Decomposition of algal cells and components and their stabilization through complexing with model humic acid-type phenolic polymers

Axenic cultures of Anacystis, Microcoleus, Plectonema and Synechococcus isolated from Greenfield sandy loam and of Anabaena flos-aquae, Nostoc muscorum and Chlorella pyrenoidosa from other sources were cultured under light and constant aeration and with [U-¹⁴C]-glucose in the nutrient medium. Whole cells, cell walls, cytoplasm and extracellular polysaccharides of selected species readily decomposed in the soil and after 22 weeks between 61 and 81% of the added C had evolved as CO₂. Complexing of cell wall and cytoplasmic preparations from A. flos-aquae and N. muscorum with model humic acid-type phenolic polymers reduced decomposition of the cell walls by 40% and of the cytoplasm by 70%. Over 50% of the residual 14C activity in the soil amended with whole algal cells remained in the 0.5% NaOH-extracted soil. With exception of Microcoleus sp. more of the residual ¹⁴C from cell walls, cytoplasm and polysaccharide fractions was present in the humic acid or fulvic acid fractions.     

THE ACCUMULATION OF SOIL ORGANIC MATTER AND ITS CARBON ISOTOPE CONTENT IN A CHRONOSEQUENCE OF SOILS DEVELOPED ON AEOLIAN SAND IN NEW ZEALAND

Soil organic matter was extracted by a mixture of O.IM Na₄P₂O: O.IM NaOH from a chronosequence of weakly weathered soils developed on aeolian sand, and fractionated into humin (non-extractable), humic acid, and fulvic acid. The mass of total organic carbon in the profiles, the ¹⁴C content and the ¹³C/12C ratios were also determined. The weight of total carbon increased rapidly at first and then gradually without attaining a steady state. This trend was also shown by the humin and fulvic acid fractions, but the humic acid fraction appeared to have reached a maximum after about 3000 years. The order of total weights of the organic fractions was humin > fulvic acid > humic acid. The evidence suggests that the proportions of the humic fractions formed by decomposition are related to soil differences but not to vegetation. The greater part of the plant material found in the soils appears in the humin and fulvic acid fractions.     

Chemical composition of the organic matter in forest soils: The humus layer

Decomposition and humification were studied within three types of forest humus (mull, moder, and mor) by means of CPMAS ¹³C NMR spectroscopy combined with degradative methods. The NMR data show that O-alkyl carbon decreases in all soils, and alkyl as well as carboxyl carbon increase as depth and decomposition increase; the percentage of aromatic carbon remains constant at about 25%. With increasing depth the amount of carbon that can be identified as belonging to specific compound classes by wet chemical methods decreases from 60% to 40%. Microbial polysaccharides and the proportion of non polysaccharide O-alkyl carbon increase with depth. A selective preservation of recalcitrant, condensed lignin structural units is also observed. In order to relate the spectroscopic and chemical data from investigations of whole soils with studies of humification, samples were fractionated into fulvic acid, humic acid, and humin fractions. The fulvic acid fraction contains large concentrations of carbohydrates irrespective of the soil horizon. The humic acid fraction contains less polysaccharides, but high amounts of alkyl carbon and aromatic structures. The percentage of aromatic carbon existing in the humic acid fraction increases with depth, probably reflecting the amount and degree of oxidative decomposition of lignin. A loss of methoxyl and phenolic groups is evident in the ¹³C NMR spectra of the humic acid fraction. The humin fraction resembles relatively unchanged plant-derived materials as evident from the lignin parameters and carbohydrate contents. All the observed data seem to indicate that humic acids originate form oxidative degradation of humin or plant litter.     

Influence of intimate association with humic polymers on biodegradation of [C]labeled organic substrates in soil

A variety of [¹⁴C]labeled organic compounds and microbial products were incubated in soil alone or intimately associated with humic acid-type polymers achieved by freeze-drying mixed solutions of the polymers and [¹⁴C]labeled compounds at pH 6. The association of Chlorella protein with the polymers reduced mineralization over 12 weeks by 41%. Similarly decomposition of cysteine and Anabaena flos-aqua cytoplasm was reduced by 26% and glycine 16%. Tyrosine, lysine, aspartic acid, serine, cytosine, glucose, ferulic acid. also polysaccharides of Leuconostoc dextranicus, Azotobacter indicus, Hansenula holstii and Anabaena flos-aqua, as well as cells and cell walls of A. flos-aqua decomposed just or almost as readily when intimately associated with humic polymers as when added alone to the soils. The association with humic polymers did not influence the distribution of residual activity in humic acid, fulvic acid and extracted soil following incubation.     

