Non-exchangeable binding of ammonium and amino nitrogen by Norway spruce raw humus

Summary The capacity of an originally acid Norway spruce raw humus to fix isotopically labelled ammonium and amino nitrogen in a form resistant to cold 1N HCl treatment was studied. The amount fixed was determined after a reaction period of 24 hours (the humus pretreated with propylene oxide), using the amount of labelled N in the HCl-leached humus residue as a basis for calculating the amount of added N fixed. The nitrogen sources used were ammonium chloride, glycine and cyanamide. It was found that the fixation of added ammonium and glycine N was exceedingly low in the H⁺-saturated raw humus (pH 3.3–3.4), but the fixation rate was rapidly increased by increasing the pH during the aerobic incubation. Maximum fixation was obtained at a final pH of 10–11. Within the acid range the fixation was constantly higher for added glycine-N than ammonium-N. On the alkaline side of the neutral point the amount of fixation tended to be similar for ammonium and glycine. In treatments with N¹⁵-labelled ammonium, it was shown that small but fully detectable amount of added N were present in the soluble organic N fraction of the HCl extract, the quantities increasing with increasing soil pH during the incubation. The fixation was increased by increasing temperature and decreased by oxidative pretreatment of the humus before the addition of N. In the nitrogen gas atmosphere the fixation figures were 40 to 50 per cent lower than for corresponding treatments in air atmosphere. When various N compounds were added in equimolar concentrations the highest fixation was recorded for cyanamide. In studying the stability of fixed N to acid hydrolysis, it was found that 54 per cent of the fixed N resisted eight hours' refluxing with 6N HCl, the corresponding figure for the native raw humus N being 19 per cent. About one third of the fixed N was liberated as ammonia during the acid hydrolysis.     

腐殖质呼吸作用及其生态学意义

腐殖质呼吸是厌氧环境中普遍存在的一种微生物呼吸代谢模式.自1996年发现以来,日益成为生态学与环境科学领域的研究热点.在厌氧条件下,一些微生物能以腐殖质作为唯一电子受体,氧化环境中的有机质或者甲苯等环境有毒物质,产生CO2,参与碳循环;同时,腐殖质呼吸作用产生的还原态腐殖质可以还原环境中的一些氧化态物质,如Fe(III)、Mn(IV)、Cr(VI)、U(VI) 、硝基芳香化合物和多卤代污染物.因此,腐殖质呼吸能够影响环境中C、N、Fe、Mn以及一些痕量金属元素的生物地球化学循环,并且能够促进重金属以及有机污染物的脱毒,在水体自净、污染土壤原位修复、污水处理等方面具有积极作用.     

Isolation of protein from humic acid extracted from soil

Summary Chromatography of humic acid in a phenol containing solvent system reveals, in the case of the three types of soil analyzed, the presence of humoprotein containing 11 per cent of nitrogen. Isolation of a humoprotein complex from humic acid, according to the method used by Kirby, followed by paper chromatography allowed the isolation of a protein fraction containing 14.8 per cent nitrogen. This fraction is not dialysable; it has a maximum absorption in ultraviolet light between 260–280 mµ, a small electronegative charge and gives rise to twenty different amino acids. This is the first time that a protein has been separated from humus. Thereby demonstrating that part of the nitrogen contained in humic acid is in the form of protein protected from decomposition.Research supported by the Institut pour l'Encouragement de la Recherche Scientifique dans l'Industrie et l'Agriculture (I.R.S.I.A.).     

