponds excluded from the study in fact reported very high values for NH4 + – of up to 25.55 mg·dm-3. The Borucinka catchment again contrasted with the Parsęta basin, with noted concentrations of ammonium-nitrogen both low and of limited variability (in the 0‑1.88 mg·dm-3 range). The average figures for all the depressions studied there was 0.09 mg·dm-3. The situation as regards the two forms of nitrogen was thus similar, with concentrations lower in the catchment of the Borucinka and higher in the basin of the Parsęta. Sizes of bodies of water would seem to be a factor influencing spatial differentiation of NH4 + concentrations. Where phosphate was concerned, kettle ponds within the Parsęta basin had a mean concentration of 0.57 mg·dm-3, with reported values from one pond to another ranging from 0 to 4.46 mg·dm-3. The Borucinka p ds again had lower concentrations of this biogenic substance across a narrower range of values (0 to 3.69 mg·dm-3, mean 0.19 mg·dm-3).

Waste compost quality assessment for efficient use in agriculture: case of the developing countries

Article

Full-text available

Sep 2021

This study aims to evaluate the quality of solid waste compounds in the Khenifra region (Morocco) and use them as an organic additive. Composting tests were undertaken at the household waste disposal and recovery site in the Khenifra city. When they enter the site, the waste undergoes a physical treatment which consists of manual sorting to remove the coarse elements, by screening through a sieve with an 80 mm mesh to reduce the waste heterogeneity. The fermentable organic matter resulting from these treatments is put back into windrows. A turnaround every two weeks to gradually homogenize waste and watering helps maintain high humidity. The evaluation criteria on which they were based were: maturity, particle size, organic matter, heavy metals and pathogenic microorganisms. The results revealed that the incorporation of a 25% compost dose into the soil resulted in a 100% germination rate for both crops (corn and sunflower), which shows that the obtained composts were mature and well decomposed. The C/N ratios which varied in the range of 13–15% reinforce the good result. The pH is slightly basic and varies between 7.9 and 8.1. Fine particles represented 61% while particles > 2 mm in size have a proportion of about 40% confirming this result. The average organic matter content in composts is approximately 19–20%, carbon 12%, nitrogen 0.77%, perfectly complying with international standards. The results for heavy metals also show relatively high values but remain within the standards with a predominance of Zn (161 mg.kg-1) and Cu (76 mg.kg-1). Microbiological analyses revealed the presence of fecal coliform bacteria and fungi of the genus Aspergillus. In general, the composts produced by solid waste in developing countries are of good quality and can be used as organic fertilizer for the soil.

Recycling of Organic Wastes through Composting: Process Performance and Compost Application in Agriculture

Article

Full-text available

Nov 2020

Composting has become a preferable option to treat organic wastes to obtain a final stable sanitized product that can be used as an organic amendment. From home composting to big municipal waste treatment plants, composting is one of the few technologies that can be practically implemented at any scale. This review explores some of the essential issues in the field of composting/compost research: on one hand, the main parameters related to composting performance are compiled, with especial emphasis on the maturity and stability of compost; on the other hand, the main rules of applying compost on crops and other applications are explored in detail, including all the effects that compost can have on agricultural land. Especial attention is paid to aspects such as the improvement of the fertility of soils once compost is applied, the suppressor effect of compost and some negative experiences of massive compost application.

Compost is a carrier medium for Trichoderma harzianum

Article

Full-text available

Aug 2020

Trichoderma spp. are one of the most commercialized fungal biocontrol agents. To improve its applicability, while preserving its effectiveness against diseases, a selection of composts were tested as carrier mediums. The population dynamic of T. harzianum was studied in three composts differing in biological characteristics based on the Nematode Index of Compost Maturity (NICM). The results showed a decline in the T. harzianum population, which became stable after six or eight weeks, irrespective of compost, concentration or sterilization. The bioassay with Rhizoctonia solani on bean showed promising results for disease control after storage of the inoculated composts. Nevertheless, T. harzianum was ineffective against R. solani in one compost with a high NICM value, likely related to its sub-optimal physicochemical characteristics and lower root colonization. Compost is a suitable carrier medium for T. harzianum, but the NICM value is not a good indicator to predict the survival rate nor the disease suppression activity of compost inoculated with T. harzianum.

Fe(II)-catalyzed transformation of Fe (oxyhydr)oxides across organic matter fractions in organically amended soils

Article

Dec 2020
SCI TOTAL ENVIRON

The Fe(II)-catalyzed transformation of ferrihydrite into highly crystalline forms may represent an important pathway for soil organic matter (SOM) destabilization under moderately reducing conditions. However, the link between redox-driven changes in soil Fe mineral composition and crystallinity, and SOM chemical properties in the field remains elusive. We evaluated abiotic Fe(II)-catalyzed mineralogical transformation of Fe (oxyhydr)oxides in bulk soils and two particle-size SOM fractions, namely the fine silt plus clay (<20 μm, FSi + Cl) and fine sand (50–200 μm, FSa) fractions of an agricultural soil unamended or amended with biochar, compost, or the combination of both. After spiking with Fe(II) and incubating for 7 days under anoxic and sterile conditions at neutral pH, the FSa fractions (Fe(II): Fe (III) molar ratios ≈ 3.3) showed more significant ferrihydrite transformations with respect to FSi + Cl fractions (Fe(II): Fe (III) molar ratios ≈ 0.7), with the consequent production of well-ordered Fe oxides in most soils, particularly those unamended or amended with biochar alone. Nonetheless, poorly crystalline ferrihydrite still constituted about 45% of the FSi + Cl fractions of amended soils after reaction with Fe(II), which confirms that the higher SOM and clay mineral content in this fraction may possibly inhibit atom exchange between aqueous Fe(II) and the solid phase. Building on our knowledge of abiotic Fe(II)-catalyzed mineralogical changes, the suppression of ferrihydrite transformation in FSi + Cl fractions in amended soils could ultimately lead to a slower turnover of ferrihydrite, possibly preserving the carbon sequestration potential associated with this mineral. Conversely, in both bulk soils and FSa fractions, the extent to which mineral transformation occur seemed to be contingent on the quality of the amendment used.

Elucidation of functional chemical groups responsible of compost phytotoxicity using solid-state 13C NMR spectroscopy under different initial C/N ratios Elucidation of functional chemical groups responsible of compost phytotoxicity using solid-state 13 C NMR spectroscopy under different initial C/N ratios

Article

Full-text available

Feb 2018
ENVIRON SCI POLLUT R

To cite this version: Khalid Azim, Youssef Faissal, Brahim Soudi, Claude Perissol, Sévastianos Roussos, et al.. Elucidation of functional chemical groups responsible of compost phytotoxicity using solid-state 13C NMR spec-troscopy under different initial C/N ratios. Abstract More than 1 million tons of fresh organic wastes is produced in the Souss-Massa region in Morocco. Tomato organic residues represent more than 25% of the total organic wastes and are deposited in uncontrolled landfills. Thus, composting can represent a valuable and pertinent solution to this environmental problem. The objectives of this experiment are to identify the potential functional groups responsible for compost phytotoxicity and to determine the optimum initial carbon to nitrogen ratio (C/N) for maximum recovery of tomato residues. The experiment consisted of the variation of the initial C/N ratios (25, 30, 35, and 40) using mixtures of different raw materials (tomato residues, melon residues, olive mill pomace, and sheep manure). Physicochemical parameters (pH, electrical conductivity, C/N ratio, and humic acid/fulvic acid ratio) were determined and spectroscopic analyses (UV-vis and NMR-13 C) were performed during the composting process along with quality parameters (germination and phytotoxicity tests) at the end. The results showed that the compost with the initial C/N ratio of 35 is the most humified with the least phytotoxic effect. The germination and phytotoxicity tests were negatively correlated with the methoxyl/ N-alkyl-C ratio and O-alkyl-C. These two functional groups are probably the origin of phytotoxicity expression in compost quality tests. Thus, a simple and precise quality test could be performed to evaluate directly the phytotoxicity and maturity of compost.

Cut flower vase life – influential factors, metabolism and organic formulation

Article

Full-text available

Nov 2019

Cut flower vase life can be extended by various natural products, but their efficacy when mixed with compost tea is not reported. A study was performed to determine cut carnation Dianthus caryophyllus cv. White Sim) vase life in 1 L of formulations (1) C3.5: 3.5% compost tea + 15 mg putrescine; (2) R5L10: C3.5 + 5 mL rosemary Salvia Rosmarinus ) + 10 mL lemon Citrus limon ) extracts; (3) R10L10: C3.5 + 10 mL rosemar y + 10 mL lemon extracts; (4) R5L20: C3.5 + 5 mL rosemary + 20 mL lemon extracts; (5) R10L20: C3.5 + 10 mL rosemary + 20 mL lemon extracts; (6) Chrysal: Floral Chrysal Clear (positive control); and (7) Dw: distilled water alone (negative control). The 15 m g putrescine significantly (P=0.002) reduced compost tea turbidity by 34%. The neutral pH of C3.5 and Dw did not change. However, pH increased by 24% in Chrysal and reduced by 39% in R5L10, R10L10 and R5L20 and by 54% in R10L20 on day 11. TDS and EC were h ighest in Chrysal from days 1 to 11. Petal discoloration, wilt, shrinkage and neck bend were delayed by C3.5 followed by Chrysal and then R5L10, but were accelerated by the other treatments. In conclusion, the cut carnation cv. White Sim longevity as influenced by variations in the vase solutions was Chrysal (14 days) > C3.5 (12.6 days) > R5L10 (10.7 days) but ≤ 9 days in the other treatments. These results were confirmed by a 2 D principal component analysis biplot. Future study will investigate microbial interaction.

Preferential uptake of hydrophilic and hydrophobic compounds by bacteria and fungi in upland and paddy soils

Article

Jun 2020
SOIL BIOL BIOCHEM

This study aimed to trace the incorporation of ¹³C-labeled hydrophilic and hydrophobic compounds extracted from maize straw into bacterial and fungal phospholipid fatty acids (PLFAs) in upland and paddy soils. In both soils, the amounts of bacterial ¹³C-PLFAs recovered from hydrophilic C were 1.2–2.8 times higher than those from hydrophobic C. By contrast, the amounts of fungal ¹³C-PLFAs recovered from hydrophobic C were 3.8–12.8 times greater than those from hydrophilic C. These results indicate that bacteria have a preference for the uptake of hydrophilic compounds, whereas fungi prefer hydrophobic compounds in both soils. The fungal preference for hydrophobic compounds is stronger than bacterial preference for hydrophilic compounds. This is partly owing to the efficient incorporation of hydrophobic compounds into actinomycete PLFA of 10Me18:0 in upland soil and bacterial PLFA of 18:1ω7c in paddy soil. Consequently, the specific uptake of hydrophilic and hydrophobic compounds from plant residues by bacteria and fungi will lead to divergent C pathways in soil.

