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1.
G. Ogner 《Geoderma》1985,35(4):343-353
Crust, felty, greasy and granular raw humus were analysed by wet chemical methods and by 13C NMR. The amounts of amino acids, monosaccharides and aliphatic dicarboxylic acids were determined and the yields compared with the 13C NMR spectra. Protein carbon constitutes 9–13%, polysaccharide carbon 8–19% dicarboxylic acids 1–2% and free carboxylic acid groups 2–4% of the total sample carbon. Degradation of greasy raw humus yields half the amount of monosaccharides and twice the amount of aliphatic dicarboxylic acids found in the other raw humus types. This result is confirmed by 13C NMR. Forty to fifty percent of the soil carbon is unaccounted for among the degradation products identified. Based on estimates of 13C NMR data, the unknown part consists of aliphatic carbon, where the C:O ratio ranges between 1 1.1:1 and 1.8:1. All data indicate great similarity between crust and felty raw humus, whereas greasy raw humus differs clearly from those two. Granular raw humus gives approximately the same amount of degradation products as crust and felty raw humus but differs in its 13C NMR spectrum. The relative proportions of all compounds identified, including aliphatic dicarboxylic acids, are approximately constant, indicating a difference in degree rather than kind of the four raw humus types.  相似文献   

2.
G. Ogner  E.T. Gjessing 《Geoderma》1975,14(2):139-145
The chemical composition of aquatic humus was investigated by permanganate oxidation. Both methylated and non-methylated samples were investigated and the results compared with those of different soil humic fractions investigated earlier.The total amount of oxidation products identified from the methylated sample was 2%, and from the non-methylated sample 0.9%. The composition of the oxidation products from methylated aquatic humus was 42% benzenecarboxylic acid methyl esters (8 different compounds), 43% methoxy-benzenecarboxylic acid methyl esters (12 compounds), 10% dimethoxy-benzenecarboxylic acid methyl esters (4 compounds), and 5% of 1, 2, 3-propanetricarboxylic acid trimethyl ester. The unmethylated aquatic humus yielded 84% benzenecarboxylic acid methyl ester (7 compounds), 7% methoxy-benzenecarboxylic acid methyl esters (2 compounds), and 9% of 1, 2, 3-propanetricarboxylic acid trimethyl ester. Three diazines isolated from methylated material were believed to be artefacts from diazomethane treatment. Two of the diazines have earlier been found by oxidation of methylated soil samples, the third, C10H12N2O6, is an oxidation product of methylated aquatic humus only.Oxidation of aquatic humus yielded more benzenecarboxylic acids and methoxy-benzenecarboxylic acids than soil humic fractions, and less dimethoxy-benzenecarboxylic acids. No aliphatic dicarboxylic acids were detected among the oxidation products of the aquatic humus.The compounds identified are mainly the same as those found by oxidation of different soil humic fractions, although their yields clearly demonstrated that the aquatic humus differed in composition from the soil fractions.  相似文献   

3.
Data on radiocarbon ages of different fractions of humus (humic acids, fulvic acids, and humin) in the profiles of chernozems are analyzed. A chronoecological grouping of humus in modern and buried (fossil) soils is suggested. An increase in the radiocarbon age of humic substances down the soil profile has a stepwise character. It is shown that the 14C content in chernozems decreases down the soil profile more somewhat slower than the 12C content. The dependence of a decrease in the humus content of buried soils on the age of burying is traced for a time span of 800 ka.  相似文献   

4.
We investigated the effect of continuous compost application on humus composition and N fertility of soils in a field subjected to double cropping (paddy rice and barley) for 25 years. Soil samples were collected from three different plots: (a) No-NF, fertilizer containing P and K but no N; (b) F, fertilizer containing N, P, and K; and (c) F+C, fertilizer plus compost. The amounts of total humus, extracted humus, and humic and fulvic acids increased in the order No-NF<F≪F+C. The amounts of humic and fulvic acids were 2.7 and 1.7 times larger in the F+C plot than in the F plot, respectively. The degree of humification of the humic acids decreased in the order No-NF<F<F+C. The absorption curves and 13C-NMR spectra (TOSS method) of the humic acids indicated the presence of lignin-like structure, and its degree was the strongest in the F+C plot. The 13C-NMR spectra showed distinct differences in the distribution of carbon species between humic and fulvic acids. In humic acids, the content of aromatic-C, ranging from 37 to 44%, was the highest among carbon species. In fulvic acids, the content of O-alkyl-C, ranging from 45 to 51%, was the highest. The amounts of phosphate buffer-extractable N (PEON) and total N (TN) increased in the order No-NF<F<F+C. The amounts of PEON and TN were 1.2 and 1.7 times larger in the F+C plot than in the F plot, respectively. Present and previous findings indicated that continuous compost application could improve various properties of soils in a field subjected to long-term double cropping.  相似文献   