土壤水分状况对14C标记秸秆的腐解及腐殖质中碳素分布的影响

¹⁴C-tracer technique and closed incubation method were used to study straw ¹⁴C decomposition and distribution in different fractions of newly formed humus under different moisture regimes. Decomposition of straw ¹⁴C was faster during the initial days, and slower thereafter. Decay rate constants of straw ¹⁴C varied from 3.29 × 10^-3 d^-1 to 7.06 × 10^-3 d^-1. After 112 d incubation, the amount of straw ¹⁴C mineralized was 1.17~1.46 times greater in submerged soils than in upland soils. Of the soil residual ¹⁴C, 9.08%~15.73% was present in humic acid (HA) and 31.01%~37.62% in fulvic acid (FA). Submerged condition favored the formation of HA, and HA/FA ratio of newly formed humus (labelled) was greater in submerged soils than in upland soils. Clay minerals affected the distribution of straw ¹⁴C in different humus fractions. Proportion of ¹⁴C present in HA to ¹⁴C remaining in soil was greater in Vertisol than in Ultisol.     

The distribution of the stable carbon isotope (13C/12C) in fractions of soil organic matter

The carbon-isotopic composition of fulvic and humic acid from the A horizons of eight soil types, developed under a wide variety of climatological conditions, was measured. The fulvic acid is always enriched in ¹³C as compared with the humic acid from the same soil by a rather constant factor of 0.9?. The fulvic acids are isotopically closer to the plant source of the organic matter and thus represent an intermediate stage in the formation of humic substances. Depth sections of peat soil showed that carbon isotopes can be used to evaluate the dynamic nature of the fulvic-acid fraction. With depth, a transfer of carbon groups from polysaccharides to fulvic acid is seen. Based on isotopic evidence it is shown that in addition to formation of β-humus, part of the fulvic acid is condensed with depth to a stable humic fraction — humin.     

Selective digestion of the peptide and polysaccharide components of synthetic humic acids by the humivorous larva of Pachnoda ephippiata (Coleoptera: Scarabaeidae)

In order to identify the potential nutrient and energy sources of humivorous beetle larvae, we carried out feeding trials with soil supplemented with specifically ¹⁴C-labeled model humic acids synthesized by peroxidase-initiated radical polymerization, using the cetoniid beetle Pachnoda ephippiata (Coleoptera: Scarabaeidae) as a model organism. Ingestion of soil by the larvae significantly increased the mineralization of humic acids labeled in their peptide (HA-*peptide) or polysaccharide components (HA-*peptidoglycan and HA-*chitin), whereas the mineralization of humic acids labeled in the aromatic components (HA-*catechol) did not increase significantly. Mineralization was accompanied by a reduction of residual radiolabel in the acid-soluble fraction and an increase in the humic acid and humin fractions of the fecal pellets. During the gut passage, the residual label in peptide or polysaccharide components was transformed into acid-soluble products, especially in the alkaline midgut. High-performance gel-permeation chromatography demonstrated that the changes in solubility were accompanied by large changes in the molecular weight of the residual material. The amount of radiolabel derived from the peptide and polysaccharide components recovered from the larval body and hemolymph was significantly higher than that derived from the aromatic component, which supports the hypothesis that humivorous beetle larvae selectively digest the peptide and polysaccharide components of humic substances, whereas the aromatic components of humic substances are not an important source of nutrients and energy. This is also the first experimental evidence that also chitin and peptidoglycan, the major structural polymers in fungal and bacterial biomass, can be protected from microbial degradation in soil by a copolymerization with phenols and might contribute substantially to the refractory nitrogen pool in soil organic matter.     