不同肥力条件下黑土及其有机无机复合体的腐殖质组成

采用Kumada法研究了不同肥力黑土及其复合体的腐殖质组成.结果表明,黑土培肥后,粉粒和细砂复合体含量增多;土壤及各级复合体游离态和结合态腐殖质含量得到不同程度提高,但游离态腐殖质的腐殖化度降低.这种作用在粉粒和细砂复合体中表现得更为明显.随复合体粒径增大,复合体有机碳含量、腐殖质提取率、游离态腐殖质含量及游离态胡敏酸的腐殖化度等均有降低趋势.胡敏酸分类结果表明,高肥土壤游离态胡敏酸均为R_p型,低肥则为R_p型和B型.随复合体粒径增大,游离态胡敏酸类型变化序列主要为:A型(粘粒)→B型(粉粒)→R_p型(细砂);无论粒径大小,结合态胡敏酸大多为A型.土壤培肥后,可使全土及各级复合体的游离态腐殖质的腐殖化度降低,进而会发生型变.在黑土中,游离态胡敏酸的型变主要体现在粉粒复合体中,结合态胡敏酸的型变主要体现在细砂复合体中.     

Differentiating chernozemic soil organic matter by acriflavine adsorption

Summary 1. Acriflavine adsorption capacities of humic substances are not easy to interpret since factors such as acid pretreatment, strength of extractant, and time and temperature of extraction all affect the data. It is thus difficult to establish with this technique whether qualitative differences exist between organic matter formed under different plant associations. 2. Acriflavine sorption capacity of the acid-precipitable humus extracted may be a measure of the efficiency of humus carbon extraction as related to the organo-mineral complexes in the soil since it correlates negatively with the clay content of the samples. 3. Acriflavine adsorption values of the acid-precipitable humus of the aeolian soils are likely to represent true or total sorption capacities of this fraction in these soils, because the clay content of these soils is low and thus extraction of those sites responsible for the acriflavine sorption reaction will be more complete.     

Humate-induced activation of human granulocytes

Naturally occurring humic substances are particular chemical compounds which are found in humus. They bind to carbohydrates, amino acids and steroids by means of hydrogen bonds, covalent bonds and epsilon donor-acceptor complexes. Three specimens of low-molecular humic substances were tested (two naturally occurring humates and one synthetically prepared humate). They were all capable of stimulating certain functions of human neutrophils (PMN), such as the respiratory burst which results in the production of toxic oxygen compounds. This PMN stimulation can be demonstrated with the help of chemiluminescence, as well as by cytochemistry and with the electron microscope. The main product of the humate-induced PMN response is H2O2. There was no activation of neutrophilic chemokinesis or chemotaxis. It is suggested that the low-molecular humic substances originating from decaying organic material contain chemical structures which can act as signals to change dormant PMN into activated cells.     

添加生化抑制剂和腐植酸的稳定性增效尿素在黄土中的施用效果

采用田间盆栽试验,研究生化抑制剂与生物刺激素腐植酸结合制成的高效稳定性增效尿素肥料在黄土中的氮素转化特征、增产效果和氮素肥料表观利用率,以探明其施用效果,为开发适宜黄土施用的新型增效尿素肥料提供理论依据。本研究以不施氮肥(CK)和施尿素氮肥(N)为对照,在尿素中分别添加腐植酸(F)、N-丁基硫代磷酰三胺(NBPT)、3,4-二甲基吡唑磷酸盐(DMPP)和2-氯-6-三甲基吡啶(CP),以及腐植酸与3种生化抑制剂分别组合(NBPT+F、DMPP+F、CP+F)。结果表明: 与N处理相比,F、NBPT+F、DMPP+F和CP+F处理均能显著提高玉米的产量、叶片叶绿素含量、叶面积指数和植株吸氮量,对土壤铵态氮和硝态氮含量也有显著影响。与单独施用生化抑制剂相比,添加腐植酸可提高玉米叶片叶绿素含量。与CP相比,CP+F玉米的植株吸氮量、叶绿素含量、氮肥吸收利用率均显著提高;与NBPT相比,NBPT+F硝化抑制率提高10.7%,但玉米产量、叶面积指数、植株吸氮量和氮肥利用率等均有所降低;与DMPP相比,DMPP+F显著降低了玉米产量、叶面积指数、植株吸氮量、氮肥利用率和硝化抑制率等。综合玉米产量、植株吸氮量、氮肥吸收利用率以及土壤铵态氮、硝态氮含量等指标,在黄土地区施用尿素肥料时,建议添加腐植酸和CP以提升尿素性能,从而提高产量和肥料利用率。     