Nitrogen release and leachable organic matter decomposition of anaerobically digested biosolids with variable pre-treatments

Article

Jan 2020

Thermal hydrolysis pretreatments (THP) coupled to anaerobic digestion (AD) are implemented to treat municipal solids, but limited study indicates whether THP-AD materials merit different land application rates than AD biosolids without THP. Three AD biosolids types with either no pretreatment, THP, or two-hour fermentation were evaluated for differences in leachable dissolved organic matter (DOM), DOM decomposition, and nitrogen (N) releases in biosolids incubated in sandy loam soil. DOM characterizations of size exclusion chromatography, FTIR, and fluorescence maxima > Ex: 400 nm indicated similarities in among AD-DOM that contrasted waste activated sludge Milorganite and Suwannee River Organic Matter (SRNOM). Fluorescence peak picking was a more adaptable analysis for shifted leachate spectra than fluorescence regional integration (FRI). Peak ratio analysis is recommended over FRI for biosolids-DOM. The 3-month net inorganic N produced in biosolids-soil incubations was 155 ± 12.1, 149 ± 18.2, 140 ± 17.4, and 354 ± 15.1 mg N/kg for AD biosolids with no pretreatment, fermentation-AD, THP-AD, and Milorganite respectively. Overall, there was limited evidence of differences in leachable organic matter quality or net mineral N release after 105 days for AD solids with or without THP. Red-shifted fluorescence of leachates decayed by day 45 in aerobic biosolids-soil incubations, suggesting that larger, complex carbon sources liberated during solids stabilization may decompose readily in soils. Overall, other variables (source material, AD operation) may have a greater influence on final nutrient releases and organic matter quality than full-scale pretreatments to AD alone. Critical and targeted application of DOM spectroscopy specific to biosolid-leachates will improve use in advanced stabilization studies.

Relation between changes in organic matter structure of poultry litter and heavy metals solubility during composting

Article

Jun 2019

Poultry litter (PL) is widely used as fertilizer because of its rich N, P and Ca content. When PL is applied to previously untreated soil, it is a potential contaminant. Composting is an alternative for stabilizing organic and mineral components. This study aimed to elucidate the structural changes and its influence on the solubility of heavy metals in poultry litter during the first 30 d of composting, which is the period when the most intense transformations occur. For this analysis, the transformation dynamics of the organic structures and the availability of mineral elements were studied via spectroscopic characterization, total heavy metal content determination and chemical fractionation at three composting times (0, 15, and 30 d). During composting, the material's aromaticity increased, while its aliphaticity decreased, and the hydrophobicity index increased as the polarity decreased. These results indicate that during the first 30 d, PL composting occurs via transformation of the most labile structures (carbohydrate, peptide and fatty acid fragments), thereby preserving the most stable and least functionalized structures. Composting increased the concentrations of Cu, Cr, Pb and Zn and the transformation of C Alk-O and C Alk-di-O associated with peptides and carbohydrates and favored solubilizing and leaching a water-soluble fraction rich in these compounds. The labile fractions of Fe and the humified organic matter fractions of Cu, Fe, Mn, Zn, and Al increased. The structural changes reduced heavy metal solubility, thus indicating that after 30 d of composting, the heavy metal contamination risk is low.

Chemical changes during composting of plant residues reduce their mineralisation in soil and cancel the priming effect

Article

Jun 2019
SOIL BIOL BIOCHEM

Manure over crop residues increases soil organic matter but decreases microbial necromass relative contribution in upland Ultisols: Results of a 27-year field experiment

Article

Jun 2019
SOIL BIOL BIOCHEM

Organic fertilizers increase soil organic matter (SOM) stocks, but the underlying processes depend on the fertilizer type and remain largely unknown. To evaluate the predominant C stabilization mechanisms, upland Ultisols subjected to 27 years of mineral and organic fertilization were analyzed for SOM content, aggregate size classes, and amino sugar composition. The long-term field experiment had seven treatments: no fertilization (Control), mineral NPK fertilizers (NPK), NPK plus lime (NPK+Lime), NPK plus peanut straw (NPK+PeanutStraw), NPK plus rice straw (NPK+RiceStraw), NPK plus radish residue (NPK+RadishResidue), and NPK plus pig manure (NPK+PigManure). The 27-year application of mineral fertilizers (NPK and NPK+Lime), NPK+crop residues, and NPK+PigManure increased SOM content by 11.0−13.2%, 16.3−25.3%, and 44.3%, respectively, compared with the Control. The aliphaticity and recalcitrance indices based on 13C nuclear magnetic resonance spectra of organic fertilizers were higher for pig manure than for crop residues. Both indices were closely correlated with SOM content after 27 years, so higher proportions of recalcitrant C in manure facilitated SOM accumulation. NPK+PigManure increased the mass proportion of large macroaggregates 2.9-fold compared with the Control, and reduced the effective diffusion coefficient of oxygen in the soil. Consequently, NPK+PigManure limited the activity and abundance of aerobes and the accessibility of SOM to microorganisms, in turn facilitating SOM accumulation. The application of mineral fertilizers, NPK+crop residues, and NPK+PigManure increased microbial necromass to 2.85−3.03, 3.21−3.45, and 3.62 g C kg−1, respectively, from 2.63 g C kg−1 in the Control. Compared with crop residues, pig manure did not affect bacterial necromass but increased fungal necromass from 2.19−2.39 g C kg−1 to 2.58 g C kg−1, which might associate with increased SOM stability. However, the relative contribution of microbial necromass to SOM was lower under NPK+PigManure than under NPK+crop residues, since more added C was protected in the NPK+PigManure soil. Our results suggest that manure may contribute to SOM accumulation and stabilization in three ways: directly through the input of recalcitrant organic C, indirectly through the stabilization of aggregates and physical protection of C, and to a lesser extent through increasing fungal necromass.

Properties of composts from household food waste produced in automatic composters

Article

Apr 2019

Pathogens Evolution During the Composting of the Household Waste Mixture Enriched with Phosphate Residues and Olive Oil Mill Wastewater

Article

Full-text available

May 2020

The composting of the household waste mixture enriched with phosphate residues and olive oil mill wastewater was assessed by monitoring the activity of micro-organisms during composting. During the composting process, the mixture exhibited a proliferation of actinomycetes during the thermophilic phase and during the maturation phase. Their quantities range from 11 × 10² UFC/g MF at the beginning of the process to 3.45 × 10⁶ UFC/g MF at the end of the process. The Pseudomeunas aeruginosa and total fungi concentration show also an increase during composting from 0.2 × 10⁶ UFC/g MF and 3.7 × 10⁶ UFC/g MF at the start of composting to a maximun of 4.1 × 10⁶ UFC/g MF, 5.1 × 10⁶ UFC/g MF after 30 days. While other pathogenic microorganisms show a distinct decrease as fecal coliforms decrease from 8 × 10⁶ UFC/g MF to 12 × 10³ UFC/g MF; Escherichia coli (E. Coli) from 7.9 × 10⁶ UFC/g MF to 14 × 10³ UFC/g MF; Fecal streptococci (S.F) varied from 7.1 × 10⁶ UFC/g MF to 10 × 10⁴ UFC/g MF ; Staphylococcus aureus (Staph) decreased from 5.2 × 10⁶ UFC/g MF to 8 × 10⁴ UFC/g MF; Clostridial spores (SCR) reduced from 6.8 × 10⁶ UFC/g MF to 11 × 10³ UFC/g MF at the end of composting. A good relationship could be noted between actinomycetes and available phsosphore, and between total fungi and NTK. The pathogenic bacteria, Staph, SCR, CF, E. Coli, S.F., show more correlations with available organic components T.O.C, O.M., C/N, mainly present in the early phases of composting. The germination test shows that the water-soluble extracts of the initial stages of composting give low germination indices (GI) between 8.18 and 3.20%. After one month of composting, a successive increase of (GI) is observed to reach a maximum of 93.67% for compost after 150 days. These results provide an idea of the quality and maturity of this compost.

Long-term application of manure over plant residues mitigates acidification, builds soil organic carbon and shifts prokaryotic diversity in acidic Ultisols

Article

Sep 2018
APPL SOIL ECOL

Addition of organic materials is believed to be a feasible practice for mitigating Ultisols acidification and loss of soil organic carbon (SOC). However, how organic materials mitigate acidification, affect SOC content and aggregation and shift microbial community structure requires further investigation. In this study, we used high-throughput sequencing of microbial DNA to evaluate the relationships between soil properties, aggregation and prokaryotic communities in soil subjected to 27 years of inorganic and organic fertilization. The field experiment included seven treatments: no fertilization (control), inorganic NPK fertilizer (I), inorganic NPK fertilizer plus liming (CaCO3) (IL), and inorganic NPK fertilizer plus peanut straw (IPS), rice straw (IRS), radish (IR), or pig manure (IPM). Amendment with NPK fertilizer plus pig manure more effectively increased soil pH, SOC, total nitrogen (TN), available phosphorus (AP) and dissolved organic carbon (DOC) compared with NPK fertilizer plus crop residues. IPM also increased the mass proportion of large macroaggregates (>2000 μm) from 7.8% in the control to 30.6% while it reduced effective diffusion coefficient of oxygen (DCo) from 12.58 × 10⁻⁶ m² s⁻¹ in the control to 2.81 × 10⁻⁶ m² s⁻¹. Application of pig manure increased prokaryotic diversity and altered prokaryotic community structure, while crop residues did not. Soil pH was the predominant factor influencing prokaryotic community structure. Bacillales and Clostridiales accounted for 47.5% and 21.4%, respectively of the indicator species in the IPM and the relative abundances of them were increased, compared with the other treatments. Furthermore, the relative abundances of Bacillales and Clostridiales were correlated with SOC, TN, AP and DOC, and negatively with DCo in the soil. Overall, our results suggest that application of NPK fertilizer plus pig manure rather than crop residues enhanced soil pH, improved SOC content and aggregation, increased prokaryotic diversity and altered community structure of prokaryote after 27-year fertilization.