5.
Incorporation of labelled 15N and 14C amino acids and nucleic bases into soil humus fractions as well as humus turnover was investigated under field conditions. The dynamics of 15N and 14C incorporation into organic matter was characterized by the following main steps: rapid incorporation of the labelled substance prevailing for the first 1–3 weeks, and decomposition of included labelled fragments prevailing beyond one month after substance addition. The annual turnover rates of N and C in humus fractions due to incorporation of amino acids and nucleic bases were calculated. The turnover rate of N in humus is two to three times that of C. The contribution of amino acids to organic matter generation is about twice as great as that of nucleic bases and other N-containing organic substances. This indicates the important role of amino acids in the humification process and humus turnover. Turnovers of humic acids (0·002 year?1 for C and 0·02 for N) are the most rapid of humic fractions investigated, and humin is characterized by the slowest turnover (0·0002 year?1 for C and 0·007 for N). There are no significant differences in the turnover rates of fulvic acid fractions (0·0002 year?1 for C) with different molecular weight.  相似文献   

6.
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.  相似文献   

7.
Dehydrogenase activity, alkaline phosphatase activity and NH4 +, NO2 − and NO3 − concentrations were monitored in an aridisol treated with three commercially available humic amendments. The materials were of plant residue, lignite and peat origins. The humus plant residues, fulvic acids, with a high content of Kjeldahl-N, sustained high enzyme activities and highest levels of NH4 +, NO2 − and NO3 −. Humus lignite (mainly humic acids) produced the highest dehydrogenase activity, whereas the alkaline phosphatase activity was not as high as that amendment with humus plant residues. The lower activity of alkaline phosphatase could not be attributed to the higher P content of humus lignite. Nitrification was also low, probably due to the low N content of this fertilizer. The amendment of humus peat origin (only humic acids) did not increase enzyme activity or inorganic N concentrations of soil. Our results show that although these materials are widely utilized and recommended as microbial and plant activators, they all behave very differently, and the effects on soil microbiological activity cannot be predicted solely on the basis of their humic and/or fulvic acid contents.  相似文献   

8.
Cyanide adsorption on sesquioxides, clay-minerals and humic substances The adsorption of cyanide (KCN) on sesquioxides, clay minerals, and humic substances at different pH-values was studied. Moreover we looked for the CN-adsorption on L-layers of the humus forms mull, moder and mor. Cyanide was only adsorbed by humic acid. The amount of CN adsorbed increased with increasing pH of the reaction solution. IR-spectroscopic investigations of CN treated humic acids revealed that the cyanide was adsorbed at low pH (<7) as HCN-molecules by formation of hydrogen bonds with COOH-, COH-, OH- and NH2-groups of the humic acid. At pH > 7 the cyanide was mainly adsorbed as CN? by charge transfer with acceptor-molecules such as chinones. The cyanide adsorption of L-layers of humus forms decreased in the order mor > mull > moder. It is surmised that the HCN-molecules were not only adsorbed by humic acids in these layers but also by oxidation products of lignin, pectin, protein, cellulose, and carbon-hydrates of fulvic acids. Solutions of K2HPO4 did not desorb cyanides from humic acids to any great extent.  相似文献   

9.
A combination of thermal analyses and 15N tracer technique for investigation of humic acids Differences in humic acids of two extreme variants of three long-term trials due to a three years intensive fertilization in a pot experiment are also to be found by means of thermogravimetry. Additionally the 15N contents of humic acids were investigated at certain temperatures according to the peaks given by thermogravimetric study. The 15N isotope is also incorporated in higher molecular compounds. The 15N content varies due to differences in humus content and composition of the soils used.  相似文献   

10.
Soil samples from the A horizon of an Eutrochrept under spruce forest and permanent grass were fractionated into clay-, silt- and sand-size separates. Humic acids extracted from each fraction were analysed by pyrolysis-gas chromatography-mass spectrometry. Protection of functional groups by simultaneous pyrolysis and methylation yielded pyrolysates in which methyl esters of fatty acids, aliphatic dicarboxylic acids, abietic acids, phenolic acids and benzenecarboxylic acids were represented. However, methylation was not complete, and unmethylated compounds were also present. Spectra showed differences in humic acid composition between size separates as well as across land use regimes. The abundance of lignin-derived pyrolysis products increased with decreasing particle size, and was greater in soil under spruce than in soil under grass. Also, the lipid components differed, with hexadecanoic and docosanoic acid methyl esters being the dominant compounds in humic acids from soil under spruce and hexadecanoic and octadecanoic acid methyl esters in the humic acids from grassland. A good correlation was found between previous 13CNMR and wet chemical data and pyrolysis data, indicating that pyrolysis-methylation can be used for fast detailed chemical characterization of humic acids extracted from size separates.  相似文献   

