Some characteristics of the humus in soil types (part 3) composition groups of humus

In most literature on soil, the term humus has been used as synonymous with soil organic matter, on the other hand, it has been applied to a portion of soil organic matter that has decomposed and has lost the structure of the original matter, from which it has derived. Scheffer and Schachtschabel ¹⁾ defined the humus not synonymously with soil organic matter, but, in a broad sense, as all the dead organic substances which are accumulated on the soil surface as well as in the soil layer, and undergo continually decomposition, alteration, and synthetic reactions. According to them, the composition groups of humus are divided into non-humic and humic, and the latter group is sub-divided into (1) fulvic acid and humo-lignin acid, (2) humic acid, (3) humin, and (4) humus coal. Some natures of these composition groups of humus are shown in Table 1.     

现代分析技术在土壤腐殖质研究中的应用

土壤腐殖质的研究已成为土壤学、环境化学和地球化学等领域的热点方向之一。应用核磁共振光谱 (NMR)、红外光谱 (IR)、荧光光谱 (FS)、电子自旋共振谱 (ESR)等现代分析技术 ,对在土壤腐殖质组成和结构研究中取得的主要成果进行了综述。     

Relationships between Collembola,soil chemistry and humus types in forest stands (France)

Soil samples were taken under four tree species in various forest sites located in southern France. For each sampled A horizon of the soil profile, pH, organic matter content, C:N ratio and amounts of exchangeable cations (K, Ca, Mg) were measured, and collembolan fauna was extracted using Berlese-Tullgren funnels. A total of 78 species representing 11 families and 47 genera were identified. The relationships between Collembola and soil parameters were determined by co-inertia analysis which corresponds to the simultaneous Correspondence Analysis of the collembolan data table and the Multiple Correspondence Analysis of the environmental data table. The analysis revealed that the distribution of 10 species was related to pH, organic matter content via C and N and to base cations (K, Ca, Mg). Samples, linking these collembolan species and chemical parameters, were clustered according to humus forms. Collembola seem to be linked closer to the physical structure of humus than to its chemical parameters. Their specific contribution to pedogenetic processes as yet remains to be clarified.     

Formation and transformation of humus substances in terms of coordination chemistry

The applicability of coordination chemistry concepts and the Ingold nucleophilicity-electrophilicity concept for explaining the mechanisms of formation and transformation of the humus-mineral soil system was considered. It was shown that the inorganic anions arriving to the soil can be coordinated not only to metal atoms but also to the carbon and phosphorus atoms from the functional groups of a humus macroligand. This results in the destruction of the humus-mineral system and the humus macroligand itself. Methodological problems related to the isolation of humus substances from the soil and their fractionation were discussed.     

鸡粪腐解过程中不同溶性腐殖质的动态变化

以鸡粪为材料,添加不同比例的铜、锌进行腐解试验,研究了腐解过程中不同溶性(游离态、松结合态、紧结合态)腐殖质及其组成的动态变化和粪肥中所添加高浓度Cu和Zn对不同提取性的腐殖质及其组成的影响.随着腐解的进行,鸡粪中可提取性的有机碳总体呈下降趋势,与总有机碳(TOC)含量变化趋势一致.在整个腐解过程中,NaOH液浸提提取松结合态腐殖质主要部分,占50%～70%.随着粪肥样品锌含量的增加,松结合态腐殖质在整个腐解期平均分配含量有所增加,而NaOH-Na_4P_2O_7液浸提提取紧结合态腐殖质则有所减少,H_2O浸提提取游离态腐殖质变化较小.随着粪肥样品铜含量的增加,松结合态腐殖质在整个腐解期平均分配含量有所增加,而游离态腐殖质则有所减少,但紧结合态腐殖质变化较小.粪肥中Cu、Zn的浓度高低会影响游离态腐殖质中富里酸(FA)和胡敏酸(HA)占TOC比例的变化趋势,铜含量较高的处理样品的松结合态腐殖质FA/TOC(2: 1和3: 1)下降幅度较大,随后皆有上升趋势,30 d后处于近水平状态,铜含量高的处理样品松结合态腐殖质HA/TOC上升幅度较大,随后呈下降趋势.铜含量较高的处理样品的紧结合态腐殖质FA/TOC(2: 1和3: 1)下降幅度较大,随后皆有上升趋势,45 d后又有所下降.在腐解过程中,各处理粪肥样品紧结合态腐殖质HA/TOC曲线表现"马鞍"形状.游离态、松结合态和紧结合态腐殖质的HA/FA分别与其对应的HA/TOC显极显著正相关关系.     