Symbiotic fungal endophyte Phomopsis liquidambari- rice system promotes nitrogen transformation by influencing below-ground straw decomposition in paddy soil

Article

Sep 2018

Aims: To explore if and how symbiotic Phomopsis liquidambari-rice system influences below-ground straw decomposition and then nitrogen(N) transformation in response to environmental N levels. Methods and results: Litter bag experiments were utilized to trace the decay process during rice growth phases (seedling (T1), tillering (T2), heading (T3) and maturing (T4) stage), with (E+) and without endophyte (E-), under low (LN), medium (MN) and high nitrogen (HN) supply. Litter, soil and plant samples were collected to evaluate the decay process, N transformations, plant quality and relative abundance of soil ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB) and P. liquidambari. The results showed that straw decomposition increased by 19·76% (LN, T2 stage), 14·05% (MN, T3 stage) and 16·88% (MN, T4 stage) in E+ pots when compared with E- pots. Further analysis revealed that no significant endophyte × N interaction was found for straw decay rate and that the decay rate was reduced by a higher N supply (LN, 37·16 ± 0·65%; MN, 32·27 ± 1·72%; HN, 29·44 ± 1·22%) at the T1 stage, whereas straw decay rate and N release increased by 9·38 and 11·16%, respectively, mainly by endophyte colonization at the T4 stage. The abundance of AOA and AOB were altered, corresponding with the decay rate. Soil mineral N, straw mineral N and plant quality were shown to increase in E+ pots, depending on environmental N conditions and growth phase. The yield increased by 2·98% for E+ plants under MN level. Conclusions: Symbiotic P. liquidambari-rice system promoted below-ground straw decomposition and N transformation, depending on environmental N levels and plant growth phase. Significance and impact of the study: This study provides evidence that fungal endophyte-plant systems are able to promote N transformation by increasing straw decomposition. A reasonable combination of N inputs could enhance its advantage in agriculture ecosystems.

Effects of Soil Fertilization Using Compost of Solid Household Waste on the Heavy Metals Content of the Productions

Article

Jul 2018

Compost as a carrier medium for entomopathogenic nematodes – The influence of compost maturity on their virulence and survival

Article

Jun 2018

The effectiveness of entomopathogenic nematodes (EPN) against pest insects is largely dependent on the method of application and nematode survival under field conditions. Nematodes must persist long enough to control pest populations, despite sensitivity to abiotic factors such as desiccation and UV light. Here we investigate the use of compost as a carrier medium for the entomopathogenic nematode Steinernema feltiae, since co-application with compost could potentially mitigate some of the negative environmental constraints of EPN application. We tested three application methods in combination with six composts of different biological maturity (defined using the Nematode Index of Compost Maturity (NICM). EPN in composts were applied to a soil and incubated in 1L pots for 12 weeks. The application methods used were aqueous application (AA), non-formulated infected host cadavers (NFC) and formulated infected host cadavers (FC). Destructive sampling was used at 4, 6, 9 and 12 weeks to test for entomopathogenic nematode survival (via extraction and enumerations) and nematode virulence based on Galleria mellonella mortality. After 12 weeks of incubation, survival ranged from 3.2% in control pots with AA, to 62% found in a mature compost applied with formulated cadavers. FC and NFC application and the use of more mature composts resulted in an improved survival. Application method had significant effects on virulence, NFC and AA had higher G. mellonella mortality than FC. A NICM immature compost significantly decreased virulence compared to a NICM mature compost, although neither were significantly better than the control. These results suggest that both application method and biological quality of a compost have to be considered for co-application of compost and EPN. Thus, the use of compost enriched with host cadavers may be an environmentally friendly way to suppress pest insects on farms while simultaneously improving soils through compost application, though economic viability would still need assessment.

Trace metal mobilization by organic soil amendments: Insights gained from analyses of solid and solution phase complexation of cadmium, nickel and zinc

Article

Feb 2018
CHEMOSPHERE

The accumulation of Cd in soils worldwide has increased the demand for methods to reduce the metal's plant bioavailability. Organic matter rich soil amendments have been shown to be effective in achieving this. However, it is not known how long these amendments can retain the Cd, and whether dissolved organic matter (DOM) released from them can enhance the metal's mobility in the environment. In this study we sought to test the Cd binding capacity of various organic soil amendments, and evaluate differences in characteristics of the DOM released to see if they can explain the lability of the Cd-DOM complexes. We collected ten organic soil amendments from around New Zealand: five different composts, biosolids from two sources, two types of peat and spent coffee grounds. We characterised the amendments' elemental composition and their ability to bind the Cd. We then selected two composts and two peats for further tests, where we measured the sorption of Ni or Zn by the amendments. We analysed the quality of the extracted DOM from the four amendments using 3D Excitation Emission Matrix analysis, and tested the lability of the metal-DOM complexes using an adapted diffusive gradients in thin-films (DGT) method. We found that composts bound the most Cd and that the emergent Cd-DOM complexes were less labile than those from the peats. Ni-DOM complexes were the least labile. The aromaticity of the extracted DOM appears to be an important factor in determining the lability of Ni complexes, but less so for Zn and Cd.

Utilization and valorization of pharmaceutical process residues: Current status and future trends

Article

Jan 2024
J CLEAN PROD

Mesophilic-thermophilic temperature-phased microbial aerobic biodegradation of food waste: feasibility study for rapid in-situ disposal strategy

Preprint

Full-text available

Apr 2022

Effective treatment of food waste (FW) is inherently difficult due to heterogeneous composition, high moisture content, and low heating value. Herein, a feasible FW disposal system via microbial biodegradation from vessel to pilot scale was developed. Facilitated by a novel microbial consortium of Bacillus amyloliquefaciens , Bacillus subtilis , and Aspergillus niger , the total solid removal was improved by 3.4-folds (46.6%) compared with negative control. To couple with bacterial growth and biodegradation related enzyme activity and reduce the electrical energy consumption, a mesophilic-thermophilic temperature-phased aerobic digestion processing was performed in a 40 L self-designed biodegradation tank via daily fed-batch mode, and up to 62.88% of protein, 62.22% of starch and 37.75% of waste oil was respectively decomposed, achieving a total mass reduction of 82.15%. Characterization of the final by-product confirmed its potential to be recycled into resources as organic fertilizers or biosolid fuel. The proposed microbial consortium agent and decentralized mass reduction strategy presented in this study offers practical and environmental approaches for FW management in urban areas.

CO-COMPOSTING PROCESS ASSESSMENT OF THREE-PHASE OLIVE MILL POMACE AND TURKEY MANURE IN MOROCCO 摩洛哥三相橄欖磨漿果渣和火雞糞的混合堆肥過程評估

Article

Full-text available

Dec 2021

Olive oil and turkey livestock activities in Morocco generate huge quantities of olive pomace and turkey manure, which cause soil, water, and environmental pollution. Composting is a suitable solution for these bio-wastes. This work aimed to study co-composting parameters evolution of three-phase olive pomace (OP) and turkey manure (TM) and evaluate final composts' quality. Four heaps (OP+TM+wheat straw) were composted at different initial carbon-nitrogen (C/N) ratios (20 and 28), moistened as needed, and turned manually once or twice a week in the open air. The studied parameters have experienced ups and downs over time depending on different phases of composting and according to the initial heaps' composition. Final composts were stable and mature with pH around neutrality, significant total nitrogen and nitrate content enhancement, and a significant reduction in organic matter for the two heaps with final values higher than 43.66%. There was a significant decrease in the C/N ratio for all heaps with final values between 11 and 13, proving the composts' stability. The increase in CEC (Cation exchange capacity) was significant with final values > 90.76 meq 100g-1 , proving good humification as well as that of CEC/Organic carbon ratio (CEC/OC) with final values >1.7 proving final composts' maturity. These results are beneficial firstly for Moroccan small-scale olive oil factories and poultry livestock farming, as it confirms the effectiveness of low-cost heap composting to manage their by-products. Secondly, farmers can use the obtained compost as an organic amendment to improve the soil's physicochemical properties and increase productivity.

Long-Term Effects of Amendment with Olive Mill Wastewater on Soil Chemical Properties, Microbial Community, and Olive Tree Vegetative and Productive Activities

Article

Full-text available

Dec 2021

The long-term effects of the olive mill wastewater (OMWW) spreading on soil chemical properties, microbial community, and olive tree parameters have been far poorly investigated. Therefore, this study aims to evaluate the effect of OMWW application on an olive orchard, and samples were collected at two different depths (0–20 cm and 20–40 cm) and 14 days, one year and two years from the end of the OMWW spreading on soil chemical characteristics and soil microbial structures. Variations of soil chemical parameters (pH, salinity, available P, and water-extractable organic C) were observed particularly at 14 days after spreading at both depths. All these parameters reached similar values to the soil after two years, except for available phosphorus. Firmicutes, Proteobacteria, and Actinobacteria are the most abundant phyla: only Firmicutes were negatively affected by the OMWW spreading after 14 days, suggesting that Gram-positive bacteria were probably negatively influenced by the addition of OMWW. The abundance of bacterial taxa in the soil is restored along time, except for the decrease of Firmicutes. This evidence suggests that the OMWW spreading in the long term does not affect the endemic soil bacterial community of the olive grove, as well as leaf net photosynthesis, the olive tree vegetative activity, yield, and fruits characteristics.

Contribution of redox-active properties of compost-derived humic substances in hematite bioreduction

Article

Sep 2021
CHINESE CHEM LETT

The compost-derived humic substances (HS) can function as electron mediators for promoting hematite bioreduction because of its redox capacity. Humification process can affect redox capacities of compost-derived HS by changing its intrinsic structure. However, the redox properties of compost-derived HS linking with hematite bioreduction during composting still remain unclear. Herein, we investigated the redox capacities of compost-derived HS, and assessed the responses of the redox capacities to the hematite bioreduction. The result showed that compost-derived HS (i.e., humic acids (HA) and fulvic acids (FA)) were able to accept electrons from Shewanella oneidensis MR-1, and the electron accepting capacity was increased during composting. Furthermore, it could be functioned as electron mediators for promoting the hematite bioreduction, achieving 1.19-2.15 times compared with the control experience. Not only the aromatic structures (quinone) but also the non-quinone structures such as nitrogen- and sulfur-containing functional moieties were served as the redox-active functional groups of compost-derived HS. Our work proved that the aromatic functional groups and the heteroatom structures (especially N) were important to the hematite bioreduction. This study highlights the redox-active properties of compost-derived HS and its impact on the microbial reduction of iron mineral. Redox capacity of compost-derived HS might mitigate the environmental risk of contaminants when the composting production was added into the contaminated soils as low-cost repair materials • Download : Download high-res image (144KB) • Download : Download full-size image .

