黑木耳菌糠与牛粪共堆腐腐殖质组成的变化

黑木耳菌糠与牛粪是典型的农业废弃物,两者共堆腐是其资源化利用的最佳途径。本文采用室内培养法,将黑木耳菌糠与牛粪按照10∶0(Ⅰ)、9∶1(Ⅱ)、7∶3(Ⅲ)、5∶5(Ⅳ)、3∶7(Ⅴ)、1∶9(Ⅵ)和0∶10(Ⅶ)7个质量比混合进行为期90d的共堆腐试验,以水溶性物质(WSS)、胡敏酸(HA)、富里酸(FA)和胡敏素(Hu)的碳含量(CWSS、CHA、CFA、CHu)、HA碱溶液E4/E6以及腐殖化指数(CHA/CFA)为评价指标,筛选最佳原料菌糠、牛粪质量比。结果表明:(1)共堆腐中牛粪比例提高可相应增加堆肥的CWSS、CHA、HA碱溶液E4/E6以及CHA/CFA,使CHu有所降低;(2)随时间的延长,堆肥中的CWSS和CHu含量逐渐下降,Ⅰ、Ⅱ、Ⅳ、Ⅵ和Ⅶ处理堆肥的CHA含量先降低再大幅度提高,而Ⅲ和Ⅴ处理的CHA含量呈逐渐增加趋势变化。在各处理中,黑木耳菌糠与牛粪按照7∶3共堆腐更有利于堆肥中CHA的积累,堆肥中HA经历了"先降解再缩合,最终分子复杂程度增加"的过程,混料中黑木耳菌糠比例提高有利于HA分子的复杂化;(3)随堆腐时间延长,除Ⅲ处理的CHA/CFA逐渐增加外,其余各...     

小分子有机物对土壤酶活性及微生物多样性的影响

  目的  稻草还田是黑土地保护的必然要求,但稻草富含木质素,单独腐解较难,能否借助美拉德（Maillard）反应底物对腐殖质形成的激发效应来加速稻草的腐解？  方法  本研究采用室内培养法,以稻草为供试对象,加入适量MnO₂粉末,分别添加葡萄糖（Glucose,Glu）、邻苯二酚（Catechol,Cat）和甘氨酸（Glycine,Gly）的单一、两两组合（Glu-Cat、Glu-Gly和Cat-Gly）溶液及其混合液（Ms）,以添加等体积无菌水为对照,接种EM微生物菌剂,在28 ℃恒温条件下培养90 d,在0、30、60和90 d分别取样进行腐殖质组成分析。  结果  ① 无论是否添加美拉德反应底物,稻草经腐解后水溶性物质碳含量（C_WSS）均有所上升,相比之下,3种美拉德反应底物混合液的添加更有利于C_WSS的提升,其次为Gly;添加美拉德反应底物更有利于胡敏素（Hu）的分解。② 添加不同美拉德反应底物溶液及其混合液的影响下,稻草腐解产物可提取腐殖酸碳含量（C_HE）的变化趋势不一。Glu-Cat处理对C_HE含量的提升作用最大,其次为Glu,而Gly和Glu-Gly处理则不利于可提取腐殖酸（HE）的形成;（3）稻草腐解过程胡敏酸（HA）分子结构先简单而后渐趋复杂,重新缩合的HA分子结构更加简单,Cat-Gly处理更有利于HA的分解,使其分子结构简单化,除此之外的其他处理,与CK相比,均可有效抑制HA分子的简单化,其中,添加葡萄糖的效果最佳,更有利于HA分子结构的稳定性,且可提升C_HA/C_FA,使腐殖质品质得以改善,而Cat不利于腐殖质品质提升、却更易促进Hu的分解。  结论  添加美拉德反应底物更有利于稻草腐解产物C_WSS的提升以及Hu的分解,添加葡萄糖更有利于提升稻草腐解产物HA分子结构的稳定性,进而改善其腐殖质品质。     