The transformation of nitrogen and carbon in the soil during humification of straw labelled with N15

Summary Laboratory tests were made on the effect of NaNO₃ or (NH₄)₂CO₃ on the dynamics of humification in the soil of oat straw tagged with N¹⁵. The mixture was incubated for 112 days, at constant temperature and moisture conditions. It was found that NH₄-N accelerated the straw humifications more than NO₃-N. Humification started directly after the straw was introduced into the soil. N¹⁵ derived from straw consituted a part of the forming humic compounds. Already after 14 days of incubation, the N¹⁵ of straw was found in all fractions of humic compounds. Mineralization accompanied humification. The added inorganic-N accelerated not only straw humification, but also the mineralization of forming humic compounds. This is why the added inorganic-N had no influence on the content of humic compounds. The decisive factor in the increase of humic and fulvic acids in the soil, was the straw. The inorganic N added to the straw, had no influence on the quality of humic acids formed in the soil.     

腐殖质在环境污染物生物降解中的作用研究进展

腐殖质物质在地球的生态环境中大量存在,它不仅可以在有毒化合物的生物降解和生物转化过程中起到氧化还原中间体的作用,加速有毒物质的降解和转化。也可以作为唯一末端电子受体,接受来自一些有机酸或者甲苯等环境中有毒物质提供的电子,偶联能量的产生,支持菌体的生长,形成一种新的细菌厌氧呼吸形式——腐殖质呼吸。因此,对腐殖质在环境有毒物质的生物降解和生物转化过程中的作用进行研究,不仪对于深入理解细菌呼吸的本质具有重要的理论意义,而且对于环境有毒物质的降解和转化以及元素的生物地球化学循环具有重要的生态学意义,同时对地球表面的有毒物质进行更有效的生物降解具有重要的现实意义。     

Immobilization and mineralization of tracer nitrogen in forest raw humus

Summary A series of laboratory incubation experiments was conducted to provide information about the effects of soil temperature on the nitrogen interchange in forest raw humus after addition of different forms of nitrogen fertilizers enriched with the N¹⁵-isotope.A positive correlation between temperature and immobilization of nitrogen (non-extractable inN KCl) added as urea-N¹⁵, was found at temperatures of 4°, 12°, and 20°C. When ammonium was added as the source of nitrogen the data indicated a gradual and continual immobilization of tracer nitrogen throughout the entire 90 days experimental period at temperatures of 4° and 12°C. At an incubation temperature of 20°C the amount of immobilized tracer nitrogen reached a relatively low but almost constant level within 10 days.A positive correlation between incubation temperature and the overall nitrogen turnover was found in the raw humus after the nitrate application. Within 3 days of incubation significant net re-mineralization of added tracer nitrate nitrogen took place at the highest temperature (20°C) used. The data show a negative correlation between incubation temperature and net accumulated nitrite-nitrate nitrogen after addition of urea, while no significant amount of nitrite-nitrate was detected in the humus after the ammonium application.At temperatures of 4° and 12°C the nitrogen added as ammonium as compared with nitrate was more rapidly used in supplying the needs of the micro-organisms decomposing forest raw humus. However, the results reveal that in spite of the presence of ammonium in the system, nitrate nitrogen is included in the pathway of the internal nitrogen cycle. Compared with the ammonium and the nitrate treatment the preferential utilization of nitrogen added as urea generally increased with increasing incubation time and temperature.Contribution from the Forest Soil Fertilization Research Group, Vollebekk, Norway. This work was supported by the Agricultural Research Council of Norway.     