Chemical composition of kettle holes as an indicator of salinity of small water bodies in northern Poland (the Parsęta catchment, the Borucinka drainage basin)

Article

Full-text available

Jan 2020

Kettle holes are commonly found in areas embraced by the last Pleistocene glaciations. They are a natural element of the landscape; together with their closed drainage basins they occupy a large proportion of the area. There are many natural conditions that determine their salinity, those listed most often including alimentation, morphometric features, the dynamics of processes taking place in a drainage basin, paths of water supply, the land-use pattern, agricultural pollution, primary production, and the kind of soil cover. The primary goal of this paper is to determine the level of salinity of kettle holes located in the area of young glacial accumulation on the basis of variations in the chemical composition of their waters. An additional goal is to establish factors, including differences in the hydrographic network and the use and development of land, affecting their salinity. The research was conducted in 6 kettle holes in the Parsęta catchment and in 10 depressions in the Borucinka drainage basin in northern Poland. Laboratory analyses concerned primarily the concentrations of ions determining the hydrogeochemical types of water. The examined kettle holes have lower electrolytic conductance than the water of lakes in the study area. This may be indicative of the dominant role of atmospheric alimentation of their waters. The ions dominating in the chemical composition of water in both drainage basins were HCO3⁻ and Ca²⁺, with elevated levels of Cl⁻, Na⁺, Mg²⁺, SO4²⁻, and sporadically of K⁺. The land-use pattern was found to have a significant effect on the level and range of concentrations of the ions under study. The highest average concentrations and their fluctuations were noted in basins located near farms.

Sugarcane bagasse amendment improves the quality of green waste vermicompost and the growth of Eisenia fetida

Article

Aug 2020

Vermicomposting is a feasible method for disposing of lignocellulosic waste while generating a useful product. The current study assessed the potential of vermicomposting green waste mixed with sugarcane bagasse in proportions of 25%, 50%, and 75% (v:v, based on dry weight). The suitability was evaluated based on the agrochemical properties, earthworm biomass, and phytotoxicity. The final vermicomposts exhibited near-neutral pH values (7.1–7.6), and lower EC values (0.43–0.72 mS/cm) and C:N ratios (14.1–19.9).The content of available nutrients and CEC for all the vermicomposts exceeded those of the control compost (without earthworms). For vermicomposts, the average values of NO3−-N, AP, AK, and CEC were 53, 517, 1362 mg/kg, and 158 cmol/kg, respectively. The total contents of heavy metals increased in all vermicompost treatments compared to control composts with the following average final percentages: Zn (2.0%), Cr (15.5%), Pb (23.4%), and Cu (44.3%), but these amounts were safe for application in agroforestry. The addition of sugarcane bagasse to green waste significantly increased the content of total humic substance, humic acid and urease activity, acid and alkaline phosphatase activity, and Eisenia fetida reproduction. The addition of 25% sugarcane bagasse to green waste decreased the toxicity to germinating seeds. These results revealed that vermicomposting is a feasible way to degrade green waste into a value-added chemical product.

Parallel faction analysis combined with two-dimensional correlation spectroscopy reveal the characteristics of mercury-composting-derived dissolved organic matter interactions

Article

Oct 2019
J HAZARD MATER

Dissolved organic matter (DOM) is regarded as the environmentally friendly substance. Strong complexes could be formed between DOM and heavy metals. Thus, the distribution, bioavailability, toxicity, and fate of heavy metals could be controlled in the environment. The widely spread method for characterizing metal-organic interactions is restricted to combine parallel faction analysis (PARAFAC) with the complexation model. However, a DOM PARAFAC component always contains two or more peaks. Therefore, the traditional method cannot reveal the inner changes of PARAFAC components or whether all the DOM peaks in one PARAFAC component are bound with metal during the metal-organic binding process. In this work, two-dimensional correlation spectroscopy (2DCOS) combined with PARAFAC and the complexation model were employed to reveal the binding speed and ability of different fluorescent peaks from DOM PARAFAC components during the binding process of mercury (Hg2+) to DOM. The results in this study showed that during the Hg2+-DOM binding process, fluorescent peaks in tryptophan-like component all presented Hg2+-binding ability. However, only humic-like component ligands showed Hg2+-binding ability. With these promising results, the true Hg2+ binding rate and ability of different DOM ligands can be revealed, which is helpful for addressing environmental pollution.

Recognition of the neutral sugars conversion induced by bacterial community during lignocellulose wastes composting

Article

Full-text available

Sep 2019
BIORESOURCE TECHNOL

The aim of this study was to explore the conversion characteristics of neutral sugars during different lignocellulose wastes composting from rice straw (RS), leaf (L) and mushroom dreg (MD). The results showed that the changes of neutral sugars were different during different wastes composting, but the changes of various hexose or pentose were similar during composting of the same material. The diversity of bacterial community led to different conversion characteristics of neutral sugars. During RS composting, each neutral sugar was transformed by a specific group of bacteria. However, a group of bacteria could transform multiple neutral sugars during MD and L composting. Furthermore, GM/AX value was first applied to composting, which could be used to characterize the conversion of neutral sugars during composting. This will help to provide more efficient recommendations for lignocellulose wastes treatment and accelerating humic substances synthesis during composting.

The Use of Microorganisms for the Biodegradation of Sewage Sludge and the Production of Biocompost for Sustainable Agriculture

Chapter

Aug 2019

Recycling by composting presents a sustainable and a cost-effective approach to reduce the high quantity of sewage sludge. In addition, the relationship between compost stability and functional microflora is reflected in the evolution of several parameters as C/N and NH4⁺/NO3⁻ ratios. However, the microorganisms that populate the substrates during composting reflect the evolution and the performance of structural stability of amended soils, the water retention capacity, and the biodegradation-humification process in compost and soil. Therefore, monitoring humic substance variation during composting is one of the methods used to estimate microorganism activity. In this study, two different mixtures were prepared. The physicochemical indices of maturity changed during composting to reach C/N around 10 and NH4⁺/NO3⁻ < 1. These two physicochemical indices of maturity presented a linear correlation with mesophilic actinobacteria with R² = 0.3 and 0.29 for C/N and R² = 0.29 and 0.41 for NH4⁺/NO3, respectively, for mixtures A and B. However, for thermophilic actinobacteria, R² = 0.78 and 0.25 for C/N, and R² = 0.73 and 0.37 for NH4⁺/NO3⁻, respectively, for mixtures A and B. The progress of physicochemical and microbial parameters is justified by the germination of turnip seeds, which exceed 100% by using final composting products. These findings clearly demonstrate that exploitation of treated sewage sludge as a soil amendment could regulate the carbon, nitrogen, phosphorus, and organic matter requirements for a sustainable agriculture in Morocco where, for example, more than 6.25 million tons of organic matter is needed.

Benefits and risks of long-term recycling of pharmaceutical sewage sludge on agricultural soil

Article

Aug 2019
SCI TOTAL ENVIRON

European policy is direct towards increasing the agricultural reuse of sludge on soil for improving the fertility; however, the effects of long-term pharmaceutical sewage sludge (PSS) application on soil properties are still unknown. Thus, the aim of this work was to evaluate the agronomic and environmental effects on soil after 17 years of organic amendment with PSS derived from daptomycin production. Five different doses of PSS were spread on lands located in Anagni, Central Italy. Physico-chemical soil properties were investigated, as well as total and bioavailable heavy metals, changes in the soil organic matter quality and biochemical functioning. PSS application showed a positive agronomic potential, improving SOM quality, increasing soil humified organic matter and raising plant nutrients. SOM dynamic was different at low and high PSS supplies, as confirmed by the chemical and biochemical analysis (e.g. C biomass, FDA hydrolysis activity, basal respiration, dehydrogenase, urease and phosphatase activities). However, in a long-term agricultural reuse, environmental risks of PSS recycling were related to the increase of some heavy metals (Hg, Zn and Cu) and exchangeable Na.

Remarking An Analisation Mustard Straw Composting and Its Evaluation for Quality Parameters Sneh Goyal Suman Chaudhary Rinku Dhanker

Article

Full-text available

Dec 2016

The mustard straw compost, prepared by using two different inocula (cattle dung+ consortium of three fungi and cattle dung alone) was evaluated for various maturity and quality parameters. The C/N ratio of compostable material dropped down from 82.41 to 17.01 and 82.60 to 21.06 after using consortium of fungi + cattle dung and cattle dung alone respectively for 90 days. Total humic substances in finished product were 260 and 239 mg/g compost with consortium of fungi + cattle dung and cattle dung alone respectively. Carbon dioxide evolution in finished product with cattle dung and consortium of fungi as inoculum was 142mg/100g and 168mg/100g in compost with cattle dung alone. About 84% seeds of wheat and 74% seeds of mustard showed germination in compost water extract under laboratory conditions. The study shows that out of two inocula used, consortium of three fungi + cattle dung was better than using cattle dung alone for carrying out mustard straw composting.

Maturity and stability evaluation of composted yard trimmings

Article

Full-text available

Mar 2003

The objective of this research was to evaluate a variety of stability and maturity indices for yard trimmings compost produced in the Puget Sound region of western Washington State. Compost samples were collected periodically during a 133-d composting cycle at a commercial composting facility, showing that indices of compost respiration rate were sensitive indicators of compost quality. All respiration rate indices identified a period of high respiration rates during active composting (first 27 d), and a period of relatively stable respiration rates during the latter part of curing (70 to 133 d). Chemical tests of compost solids showed less promise as maturity indicators, but provided valuable information on final compost quality. Mature yard trimmings compost had a C:N of 12, an NH4-N to NO3-N ratio of less than 4, a cation exchange capacity (CEC) of 400 cmol per kg of compost-C, and a pH between 6.5 and 7.0. Seed germination tests and sensory tests (color and odor) were of limited value in assessing compost maturity. Fully-cured compost produced with forced aeration had a Solvita CO2 test value of 6 to 7 and a respiration rate via the alkaline trap method of 2 Mg CO2-Cg compost-C-1 d-1. It reheated less than 2°C in an insulated Dewarflask in a 7 d incubation. Further evaluation and calibration of respiration test protocols for compost quality assurance testing programs are recommended.