不同形态氮素配比对添加玉米秸秆白浆土腐殖质组成的影响

微生物对铵态氮(NH4+)和硝态氮(NO3-)具有不同的生物偏好性,两者电荷恰好相反致使两类离子具有各异的生物化学特征,两者间丰度的比例变化势必会影响土壤腐殖化的方向。论文以添加玉米秸秆的白浆土作为供试对象,通过添加相同氮素数量、不同形态氮素配比(NH4+∶NO3-为4∶1、NH4+∶NO3-为1∶1和NH4+∶NO3-为1∶4),试图揭示其对腐殖质组成变化的差异影响,结果表明:(1)无论外源氮素以何种形态为主,秸秆-白浆土混料中的微生物活性均可获得提升,其对混料中较易利用的水溶性有机碳(CWSS)、可提取腐殖酸(CHE)及胡敏酸(CHA)等组分皆可产生矿化分解作用,相比之下,铵硝等比例供应对CWSS及惰性的胡敏素组分(CHu)均可产生较为强烈的分解转化,在其驱动下,微生物对混料CHA的降解程度最高,使之结构趋于简单的程度最大,但CHA组分在此过程有"再合成"的可能;(2)受到硝态氮占优的供氮影响下,微生物可消耗混料CHE并使之降解片段进入CHu组分,不利于腐殖质活性的增加;(3)微生物利用外源以铵态氮为主的氮素形态更有利于其对CHA中较为简单有机分子片段的降解并使之向富里酸(CFA)转化,有利于腐殖质活性提升。     

鸡粪腐解过程腐殖质结合态铜变化及其与铜淋失的关系

采用H2O、NaOH以及NaOH-Na4P2O7混合液3种浸提剂对不同腐解期鸡粪中的腐殖质结合态铜（HS-Cu）进行提取,在研究腐殖质碳和铜变化的基础上,通过粪肥淋溶试验,研究了铜淋失量变化以及与腐殖质结合态铜的关系。结果显示,鸡粪中以NaOH-Na4P2O7提取的HS-Cu最高,平均占粪肥全铜量的46.8%;其次是NaOH提取的HS-Cu,平均占全铜量的34.5%,H2O提取的HS-Cu最少,仅占全铜量的6%左右。随腐解进行,NaOH-Na4P2O7提取的HS-Cu逐渐增加,而NaOH提取的HS-Cu在腐解50d以前呈增加趋势,而50d以后变化不大;H2O提取的HS-Cu在腐解21d前明显增加,21d后则下降。NaOH-Na4P2O7提取的HS-Cu以胡敏酸结合态（HA-Cu）为主,H2O提取的HS-Cu则以富里酸结合态(FA-Cu)为主;NaOH提取的HS-Cu在腐解50d以前以FA-Cu为主,50d以后则以HA-Cu 为主。粪肥铜淋失量在腐解35d以前随腐解进行逐渐增加,35d以后有所降低;淋失量平均占全铜量的20%左右。铜淋失量与H2O、NaOH提取的HS-Cu或腐殖质碳呈显著正相关,而与NaOH-Na4P2O7提取的HS-Cu无相关。     

长期施肥对土壤腐殖质组成的影响

利用微区 (1m2 ) 16年定位试验研究了不同施肥措施在相同气候条件、轮作制度及相同管理措施下对山东省三大主要土类———棕壤、潮土、褐土腐殖质组成的影响。结果表明长期施用化肥可使三种土壤腐殖质各组分积累 ;氮钾肥提高了土壤腐殖酸碳与有机碳的比值 ,降低腐殖酸活性 (提高HA/FA比值 ) ;与单施化肥比较 ,化肥配施有机肥大幅度增加了土壤胡敏素和腐殖酸数量 ,并降低了土壤胡敏素和腐殖酸的比值     

