水稻土的腐殖质组成

土壤的有机质状况与成土条件之间有着紧密的联系。借助于腐殖质形成分析法,ТюРин确定了腐殖质形成过程的地带性规律。他指出,不同发生学土类,其腐殖质形成有着明显的不同^[1]。Кононова把土壤腐殖质看作为一个高分子物质体系,她证明成土条件对腐殖质的影响,不仅表现在分祖形成方面,而且也表现在胡敏酸的本性方面^[2]。另一方面,一些工作表明,有机厦状况的不同又将对土壤形成过程和土壤性质产生不同的影响^[3]。因此,研究土壤的腐殖质状况,不仅有助于对土壤性质的了解,而且可为成土过程,从而为土壤分类提供有益的资料。     

不同熟化度红壤及红壤性水稻土的腐殖质组成及其特性

土壤腐殖质是评价红壤肥力的重要因素^[2],根据前人研究^[8,3,1]:一般土壤腐殖质的含量及组成受土壤地带性的影响。胡敏酸与富啡酸的比值自南向北逐渐递增,红壤胡敏酸与富啡酸的比值小于1。本文着重研究同一地区自然成土因素类同的情况下,红壤通过水旱耕作和培肥,土壤腐殖质的组成及特性的变化。     

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.     

水旱轮作条件下土壤有机无机复合状况的研究

在黄棕壤和灰潮土上进行水旱轮作条件下土壤有机无机复合状况变化的研究表明:1.水改旱有利于促进土壤有机质与土壤矿质部分的复合,增加土壤有机无机复合量,旱改水则使游离态有机质增多。2.水改旱后,土壤所复合的腐殖质中紧结态的相对较多,同时松结态和紧结态腐殖质的易氧化部分增多,能促使结合态腐殖质的氧化更新;旱改水后,松结态腐殖质相对增多,以及松结态和紧结态腐殖质的难氧化部分增多。3.水改旱后可导致土壤腐殖质组分上的差异,即HA-B/FA-B的比值升高;HA-A/FA-A的比值下降。4.水改旱后土壤碳、氮含量除细粘粒复合体中有增加外,其他粒径复合体中的都减少了,而磷、硫含量在粗粘粒和细粘粒复合体中均有明显增加,说明水改旱有利于缩短土壤有机质以及氮、磷、硫养分的循环周期,促进其易矿化性。     

Characters of humus formed under rice cultivation

To characterize the nature of humus in paddy soils, a comparison was made between the properties of humus in paddy soils and those in adjacent unflooded arable soils.

Rice cultivation generally brought about a considerable increase in organic matter and in the PQ-value, with the exception of Andosol-paddy soils in which organic matter tended to decrease somewhat and the PQ-value remained virtually unchanged. The humification degree of humic acid as judged from Δ log k and RF values was generally lowered by rice cultivation except in the case of Yellow soil-paddy soil in which humic acid was originally low in the degree of humification.

The accumulation of poorly humified humic acid may be a characteristic feature common to all paddy soils. These changes by rice cultivation are observed only in the upper part of the profiles, and seem to be associated with seasonally flooded conditions ot paddy soils. Iron oxides accumulated in subsurface soil have virtually no effect on the properties of humus.     

