High Degree Of Humification Research Articles

Partial Oxidation of Char to Enhance Potential Interaction With Soil

Production of char and its application to soil are a strategy to reduce the increasing rate of atmospheric C. However, a large proportion of C in materials is lost during the charring process, and the strong interaction with soil particles is not anticipated because of the lack of functional groups such as carboxyl groups. We obtained chars from Japanese cedar (Cryptomeria japonica) sapwood using various heating conditions and oxidized them with HNO3, H2O2, or RuO4 to enhance their potential adsorption to soil particles. The yields of char, oxidized char, and humic acid (HA)-like substances and their structural properties examined using UV-visible, IR, and 13C nuclear magnetic resonance spectroscopies as well as X-ray diffraction profile analysis suggested that HNO3 oxidation of char produced by heating at 400°C for 1 h (designated JC400/1) was effective. Whereas H2O2 and HNO3 oxidations increased the amount of HA-like substances in chars, and the HNO3 oxidation also increased the degree of humification, RuO4 oxidation produced no effect. The JC400/1 oxidized with HNO3 produced the maximum yield (299 mg C g−1 char C) of HA-like substances with the highest degree of humification. Aromatic C accounted for 76% to 79% of the total C in JC400/1 both before and after oxidation treatments, whereas carboxyl C was increased by oxidation to a greater extent by HNO3 oxidation. X-ray diffraction profile analysis suggested a decrease in condensed aromatic structures in JC400/1 through H2O2 and HNO3 oxidations, and larger nuclei were maintained after HNO3 oxidation.

Humus distribution and forms in the sediments from shallow Iakes in the middle and lower reaches of the Yangtze River

The organic matter(OM) content,compositions and fractions of shallow lake sediments were studied by chemical method from in the middle and lower reaches of Yangtze River.The results showed that the OM content varied greatly from 0.98% to 11.0 %,higher in the heavily polluted sediments than those in the light polluted ones.The distributions of OM content were closely related to lake pollution levels and human activity intensity.HA content was 1.03-6.73g/kg,and FA content is higher than the HA,from 2.73 to 9.77g/kg.Humin was the main fractions of humus,varing from 5.89 to 55.57g/kg.PQ(HA/(FA+HA)) ratio varied from 23.04% to 50.56%,and the mean content of PQ was 32.72%.PQ content were higher in the heavily polluted sediments than those in the light polluted ones,which indicated that there was a higher degree of humification in heavy polluted sediments.Combination of three kinds of humus content in the form of tightly bound humus content was the highest,and content was 3.21-47.76g/kg;followed by loosely combined humus content between 0.86-6.92g/kg.The stable combined humus were the lowest,the content varied from 0.72 to 3.89 g/kg.The loose/tight ration in the sediments were also negatively correlated with OM,TP and TN,which showed that heavily polluted shallow lakes had higher humification and humus accumulation.So humus should be paid more attention to the carbon cycling and eutrophication control in lakes.

Stabilization process within a sewage sludge landfill determined through both particle size distribution and content of humic substances as well as by FT-IR analysis

Landfill is largely considered as a reliable option for sewage sludge disposal in most metropolitan areas worldwide due to the huge quantities of this waste to be disposed of and the relatively low costs of such a kind of sludge management. It has been found that the sludge in the landfill degrades rapidly and becomes stabilized within a few years. In the present study, the sludge from different landfill stages was characterized by particle size distribution, humic substances contents and elemental composition, and Fourier transform infrared spectroscopy (FT-IR), as the landfill time increased. In general, the mean particle size of the sludge increased from 37 μm at day 0 to 143 μm at 300 days and the corresponding median particle size increased from 13 to 70 μm. The stability of particle size distribution can be assessed by the mean or median particle size. The humic acid (HA) and fulvic acid (FA) contents extracted from dry sludge after different landfill periods increased from 4.2 and 2.7% of day 0 to 5.6 and 3.1%, respectively, at 400 days, thereby indicating that the stabilization process of sludge in a landfill is also a humification process. The HA samples contained more carbon and nitrogen, and less hydrogen and oxygen than the FA samples, indicating a high degree of maturity and humification of these HA samples. The FT-IR spectra indicated that easily degradable organic matter components, such as aliphatic chains and protein, were distinctly decomposed during landfill. Based on the changes in the band relative intensity, it was concluded that after 300 days in a landfill the sludge is still in the process of degradation and maturity.