两种生物质炭对酸性紫色土腐殖质组成的影响

生物质炭的性状与原料中木质纤维含量密切相关,为探明不同原料生物质炭对土壤腐殖质组成的影响,选取玉米秸秆和紫茎泽兰分别作为纤维类和木质类原材料制备生物质炭,向酸性紫色土分别添加5%玉米秸秆生物质炭（MB）和5%紫茎泽兰生物质炭（EB）,测定90 d室内培养期间土壤胡敏酸（HA）、富里酸（FA）、胡敏素（HM）含量以及HA光学性质和元素组成变化。结果表明：MB和EB的比表面积分别为2.32 m²·g^-1和0.72 m²·g^-1,总孔体积分别为42.71 mm³·g^-1和12.59 mm³·g^-1,碳与氢元素摩尔比（C/H）分别为1.91和1.46,氧、硫之和与碳元素摩尔比[（O+S）/C]分别为0.09和0.16,玉米秸秆生物质炭的吸附能力更强、有机质成分的缩合度更大且氧化度更小。与对照（不添加生物质炭,CK）相比,培养结束后,施入生物质炭的土壤HA、FA和HM含量分别显著增加（P<0.05）65.59%~102.82%、85.87%~118.54%和137.25%~161.23%,MB处理对这3种腐殖质含量的增加效应较EB处理更明显。培养结束时添加生物质炭的土壤HA/土壤有机碳（SOC）降低13.53%~27.06%,FA/SOC降低6.81%~18.03%,其中EB处理的降低效应达显著水平;HM/SOC则增加4.58%~11.40%,其中MB处理的增加效应达显著水平。添加生物质炭的土壤HA色调系数（ΔlgK）增加2.40%~5.60%,HA的缩合度（C/H）降低3.51%~11.81%,（O+S）/C增加1.51%~8.74%。总体来看,施入生物质炭均能相对增加腐殖质各组分含量,降低C/H,提高HA的氧化度[（O+S）/C],且纤维类原料（玉米秸秆）生物质炭的效果更明显。纤维类原料（玉米秸秆）生物质炭显著提高了稳定性较高的土壤胡敏素碳比例（HM/SOC）,但降低了土壤HA的稳定性[HA的C/H降低,（O+S）/C增加];木质类原料（紫茎泽兰）生物质炭显著降低土壤胡敏酸碳比例（HA/SOC）和富里酸碳比例（FA/SOC）,对HM/SOC增加效益不显著,反之提高了土壤易分解有机碳比例。     

不同腐解方式下棉秆腐解液对棉花枯、黄萎病菌的化感效应

采用自然腐解与接种微生物人工腐解两种方式分别处理棉秆,研究了两种腐解物水浸提液对棉花枯、黄萎病菌的化感效应。结果显示,两种腐解液对枯、黄萎病菌的菌丝生长及孢子萌发均具有较强的抑制作用,抑制强度整体上随着腐解液浓度的升高而增大。棉秆自然腐解液对枯、黄萎病菌菌丝生长的最大抑制率分别为58.17%、48.16%,对孢子萌发的最大抑制率分别为23.29%、16.22%,对枯、黄萎病菌毒力的有效中浓度（EC50）分别为33.20、45.20g·L-1;人工腐解液对枯、黄萎病菌菌丝生长的最高抑制率分别为71.63%、79.04%,对孢子萌发的最高抑制率分别为35.45%、42.74%,EC50分别为24.18、20.75g·L-1。表明棉秆腐解后具有作为植物源抑菌剂的开发潜力,并且采用人工方式腐解棉秆能有效提高腐解液对棉花枯、黄萎病菌的抑制强度。     

不同有机物料对黑土腐殖质元素组成的影响

采用盆栽试验,研究施用动物粪便、动物残体、草本残体、木本残体5年后对黑土胡敏酸（HA）、富里酸（FA）和胡敏素（HM）元素组成的影响。结果表明：与CK相比,有机物料施用5年后,黑土HA的C、H含量均显著降低,而缩合度及含氮基团数量提高,并以木本残体作用最显著。除动物粪便处理HA的N含量与CK的大致相同外,其余有机处理N含量均显著提高,各处理HA的O含量由大到小依次为木本残体〉草本残体〉动物粪便〉CK〉动物残体,且各处理差异显著。有机物料的施用可以降低FA的缩合度,并以草本残体作用最显著,同时草本残体施用提高了FA的N含量。而动物残体使FA的H含量显著降低。有机物料FA的C含量表现为草本残体〉木本残体〉CK〉动物残体〉动物粪便,而O含量及氧化度由大到小依次为动物残体〉动物粪便〉CK〉木本残体〉草本残体,且各处理间差异显著。有机物料的施用使HMi的C、H含量下降而使O含量上升,并以草本处理作用最显著,同时草本处理也使HMi的N含量降低。施用有机物料使HMc的氧化度、芳香度提高,结构变复杂。     