THE ORIGIN OF SOIL POLYSACCHARIDE: TRANSFORMATION OF SUGARS DURING THE DECOMPOSITION IN SOIL OF PLANT MATERIAL LABELLED WITH 14C

Incubation of soil with ¹⁴C-rye straw for 448 days resulted in the evolution of about 50 per cent of the carbon of the substrate as CO₂ The two main sugars of the straw, glucose and xylose, were degraded to approximately the same extent (70 per cent). The same results were obtained whether the soil was derived from granitic or basic igneous parent material. There was very little transformation of the substrate to galactose, mannose, arabinose, rhamnose, or fucose, and a much slower rate of degradation than with soil incubated with ¹⁴C-glucose over a similar period. Hydrolysis of the soil samples by a preliminary treatment with 5 N H₂SO₄, before treatment with 24 N H₂SO₄, followed by heating with N H₂SO₄ did not release significantly greater amounts of sugar than treatment with 24 N H₂SO₄ and N H₂SO₄ alone. Separate analysis of the hydrolysates showed that 90 per cent of each of galactose, mannose, arabinose, xylose, rhamnose, or fucose had been extracted by 5 N H₂SO₄, but only 50 per cent of the glucose. Fractionation of the straw-soil mixture after 224 days incubation showed that the specific activity of the glucose was higher in the humin fraction than in the fulvic acid, as would be expected if the remaining ¹⁴C were still in the form of unchanged plant material. This evidence that plant polysaccharide persists in soil could explain the presence of much of the xylose in the soil organic matter.     

Comparisons of soil organic matter and its fractions by pyrolysis mass-spectrometry

Pyrolysis mass-spectra from a sample of the A₁-horizon of a soil from southern Spain showed predominant peaks related to furan derivatives similar to those observed from complex polysaccharides in which not only hexoses but also pentoses and deoxyhexoses were constituent units. Smaller peaks, typical for protein materials and phenolic units, were also observed. On the other hand, typical peaks for the methoxyphenols of lignins were very small and indicated only limited amounts of undecomposed lignin residues in this soil sample. Peaks related to benzene or toluene were also very small.Humic acid samples from this soil showed much more prominent signals related to protein materials, benzene and phenolic derivatives and weaker polysaccharide-related signals than did the entire sample. Typical lignin related peaks were small or insignificant. Spectra from the grey or brown humidic acid fractions were much like those of the parent humic acid. Brown humic acid, however, showed stronger signals for nitrogen and sulphur compounds, indicating a higher content of protein-like materials in this fraction. Preparations of humic acid hydrolyzed by 6 N HCl showed in their pyrolysis products a marked increase in phenols and methoxyphenols.In its pyrogram, humin resembled humic acid, but signals for complex polysaccharides were more evident. Lignin-like materials seem not to be higher in this fraction. Hymatomelanic acid showed prominent signals related to polysaccharides and lignin. Pyrograms from the soil polysaccharides showed the characteristic pattern of a complex polysaccharide with the presence of fragments from polymers of amino acids or amino sugars. Fulvic acid spectra showed obvious dissimilarities to those from humic acid in that signals for protein, as well as those related to phenols, were low. Depending upon the isolation method, the fulvic acid preparations showed differing signals related to polysaccharide or phenolic materials.     

Transformation and mineralization of 14C-labeled cellulose, peptidoglycan, and protein by the soil-feeding termite Cubitermes orthognathus

 We performed feeding trials with the soil-feeding termite Cubitermes orthognathus using soil spiked by uniformly ¹⁴C-labeled preparations of cellulose, peptidoglycan, protein, and bacterial cells (Bacillus megaterium and Escherichia coli). When incubated in soil for 8 days in the absence of termites, cellulose and peptidoglycan showed low mineralization rates (0.5% and 0.2%, respectively). However, when termites were present, their mineralization rates strongly increased (21.6% and 30.6%, respectively). The mineralization rate of protein was 12.4% in the control soils and increased to 36.2% in the presence of termites. Mineralization of bacterial cells in control soils occurred in two phases (rapid mineralization during the first 4–5 days and stabilization thereafter). When termites were present, the rates of mineralization of bacterial cells increased and the stabilization phase was abolished. In all cases, radiolabel accumulated in the termites and the solubility of the labeled compounds located in the gut increased strongly. Mineralization was accompanied by transformation of residual carbon from the humic acid fraction to the fulvic acid fraction during gut passage. High-performance gel permeation chromatography demonstrated a strong shift in the size distribution of the residual carbon from high-molecular-weight towards low-molecular-weight molecules in the gut of termites and an accumulation of small molecules in the termite bodies. The present study provides strong evidence that structural polysaccharides of plants and bacteria and microbial biomass are carbon and energy sources for soil-feeding termites. Received: 29 May 2000     

On the components of soil humic acids (part 9)