Assessment of three vermicomposts as organic amendments used to enhance diuron sorption in soils with low organic carbon content

SummaryVermicomposts from the wine and distillery industry containing spent grape marc (V1), biosolid vinasse (V2) and alperujo (V3) from the olive‐oil industry were investigated as organic amendments to a sandy and a clay soil with low organic carbon (OC) contents (≤1%). The sorption‐desorption process was studied in batch experiments using diuron as a non‐ionic herbicide model. The effect of soil and vermicompost characteristics, the solution's ionic strength and incubation time of amended soils on the sorption process was studied. The addition of vermicompost changed soil properties and enhanced sorption capacity by two‐ to four‐fold. The Koc variability showed that exogenous OC composition influenced diuron sorption. Vermicompost V1, which had the largest OC and lignin content, recorded the largest sorption increment. Vermicompost V3, which had the greatest dissolved organic carbon content and a high degree of humification, made the smallest contribution to sorption. Sorption was also dependent on extraneous calcium in the solution. The incubation of amended soils reduced diuron sorption efficiency except with V3. Pyrolysis‐gas chromatography (Py‐GC) analysis was a useful tool to characterize the vermicomposts and to understand the variation of diuron sorption constants after vermicompost incubation. This research encourages the use of vermicompost from agro‐industrial wastes as a sustainable means to minimize the side effects of neutral herbicides.

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

In the Earth's carbon cycle, C stocks in the soil are higher than in vegetation and atmosphere. Maintaining and conserving organic C concentrations in the soil by specific management practices can improve soil fertility and productivity. The aim of this study was to evaluate the impact of agricultural management techniques and influence of water regime (flooded or drained) on the structure of humic substances by excitation/emission matrix fluorescence. Six samples of a Planosol (Planossolo by the Brazilian System of Soil Classification) were collected from a rice field. Humic substances (HS) were extracted from flooded and drained soil under different agricultural management techniques: conventional tillage, reduced tillage and grassland. Two peaks at a long emission wavelength were observed in the EEM spectra of HA whereas those of the corresponding FA contained a unique fluorophore at an intermediate excitation/emission wavelength pair (EEWP) value. The fluorescence intensity measured by total luminescence (FI TL) of HA was lower than that of the corresponding FA. A comparison of all samples (i.e., the HA values compared to each other) revealed only slight differences in the EEWP position, but the FI TL values were significantly different. In this soil, anoxic conditions and reduced tillage (little plowing) seem to favor a higher degree of humification of the soil organic matter compared with aerated conditions and conventional tillage.

Climate changes in East China since the Late-glacial inferred from high-resolution mountain peat humification records

High-resolution peat humification records were obtained from Dajiuhu of the Shennongjia Mountains and Qianmutian of the Tianmu Mountains to study climate changes in East China. The analyses of pollen, organic matters, TOC, and Rb/Sr indicate a high degree of peat humification and thus strong decomposition of organic matter when climate was dry. Conversely, when climate was humid, the degree of humification is low because peat was preserved in a waterlogged condition. Peat humification from Dajiuhu occurred not only during the Younger Dryas (about 11.4–12.6 cal ka BP), the Bolling-Allerod Warm Period (12.6–15.2 cal ka BP), and the Oldest Dryas (about 15.2–16.0 cal ka BP), but also during the early Holocene (about 11.4–9.4 cal ka BP), the 8.2 cal ka BP cold event, and the Holocene Optimum (about 7.0–4.2 cal ka BP). Both peat humification records since nearly 5 ka BP are consistent, showing that mountain peatland has synchronous responses to the East Asia monsoon-induced precipitation. The LOI data confirm the above observation. The monsoon precipitation since nearly 5 ka BP recorded in these two peat profiles can be divided into three phases. During 4.9–3.5 ka BP, precipitation amount was high but fluctuated greatly. During 3.5–0.9 ka BP, precipitation amount was low. During 0.9–0 ka BP, degree of humification reduced gradually, indicating the increase of monsoon precipitation. Contrast to other high-resolution records from East China monsoon region shows that the monsoon precipitation records of the two peat profiles since nearly 16 ka BP are controlled by a common forcing mechanism of summer solar radicalization in the Northern Hemisphere.