稻草腐解过程中形成胡敏酸的组成和结构研究

通过稻草腐解实验,采用化学分析方法,研究了稻草腐解过程中土壤胡敏酸的化学特征的动态变化,旨在丰富农作物秸秆还田过程中的胡敏酸化学组成、性质与结构变化的特征。在试验培养条件下,施用稻草后土壤的有机碳含量提高了31.71%,腐殖质含量增加了51.93%,都在90d时达到最大值。施用稻草45d时的PQ值(HA在HS中所占的比例)明显降低,在90d和135d时的PQ值与45d时变化不大。施用稻草后土壤胡敏酸的色调系数(ΔlogK)逐渐减少,相对色度(RF)值迅速增大,胡敏酸的氧化程度和芳构化程度增强。胡敏酸的元素组成以碳为主,含量在52%左右,其次为氧。H/C的比值逐渐降低,O/C的比值不断增大。羧基和酚羟基为主要的酸性基团。羧基含量先降低,后随着腐解的进行,其含量不断升高;酚羟基的含量变化与羧基的含量变化趋势相反;羰基含量逐渐增加。施用稻草会引起紫色水稻土胡敏酸化学组成和结构的变化。     

有机物料对不同作物根系土壤腐殖质组成和结构的影响

为探讨施用有机物料后不同作物根系土壤腐殖质各组分含量和胡敏酸元素组成的变化情况,以吉林农业大学试验田培肥2a的黑土为研究对象,试验选取3种作物(玉米、大豆、白菜),每种作物设4种施肥处理,包括化肥(CK)、玉米秸秆配施化肥、树叶配施化肥和鸡粪配施化肥。采用腐殖质修改法提取水溶性物质(WSS)、胡敏酸(HA)、富里酸(FA)、胡敏素(HM),利用重铬酸钾外加热法测定腐殖质各组分有机碳含量,采用分光光度计法测定HA和FA的光学性质,通过光密度E_4/E_6值和元素组成分析HA的结构变化。结果表明:土壤总有机碳(TOC)和腐殖质各组分有机碳含量均表现为白菜玉米大豆。相比CK,配施有机物料后作物根系土壤TOC、WSS、HA含量分别显著增加5%~8%,34%~55%,8%~20%,FA含量变化不明显。相比树叶和鸡粪,秸秆可显著提高TOC含量;WSS在各物料之间差异不明显;HM含量表现为秸秆树叶鸡粪CK。有机物料对PQ值的影响因作物而异,秸秆和鸡粪对玉米、大豆根系土壤PQ值(HA占腐殖酸的比率)的影响相似,而鸡粪对白菜根系土壤PQ值的影响显著高于玉米秸秆。施用有机物料后HA的E_4/E_6未发生明显改变,FA的E_4/E_6显著提高。有机物料使根系土壤HA缩合度升高,分子结构更加复杂,且有利于HA含氮基团的形成,以秸秆处理作用最好。由此可见,有机物料具有良好的培肥效果,其中鸡粪对白菜根系土壤培肥效果最显著,秸秆与鸡粪对玉米、大豆根系土壤培肥效果相似,均显著高于化肥。     

黑木耳菌糠改良苏打盐碱土效果研究

通过盆栽试验,初步研究了种植黑木耳后的下脚料(即菌糠)对苏打盐碱土的改良作用。结果表明:黑木耳菌糠施入苏打盐碱土后,土壤理化性状发生了显著改善;随菌糠用量的增加,其物理性质主要表现为:土壤团聚能力增强;土壤田间持水能力增强;其化学性质表现为:土壤pH值随菌糠用量的增加而降低,土壤可溶盐组成中CO32-和HCO3-的含量随菌糠用量增加而减少,当菌糠用量达50.0 g/kg时,CO32-消失;Cl-,SO42-含量同全盐量的变化规律一致,随菌糠用量的增加而提高;其可溶盐中Ca2 ,Mg2 ,K 、Na 含量增加。而土壤交换性阳离子组成中Ca2 ,Mg2 含量增加,交换性Na 含量降低,阳离子交换量增加,其碱化度降低。且交换性Ca2 ,Mg2 含量与菌糠用量成正相关关系;交换性Na 含量、碱化度与菌糠用量成负相关关系。即黑木耳菌糠施入苏打盐碱土后,改善其理化性状,创造了宜于作物生长的土壤环境。施用菌糠提高了土壤肥力,在施入菌糠的苏打盐碱土上种植牧草,提高其地上部生物量。菌糠作为有机改良剂改良苏打盐碱土是可行的。     

Variation in the C:N ratio of substrate mineralized during forest humus decomposition