11.
The humus status of young different-aged soils developed on tailings of different quarries of Quaternary and pre-Quaternary raw materials in Leningrad oblast was studied. Organic profiles were characterized; the humus accumulation rates, the organic matter reserves, the humus enrichment with nitrogen, the degree of humification of the organic matter, and the contents of separate fractions of humus acid in soils on different tailing rocks were estimated. The composition of humic acids was also studied. It was shown that the lithological features of the tailings determining the chemical processes of the profile differentiation of humic substances and the ecogenetic successions of vegetation also determine the rate and direction of the humus accumulation in the soils during similar periods of biological activity in the southern taiga.  相似文献   

12.
Changes in the humus status of acid brown forest soils used for tea growing have been studied in a long-term stationary experiment after 20 years of the application of mineral fertilizers in increasing doses. It is shown that long-term tea growing has resulted in a reliable increase in the humus content within the upper cultivated horizon (Ap, 0–40 cm) at the expense of the nonhydrolyzable fraction of humus (humin) and the first fractions of humic and fulvic acids. The fractional composition of humus has changed against the background of a stable fulvate type of humus (Cha/Cfa < 0.5). The portion of the first fraction of humic and fulvic acids in the total amount of humus has increased, as well as the portion of the first fraction of humic acids in the total amount of humic acids. These changes are due to the enhanced humification of plant residues with a parallel decrease in the contents of the second (Ca-bound) and third (bound with clay and stable sesquioxides) fractions of humic substances.  相似文献   

13.
作物秸秆碳在土壤中分解和转化规律的研究   总被引：12，自引：4，他引：12  
采用14C标记秸秆,在大田和实验室的研究结果表明,秸秆的分解速率主要取决于C/N比。施入土壤后,土壤微生物迅速增加,尤其是细菌。秸秆降解首先形成非结构物质,其中大部分转化为富里酸,进而转化为胡敏酸。分解产物对土壤腐殖质的更新,从腐殖质表面官能团或分子断片开始,逐步进行。非结构物质可与腐殖酸的单个分子产生交联作用,在一定条件下,交联的复合分子可进入腐殖质分子核心的成分中。腐殖酸单个组分在土壤中的转化和重新分配,仅仅与腐殖质表面官能团的反交换过程密切相关。粘土矿物选择性吸附胡敏酸,而且优先吸附胡敏酸中低分子成分。  相似文献   

14.
An approximate calculation was made for the ion exchange of black humic acids and the related fulvic acids with the cations H+, K+, Na+, Ca2+, Mg2+, Zn2+, Mn2+, Cu2+, Fe3+, and Al3+. The calculation was based on the method of physicochemical simulation, the concepts of the chemical potentials of the elements, the experimental study of the equilibriums, and the determination of the activity coefficients of the monoionic forms of humus acids. Because of the presence of different functional groups, humus acids are considered as two-phase systems with specific activity coefficients for the monoionic forms of these acids in each phase. Examples of experimental studies and practical calculations of ion-exchange equilibriums in wide ranges of humus and solution cationic compositions were compared. Although the proposed approaches require perfecting, they can be used for solving practical problems and controlling equilibriums at the experimental stage.  相似文献   

15.
The results of humus composition analysis of each fraction separated physically from each horizon of the five forest soils used in the last paper (3) were presented.

Regular changes in humus composition were observed with the gradation of horizons and With the decrease in particle size. Most of the humic acids from plant residual fractions belonged to the Rp type; hurnic acids from the L layers showed a tannin-like character which disappeared with the progress of decomposition, and humic acids from the smaller particle fractions of the layers contained a Pg fraction.