Adsorption strength of zinc for soil humus

In the previous paper (1), the author reported that when zinc sulfate and zinc-EDTA were added to soils, the percentage of exchangeable zinc, which has a lower degree of adsorption strength, to the total zinc adsorbed was higher in mineral soils, and the percentage of chelated zinc, which has higher degrees of adsorption strengths, was higher in humic soils. and that the percentage of chela ted zinc increased with the progress of humification in humic soils.     

Adsorption strength of zinc for soil humus

Soil humus plays a significant role in the cation exchange of a soil. YOSHIDA (1) showed that, as a general rule, divalent ions such as calcium and magnesium were adsorbed more strongly onto humus than monovalent ions such as ammonium and potassium in an ion-exchange reaction. He did not, however, describe the behavior of heavy metal ions. BREMNER et al. (2) first suggested that soil organic matter forms complexes with polyvalent cations. HIMES and BARBER (3) found that soil organic matter reacts with divalent metal ions in a manner similar to the chelation reaction. Reviews of the soil organic matter-metal complex have been written by BREMNER et al. (2) and KAWAGUCHI, MATSUO and KYUMA (4).     

秸秆还田深度对黑土腐殖质和酶活性的影响

在田间条件下对耕地黑土3个土层(0~15、15~30、0~30 cm)进行玉米秸秆还田试验,研究不同秸秆还田深度土壤腐殖质各组分含量、土壤酶活性的变化及其相关性。结果表明:还田深度0~15、15~30、0~30cm土壤总有机碳含量与初始相应层次土壤分别增加9.5%、9.9%、10.7%,与0~15 cm相比,秸秆还田深度为15~30 cm时,有利于土壤有机碳的积累。与初始相应层次土壤比,未秸秆还田的土壤总有机碳含量降低了5.8%。土壤各组分有机碳含量与土壤蔗糖酶活性之间显著(或极显著)相关,土壤胡敏素碳含量与土壤过氧化氢酶活性之间显著相关,土壤富里酸碳含量与土壤脲酶活性之间显著相关。     

Features of natural stability and agrogenic transformation of soil humus

The stabilities of the humus in different soil types (a soddy-podzolic soil from Moscow oblast, a deep typical chernozem from Kursk oblast, and a typical sierozem) have been compared on the basis of long-term studies of the composition, structural features, and properties of the humus acids formed under contrasting climatic conditions. The transformation features of the humic substances under agrogenic impacts of different intensities and durations have been studied by the example of a soddy-podzolic soil as a soil susceptible to environmental changes. The features of degradation of the humus quality and their manifestation at different levels of the structural organization of the humus system have been characterized.     

生物炭对紫色土中腐植酸淋溶的影响

为了减少紫色土腐植酸的流失,提高龙川江流域紫色土肥力,采用土柱室内模拟方法,通过模拟降雨淋溶,研究了不同生物炭处理下(CK、1%、3%、5%和10%)对紫色土淋溶液p H值、电导率、体积以及胡敏酸和富里酸的影响。结果表明:在29 d试验过程中,淋溶液的p H值和电导率随着生物炭比例增加而增加;与CK相比,在1%、3%、5%和10%的生物炭处理条件下紫色土水分损失分别减少了6.33%、10.13%、16.46%和25.32%;胡敏酸浓度和累积淋失量随着生物炭比例增加而减小;除了1%和3%之外,富里酸浓度和累积淋失量也随着生物炭比例增加而减小;生物炭比例为10%的处理条件下对紫色土淋溶液中胡敏酸和富里酸浓度及累积淋失量最小,胡敏酸浓度和累积淋失量分别为1.46 mg/L、0.12 mg,富里酸浓度和累积淋失量分别为149.64 mg/L、29.60 mg,该处理有利于更大程度吸附胡敏酸和富里酸,减少其流失。     

红壤复合胶体腐殖质的特性

对闽北6个样品测定结果表明,红壤复合胶体中C、N含量较高,其腐殖质的C/N和HA/FA、胡敏酸的芳构化度和腐殖质氧化稳定性系数均较重组小,而松结合态/紧结合态腐殖质的比值则较大.这些特性有利于土壤养分保存与供应和改善土壤结构.     