The carbohydrates in soil organic matter seem to be derived from undecomposed or partially decomposed plant and microbial residues, In soil, these carbohydrates exist chiefly in such from as polysaccharide hemicellulose, and their polyuronide has been the chief object of investigation^1)-3). In various soil, the polyuronide is found in a large quantity in fulvic fraction of soil organic matter and has been considered as important in connection with the physical structure of soil^4),5). According to Lynch ⁵⁾, the carbohydrate content of humic acid is markedly smaller than that of fulvic acid. His work also indicates that a' considerable change is noted in the content and composition of the carbohydrate in humic acid because of the addition of some organic substances to the soils, or of the cultivation of virgin soils. Further, some investigators⁷⁾ believe that uronic acid is introduced into the aromatic structure of the humic acid by changing into pentose and furan. Accordingly, it seems that the role of carbohydrate in the formation of soil humic acid should not be overlooked.     

Degradation and humification of maize straw in soil microcosms inoculated with simple and complex microbial communities

Microbial communities are responsible for soil organic matter cycling and thus for maintaining soil fertility. A typical Orthic Luvisol was freed from organic carbon by thermal destruction at 600°C. Then the degradation and humification of ¹⁴C‐labelled maize straw by defined microbial communities was analysed. To study the role of microbial diversity on the humification of plant material, microcosms containing sterilized soil were inoculated with a natural microbial community or with microbial consortia consisting of bacterial and fungal soil isolates. Within 6 weeks, 41 ± 4% of applied ¹⁴C‐labelled maize straw was mineralized in the soil microcosms containing complex communities derived from a soil suspension, whilst the most efficient communities composed of soil isolates mineralized less than 35%. The humification products were analysed by solution state ¹³C‐NMR‐spectroscopy and gel permeation chromatography (GPC). The analyses of humic acids extracts by solution state ¹³C‐NMR‐spectroscopy revealed no difference in the development of typical chemical functional groups for humic substances during incubation. However, the increase in specific molecular size fractions of the extracted humic acids occurred only after inoculation with complex communities, but not with defined isolates. While it seems to be true that redundancy in soil microbial communities contributes to the resilience of soils, specific soil functions may no longer be performed if a microbial community is harshly affected in its diversity or growth conditions.     

Peanut Straw Decomposition Products Promoted by Chemical Additives and Their Effect on Enzymatic Activity and Microbial Functional Diversity in Red Soil

ABSTRACT

The objectives of the present study were to determine the promotional effect of chemical additives on quality of peanut straw decomposition products and to evaluate the influence of the resulting products on soil biological properties. Straw was mixed with or without chemical additives, such as iron(II) sulfate (FeSO₄), alkali slag, or FeSO₄ combined with alkali slag, and decomposed for 50 days. The decomposition products were used as organic fertilizer and added to red soil for an incubation experiment. The chemical additives increased total organic carbon (C), total nitrogen (N), and available N content but decreased the C:N ratios in decomposition products compared to controls. Adding FeSO₄ gave the highest humic acid content (HA, 30.34 g kg^?1) and ratio of humic to fulvic acid (HA/FA, 0.53) and the lowest ratio of HA absorption value at 465 nm to that at 665 nm (E₄/E₆, 6.05), suggesting high humification of decomposition products. Application of the resulting products to soil increased soil urease and invertase activities. BIOLOG analysis showed that microbial C utilization ability, Shannon–Weaver diversity, and McIntosh evenness indexes were improved by the organic fertilizer promoted by chemical additives. Principal component analysis indicated that microbial community structures were also influenced by different amendments in decomposition products. Our study provides a reference point for acquiring high quality straw compost and improving soil biological functions by organic fertilizer.     

Transformation of organic matter from maize residues into labile and humic fractions of three European soils as revealed by 13C distribution and CPMAS-NMR spectra