Difference in the chemical composition of dissolved organic matter from waste material of different sources

Article

Full-text available

Jan 2002

The chemical composition of waste-material-derived dissolved organic matter (DOM) was characterized by chemolytic analyses and 1H, 13C and 31P nuclear magnetic resonance (NMR) spectroscopy. Dissolved organic matter was extracted by water from an aerobic fermented urban waste compost, a sewage sludge and a pig slurry and then fractionated using the XAD-8 method. The amount of water-extractable dissolved organic carbon (DOC) ranged from 3% in the sewage sludge to 22% in the pig slurry. Dissolved organic matter isolated from pig slurry was equally distributed between hydrophilic and hydrophobic DOC, whereas in the sewage-sludge-derived material the hydrophobic fraction was predominant. Dissolved organic C from the urban waste compost was mainly within the hydrophilic fraction. Wet-chemical analysis and 1H- and 13C-NMR spectra showed that both DOM fractions from the urban waste compost were low in neutral, acidic and amino sugars as well as in lignin-derived compounds. In turn, the materials were rich in low-molecular-weight aliphatic compounds. The chemical structure of both fractions is probably the result of the intensive transformation of urban waste compost during its fermentation. The hydrophilic fractions of DOM from sewage sludge and pig slurry contained considerable amounts of carbohydrates but were also rich in low-molecular-weight aliphatics. The respective hydrophobic fractions had the largest contents of CuO-extractable phenols which may in part derive from sources other than lignin. By contrast with the other materials, the hydrophobic fraction from the pig slurry seemed to contain polymeric rather than low-molecular-weight material. The 31P-NMR spectrum of the hydrophilic DOM fraction from urban waste compost did not show signals of inorganic or organic P compounds while the spectrum of the hydrophobic fraction revealed traces of monoester P, diester P, and orthophosphate. 31P-NMR spectroscopy suggested that both the hydrophobic and hydrophilic fractions from pig slurry did not contain organic P. The hydrophilic DOM fraction from sewage sludge contained orthophosphate, organic monoester P and a little pyrophosphate. The hydrophobic fraction contained mainly organic diester P and smaller amounts of teichoic acids and organic monoester P. Considering that water-soluble fractions of urban waste compost contained no easily plant-available P and a low content of labile organics, we conclude that this material contains less labile nutrients and is more refractory than the soluble constituents of pig slurry and sewage sludge.

Effect of phenolic compounds on the germination of six weed species

Article

Full-text available

Jun 1999

Low molecular weight phenolic compounds have been identified in fresh leaves and in soils in which leaves of five varieties of Capsicum annuum L. were decomposing. Six phenolic compounds were tested in laboratory bioassays for their allelopathic effects on germination and seedling growth of six weeds. Ferulic acid, gallic acid, p-coumaric acid, p-hydroxybenzoic acid, vanillic acid, and p-vanillin were bioassayed in concentrations of 10, 1, 0.1, and 0.01 mM. Equimolar mixtures containing all these phenolics were prepared at the final total concentration of 10, 1, 0.1, and 0.01 mM to test for possible interactive effects. Chenopodium album L., Plantago lanceolata L., Amaranthus retroflexus L., Solanum nigrum L., Cirsium sp. and Rumex crispus L. were the selected target weeds. The highest concentration of the compounds inhibited the germination of all these weeds, but lower concentrations had no effect or were stimulatory. However, effects varied with the weed species, the concentration of the compound tested and the compound itself. In assays with the mixture of phenolics we found evidence of some additive effects.

Seasonal variations in the chemical composition of dissolved organic matter in organic forest floor layer leachates of old-growth Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) stands in northeastern Bavaria, Germany

Article

Full-text available

Aug 2001

Organic matter dissolved in thepercolation water of forest soils contributeslargely to element cycling and transport ofnatural and anthropogenic compounds. The wayand extent to which these processes areaffected depends on the amount and the chemicalcomposition of soluble organic matter. Becausethe amount of soluble organic matter variesseasonally with changes in the microbialactivity in soil, it seems reasonable to assumethat there may be also seasonal changes in thechemical composition of dissolved organicmatter. We examined dissolved organic matter inthe seepage waters of organic forest floorlayers over a 27-month period (1997–1999) intwo forest ecosystems, a 160-year-old Scotspine (Pinus sylvestris L.) stand and a90-year-old European beech (Fagussylvatica L.) forest. The forest floorleachates were analysed for bulk dissolvedorganic C, C in hydrophilic and hydrophobicdissolved organic matter fractions,lignin-derived phenols (CuO oxidation),hydrolysable neutral carbohydrates and uronicacids, hydrolysable amino sugars, and stablecarbon isotope composition. In addition, westudied the samples by use of liquid-state13C-nuclear magnetic resonance (NMR)spectroscopy.For both investigated forest sites we foundthat the dissolved organic carbonconcentrations in forest floor leachates werelargest during summer. They peaked after rainstorms following short dry periods (106–145 mgdissolved organic C l–1). The proportionsof C in the hydrophilic fractions were largestin winter and spring whereas in summer andautumn more C was found in the hydrophobicfraction. According to liquid-state 13C-NMR spectroscopy, summer and autumn samples hadlarger abundances of aromatic and aliphaticstructures as well as larger proportions ofcarboxyl groups whereas the winter and springsamples were dominated by resonances indicatingcarbohydrates. Wet-chemical analyses confirmedthese results. Winter and spring samples wererich in neutral carbohydrates and amino sugars.The summer and autumn samples contained morelignin-derived phenols which were also strongeroxidised than those in the winter and springsamples. Seasonal changes of 13C valueswere found to reflect the changes in thechemical composition of dissolved organicmatter. Most negative values occurred whenisotopically light lignin-derived compoundswere abundant and less negative values whencarbohydrates predominated.The different vegetation, age of thestands, and underlying mineral soils resultedin different concentrations of dissolvedorganic carbon and in differences in thedistribution between hydrophobic andhydrophilic organic carbon. Despite of this,the results suggest that the trends in temporalvariations in the composition of dissolvedorganic matter in forest floor seepage waterwere remarkably similar for both sites.Dissolved organic matter in winter and springseems to be mainly controlled by leaching offresh disrupted biomass debris with a largecontribution of bacterial and fungal-derivedcarbohydrates and amino sugars. Dissolvedorganic matter leached from the forest floor insummer and autumn is controlled by thedecomposition processes in the forest floorresulting in the production of stronglyoxidised, water-soluble aromatic and aliphaticcompounds. The chemical composition ofdissolved organic matter in forest floorseepage water in winter and spring indicateslarger mobility, larger biodegradability, andless interaction with metals and organicpollutants than that released during summer andautumn. Thus, the impact of dissolved organicmatter on transport processes may varythroughout the year due to changes in itscomposition.

Biodegradation of Lignin in a Compost Environment: A Review

Article

Full-text available

Apr 2000
BIORESOURCE TECHNOL

Composting is nowadays a general treatment method for municipal solid waste. Compostable household waste contains, together with vegetable material, varying amounts of papers and boards. In the European Union composting is regarded as one recycling method for packages and this will probably favour compostable packages, like papers and boards, in the future. Paper is made up of lignocellulose and it may contain up to 20% of lignin. Efficient degradation of papers in composting plants means that biodegradation of lignin is also needed. However, very little is known about lignin degradation by mixed microbial compost populations, although lignin degradation by white-rot fungi has been extensively studied in recent years. Organic material is converted to carbon dioxide, humus, and heat by compost microorganisms. It is assumed that humus is formed mainly from lignin. Thus, lignin is not totally mineralized during composting. The elevated temperatures found during the thermophilic phase are essential for rapid degradation of lignocellulose. Complex organic compounds like lignin are mainly degraded by thermophilic microfungi and actinomycetes. The optimum temperature for thermophilic fungi is 40–50°C which is also the optimum temperature for lignin degradation in compost.

Characterization of Compost Leachate Fractions Using NMR Spectroscopy

Article

Jun 1995

A distilled water leachate was prepared from a hardwood-leaf compost. The 13C NMR (nuclear magnetic resonance) spectra of organic acids isolates from this leachate provided support for the hypothesis that the composition of the dissolved organic carbon (DOC) in the leachate is very similar to that in natural soil pore waters. The leachate DOC was adsorbed by a model mineral surface, and the organic coating on the surface was characterized by solid-state 13C NMR spectroscopy.

Relating Compost Measures of Stability And Maturity to Plant Growth

Article

Jul 2013

Assessment of compost maturity is important for successful use of composts in agricultural and horticultural production. We assessed the “maturity” of four different sawdust-based composts. We composted sawdust with either cannery waste (CW), duck manure (DM), dairy (heifer) manure (HM) or potato culls (PC) for approximately one year. Windrows were turned weekly for the first 60 days of composting, covered for four winter months and then turned monthly for six more months. We measured compost microbial respiration (CO2 loss), total C and N, C:N ratio, water soluble NO3-N and NH4-N, dissolved organic carbon (DOC), pH and electrical conductivity at selected dates over 370 days. Compost effects on ryegrass biomass and N uptake were evaluated in a greenhouse study. We related compost variables to ryegrass growth and N uptake using regression analysis. All composts maintained high respiration rates during the first 60 days of composting. Ammonium-N concentrations declined within the first 60 days of composting, while NO3-N concentrations did not increase until 200+ days. After 250+ days, DM and PC composts produced significantly more ryegrass biomass than either CW or HM composts. Total C, microbial respiration and water-extractable NO3-N were good predictors of compost stability/maturity, or compost resistance to change, while dissolved organic carbon, C:N ratio and EC were not. The compost NO3-N/CO2-C ratio was calculated as a parameter reflecting the increase in net N mineralization and the decrease in respiration rate. At ratio values >8 mg NO3-N/mg CO2-C/day, ryegrass growth and N uptake were at their maximum for three of the four composts, suggesting the ratio has potential as a useful index of compost maturity.