Bioconversion of garden waste,kitchen waste and cow dung into value-added products using earthworm Eisenia fetida

Solid waste management is a worldwide problem and it is becoming more and more complicated day by day due to rise in population, industrialization and changes in our life style. Transformation of industrial sludges into vermicompost is of double interest: on the one hand, a waste is converted into value added product, and, on the other, it controls a pollutant that is a consequence of increasing industrialization. Garden waste, kitchen waste and cow dung were subjected to recycle through vermicomposting by using the epigeic earthworm Eisenia fetida under field conditions. The pH, moisture content, total organic carbon, humus, nitrogen, phosphorous and potassium in vermicompost was analysed. It was found that moisture content, total organic carbon, humus, nitrogen, phosphorous and potassium was high in cow dung, followed by kitchen waste and garden waste. This study clearly indicates that vermicomposting of garden waste, kitchen waste and cow dung can not only produce a value added produce (vermicomposting) but at the same time reduce the quantity of waste.     

Changes in the biological activity of agropyrene on combined application with humus substances in the cultivation ofScenedesmus obliquus (TURP.) krüger

The work is concerned with the question of the effect of humic acids on the biological action of agropyrene, the effective substance from the rootstock of Agropyron repens (L.) P. BEAUV. The test organism was the alga Scenedesmus obliquus (TURP.) KRÜGER, cultivated in mineral solution. The basic biological test was the determination of the number and size of the cells of this alga. It was found that the way in which agropyrene acts on combined application with humus acids depends on which humus fraction is used. It can display a synergic action if humic acid is used, since this substance probably facilitates the penetration of agropyrene into the cells. On the other hand, fulvic acid counteracts the activity of agropyrene and this most probably by mutual binding and blocking of active groups and links.     

The effect of humus fractions on the phosphorylase activity of wheat (Triticum aestivum L.)

The liberation of phosphoric acid from glucose-1-phosphate, catalyzed by phosphorylase was studied in wheat growing in sand cultures with an addition of humic acid and hymatomelanic acid. It was found that the phosphorylase activity of tissues changes under the influence of humic acid very significantly. The maximum activity is reached at 10 mg humic acid/liter. The overground organs are less sensitive, as a stimulation effect is reached there only at 400 mg/liter. The effect of hymatomelanic acid is negligible in comparison with that of humic acid. The observed phenomenon is related to the effect of humus substances on the equilibrium of saccharides and on the distribution of dry matter in the plant.     

Contribution of bacterial cell nitrogen to soil humic fractions

Summary Living cells ofSerratia marcescens, uniformly labelled with¹⁵N, were added to samples of maple (Acer saccharum) and black spruce (Picea mariana) forest soils. After different periods of incubation from zero time to 100 days, the soils were subjected to alkali-acid and phenol extraction to provide humic acid, fulvic acid, humin and humoprotein fractions. Significant amounts of the cell nitrogen were recovered in the humic and fulvic acids immediately after addition. After incubation, less cell, nitrogen appeared in the humic acid and more in the fulvic acid. The amount of cell nitrogen recovered in the humin fraction increased with incubation. Roughly 5 to 10 per cent of the added cell nitrogen was found as amino acid nitrogen from humoprotein in a phenol extract of the humic acid. The data are consistent with the occurrence of co-precipitation of biologically labile biomass nitrogen compounds with humic polymers during the alkaline extraction procedure involved in the humic-fulvic fractionation.     