The dynamics of incorporation of fresh organic residues into the various fractions of soil organic matter have yet to be clarified in terms of chemical structures and mechanisms involved. We studied by ¹³C‐dilution analysis and CPMAS‐¹³C‐NMR spectroscopy the distribution of organic carbon from mixed or mulched maize residues into specific defined fractions such as carbohydrates and humic fractions isolated by selective extractants in a year‐long incubation of three European soils. The contents of carbohydrates in soil particle size fractions and relative δ¹³C values showed no retention of carbohydrates from maize but rather decomposition of those from native organic matter in the soil. By contrast, CPMAS‐¹³C‐NMR spectra of humic (HA) and fulvic acids (FA) extracted by alkaline solution generally indicated the transfer of maize C (mostly carbohydrates and peptides) into humic materials, whereas spectra of organic matter extracted with an acetone solution (HE) indicated solubilization of an aliphatic‐rich, hydrophobic fraction that seemed not to contain any C from maize. The abundance of ¹³C showed that all humic fractions behaved as a sink for C from maize residues but the FA fraction was related to the turnover of fresh organic matter more than the HA. Removal of hydrophobic components from incubated soils by acetone solution allowed a subsequent extraction of HA and, especially, FA still containing much C from maize. The combination of isotopic measurements and NMR spectra indicated that while hydrophilic compounds from maize were retained in HA and FA, hydrophobic components in the HE fraction had chemical features similar to those of humin. Our results show that the organic compounds released in soils by mineralization of fresh plant residues are stored mainly in the hydrophilic fraction of humic substances which are, in turn, stabilized against microbial degradation by the most hydrophobic humic matter. Our findings suggest that native soil humic substances contribute to the accumulation of new organic matter in soils.     

The process of manganese depositton in paddy soils

Abstract

The changes in quality and quantity of phenolic substances in the decaying process of rice straw in a soil were compared under moist and flooded conditions for 200 days. The amounts of phenolic substances divided into fractions of humic acid and fulvic acid, ether- and butanol-extractable and organic solvent-unextractable fractions, then the amounts of individual phenolic acids were determined. The following results were obtained.

1) Alkali-extractable total phenolics as well as individual phenolic acids decreased more rapidly under moist, than under flooded, conditions as rice straw decayed in the soil. The phenolics present were mainly attributable to the straw, not to the soil.

2) The decrease in the level of total phenolics in the early stage of the decaying process was mainly due to the decrease in ether-extractable phenolic compounds in the fulvic acid fraction, and in the later stage, was mainly due to the decrease in butanol-extractable phenolics in the humic acid fraction.

3) The amounts of butanol-extractable phenolics and organic solvent-unextractable phenolics were larger in humic acid than in fulvic acid. On the other hand, a larger amount of organic solvent-extractable phenolics, especially ether-extractable phenolics, was present in fulvic acid.

4) The degradation patterns and pathways of individual phenolic acids in the decaying process of rice straw in soil were found to be the lame as those of decaying straw without soil which were reported previously.

5) The level of phenolic substances in the humic acid was not greatly changed during the decaying process, but the phenolic substances in fulvic acid rapidly increased for 30 days and then rapidly decreased to a constant level.     

The fate of catechol in soil as affected by earthworms and clay

The effect of endogeic earthworms (Octolasion tyrtaeum) and the availability of clay (Montmorillonite) on the mobilization and stabilization of uniformly ¹⁴C-labelled catechol mixed into arable and forest soil was investigated in a short- and a long-term microcosm experiment. By using arable and forest soil the effect of earthworms and clay in soils differing in the saturation of the mineral matrix with organic matter was investigated. In the short-term experiment microcosms were destructively sampled when the soil had been transformed into casts. In the long-term experiment earthworm casts produced during 7 days and non-processed soil were incubated for three further months. Production of CO₂ and ¹⁴CO₂ were measured at regular intervals. Accumulation of ¹⁴C in humic fractions (DOM, fulvic acids, humic acids and humin) of the casts and the non-processed soil and incorporation of ¹⁴C into earthworm tissue were determined.Incorporation of ¹⁴C into earthworm tissue was low, with 0.1 and 0.44% recovered in the short- and long-term experiment, respectively, suggesting that endogeic earthworms preferentially assimilate non-phenolic soil carbon. Cumulative production of CO₂-C was significantly increased in casts produced from the arable soil, but lower in casts produced from the forest soil; generally, the production of CO₂-C was higher in forest than in arable soil. Both soils differed in the pattern of ¹⁴CO₂-C production; initially it was higher in the forest soil than in the arable soil, whereas later the opposite was true. Octolasion tyrtaeum did not affect ¹⁴CO₂-C production in the forest soil, but increased it in the arable soil early in the experiment; clay counteracted this effect. Clay and O. tyrtaeum did not affect integration of ¹⁴C into humic fractions of the forest soil. In contrast, in the arable soil O. tyrtaeum increased the amount of ¹⁴C in the labile fractions, whereas clay increased it in the humin fraction.The results indicate that endogeic earthworms increase microbial activity and thus mineralization of phenolic compounds, whereas clay decreases it presumably by binding phenolic compounds to clay particles when passing through the earthworm gut. Endogeic earthworms and clay are only of minor importance for the fate of catechol in soils with high organic matter, clay and microbial biomass concentrations, but in contrast affect the fate of phenolic compounds in low clay soils.     