红壤腐殖质组成变化特点及其与肥力演变的关系

本文根据面上采样分析和田间定位试验结果,研究红壤腐殖质组成性质变化特点及其与红壤肥力演变的关系。结果表明,旱地红壤腐殖质的H/F比值主要分布在0.1 ~ 0.4,红壤水稻土主要分布在0.3 ~ 0.7,且有从南到北升高,从东到西降低的变化趋势;红壤腐殖质的H/F比值与土壤有机碳含量呈正相关,但在停止外源碳进入8年后,土壤腐殖质的H/F比值和E4值有升高的趋势,侵蚀降低红壤腐殖质的H/F比;土地利用方式的变更由于改变了系统的物质循环状况,对土壤腐殖质的H/F比有明显影响,荒草地和次生林地改为园地,明显提高土壤有机碳含量和腐殖质的H/F比值。     

On the complex formation between soil humus and polyvalent cations

In 1946 BREMNER et al.(1) suggested a theory that, in soils, polyvalent metals are combined with organic matter as metal-organic matter complexes, and that these complexes are insoluble in solvents that do not themselves form complexes with metals. The principle of one of the most prevailing methods for humus extraction, the neutral sodium pyrophosphate extraction proposed by BREMNER and LEES (2), is a corollary of the theory.     

Contribution of organic amendments to soil organic matter detected by thermogravimetry

Sustainable soil management requires reliable and accurate monitoring of changes in soil organic matter (SOM). However, despite the development of improved analytical techniques during the last decades, there are still limits in the detection of small changes in soil organic carbon content and SOM composition. This study focused on the detection of such changes under laboratory conditions by adding different organic amendments to soils. The model experiments consisted of artificially mixing soil samples from non‐fertilized plots of three German long‐term agricultural experiments in Bad Lauchstädt (silty loam), Grossbeeren (silty sand), and Müncheberg (loamy sand) with straw, farmyard manure, sheep faeces, and charcoal in quantities from 3 to 180 t ha^?1 each. In these mixtures we determined the organic carbon contents by elemental analysis and by thermal mass losses (TML) determined by thermogravimetry. The results confirmed the higher reliability of elemental analysis compared to TML for organic carbon content determination. The sensitivity of both methods was not sufficient to detect the changes in organic carbon content caused by small quantities of organic amendments (3 t ha^?1 or 0.1–0.4 g C kg^?1 soil). In the case of elemental analysis, the detectability of changes in carbon content increased with quantities of added amendments, but the method could not distinguish different types of organic amendments. On the contrary, the based on analysis of degradation temperatures, the TML allowed this discrimination together with their quantitative analysis. For example, added charcoal was not visible in TML from 320 to 330°C, which is used for carbon content determination. However, increasing quantities of charcoal were reflected in a higher TML around 520°C. Furthermore, differences between measured (with TML_110–550) and predicted mass loss on ignition using both organic carbon (with TML₃₃₀) and clay contents (with TML₁₄₀) were confirmed as a suitable indicator for detection of organic amendments in different types of soils. We conclude that thermogravimetry enables the sensitive detection of organic fertilizers and organic amendments in soils under arable land use.     

粘土矿物对土壤腐殖质化学性质的影响

Chemical characteristics of humic substances in soils with different mineralogical characteristics and under different utilization paterns in Zhangpu,Fujian Province,together with two pairs of cultivated soils in North China Plain were studied by chemical analysis,visible and IR spectroscopy and ^13C NMR spectrometry.For soils in Zhanpu the HA/FA ratio and both the aromaticity and the degree of humification of HA were higher in soils with montmorillonite as the predominant clay mineral than in those with kaolinite as the predominant clay mineral,provided these soils were under the same utilization pattern.While for each pair of soils with similar mineralogical characteristics the HA/FA ratio was higher and the C/H ratio and the contnet of carboxyl group of HA were lower in paddy soil than in upland soil.Among the upland soils(or paddy soils)studied the Ha/FA ratio of soil in Zhangpu with kaolinite as the predominant clay mineral was the lowest,and that of soil in Zhangpu with montmorillonite as the predominant clay mineral was the highest .the lowest.and that of soil in Zhangpu with montmorillonite as the predominant clay mineral was the highest It was concluded that the presence of montmorillonite favored the fromation and maturation of humic acid.     