Anaerobic mineralization of toluene by enriched sediments with quinones and humus as terminal electron acceptors

The anaerobic microbial oxidation of toluene to CO(2) coupled to humus respiration was demonstrated by use of enriched anaerobic sediments from the Amsterdam petroleum harbor (APH) and the Rhine River. Both highly purified soil humic acids (HPSHA) and the humic quinone moiety model compound anthraquinone-2,6-disulfonate (AQDS) were utilized as terminal electron acceptors. After 2 weeks of incubation, 50 and 85% of added uniformly labeled [(13)C]toluene were recovered as (13)CO(2) in HPSHA- and AQDS-supplemented APH sediment enrichment cultures, respectively; negligible recovery occurred in unsupplemented cultures. The conversion of [(13)C]toluene agreed with the high level of recovery of electrons as reduced humus or as anthrahydroquinone-2,6-disulfonate. APH sediment was also able to use nitrate and amorphous manganese dioxide as terminal electron acceptors to support the anaerobic biodegradation of toluene. The addition of substoichiometric amounts of humic acids to bioassay reaction mixtures containing amorphous ferric oxyhydroxide as a terminal electron acceptor led to more than 65% conversion of toluene (1 mM) after 11 weeks of incubation, a result which paralleled the partial recovery of electron equivalents as acid-extractable Fe(II). Negligible conversion of toluene and reduction of Fe(III) occurred in these bioassay reaction mixtures when humic acids were omitted. The present study provides clear quantitative evidence for the mineralization of an aromatic hydrocarbon by humus-respiring microorganisms. The results indicate that humic substances may significantly contribute to the intrinsic bioremediation of anaerobic sites contaminated with priority pollutants by serving as terminal electron acceptors.     

Effects of low pH and humus on the survivorship, growth and feeding of Gammarus pulex (L.) (Amphipoda)

SUMMARY. 1. The toxicity to the freshwater amphipod Gammarus pulex (L.) of soft water (pH6.0) with three concentrations of XAD-extracted aquatic humus was treated in the laboratory.
2. Exposure to pH6.0 water without humus added resulted in 92% mortality after 3 weeks. Humus, added at concentrations of 7 and 20 g Cm ³, decreased the mortality to 80% and 64% in the same period.
3. Surviving animals kept at pH6.0 had a lower growth rate, lower food conversion efficiency and higher body water content than animals kept at pH 7.3.
4. Humus had no significant effects on growth, food conversion or body composition of G. pulex kept at pH 6.0. However, there was a tendency for growth and food conversion to increase, and for body water content to decrease with increased humus concentration. The effects of humus on growth and food conversion of G. pulex observed in this study do not support the contention that humus acts as a free coupler to lower metabolic efficiency. On the contrary, humus tended to benefit food conversion.
5. It is suggested that low concentrations of humus can be directly beneficial to organisms in acidified water in ways other than by complexing toxic metals.     

The influence of humic substances on the molecular weight distributions of phosphate and iron in epilimnetic lake waters

1. The influence of humic substances on the association of free inorganic iron and phosphate with material of larger molecular weight was investigated in epilimnetic samples from two humus‐rich lakes of contrasting ionic strength. After modification of the molecular weight distribution of the humic substances in the samples using dialysis and ultrafiltration, the molecular weight distribution of added radioisotopes ( Fe3+ and PO43?) was assessed using gel filtration chromatography.
2. The association of Fe3+ and PO43? with larger molecular weight fractions (>50 000 and 10 000–50 000 Da) was not in general related to the quantity of humic substances of the same molecular weight in the samples. However, the proportions of Fe3+ and PO43? observed in higher molecular weight peaks were strongly correlated to the quantity of humic substances of the same molecular weight in (a) the 10 000–50 000 Da peak in the sample of low ionic strength at pH 5.5 and pH 7.0, and (b) the> 50 000 Da peak in the sample of higher ionic strength at pH 4.0.
3. It was concluded that humic substances promote the association of Fe3+ and PO43? with higher molecular weight fractions primarily by acting as peptizing agents for inorganic colloids containing Fe and P. Association of Fe3+ and PO43? with material of higher molecular weight via the formation of humic substance‐Fe3+–PO43? complexes was identified but only at specific pH and within specific molecular weight ranges for each of the epilimnetic lake water samples studied.     