Decomposition of 14C-labeled glucose,plant and microbial products and phenols in volcanic ash-derived soils of chile

During 4 months from 70 to 79% of the carbon of added glucose, cellulose, and Leuconostoc dextranicus polysaccharide had evolved as CO₂ from normal agricultural soils of Chile and California. The presence or additions of allophanic material reduced losses of glucose C by about 25% and of the C of the polysaccharides by 36–65%. From wheat straw, the polysaccharide fraction of wheat straw, and protein, C losses were 60, 78 and 67%, respectively, in the normal soils. Reductions related to allophane were about 41–67%. For a number of microbial cells, C loss reductions due to allophanic materials ranged from 31 to 55%. Carbon losses from catechol and ferulic acid were more related to reactivities of the phenols, the soil pH, and the organic matter content of the soil than to the presence or absence of allophanic material.     

The influence of humus fractionation on the chemical composition of soil organic matter studied by solid-state 13C NMR

Four samples of soil organic matter and their humic acids, fulvic acids and humin were studied with solid-state ¹³CP MAS NMR. The whole soil samples were fractionated using NaOH and HCl in order to extract humic acids, fulvic acids and humin. This investigation indicates that conventional humus fractionation does not significantly change the content of different functional groups in soil.     

Incorporation of nitrogen from urea fertilizer into soil organic matter in rice paddy and cassava upland fields in Indonesia

Incorporation of newly-immobilized N into major soil organic matter fractions during a cropping period under paddy and upland cropping systems in the tropics was investigated in Jawa paddy fields with and without fish cultivation and a Sumatra cassava field in Indonesia. ¹⁵N-labelled urea (¹⁵N urea) was applied as basal fertilizer, and the soil samples were collected after harvest. The percentage of distribution of the residual N in soil from ¹⁵N urea into the humic acids, fulvic acid fraction, and humin were 13.1–13.9, 19.0–20.5, and 53.4–54.3%, respectively, for the Jawa paddy soils, and 14.9, 27.4, and 52.4%, respectively, for the Sumatra cassava soil. These values were comparable to the reported ones for other climatic zones. The percentage of distribution of ¹⁵N urea-derived N into humic acids was larger than that of total N into the same fraction in all the soils. The distribution into the fulvic acid fraction was also larger for ¹⁵N urea-derived N than for total N in the Jawa soils. Humic and non-humic substances in the fulvic acid fraction were separated using insoluble polyvinylpyrrolidone (PVP) into the adsorbed and non-adsorbed fractions, respectively. Less than 5% of the ¹⁵N urea-derived N in fulvic acid fraction was detected in the PVP-adsorbed fraction (generic fulvic acids). The proportion of non-hydrolyzable N remained after boiling with 6 M HCl in the ¹⁵N urea-derived N was 9.4–13.5%, 17.3–26.7%, and 8.4–16.6% for the humic acids, generic fulvic acids, and humin, respectively. The significantly low resistance to acid hydrolysis suggested that the ¹⁵N urea-derived N was less stable than the total N in soil regardless of the fractions of humus.     

接种微生物条件下牛粪＋麦秸堆腐过程有机组分的动态变化

大量排放的畜禽粪便若利用不当则会对环境构成威胁,经微生物发酵、制成高效有机肥料是粪肥与秸秆综合利用的一种重要方式。试验以牛粪添加不同比例的小麦秸秆为原料,在接种和非接种微生物的条件下进行堆腐,研究了腐解过程有机组分及腐殖物质的动态变化。结果表明,随着腐解进行,乙醇溶性组分含量逐渐降低;水溶性组分含量先升高再降低;半纤维素和纤维素含量随腐解进行呈现一定波动,但总体呈降低趋势;木质素含量呈增加趋势;全碳含量降低,腐殖物质碳占全碳的比例逐渐增加,H/F比值逐渐升高。秸秆的加入比例越高越有利于木质素的积累,牛粪所占比例越大则越有利于腐殖物质的形成。接种微生物可促进有机物料中各有机组分的分解,并有利于腐殖物质的形成。