Fluorescence spectroscopy studies of humic substance fractions isolated from permanently frozen sediments of Yakutian coastal lowlands

Predictions of global warming render studies of organic matter stored in permanently frozen sediments of northernmost areas particularly topical. This paper offers results of fluorescence spectroscopy applied to the study of humic and/or humic-like fractions gained from polygenetic syncryogenic sediments in northern Yakutia in comparison with humic substances (HS) from recent soil and the Nordic (NOM) reference of aquatic natural organic matter. To isolate HS fractions from sediment and soil samples the method of sequential extraction with sulfonate resin (HS-S fraction), carboxylate resin (HS-C fraction) and 0.1 M NaOH (HS-A fraction) was used. The HS extracts were filtered through a 0.45 μm membrane filter, following which part of each HS fraction was broken down into humic acids (HA) and fulvic acids (FA). Synchronous fluorescence spectra were obtained on aqueous solutions of all specific HS fractions as well as HA and FA fractions isolated thereof and NOM. Variations in the main peak position and intensity seen on the synchronous fluorescence spectra of HS-S, HS-C and HS-A extracted from the same soil/sediment sample are apparently indicative of the distinct degree of humification of the isolated fractions. It was found that HA fractions, compared to FA fractions, show a more varied array of fluorescence observations which change depending on the source of HS. Consistent with fluorescence-produced characteristics for HS and HA fractions, sediment samples can be classified into two groups, one comprising Pleistocene sediments of the ice complex, the other sediments of the Holocene thickness and Pleistocene buried soil. The HS and HA of the first group manifest dominating peaks in the low- and intermediate-wavelength spectral regions, which is indicative of a relatively low degree of humification and certain similarity to NOM. The HS and HA fractions of the second group show a fluorescence signals set typical of recent soil, where the dominating peak of a particular fraction occurs in the long-wavelength region peculiar to a high degree of humification. An examination of experimental data suggests essential bioclimatic fluctuations in the region over the period of the studied sediments formation.

Study of the biodegradation and transformation of olive-mill residues during composting using FTIR spectroscopy and differential scanning calorimetry

The aim of this work was to investigate the structural transformations occurring in organic matter and their relationships with organic matter stability during the composting of two different solid olive-mill residues (SOMR). Raw materials were prepared from SOMR (compost C1) and from a mixture of SOMR and olive-mill wastewater for compost C2. Composts evolution was monitored by direct Fourier transform infra-red (FTIR) spectroscopy and differential scanning calorimetry (DSC) and by physicochemical parameters. Results showed that both wastes are suitable for composting and showed a strong thermophilic phase extending over the first 2 months, progressively and slowly reaching maturity after approximately 6 months. By the end of the thermophilic phase the water-soluble phenol content decreased by 93% and the pH and organic matter loss became more stable, oscillating around 8.5 and 41%, respectively. DSC and FTIR results showed that the biodegradation of the heterogeneous raw material is progressive and can be mainly attributed to a loss of aliphatic and peptidic structures and to an increase of the aromatic structures which essentially occurs during the maturity phase. By the end of the maturity phase, the two composts showed DSC and FTIR spectra typical of humic-like substances confirming the high degree of humification of the end products.

Elemental and spectroscopic characterization of humic-acid-like compounds during composting of olive mill by-products

Humic acids (HAs) were isolated at different stages of composting from two piles of solid olive mill residues (SOR) treated for the first 30 days with tap water (pile C1) or olive mill wastewater (pile C2), for a total composting period of 9 months. The HA fractions were characterized by elemental analysis, UV-visible, Fourier transform infrared and fluorescence spectroscopy in order to monitor humification process and the maturity of the composts. As composting proceeded, the elemental composition of the humic acids showed a decrease in C and H content, and in the C/N ratio, and an increase in N and O contents and in the C/H and O/C ratios. These changes could be attributed to a loss of aliphatic groups and to an increase of aromatic character, polycondensation and degree of oxidation of the HAs. Spectroscopic data agree and support these results, suggesting that the chemical and structural features of the HAs of both composts tend to reach those typical of native soil HAs, that is compounds with a high degree of humification and a high molecular weight and complexity. Therefore, both composting processes seem suitable to produce well-humified organic matter, with important benefits for their use in soil amendment. No differences appeared between the two treatments concerning the humic character of the two final composts.