Laboratory incubations of sieved (<2mm) forest humus were used to study the response of C and N mineralization to perturbation. Considerable variation in the ratio of mineralized C to mineralized N was observed. This ratio widened with increasing temperature. At constant temperature, addition of P stimulated CO₂-C evolution and reduced NH₄⁺-N production, also widening the C:N ratio of substrate mineralized. Addition of weak base stimulated mineralization of N more than C, reducing the C:N ratio of substrate mineralized. Addition of weak acid, mineral-N, or excessive amounts of water inhibited CO₂-C evolution while stimulating production of NH₄⁺-N, resulting in a “negative correlation” between the two, and reducing the C:N ratio of substrate mineralized still further.Results were interpreted in terms of effects on microbial biomass. A relatively benign treatment (P addition) may promote microbial growth and respiration, reducing net N availability. A moderate perturbation (addition of weak base) favors new organisms growing partly at the expense of microbial necromass. These organisms will mineralize some necromass-N, increase net N mineralization, and reduce the C:N ratio of substrate mineralized. Under severe conditions (addition of acid) the C:N ratio of substrate mineralized approaches that of the microbial biomass itself, suggesting that the biomass is the primary substrate mineralized. Microbial mortality is likely to be a significant factor affecting the supply of N in field situations, and should be included in any general model of soil N mineralization processes.     

代料地栽黑木耳技术要点

本文得到黑龙江省科学院应用微生物所郭砚翠研究员、中国农科院土肥所张金霞研究员、黑龙江省食用菌中试基地孟继海技术员的悉心指导,在此谨表谢意。　　代料地栽黑木耳技术的应用使我国黑木耳产业有了较快的发展。但在生产中必须规范操作技术,方可达到预期的经济效益。1　菌种     

Progress of the Maillard reaction and antioxidant action of Maillard reaction products in preheated model systems during storage

The progress of the Maillard reaction and the effect of Maillard reaction products (MRPs) on lipid oxidation in preheated model systems containing pregelatinized starch, glucose, lysine, and soybean oil have been studied during storage. The samples, either containing all components or excluding one or more of them, were heated at 100 degrees C for 90 min and then stored for up to 180 days at 25 degrees C. Browning indices and lipid oxidation were measured, and the results showed that, in samples containing oil, the Maillard reaction had a significant rate also at room temperature and confirmed the ability of MRPs to retard peroxide formation. Under the conditions adopted the rate of the Maillard reaction was increased by the presence of the oil and its oxidation products. The antioxidant action of the MRPs was also evaluated using a peroxide scavenging test based on crocin bleaching. The results demonstrated that antioxidant activity developed with increased browning of the samples.     

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

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

Formation of Maillard reaction products during heat treatment of carrots

As indicators of the early stage of the Maillard reaction in carrots, N-(furoylmethyl) amino acids (FMAAs) formed during acid hydrolysis of the corresponding Amadori products were analyzed using RP-HPLC with UV detection. N(ε)-FM-Lys (furosine), FM-Gly, FM-Ala, FM-Val, FM-Ile, FM-Leu, and FM-GABA were identified using synthesized standard material by means of mass spectrometry. Furthermore, N(ε)-carboxymethyllysine (CML) and pyrraline were analyzed as indicators for advanced stages of glycation. For commercial samples with high water content, the formation of Amadori compounds predominates, whereas the advanced stage of Maillard reaction plays only a minor part. Carrot juices, baby food, and tinned carrots showed quite low rates of amino acid modification up to 5%. For dehydrated carrots, significantly higher values for Amadori products were measured, corresponding to a lysine derivatization of up to 58% and nearly 100% derivatization of GABA. Drying experiments revealed great differences in reactivity between the amino acids studied. Whereas furosine reached constant values quite quickly, some FMAAs showed a continuous increase with heating time, indicating that selected FMAAs can be used as a hallmark for the early Maillard reaction to control processing conditions.     

Effects of in-situ straw decomposition on composition of humus and structure of humic acid at different soil depths

Purpose

Returning straw to soil improved soil carbon sequestration capacity and increase soil organic matter. However, in different soil depth, especially in subsoil, there were few studies on the effects of straw decomposition on soil carbon sequestration and the properties of humic substances. Therefore, an in-situ incubation study, with six different straw rates and three different soil depths, was carried out to explore the effects of straw decomposition on soil organic carbon and humic substance composition at different soil depths.

Materials and methods

The experiment was composed of six straw rates: 0, 0.44, 0.88, 1.32, 2.64, and 5.28% of soil dry mass. The maize straw was proportionately mixed with soil and put into nylon bags. Then, the nylon bags were buried in soil at three depths (15, 30, and 45 cm) and the straw decomposition trial lasted for 17 consecutive months in-situ. Soil samples were collected after completion of the field trial. Humic substances were quantitatively and qualitatively analyzed using the modification method of humus composition and the methods specified by the International Humus Association. Fourier transform infrared spectroscopy and fluorescence spectroscopy were used in this study.