Influence of humus substances on the toxic effect of 2-methyl-4-chlorphenoxyacetic acid

Effect of humus fractions on the toxicity of 2-methyl-4-chlorphenoxyacetic acid (MCPA) was examined in water cultures. Humus fractions and different MCPA quantities were added to Richter's nutrient solution used for maize (Zea mays L., cv. Ko?ovská raná) cultivation. The results show that MCPA and humus substances in the applied concentrations intensively influence the maize root system, especially the rhizodermis and apical meristem cells. MCPA reduces ion absorption, induces phosphorus excretion from root, reduces tissue hydratation and relatively quickly kills these cells, at the end stage and/or in the highest concentration. Humus fractions have an unambiguously positive effect on these processes, they increase the cell vitality. When humus substances are applied, the MCPA effect does not appear in potassium and nitrogen absorption, the inhibitory effect is maintained in phosphorus absorption and in tissue hydratation even with the most effective fraction—with fulvo acids. But all fractions increased the cell vitality of sorption tissue and meristems in the presence of MCPA.     

Nitrogen transformations in limed and nitrogen fertilized soil in Norway spruce stands

Nitrogen transformations in the soil, and the resulting changes in carbon and nitrogen compounds in soil percolate water, were studied in two stands of Norway spruce (Picea abies L.). Over the last 30 years the stands were repeatedly limed (total 6000 kg ha^–1), fertilized with nitrogen (total about 900 kg ha^–1), or both treatments together. Both aerobic incubations of soil samples in the laboratory, and intact soil core incubations in the field showed that in control plots ammonification widely predominated over nitrification. In both experiments nitrogen addition increased the formation of mineral-N. In one experiment separate lime and nitrogen treatments increased nitrification, in the other, only lime and nitrogen addition together had this effect. In one experiment immobilization of nitrogen to soil microbial biomass was lower in soil only treated with nitrogen. Soil percolate water was collected by means of lysimeters placed under the humus layer and 10 cm below in the mineral soil. Total N, NH₄-N and NO₃-N were measured, and dissolved organic nitrogen was fractioned according to molecular weight. NO₃-N concentrations in percolate water, collected under the humus layer, were higher in plots treated with N-fertilizer, especially when lime was also added. The treatments had no effect on the N concentrations in mineral soil. A considerable proportion of nitrogen was leached in organic form.     

Phosphorus Limitation in Boreal Forests: Effects of Aluminum and Iron Accumulation in the Humus Layer

Plant growth in boreal forests is generally considered to be predominantly nitrogen (N) limited, but forested groundwater discharge areas may be exceptions. In this study, we conducted tests to determine whether highly productive forested groundwater discharge areas generally differ from adjacent groundwater recharge areas in terms of humus chemistry and the availability of phosphorus (P) and N to plants. We investigated six forested sites, divided into groundwater discharge and adjacent groundwater recharge areas, in northern Sweden. The humus layers of the forested groundwater discharge areas were clearly distinguished from the adjacent groundwater recharge areas by having higher acid-digestible calcium (Ca) and/or aluminium (Al) and iron (Fe) content and higher organic P and N content. Soil solution inorganic N (NH₄ ⁺ and NO₃ ⁻) and pH were higher in the groundwater discharge areas than in the groundwater recharge areas. The organic P content showed a positive linear relationship to the Al and Fe content in the humus layer, indicating that organic P is associated with Al and Fe compounds in the humus. A plant bioassay using humus substrate from one groundwater discharge area and the adjacent groundwater recharge area found that plants grown in groundwater discharge area humus (with a high P-fixation capacity) increased their biomass upon P fertilization, whereas no growth response was found for N additions. By contrast, plants grown in humus from the groundwater recharge area did not respond to added P unless N was added too. This study suggests that groundwater discharge can affect the nutrient availability of N and P both directly, via increased P fixation due to the redistribution of Al and Fe, and indirectly, via the inflow of groundwater high in Ca and alkalinity, maintaining a high pH in the humus layer that favors in situ N turnover processes. Received 2 March 2001; Accepted 9 November 2001.