Phosphorus fractions in arable and mountain soils and their humic acids

Soil phosphorus (P) can exist in various inorganic (Pi) and organic forms (Po). Specific determination of Pi can be obtained by fractionate methods. However, the discrimination between the chemically different forms of Po in soil is not simple. Nowadays, the method of choice for the determination of various soil inorganic and organic P compounds is <sup>31</sup>P NMR. In this paper, the determination of various phosphorus forms (available P, total P, Pi and Po fractions) in arable and mountain soils is presented. Besides, the detailed characterisation of P compounds in humic acids (HA) is also shown. The results obtained show that the highest content of the available P can be found in arable soils with a high input of fertilisers, and that the predominant part of Pi is included in hardly soluble fractions, mainly in the soil types with neutral soil reaction. Our data also show the correlation between total P and Po, the dominant form of P in the topsoil of mountain soils. Phosphomonoesters represent the major types of P in HA structure. The correlations between phosphomonoesters of type I and some humification parameters of HA and qualitative parameters of soil organic matter suggest that higher amounts of more recalcitrant monoesters can be found in more mature soil organic matter with a higher humification degree.

Evaluation of two different aeration systems for composting two-phase olive mill wastes

Composting of two-phase olive mill waste (TPOMW) mixed with sheep litter and grape stalks was performed using two different aeration systems: forced aeration and windrow turning. The aim was to find out which of these technologies was the most appropriate for the composting of these materials. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, biodegradation of organic matter fractions (carbohydrates, lipids, phenols, lignin, cellulose and hemicellulose) and nitrogen loss. Besides, the quality of the final composts was compared in terms of their main chemical characteristics (total N, N-NH 4 +, N-NO 3 −, P 2O 5, K 2O, pH, electrical conductivity, polymerisation degree, humification degree and germination index) and their hygienisation degree (faecal coliforms and faecal streptococci). The study revealed that forced aeration of static pile presents several drawbacks for the composting of two-phase olive mill waste due to its physical properties. Several windrow turnings were required to avoid the formation of preferential air path-flows, the compaction and heterogeneous drying of the material. Piles elaborated by windrow turning showed a longer thermophile phase which lead to a higher degradation of fibres and a greater loss of nitrogen. The quality of the end products obtained by both methods was quite similar, although the organic matter of composts prepared by windrow turning had a higher humification degree. Turnings of TPOMW composting piles are necessary for the normal development of the process and the high investment necessary to implement the forced aeration could be avoided. The benefits that forced aeration introduces by means of the control of temperature can be obtained by optimising pile size and turning frequency.

Characterization of fulvic acids during olive mill waste composting (Elemental, Thermal and fluorescence analyses)

Elemental analysis, fluorescence spectroscopy and differential scanning calorimetry (DSC) were applied to the study of fulvic acids isolated from different stages during olive mill waste composting. The fulvic extracted acids are characterized by a high nitrogen content and O/C ratio values that may result from the high degree of humification and the synthesis of more condensed humic complexes. This was confirmed by fluorescence spectroscopy in the synchronous-scan mode by the decrease of shoulder intensities at intermediate wavelengths indicating the increase of polycondensation and conjugation of unsaturated structures and the greater uniformity of fluorophores. Fluorescence spectra in the emission, excitation and synchronous modes became simpler with compost maturation. This was confirmed by DSC results which proved the high degree of polycondensation of aromatic nuclei of fulvic acid molecules during olive mill waste composting.

Stepwise Rock-Eval pyrolysis as a tool for typing heterogeneous organic matter in soils

This paper presents an application of Rock-Eval pyrolysis for estimating the proportion of the components with different thermal stability in soil organic matter, the maturity of which corresponds to the early stage of diagenesis. For testing the validity of the modified Rock-Eval method, parallel series of pyrolysis were carried out on sedimentary rock samples. The temperature program was selected on the basis of the results obtained from stepwise Rock-Eval pyrolyses and from the mathematical deconvolution of pyrograms. The proportion of the original biomolecules in soil organic matter was calculated by the integration of pyrograms below 350 °C and could be determined rapidly by one single pyrolysis using 350 °C as initial cracking temperature. At 380 °C, both the mathematical and the experimental methods provide reliable information about the proportion of the humic substances. Conversely, for rock samples, mathematical deconvolution of the pyrograms showed the heterogeneity of the sedimentary organic matter, the maturity of which corresponds to late diagenesis, without any estimation of the proportion of the different components. The rate of organic carbon accumulation in the studied soils and the decomposition rate of biopolymers were interpreted as a function of land-use and redox conditions. Differences in the precursor vegetation and in the environmental parameters resulted in markedly reduced carbon storage and higher degree of humification in the agricultural soil than in the adjacent forest soil. Redox conditions strongly affected both the amount and the elemental composition of the stored organic matter. The decomposition rate of biopolymers appeared to be controlled mainly by the contribution of resistant lignin components to the source biomass and, to a lesser extent, by redox conditions.