As for humic acids from the A horizon, they all belonged to the P or B type and contained a Pg fraction. In addition, it was concluded that the humification process in the mineral layer Was clearly different from that in the organic layer.  相似文献   

16.
Ion exchange equilibriums in a complex of brown humic acids (HAs) and related fulvic acids (FAs) with cations (H+, K+, Na+, Ca2+, Mg2+, Zn2+, Mn2+, Cu2+, Fe3+, and Al3+) have been studied, and the activity coefficients of the acid monoionic forms have been determined. The composition of the stoichiometric cell in the system of black and brown HAs and related FAs in a leached chernozem of the Ob’ region has been calculated with consideration for the earlier studies of the ion exchange properties of black HAs and related FAs. It has been shown that hydrogen, calcium, magnesium, aluminum, and iron are the major components in the exchange complex of humus acids in the leached chernozem with the other cations being of subordinate importance. In spite of some differences between the analytical and calculated compositions of the humus acids, the results of the calculations can be considered satisfactory. They indicate that calculations are feasible for such complex objects as soils, and their accuracy will improve with the expansion of the experimental studies. The physicochemical simulation of the transformation of the humus acid composition under different acid-base conditions shows that the contents of most cations decrease under alkalization, and hydroxides or carbonates become the most stable forms of these cations. Under the acidification of solutions, the binding of alkaline and alkaline-earth elements by humus acids decreases and the adsorption of iron and aluminum by humus acids increases.  相似文献   

17.
We evaluated the effect of soil conservation by weeds on the degradation and generation of humic acids, fulvic acids, and water‐soluble non‐humic substances (WS‐NHS) in a red‐acid soil (Vertic Dystrudept) (Indonesia) from the changes in humus composition and stable carbon isotopic ratio (δ13C). Three plots, a weeded plot (T‐1; the common practice), a plot covered with Paspalum conjugatum Berg., a C4 plant (T‐2), and a plot in which native weeds were allowed to grow (T‐3), were prepared. An incubation experiment determined the δ13C values of the humus fractions generated from Paspalum in soil. Based on the increase in δ13C value, the proportion of total C that originated from Paspalum C after 4 years under coffee was 16 ± 4% in the T‐2 topsoil (0–10 cm). Humic and fulvic acids in the T‐1 topsoil decreased to 46 and 84%, respectively, whilst both increased or remained constant in the T‐2 and T‐3 soils. The WS‐NHS content varied little and was independent of land management. The preferential loss of the humic acids with a smaller degree of humification as assessed by their darkness in colour was shown in T‐1. The decrease in the degree of humification suggested the accumulation of the weed‐derived humic acids in T‐2 and T‐3. In the T‐2 topsoil, 36 ± 2%, 13 ± 3% and 15 ± 2% of C in the humic acids, fulvic acids and WS‐NHS, respectively, were estimated to be Paspalum‐derived after 4 years. The estimated initial C loss during the same period was 17 ± 3%, 14 ± 2% and 7 ± 2%, respectively, for those fractions, which suggests the fastest turnover rate for the humic acids and significant retardation of their degradation in soil colonized by weeds.  相似文献   

18.
《CATENA》2001,43(3):191-202
Changes in humus resulting from up to 20 years' irrigation with slightly saline water were studied in dry steppe soils in southwest Siberia. The amounts of brown humic acids and of the Pg fraction increased with the period of irrigation, and their maximum amounts occurred at greater depths in the profile. Other fractions of humus and humic acids fluctuated within the limits typical of dry steppe soils. The humus therefore remained essentially stable under irrigation for up to 20 years.  相似文献   

19.
I. Absorption Spectra of Some Artificial Humic Acids

It is a well known fact that numerous dark brown or black and amorphous substances cap be produced from organic compounds by purely chemical processes. Some of them are called artificial humic acids, and have been used as a model of soil humic acids by many workers. But it is doubtful whether such artificial humic acids are considered to be a model of soil humic acids, even if there can be found any similarities in their properties. However it may be an useful method for the study of humus formation to compare artificial humic acids with soil humic acids, and to make efforts to find a good model or to prepare artificial humic acids comparable to soil humic acids under laboratory conditions. For this purpose, first of all, the author prepared artificial humic acids from glucose, hydroquinone and lignin, and their absorption spectra were determined.  相似文献   

20.
Humus dynamics in four Austrian forest soils The humus of four Austrian forest soils was characterized by means of a chromatographic and a mass spectrometric (δ13C, δ15N) method. With this combination it was possible to explain changes in the humic acid systems within the profiles. The leaching of humic acids in a Spodo-Dystric Cambisol and therefore the beginning of podsolization could be deduced. In a Stagno-Dystric Gleysol processes of dehumification were determined. The value of non humic substances was enhanced within the profile of a Fluvi-Calcaric Fluvisol. The δ15N-values increased in the four profiles much more with depth than the δ13C-values. This indicated the rapid mineralization of organic nitrogen.  相似文献   

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