Characterization of Dissolved Organic Matter Extracted from Composted Municipal Solid Waste

Article

Mar 1998

The properties and transformation of dissolved organic matter (DOM) extracted from municipal solid waste compost at five stages of composting were studied using a chemical fractionation scheme. We fractionated the DOM into hydrophobic or hydrophilic neutrals, acids, and bases, and obtained solid-state cross polarization magic angle spinning (CPMAS) 13C-nuclear magnetic resonance (NMR) spectra of the unfractionated DOM and of the different fractions. The hydrophobic acid (HoA) fraction was the dominant hydrophobic fraction, exhibiting a moderate increase during composting. The hydrophobic neutral (HoN) fraction increased sharply while the hydrophobic bases (HOB) fraction decreased during composting. The hydrophilic neutrals (HiN) represented the major fraction of the hydrophiles until 120 d of composting, decreasing thereafter by 38%. The 13C-NMR spectra of the unfractionated DOM revealed an increasing level of aromatic structures in the residual DOM with composting time. The 13C-NMR spectra of the HoA fraction suggested a polyphenol-humic structure, whereas the HoN spectra exhibited strong aliphatic features. The spectra of the HiN fraction confirmed its polysaccharide nature and the hydrophilic bases (HiB) fraction contained mainly proteins and carbohydrate-amino complexes. A comparison between the 13C-NMR spectra of HoA and fulvic acid (FA) indicated the former to be the most soluble FA fraction. The steady DOM concentration and the relative decrease of HiN as the HoA and HoN fractions increased indicates that DOM at the final stage of composting contained less bioavailable organic matter and more macromolecules related to humic substances. The constant level of DOM observed during the curing and maturation stages represents a steady-state situation during which the chemical composition is continually changing.

Chemolytic Analysis of Organic Matter during Aerobic and Anaerobic Treatment of Municipal Solid Waste

Article

Jul 2000

The aim of our study was to elucidate the mineralization, transformation, and stabilization of organic matter (OM) of municipal solid waste (MSW) during four types of aerobic and anaerobic treatment with respect to methane and leachate emissions of treated waste in the landfill. The treatments were (i) windrow composting with and (ii) without pressure aeration, (iii) alternating aerobic and anaerobic treatment in bioreactors, and (iv) anaerobic digestion in a solid-state fermentation system. The composition of OM was assessed using the following geochemical methods: two-step acid hydrolysis and colorimetric detection of carbohydrates, colorimetric detection of proteins, CuO oxidation analysis of lignin, and gravimetric determination of lipids. Organic matter losses between 53 and 75% were achieved by all treatments. Carbohydrates are the most relevant compound class for landfill emissions and exhibited the highest mass losses (71 to 88%) during treatment. Hence, a substantial reduction of landfill emission potential was assumed. Protein and lipid losses were lower due to microbial resynthesis and recalcitrance. Lignin was degraded only to a minor extent and experienced no important structural changes. In summary, during the degradation of MSW, the OM composition shifted from easily degradable to recalcitrant compounds, indicating stabilization of MSW. Compared with humified OM of natural topsoil horizons, treated MSW showed slightly higher cellulose and lipid contents. Pressure aeration was essential for achieving optimal degradation rates during aerobic composting. Anaerobic digestion combines high degradation rates and possible energy recovery from methane.

Estimating the Percent Aromatic Carbon in Soil and Aquatic Humic Substances Using Ultraviolet Absorbance Spectrometry

Article

Jan 1992

The aromatic C content of humic substances is an important chemical property that can be used to explain formation, source, and potential interactions of the humic substances with pesticides and other contaminant organics. The relationship between the UV absorptivity at 272, 254, and 205 nm of six aquatic fulvic acids, eight soil fulvic acids, and four water soluble organic C (WSOC) fractions, and their aromatic C content, as determined by 13C cross-polarization magic angle spinning nuclear magnetic resonance (CPMAS NMR) spectroscopy was evaluated. The percent aromatic C (determined by NMR) for the pooled soil and aquatic fulvic acids and WSOC fractions data was poorly correlated (r < 0.7) with the UV absorptivity measurements at all three wavelengths. When the soil fulvic acid was considered individually, however, a relatively high correlation (r = 0.80 to 0.85, P < 0.05) resulted for the prediction of aromatic C content using UV absorptivity. Poor correlations were found for the other individual fractions. Our data suggest that the prediction of aromatic C content using UV absorptivity was applicable only for base-extracted soil fulvic acids and not for the aquatic fulvic acids and soil WSOC fractions used in this study.

Diagenesis of conifer needles in a coastal marine environment

Article

Oct 1989
GEOCHIM COSMOCHIM AC

Physically intact fir, hemlock and cedar needles were isolated from different horizons of a sediment core from a coastal marine bay (Dabob Bay, Washington State, U.S.A.) and from nearby trees and forest litter. Green fir, hemlock and cedar needles were all characterized by glucose-rich aldose mixtures (~30% of tissue carbon), the production of vanillyl and cinnamyl CuO-derived phenols (~8% of tissue carbon) and the presence of both pinitol and myo-inositol (1–2% of tissue carbon). Needles from forest litter were enriched in lignin phenols and non-glucose aldoses and depleted in glucose and cyclitols.

Lignin in Particle-Size Fractions of Native Grassland Soils as Influenced by Climate

Article

Sep 1999
SOIL SCI SOC AM J

The turnover of soil organic carbon (SOC) in grasslands can be predicted as a function of climate, plant lignin content, texture, and kinetically defined C pools. Particle-size fractionation has been used to identify soil C pools. This study was conducted to investigate influences of climate on the dynamics of lignin in particle-size fractions. Composite samples were taken from the top 10 cm of 18 native grassland sites along temperature and precipitation transects from Central Saskatoon, Canada, to South Texas. Lignin-derived phenols were determined in the <2 μm (clay), 2- to 20-μm (silt), 20- to 250-μm (fine sand) and 250- to 2000-μm (coarse sand) size separates. With decreasing particle size the concentration of lignin-derived phenols decreased significantly from 72 g kg 1SOC in the coarse sand fractions to 12 g kg 1SOC in the clay fractions. Increasing phenolic acids to aldehyde ratios indicated that side chain oxidation proceeded as particle size decreased. Moreover, these ratios decreased in fractions <250 μm with increasing mean annual temperature (MAT) at the sites. This suggests that the degree of lignin decomposition decreased with increasing MAT, possibly because there was a lack of additional C sources, such as saccharides of root litter, which are needed for the cometabolic decay of lignin.

Properties of Fine and Water-Soluble Fractions of Several Composts

Article

Dec 1991

Aoyama Masakazu

Four composts, prepared from cow feces (A), city refuse (B), cow feces plus saw-dust (C), and swine feces plus saw-dust (D), were each separated into four fractions. These consisted of the coarse fraction, Fl (sedimented at 4°C), the fine fractions, F2 (sedimented by centrifugation at 10,000×g), and F3 (sedimented by centrifugation at l00,000×g), and the water-soluble fraction, F4 (supernatant of F3). Electronmicroscopic observation, elemental analysis, and incubation study for estimating the mineralizable organic nitrogen were carried out on each fraction. The results obtained are as follows: 1) By electronmicroscopic observation, bacterial cells, their cell walls or cell membranes, and amorphous substances were identified in fraction F2; membranous and filamentous materials probably derived from bacterial cells, and amorphous substances were revealed in both fractions F3 and F4.2) Nitrogen was concentrated in fractions F2–F4, and the C/N ratios of the fractions F2–F4 obtained from composts A and B, which did not contain saw-dust, were low, whereas those obtained from composts C and D, which contained saw-dust increased with decreasing particle size.3) In the H/C–O/C diagram, plots of the fine fractions F2 and F3 of each compost were located between those of the bacterial cell fractions and humic substances, while the plot of the water-soluble fraction F4 of each compost was located between those of Rp type humic acids and fulvic acids.4) The percentage mineralization of organic nitrogen was relatively higher in fractions F2–F4 than in fraction F1, regardless of the C/N ratios.

Analysis of Carboxyl Groups in Soil Humic Acids By A Wet Chemical Method, Fourier-Transform Infrared Spectrophotometry, and Solution-State Carbon-13 Nuclear Magnetic Resonance. A Comparative Study

Article

Mar 1997
SOIL SCI

Carboxyls are important functional groups that affect polarity and reactivity in humic acids (HAs). Carboxyls were analyzed in eight soil HAs by three methods based on widely differing principles: (i) wet chemical analysis, (ii) Fourier-Transform Infrared spectrophotometry (FT-IR), and (iii) liquid-state 13 C Nuclear Magnetic Resonance (13C NMR). The objective was to uncover the suitability of each of these methods for the analysis of COOH groups in HAs and the extent to which the three methods agreed with each other in quantitative measurements of COOH groups in HAs. In regard to reaction mechanisms, the chemical Ca-acetate method is based on ion-exchange of H of COOH for Ca of Ca-acetate. From FT-IR spectra of HAs, COOH groups were determined by totaling absorbances at 1720-1710 cm-1 (COOH) and 1620-1600 cm-1 (COO-), whereas from 13C NMR spectra of HAs, COOH groups were computed by integration of 175-185 ppm area. Good correlations were found between the three methods although the COOH values computed by 13C NMR were higher, as a result of the inclusion of small amounts of esters, amides, and lactones, than those obtained by the other two methods. Thus, depending on the equipment and facilities available, soil scientists have a choice of methods that can be used for determining COOH groups in HAs.

Applications of Nmr to Soil Organic Matter Analysis: History and Prospects

Article

Mar 1996
SOIL SCI

Caroline M. Preston

More than 30 years have passed since the first application of nuclear magnetic resonance (NMR) spectroscopy to soil organic matter (SOM). Since then, there has been an explosion of applications using 1H, 13C, 31P, and 15N NMR on both solution and solid-state samples. These have greatly enhanced our understanding of all areas of SOM research, including understanding the nature of decomposition, and the effects of cultivation, characterization of organic forms of N and P, and interactions of SOM with xenobiotics and metals. However, in many ways, NMR remains underutilized, and applications continue to be severely hampered by the lack of instrumentation, expertise, and opportunities for graduate training. This article attempts to give a broad overview of accomplishments as well as suggestions for new opportunities.

Characterization of lignin by Gas Capillary Chromatography of Cupric Oxide Oxidation Products

Article

Nov 1981

A sensitive, reproducible method is described for the characterization of lignin in untreated plant and geochemical samples containing 10 mg or less organic matter. The whole sample is treated with alkaline cupric oxide at 170 degrees to produce simple lignin- derived phenols that are extracted with ethyl oxide and analyzed by gas capillary chromatography on fused silica columns. A pattern of 11 or less phenols is produced that reflects the relative concentration and plant tissue sources of lignins present in the sample.