Soil Organic Carbon Fractions Under Different Land Uses in Mardi Watershed of Nepal

This study was conducted to investigate the organic carbon (C) content and its chemical fractions in soils under forest, grassland, and agricultural uses in the Mardi Watershed of Nepal. Surface soil samples from 0 to 15 cm were collected. Classical extracting procedure with alkali and acid solution was used to separate humic acid (HA), fulvic acid (FA), and humin fractions. Hydrogen peroxide was used to separate black carbon (BC) from humin. The results showed that higher amounts of total soil organic carbon (SOC), as well as of different SOC fractions, i.e., FA, HA, humin and BC, existed in the forest soils compared to those from grassland and agricultural areas. The carbon proportion of FA, HA, and humin fractions accounted for 25, 29, and 37% of the total SOC in forest soils. The corresponding values were 34, 27, and 36% in grassland, and 28, 18, and 54% in agricultural land. The grassland soil showed a higher FA fraction, while the agricultural soil contained lower HA fraction and higher humin fraction as compared to the forest soil. Forest soil showed higher HA/FA ratio and lower (HA + FA)/SOC ratio, indicating high degree of humification and large humification rate in this soil. Black carbon contents occupied 3.4, 3.4, and 11.5% of SOC under forest, grass, and agricultural lands, respectively.

Semiquantitative GC/MS analysis of thermochemolysis products of soil humic acids with various degrees of humification

Thermochemolysis with tetramethylammonium hydroxide (TMAH) was conducted for 18 humic acids (HAs) obtained from a wide range of soils, and the yields and compositions of the released compounds were analyzed in terms of the degree of humification and the proportions of C species estimated by 13C CPMAS NMR. Eighty-six peaks could be assigned on GC/MS chromatograms, and notable differences in the kind of compound assigned were not found among the HAs. The total yields of aliphatic compounds ranged from 0.40 to 4.2 mg/g. C 12- to C 18-even fatty acid methyl esters (FAMEs) accounted for 30–66% of the entire aliphatic compounds assigned, followed by C 20- to C 34-even FAMEs (4.8–47%), C 9- to C 33-odd FAMEs (11–26%), and C 16- to C 30-even dicarboxylic acid dimethyl esters (DAMEs; 0.3–9.1%). The total yields of aliphatic compounds decreased with decreasing gross alkyl C during the progress in the degree of humification, although their proportion in gross alkyl C was small. On the other hand, the total yields of aromatic compounds ranged from 1.7 to 37 mg/g. Of these, 7.5–82% and 0.12–64% were phenol derivatives that were possibly derived from lignin and benzenepolycarboxylic acid polymethyl esters, respectively. The yields of phenol derivatives and stilbene compounds, possibly originating from lignin dimers, decreased with an increase in the degree of humification, contrary to the increase in the proportion of aromatic C in total C. The yields of heterocyclic compounds, namely, indole and proline derivatives, were also higher in HAs with lower degrees of humification. The variation in the yield of benzenepolycarboxylic acid polymethyl esters suggested parallel progression of oxidation with increasing degree of humification. Aromatic compounds responsible for the high aromaticity and the dark color of HAs, such as quinones and polycyclic compounds, were not detected even in HAs with a high degree of humification.

Characterization of fulvic acids by elemental and spectroscopic (FTIR and 13C-NMR) analyses during composting of olive mill wastes plus straw

Elemental, functional and spectroscopic analyses (FTIR, 13C-NMR) were performed to study fulvic acids of composted olive mill wastes plus cereal straw, in order to follow the maturity of the final product during composting. The extracted fulvic acids were characterized by high nitrogen, acidic functional group and phenolic hydroxyl contents that might have resulted from the high degree of humification and the synthesis of more condensed humic complexes. This was confirmed by a decrease of alcoholic and aliphatic structures and an increase of aromatic structures, as shown by the FTIR and 13C-NMR analyses. The results showed that stability of the final product was reached after 12 months of composting and that fulvic acid levels could constitute an additional tool to assess final product maturity and its agronomic value.