有机物料对白土土壤胡敏酸结构特征的影响

【目的】研究有机物料施入对白土土壤的腐殖质含量组成和胡敏酸(HA)结构特征的影响,为明确不同腐殖质组分对土壤肥力的影响提供理论依据。【方法】供试土壤为江苏省溧阳市南渡镇"白土改良大田示范试验核心区"的南方中低产水稻土(白土)。试验设秸秆还田(ST)、施有机肥(OM)和对照(CK,不施有机物)3个处理,培肥3年。同时采集试验田周围相邻的江苏省耕地质量监测点(2007~2013年)的每年施化肥(LAF)和长期不施肥(NF)的两种处理土壤进行比对研究。分别测定土壤的基本理化性质及其腐殖质含量的组成,并提取土壤胡敏酸(HA)固体样品利用红外光谱和元素分析来进行结构表征。【结果】秸秆还田和施有机肥处理的有机碳、全氮含量明显高于对照;与对照相比,施有机物料土壤HA的E4/E6比值增加,且秸秆还田施有机肥对照。红外光谱显示,试验区域和耕地监测点的不同处理土壤HA均在1650 cm-1处(酰胺I带)和1550 cm-1处(1500~1580 cm-1酰胺II带伸缩振动)有特征吸收。施有机肥和秸秆还田处理土壤HA的2920/1720、2920/1650比值显著大于对照。在元素组成上,OM、ST处理的土壤腐殖质(HA)中C、H、N的含量比均高于CK,相对长期施化肥(LAF)和不施肥(NF)的土壤有明显提高,而氧元素的含量呈降低的趋势;OM和ST处理土壤HA的[H]/[C]和[O]/[C]原子数比均低于CK;与LAF和NF处理相比,试验区域各处理土壤腐殖质的[H]/[C]和[O]/[C]原子数比均有明显降低。【结论】有机物料施入土壤后可增加土壤有机碳含量,改善土壤理化性质,提高作物产量和品质,且施入土壤的有机物料可转化为新的腐殖质,降低土壤的腐殖化程度。土壤腐殖质(HA)的红外光谱分析说明,白土土壤HA具有明显的酰胺类化合物特征。有机物料施入后使得土壤脂族性增强,羧基量减少,芳香度降低;秸秆还田和施有机肥处理与对照相比,土壤HA的[H]/[C]和[O]/[C]比均有下降的趋势,且HA的氮素含量明显增加,这显示有机物料施入后白土土壤腐殖质发生"脱水"过程,同时也反映了白土土壤腐殖质形成的特征。     

我国几种土壤中腐殖质性质的研究

研究了几种土壤腐殖酸的基本性质,其中包括土壤的腐殖质组成,胡敏酸以及富里酸的元素组成,含氧官能团含量,光密度值与芳化度等,计算了E₄与E₄/E₆比值与上述性质的相关系数。结果表明土壤腐殖质组成和性质与其形成条件有着密切的联系,并且有一定的地带规律性。水稻土中有机质含量增加,HA/FA比值变高,其活性HA显著降低,说明水稻土有利于有机质的积累并改变了腐殖质的组成。E₄、E₄/E₆比值与元素组成,C/H比值,含氧官能团及芳化度之间的相关系数表明E₄除了与C%,O%,酚羟基-O%,醌基-O%呈极显著或显著相关外,还与C/H比值及芳化度呈极显著相关,因此E₄值可作为腐殖物质芳化度的一个指标。     

Composition and Structural Features of Calcium—Bound and Iron—and Aluminium—Bound Humus in Soils

Calcium-bound and iron-and aluminium-bound humus extracted from different soils collected from north to south of China were characterized by chemical and spectroscopic methods.Meaningful differences in the composition and structure between them were revealed by ^13 C NMR,visible spectroscopy and elemental analysis.Results showed that the contents of carbon,hydrogen and nitrogen were higher in iron-and aluminium-bound humus than in calcium-bound humus while oxygen content in calcium-bound humus was shown to be higher .The calcium-bound humus had higher C/N and O/C ratios than iron-and aluminiumbound humus.The calcium-bound humic acid(HA1) showed higher E4/E6 ratios than iron-and aluminumboud,humic acid(HA2)while iron-and aluminum-bound fulvic acid(FA2) showed higher E4/E6 ratios than calcium-bound fulvic acid(FA1).An inverse relationship between E4/E6 ratios and aromaticity as determined by 13C NMR spectra was observerd for HA and FA from black soil.The 13C NMR spectroscopy revealed that HA2 was more aromatic than HA1.On the other ,FA1 exhibited a higher aromaticity than FA2.     