Alteration of gymnosperm and angiosperm lignin during decomposition in forest humus layer

Article

Jan 1986
J PLANT NUTR SOIL SC

In the present investigation an attempt was made to characterize lignin decomposition in three forest humus profiles by the examination of their contents of simple lignin-derived phenolic compounds obtained from alkaline CuO oxidation. The total amounts of p-hydroxybenzoic, syringic, vanillic, p-coumaric and ferulic acids, p-hydroxybenzaldehyde, syringaldehyde and vanillin were determined. The acid to aldehyde weight ratios of the syringyl and vanillyl units, the weight ratio p-coumaric/ferulic acids and the weight ratios of syringyl and cinnamyl phenols, respectively, to vanillyl phenols were used for the characterization of the gymnosperm and angiosperm lignin in different stages of the decomposition process. The patterns of these parameters with depht point to a considerable decomposition and chemical alteration of the lignin molecule during biodegradation.

Sources and composition of soil organic matter fractions between and within aggregates

Article

Jan 2002
EUR J SOIL SCI

It is generally accepted that particulate organic matter derives from plants. In contrast, the enriched labile fraction is thought by many to derive from microbes, especially fungi. However, no detailed chemical characterization of these fractions has been done. In this study, we wanted to assess the sources (plants or microbes; fungi or bacteria) and degree of microbial alteration of (i) three particulate organic matter fractions – namely the free light fraction (1.85 g cm−3), the coarse (250–2000 μm) and the fine (53–250 μm) intra-aggregate particulate organic matter fractions – and of (ii) three density fractions of fine-silt associated carbon – namely < 2.0, 2.0–2.2 (i.e. enriched labile fraction) and > 2.2 g cm−3– by analysing the amino sugars, by CuO oxidation analyses, and by 13C-, 1H- and 31P-NMR analyses. Macroaggregates (250–2000 μm) were separated by wet-sieving from a former grassland soil now under a no-tillage arable regime. The three particulate organic matter fractions and the three density fractions were isolated from the macroaggregates by a combination of density flotation, sonication and sieving techniques. Proton NMR spectroscopy on alkaline extracts showed that the enriched labile fraction is not of microbial origin but is strongly degraded plant material that is enriched in aliphatic moieties partly bound to aromatics. In addition, the enriched labile fraction had a glucosamine content less than the whole soil, indicating that it is not enriched in carbon derived from fungi. Decreasing yields of phenolic CuO oxidation products and increasing side-chain oxidation in the order coarse intra-aggregate particulate organic matter < fine inter-aggregate particulate organic matter < fine-silt fractions indicate progressive alteration of lignin as particle size decreases. The light fraction was more decomposed than the coarse inter-aggregate particulate organic matter, as indicated by (i) its larger ratio of acid-to-aldehyde of the vanillyl units released by CuO oxidation, (ii) the smaller contribution of H in carbohydrates to total extractable H as estimated by 1H-NMR spectroscopy, and (iii) a larger contribution of monoester P to total extractable P in the 31P-NMR spectra. In conclusion, the four fractions are derived predominantly from plants, but microbial alteration increased as follows: coarse inter-aggregate particulate organic matter < light fraction ≈ fine inter-aggregate particulate organic matter < enriched labile fraction.

Formation and mobilization pathways of dissolved organic matter: evidence from chemical structural studies of organic matter fractions in acid forest floor solutions

Article

Jan 1994
ORG GEOCHEM

Dissolved organic matter (DOM) is well recognized to influence the geochemistry of ecosystems. This study was conducted to determine the pathways of DOC mobilization in the forest floor of coniferous forests. DOM from the forest floor of two acid forest soils in the Fichtelgebirge (Germany) was fractionated into hydrophobic acids and neutrals, and hydrophilic acids and neutrals. Carbon distribution at both sites was similar: 53 and 52% hydrophobic acids, 23 and 22% hydrophilic acids, 10 and 11% hydrophobic neutrals, and 7 and 8% hydrophilic neutrals, respectively. Structural composition of the DOM fractions was determined using chemical degradation, FT-IR and 13C NMR spectroscopy, as well as pyrolysis-field ionization mass spectrometry.Results indicate different chemical composition of the DOM fractions within each site. Hydrophobic acids show high concentrations of carboxyl and hydroxyl groups, and a high ratio of vanillic acid to vanillin (ca 1.0), both indicating a high degree of biodegradation of plant-derived compounds. Carbohydrates are covalently bound to apolar moieties and from carbohydrate composition a lignocellulose nature of the hydrophobic acid fraction is suggested. Hydrophilic acids can be differentiated from the hydrophobic acids by their higher degree of oxidative biodegradation. The hydrophilic acid fraction also exhibits a higher ratio of microbially released polysaccharides versus plant-derived polysaccharides. Hydrophobic neutrals show the closest relationships to the refractory soil humin, with less degraded dimeric ‘condensed’ lignin subunits and relatively high contents of non-carbohydrate aliphatics. Hydrophilic neutrals are enriched in carbohydrates mobilized by enzymatic cellulose and hemicellulose breakdown, as well as from microbial origin. We conclude that DOM release into forest floor solution is related to microbial activity by oxidative degradation of plant-derived organic matter (e.g. water-soluble lignin and lignocellulose fragments) and by production of microbial metabolites (e.g. polysaccharides). Overall evidence suggests that hydrophobic acids (i) represent intermediates in organic matter decomposition, which can be further degraded to hydrophilic acids and CO2, and (ii) are precursors of humic substances in illuvial horizons after precipitation/adsorption.

Determination of neutral and acidic sugars in soil by capillary gas-liquid chromatography after trifluoracetic acid hydrolysis

Article

Dec 1996
SOIL BIOL BIOCHEM

A new method for the simultaneous, quantitative determination of neutral and acidic sugars liberated from non-cellulosic soil carbohydrates is described. A single hydrolytic step with 4 M trifluoroacetic acid (TFA) at 105°C for 4 h is suggested to be more effective in releasing sugar monomers from soil than other recommended hydrolysis procedures (2.5 M H2SO4 reflux for 20 min followed by 12 M H2SO4 for total sugar hydrolysis; 1 M HCl for 5 h at 105°C or for 7 h at 100°C; 4 M TFA at 125°C for 1 h or 2 M TFA at 105°C for 2 h). Different materials were tested for purification (cation exchange resin, activated carbon, C-18, XAD-4, XAD-7), and the combination of the cation exchange resin and of XAD-7 is recommended. Analysis of purified monomers involved separation of O-methyl-oxime-trimethylsilyl derivatives by capillary gas-liquid chromatography in 21 min. Results were compared with those obtained from spiked soil samples, resulting in a high recovery of standard mixtures (70–109% for individual sugars) processed in the way proposed here. The method was sensitive and characterized by simple, accurate and rapid work-up and, therefore, is suitable for routine use.

The lignin component of humic substances: Distribution among soil and sedimentary humic, fulvic, and base-insoluble fractions

Article

Oct 1984
GEOCHIM COSMOCHIM AC

Vanillyl, syringyl and cinnamyl phenols occur as CuO oxidation products of humic, fulvic and base-insoluble residual fractions from soils, peat and nearshore marine sediments. However, none of these lignin-derived phenols were released by CuO oxidation of deepsea sediment or its base-extractable organic fractions. Lignin analysis indicated that peat and coastal marine sediments contained significantly higher levels of recognizable vascular plant carbon (20–50%) than soils and offshore marine sediments (0–10%).Although accounting for less than 20% of the total sedimentary (bulk) lignin, lignin components of humic acid fractions compositionally and quantitatively resembled the corresponding bulk samples and baseinsoluble residues. Recognizable lignin, presumably present as intact phenylpropanoid units, accounted for up to 5% of the carbon in peat and coastal humic acids but less than 1% in soil humic acids. Fulvic acid fractions uniformly yielded less lignin-derived phenols in mixtures that were depleted in syringyl and cinnamyl phenols relative to the corresponding humic acid fractions.Within the vanillyl and syringyl families the relative distribution of acidic and aldehydic phenols is a sensitive measure of the degree of oxidative alteration of the lignin component The high acid/aldehyde ratios and the low phenol yields of soils and their humic fractions compared to peat and coastal sediments indicate extensive degradation of the lignin source material. Likewise, the progressively higher acid/aldehyde ratios and lower phenol yields along the sequence: plant tissues (plant debris)-humic acids-fulvic acids suggest that this pattern represents the diagenetic sequence for the aerobic degradation of lignin biopolymers.

Early diagenesis of mangrove leaves in a tropical estuary: Molecular-level analyses of neutral sugars and lignin-derived phenols

Article

Jul 1990
GEOCHIM COSMOCHIM AC

Leaves of the red mangrove, Rhizophora mangle, were collected from trees and submerged sediments in a tropical mangrove swamp in the Bahamas. Weight-to-area measurements indicated that the most highly degraded black-colored leaves had undergone a 36% loss in ash-free dry weight (AFDW). Green leaves were characterized by an abundance of cyclitols (8.5% AFDW), glucose-rich aldose mixtures (20% AFDW) and relatively low yields of lignin-derived phenols (2% AFDW). Cyclitols were rapidly lost from senescing and submerged decomposing leaves, whereas the overall yields of aldoses and lignin-derived phenols remained fairly constant throughout the various stages of leaf decay. Decomposition patterns were therefore unusual in that lignin was lost at about the same rate as polysaccharides. Variable loss rates were observed within the individual aldoses, indicating the following stability series (most to least stable) for submerged leaves: hemicelluloses > cellulose > pectins and gums. Compositional patterns of lignin-derived phenols remained fairly constant throughout decomposition and were characterized by unusually high acid-to-aldehyde ratios (0.4) in all leaf samples.