The influence of humic acid quality on the sorption and mobility of heavy metals

Mobile and potentially mobile forms of heavy metals are probably one of the most important toxic hazards in the environment. Besides pH, which is a factor influencing the mobility/availability of heavy metals to the greatest extent, the content and mainly the quality of soil organic matter play a very important role in the evaluation of heavy metal behaviour in the environment. The fraction of metals bound to organic compounds is exclusively associated with humic substances and particularly with humic acids (HA). A relationship between the parameters reflecting the actual structure of humic acids and mobile or potentially mobile fractions of heavy metals was studied in 12 soil localities representing different soil types. It can be stated on the basis of the acquired data that heavy metals tend to form complexes with soil organic matter that are different for each metal. The results suggest that copper is bound mainly in an unavailable form (significant correlations of fraction IV with HA parameters) and cadmium prefers exchangeable forms (significant correlations of fraction I with HA parameters) and is more available. It can be assumed on the basis Spearman’s correlations that mobile fractions of cadmium are predominantly bound to the aliphatic part of humic substances, and copper prefers strong bonds to humic acids with a high degree of humification.

Relation of chemical properties of soil humic acids to decolorization by white rot fungus–Coriolus consors

Humic acids (HAs) from 15 different soil samples were added to Czapek-Dox media inoculated with Coriolus consors IFO 9078. After 14 d incubation, decolorization of these culture media at 600 nm absorbance was measured. The aromaticity, the E 1% 600 value, the total acidity, and the elemental composition of the HAs were also determined, and the relationships between the decolorization and the chemical properties of HAs were examined. Percentage of decolorization of these culture media ranged from 8.8 to 39.5%. Andisol HAs showed a lower percentage of decolorization than the Inceptisol HAs. Percentage of decolorization showed highly negative correlations for the aromaticity, the E 1% 600 value, and the O / H ratio, and highly positive correlations for the hydrogen content and the H / C ratio. In particular, the highest correlation coefficient (r = −0.836**) was obtained between the aromati city and the decolorization. In addition, the HAs with a lower decolorization were arranged in the direction of dehydration on the H / C versus O / C diagram. These results showed that HAs with a higher aromaticity and a higher humification degree, showed a higher resistance to microbial decolorization by C. consors.

KHS reports profitable year

Humic substance (HS) in sediment can affect hydrophobic organic compound distribution, transportation, bioavailability, and toxicity. This study investigated the HS (BKHS) extracted from sediment and separated it into low molecular humic (LMHS, <1 kDa) and high molecular humic substances (HMHS, 1 kDa–0.45 μm). Nonylphenol (NP), octylphenol (OP), and bisphenol A (BPA) have a significant sorption capacity for HMHS and BKHS solutions. They are xenoestrogenic endocrine-disrupting compounds that are widely produced and discharged to the environment. The log KHS values of the BKHS and HMHS solutions were between 4.74–5.09 L kg-C−1 and 4.57–5.09 L kg-C−1, respectively. However, the three compounds were not sorbed by the LMHS solution. The average values of SUVA254 for HMHS and LMHS were 4.29 and 1.31 L m−1 mg-C−1 and the average values of A250–400 for HMHS and LMHS were 18.1 and 4.51 nm cm−1, respectively. The HMHS peak position in the fluorescence excitation/emission matrix at longer wavelengths corresponded to the peak position of LMHS, which indicates that the HMHS had a higher degree of humification than the LMHS. The results suggested that the KHS value's dominant factor was the degree of HS humification.

Botanical composition of peat and degree of peat decomposition in three temperate peatlands

Models of peat accumulation assume that peat decomposition occurs mostly above the water table, with little or no decomposition once peat enters the deeper, saturated, anoxic zone. However, few such measurements of peat decomposition exist. In this paper we quantified differences in degree of decomposition, botanical composition, and organic chemical composition of peat from three temperate peatlands with different water table levels. All sites had a thick layer of herbaceous peat, capped by a layer of Sphagnum peat. The lignin content and degree of decomposition, measured by the pyrophosphate index, generally increased with depth. Analysis of the lignin with cupric oxide (CuO) oxidation revealed most of the chemical differences between peat deposits occurred in the upper, aerated peat layer, as expected. The upper layer of Sphagnum peat was characterized by high p-hydroxyl phenolic yield, whereas Sphagnum peat below the water table exhibited a high degree of humification and high yield of vanillyl oxidation products despite being of similar botanical composition. Surprisingly, herbaceous peat below the water table was similar in terms of degree of decomposition to younger herbaceous peat. The results confirm that peat decomposition occurs mostly above the water table, although botanical source, climate, and local hydrology interact to create multiple trajectories in peat chemistry.