Results and discussion

Results indicated that CO₂ concentration increased with increase in soil depth. Compared with the “zero” straw control, soil organic carbon contents in the treatments amended with 1.32, 2.64, and 5.28% maize straw increased significantly, and most accumulations were at 30–45 cm depths. FTIR and fluorescence emission spectra analyses indicated that the addition of straw enhanced the aliphatic structure and decreased the aromaticity of humic acid (HA), that was to say that HA molecular structure approaches to the development of simplification and younger. The maximum change in HA molecular structure was under the 5.28% treatment in the 30–45 cm depth.

Conclusions

Returning maize straw to the subsoil layers is more conducive to the accumulation of soil organic carbon and improvement of the quality and activity of HA and the organic carbon in the subsoil can be renewed.

     

不同栽培模式对光伏大棚黑木耳产量及营养品质的影响

为掌握陇中旱作区不同栽培模式下光伏钢架大棚黑木耳产量及营养品质的变化规律,提高黑木耳产量和品质。以黑木耳品种黑威15号为指示品种,在通渭县光伏基地光伏钢架大棚内对黑木耳进行立体吊袋、棚架层排、塑料袋地栽3种不同栽培模式的比较试验。结果表明,与塑料袋地栽相比,立体吊袋栽培、棚架层排栽培的黑木耳营养品质均有所提升,尤其以总糖、粗蛋白、粗纤维、可溶性糖、总氨基酸等营养成分含量提升明显。立体吊袋栽培表现更优,立体吊袋栽培的黑木耳总糖、灰分、粗蛋白、粗纤维、可溶性糖、总氨基酸等营养成分含量分别较塑料袋地栽提升了46.93%、36.48%、36.25%、68.49%、68.32%、15.89%,差异达显著水平。采用立体吊袋栽培生产时,黑木耳平均生长速度最快,为0.25 cm/d;成品率高,为98.5%;黑木耳原基形成时间和出耳周期短,分别为19、16 d;黑木耳子实体外观品质最优(单耳鲜重最大,耳片的长度和宽度最高),商品等级高;单袋鲜耳总产量、单袋平均干耳产量均最高,分别为1 071.4、85.3 g,分别较塑料袋地栽增加了473.4、26.9 g,增幅为79.2%、46.1%,增产达显著水平,且各茬次鲜耳产量分布最佳。综合考虑认为,立体吊袋栽培模式在陇中旱作区黑木耳生产上有良好的推广应用前景。     

Studies on tile composition of aromatic nuclei of humus

X-ray diffraction analysis of humic acid (1) revealed that. among four types of humic acid. A. D. Rp and P type according to the classification system proposed by Kumada (2), only A type had the distinct diffraction band corresponding to (002) spacing of amorphous carbon. It was also reported that several artificial humic acids prepared from anthraquinone, hydroxyanthraquinone. charcoal. anthracite etc. showed high similarity to A type humic acid in their spectrophotometric properties and stability toward oxidizing reagent (3).     

Effect of earthworms on decomposition processes in raw humus forest soil: A microcosm study

Summary The earthworms Lumbricus rubellus (Hoffmeister) and Dendrobaena octaedra (Savigny) were studied in the laboratory to determine their effects on decomposition and nutrient cycling in coniferous forest soil. CO₂ evolution was monitored, and pH, PO ₄ ^3– –P, NH ₄ ⁺ –N, NO ₃ ^– –N, total N, and total C in the leaching waters were measured. After three destructive samplings, numbers of animals, mass loss, pH, and KCl-extractable nutrients were analysed.The earthworms clearly enhanced the mass loss of the substrate, especially that of litter. L. rubellus stimulated microbial respiration by 15–18%, whereas D. octaedra stimulated it only slightly. The worms significantly raised the pH of the leaching waters and the humus; L. rubellus raised the value by 0.2–0.6 pH units and D. octaedra by 0.1–0.4 units. Both worms increased N mineralization. Although the biomass of both worms decreased during the experiment, the N released from decomposing tissues did not explain the increase in N leached in the presence of earthworms. The worms influenced the level of PO ₄ ^3– –P only slightly.