Near-infrared characteristics of forest humus are correlated with soil respiration and microbial biomass in burnt soil

Near-infrared spectroscopy and soil physicochemical determinations (pH_H2O, organic matter content, total C content, NH _inf4 ^sup+ , total N content, cation-exchange capacity, and base saturation) were used to characterize fire-or wood ash-treated humus samples. The spectroscopic and the soil physicochemical analysis data from the humus samples were used separately to explain observed variations in soil respiration and microbial biomass C by partial least-square regression. The first regression component obtained from the physicochemical and spectroscopic characterization explained 10–12% and 60–80% of the biological variation, respectively. This suggests that information on organic material collected from near-infrared spectra is very useful for explaining biological variations in forest humus.     

基于热分析技术的土壤有机质含量和稳定性分析

土壤有机质(soil organic matter,SOM)含量及其稳定性是评价土壤质量的重要指标。传统的化学氧化技术测定SOM时可能氧化不完全,费时费力,容易污染实验室环境;干烧法(例如,元素分析法)分析成本高,而且化学氧化法和干烧法都难以提供SOM稳定性的信息。该文探讨应用热分析技术测定SOM含量及热稳定性的可行性。土壤样品采自位于湖南省宁乡县的稻田施肥长期定位试验,采用湿筛法将耕层土壤样品分为2、0.25~2、0.05~0.25以及≤0.05 mm 4个粒级团聚体,利用热重分析(thermogravimetry,TG)和差示扫描量热分析(differential scanning calorimetry,DSC)技术测定土体及团聚体中SOM含量和稳定性。结果表明:1)土壤中存在2类热稳定性不同的SOM:一类为热易分解型,分解温度为200~350℃;另一类为热稳定性型,分解温度为350~550℃;2)热分析技术测定的土体和团聚体中SOM质量分数范围为4%~8%,而元素分析仪得到的SOM质量分数范围约为3%~6%,热分析法结果比元素分析法的结果平均高估2.10百分点,但二者存在显著线性相关(r=0.88,P=0)。因此,可以利用该系数(2.10%)将热分析技术测定的SOM含量校正为元素分析法测定的结果;3)SOM的热稳定性可以用热易分解SOM占总SOM的比例(Exo1/Exot)和SOM分解一半时的温度(TG-T50)来表征,Exo1/Exot和TGT50呈良好的负相关(r=-0.95,P=0),但Exo1/Exot对SOM的热稳定性更加敏感,因此用Exo1/Exot表征SOM的热稳定性可能更为合理;4)Exo1/Exot与碳水化合物、烷烃类、芳香族的傅立叶转换红外线光谱吸光度以及土壤基础呼吸和微生物代谢熵q CO2呈显著正相关,说明SOM的热稳定性与化学稳定性、生物稳定性存在良好的一致性;5)长期有机肥和化肥配施显著提高了土体及各粒级团聚体的SOM含量,秸秆还田也具有较好的效果,但单施化肥无明显效果;0.25~2 mm粒级的团聚体是贮藏SOM的优势粒级,其次为2和≤0.05 mm的团聚体;6)对于同一粒级团聚体或土体,与单施化肥和不施肥相比,有机肥配施化肥和秸秆还田下的SOM热稳定性有降低趋势;尽管SOM热稳定性在各粒级团聚体和土体中存在一定差异,但是各施肥处理中没有一致规律。利用热分析技术测定SOM含量和热稳定性具有可行性,可以应用于研究农田管理措施对SOM含量和稳定性的影响和综合评价土壤质量。     

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。     

Interaction between humus form and herbicide toxicity to Collembola (Hexapoda)

Laboratory experiments were conducted using intact collembolan communities, exposed to Madit D^®, a phenylurea herbicide (active ingredient isoproturon). Effects were investigated using two distinct humus types, an acid Dysmoder and a neutral Eumull. Within two weeks, no effect of the herbicide was displayed by the Eumull population, while the Dysmoder population was stimulated. When animals were able to escape from the herbicide through a perforated wall separating two compartments filled with natural soil, the behavior of collembolan communities exhibited interactive (non-additive) effects of humus type and herbicide application. The combination of an acid soil (supposedly providing greater tolerance to organic pollutants) with a neutral soil, increased biodiversity of Collembola, but caused the disappearance of some acido-sensitive species, pointing to complex relationships between pesticides, soils and soil organisms. Parallel experiments with single species demonstrated that at the recommended dose Madit D^® may cause avoidance effects, but no toxicity.