Changes in properties of soil derived organic matter induced by biodegradation

Article

Aug 2003
SOIL BIOL BIOCHEM

Properties of dissolved organic matter (DOM) determine its biodegradation. In turn, biodegradation changes the properties of the remaining DOM, which may be decisive for the formation of stable organic carbon in soil. To gain information on both mechanisms and controlling factors of DOM biodegradation and the properties of biodegraded DOM, we investigated changes in the composition of 13 different DOM samples extracted from maize straw, forest floors, peats, and agricultural soils during a 90-day incubation using UV absorbance, fluorescence emission spectroscopy, FTIR-spectroscopy, 1H-NMR spectroscopy, pyrolysis-field ionization mass spectroscopy (Py-FIMS), and 13C natural abundance before and after incubation. Changes in the DOM properties were related to the extent of biodegradation determined by the release of CO2. Increasing UV absorption and humification indices deduced from fluorescence emission spectra, and increasing portions of aromatic H indicated relative enrichment of aromatic compounds during biodegradation. This enrichment significantly correlated with the amount of DOC mineralized suggesting that aromatic compounds were relatively stable and slowly mineralized. 13C depletion during the incubation of highly degradable DOM solutions indicated an enrichment of lignin-derived aromatic compounds. Py-FI mass spectra indicated increasing contents of phenols and lignin monomers at the expense of lignin dimers and alkylaromatics during incubation. This partial degradation of higher-molecular, lignin-derived DOM compounds was accompanied by relative increases in the proportions of lower-molecular degradation products and microbial metabolites. Carbohydrates, especially when abundant at high initial contents, seem to be the preferred substrate for microorganisms. However, four independent methods suggested also some microbial production of carbohydrates and peptides during DOM degradation. After incubation, the composition of highly degradable DOM samples became similar to relatively stable DOM samples with respect to aromaticity, carbohydrate content, and thermal stability. We conclude that DOM biodegradation seems to result in organic matter properties being a precondition for the formation of stable carbon. These structural changes induced by DOM biodegradation should also result in stronger DOM sorption to the soil matrix additionally affecting DOM stabilization.

Dissolved Organic Carbon (DOC) as a Parameter of Compost Maturity

Article

Nov 2005
SOIL BIOL BIOCHEM

Despite numerous investigations of the maturation process of composts, a simple and straightforward parameter which can predict plant response upon compost application has yet to be defined. In light of results accumulated over a decade, we examined simple, chemical parameters of three composts from three types of source materials (municipal solid waste (MSW), separated cow manure (CSM), biosolids (BS)). These materials were composted using different procedures and facilities. The chemical parameters were correlated to the growth response of cucumbers or ryegrass sown in potting media amended with the composts sampled at different stages of the process. The dissolved organic carbon (DOC) concentration of all composts decreased rapidly within the first month, then, towards the end of the process, stabilized at concentration below 4 g kg−1. DOC correlated highly and significantly to the absorbance at 465 nm in all composts, and also to the C/N ratio. Nitrate evolution was similar in all composts, but the final concentrations differed among them. Plant biomass increased with composting time. For CSM and BS compost maximum biomass was reached when the DOC reached levels below 4 g kg−1. DOC concentration is suggested for use as a simple method of determining maturity, with 4 g kg−1 recommended as a threshold level indicating maturity. Absorbance at 465 nm can be used instead of DOC concentration after appropriate calibration.

Maturity and Stability Parameters of Composts Prepared with a Wide Range of Organic Wastes

Article

Jan 1998
BIORESOURCE TECHNOL

Seven different composts were prepared in a pilot plant by the Rutgers static-pile system using a wide range of wastes: sewage sludge, poultry manure, pig slurry, olivemill wastewater, city refuse and the lignocellulosic wastes cotton waste, maize straw and sweet sorghum bagasse. Their chemical and biological properties were studied at four stages of the composting process: in the initial mixture, at the thermophilic phase, at the end of the active phase and after two months of maturation. The following maturity indices were established: C/N < 12, Cw < 1.7%, Cw/Norg < 0.55. NH4/NO3 < 0.16, and NH4-N < 0.04%, with a germination index greater than 50%. In addition, some carbon mineralization parameters could also be used as maturity indices: mineralized-C in 70 days (Cm) < 30%, rapidly mineralizable-C (CR) < 7.2% and a slow mineralization rate (CS × KS) < 0.35% day−1. Maturation indices based on humification of the organic matter and the cation exchange capacity of different composts could not be found, since the values for mature compost depended on the wastes from which the composts were made.

Gas chromatograph1c determination of muramic acid, glucosamine, mannosamine, and galactosamine in soils

Article

Sep 1996
SOIL BIOL BIOCHEM

Muramic acid, glucosamine, mannosamine and galactosamine in soils may be useful for elucidating the microbial origin of soil organic nitrogen. Therefore, a method was developed to determine the aldononitrile acetate derivatives of the four amino sugars simultaneously in the 6 m HCl hydrolysates of soil samples by means of high resolution gas liquid chromatography. This method was sensitive enough to detect less than 10 μg muramic acid ml−1 and less than 20 μg ml−1 of the other three amino sugars. The maximum release of amino sugars was found after 6 to 8 h hydrolysis at 105°C. Impurities in the acidic hydrolysates were removed simply by neutralisation with KOH solution. The recovery of amino sugars after hydrolysis and purification was more than 90% on average. The method was applied to determine amino sugars in eight soils with different properties. The coefficients of variation averaged 6.1% for glucosamine and galactosamine and 10.9% for muramic acid and mannosamine.

The Science of Composting

Article

Jan 1998

Eliot Epstein

The role of Polyphenols in terrestrial ecosystem nutrient cycling

Article

Jul 2000
TRENDS ECOL EVOL

Interspecific variation in polyphenol production by plants has been interpreted in terms of defense against herbivores. Several recent lines of evidence suggest that polyphenols also influence the pools and fluxes of inorganic and organic soil nutrients. Such effects could have far-ranging consequences for nutrient competition among and between plants and microbes, and for ecosystem nutrient cycling and retention. The significance of polyphenols for nutrient cycling and plant productivity is still uncertain, but it could provide an alternative or complementary explanation for the variability in polyphenol production by plants.

Estimation of the Hydrophobic Fraction of Dissolved Organic Matter in Water Samples Using UV Photometry

Article

Dec 2002
WATER RES

In this study, we tested a simple and rapid method for the estimation of carbon in the hydrophobic fraction of dissolved organic matter (DOM) of different origin (spruce, pine, and beech litter) in soil water. The method is based on the fact that the hydrophobic fraction of DOM contains almost entirely the aromatic moieties of DOM. Thus, it showed a clearly distinct light absorption at 260 nm compared to the hydrophilic fraction. This light absorption was directly proportional to the concentration of the hydrophobic fraction. Moreover, it was independent of the concentration of the hydrophilic fraction. We compared the concentrations of hydrophobic DOM estimated by the UV method with those of the conventional fractionation using chromatographic columns of XAD-8 macroporous resin and found an excellent agreement between the two methods for both solutions from laboratory sorption experiments and field samples of forest floor leachates and subsoil porewaters. In addition, the absorption at 260 nm of hydrophobic DOM proved to be independent of pH values ranging from 2.0 to 6.5. Compared to the conventional chromatographic fractionation, the method using the UV absorption at 260 nm is less time consuming, needs a much smaller sample volume, and showed a better reproducibility. However, its use is restricted to water samples of low nitrate (< 25 mg L(-1)) and Fe (< 5 mg L(-1)) concentrations and, probably, with the hydrophobic fraction dominated by aromatic compounds deriving from degradation of lignin.

The effect of lignin and sugars to the aerobic decomposition of solid wastes

Article

Dec 2003
WASTE MANAGE

A series of experimental runs were conducted from 1995 to 1999 in Madison (WI, USA) with the goal to investigate the biodegradation process of seven (7) solid waste components and mixtures of them under near optimal aerobic conditions. It was shown that substrates with high initial lignin contents or high initial HWSM contents were observed to have relatively low and high degradation extents, respectively. Two linear equations were derived that correlate degradation extent (as indicated by the volatile solids reduction) to initial lignin and initial HWSM contents separately. The lignin equation was compared to a similar equation previously developed for anaerobic environments by Chandler et al. (Predicting methane fermentation biodegradability. In: Biotechnology and Bioengineering Symposium No. 10 (1980) New York: John Wiley & Sons). With comparison to the Chandler formula, lignin was found to be less inhibitory to the overall substrate decomposition in aerobic environments compared to anaerobic ones. Cellulose loss contributed to a higher than 50% to the overall dry mass loss for all substrates studied. In addition, the cellulose to lignin (C/L) ratio appeared to be a relatively accurate compost maturity indicator, since it reduced to a value less than 0.5 for most substrates that had reached their degradation extent.

Changes in the chemical characteristics of water-extractable organic matter during composting and their influence on compost stability and maturity

Article

Aug 2007
BIORESOURCE TECHNOL

Composting is the biochemical transformation of waste organic matter by microorganisms whose metabolism occurs in the water-soluble phase. Therefore, a study of the changes occurring in compost dissolved organic matter can be useful for assessing its stability and maturity. In light of the variety of parameters generally utilized to study composting processes, this work aims at identifying the major chemical processes that occur in solution and their influence on the attainment of stability and maturity with composting time. Compost stability, assessed by means of respirometric analysis which determined oxygen demand as a result of mineralization of the compost's organic matter, and compost maturity evaluated with Lepidium sativum L. seed bioassays, were found to be highly related to the nature and content of water-soluble organic matter. Moreover, fractionation of the water-extractable organic carbon showed that the ratio of hydrophobic to hydrophilic carbon increased to values greater than unity for stabilized compost. These results together with the analysis for non-cellulosic polysaccharides, phenolic compounds and organic nitrogen within the water extracts, confirmed the influence of solubilization, mineralization and organic matter transformation on the quality of the final compost.

Table 4 Hydrolysable amino sugar content of compost and water-extractable organic matter during composting Composting time (days) Maturity and stability evaluation of composted yard trimmings

Jan 2003
96-112

L J Brewer
D M Sullivan

Table 4 Hydrolysable amino sugar content of compost and water-extractable organic matter during composting Composting time (days) Brewer, L.J., Sullivan, D.M., 2003. Maturity and stability evaluation of composted yard trimmings. Compost Sci. Util. 11, 96–112.

Methods using amino sugars as markers for microbial residues in soil

Jan 2001
233

Amelung

Amelung, W., 2001. Methods using amino sugars as markers for microbial residues in soil. In: Lal, R., Kimble, J.M., Follett, R.F., Stewart, B.A. (Eds.), Assessment Methods for Soil Carbon. Lewis Publishers, Boca Raton, FL, pp. 233-272.

Properties of fine and water-soluble fractions of several composts. II. Organic forms of nitrogen, neutral sugars, and muramic acid in fractions

Jan 1991
629

Aoyama

Changes in the chemical composition of water-extractable organic matter during composting: Distribution between stable and labile organic matter pools

Abstract

No full-text available

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