太湖流域水稻土的磁化率剖面

土壤磁学是一门新兴的土壤学分支学科。它以研究土壤磁性为中心内容,把现代磁学理论以及磁测、磁查和磁诊断等研究手段和方法应用到土壤学中来^[2]。土壤磁性的强弱,可用磁化率作为指标。土壤磁化率的大小,主要决定于含铁矿物的种类和数量,特别是强磁性矿物(亚铁磁性的磁铁矿Fe₂O₃·FeO和磁赤铁矿γ-Fe₂O₃)的数量。     

母质对新形成腐殖质的影响

本文研究了在旱地和水田条件下,母质对新形成腐殖质的影响.供试物料为紫云英、绿萍、稻草和水葫芦.结果表明:1.除绿萍外,各物料腐解三年后均已分解较完全.腐解产物的C/有机N值和腐殖质组成均随原始物料而异.2.当植物物料和母质相同时,与水田条件下的相比,旱地条件下的腐解产物的C/有机N值大多较窄,中性糖量较高,六碳糖/五碳糖值较宽,腐殖酸的提取率较高.3.当水分条件和植物物料相同时,与第四纪红色粘土中的相比,下蜀黄土中腐解产物的胡敏酸的C/N值大多较窄,六碳糖/五碳糖值和胡敏酸/富里酸值大多较宽.作者认为,二者中腐殖质组成的差别在一定程度上系由于粘土矿物的组成不同所致.     

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.     

珠江三角洲地区土壤与表层沉积物有机质的性质结构研究

通过分析海洋、河流、池塘和稻田四种热带 /亚热带土壤与表层沉积物及用化学方法分离的有机质 ,证明了土壤与沉积物有机质是高度不均匀的 ,除了包括腐殖酸和演化程度较深的干酪根外 ,强调了演化程度更深的碳黑的存在 ,并对不同有机质的来源、性质和结构进行了表征。腐殖酸和干酪根来源于生物体的演化 ,在结构上后者比前者致密 ;碳黑来源于化石燃料和生物体的不完全燃烧 ,具有更致密的结构 ,对有机质的非均质性影响很大。因此可认为 ,系统地研究土壤与表层沉积物有机质的非均质性及组分特征对了解地球表层的生物地球化学过程和疏水性毒害有机污染物在环境中的迁移具有重要的意义。     

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.     

ASI法测定土壤有效磷、有效钾和铵态氮与我国常规分析方法的相关性

用ASI法测定了土壤有效磷、有效钾和铵态氮，并与我国常规分析方法进行了相关性研究。结果表明：（1）ASI—P与Olsen—P呈极显著正相关，其相关系数在水作条件下比旱作条件下高，在酸性条件下比中、碱性条件下高，随着土壤pH值升高，两者的相关系数迅速降低；（2）ASI—K与NH4OAc—K呈极显著正相关，其相关系数在旱作条件下比水作条件下高，在碱性条件下比中、酸性条件下高，且对pH值和水分条件的变化均较敏感；（3）ASI—N比碱解N低得多，且在水作条件的中、酸性pH范围相关性较好。     

长期秸秆还田对土壤肥力质量的影响

从20世纪80年代开始,分别在江苏常熟和江西进贤布置长期定位试验,研究秸秆还田对乌栅土及红壤性水稻土土壤肥力的影响.结果表明:无论是乌栅土还是红壤性水稻土,秸秆与化肥配合施用下,土壤全N、全P、速效P和速效K含量与不施肥的CK处理相比显著提高;另外,红壤性水稻土的秸秆还田土壤全N、全P、速效P含量与单一施用化肥处理相比显著提高(P＜0.05).同样,上述两种土壤的土壤有机质含量较单一施用化肥的处理显著增加,而且从腐殖质的组分分析可知:腐殖酸C、胡敏酸C与富里酸C的比值均显著提高,表明土壤有机质品质得以改善.因此,长期的秸秆与化肥配合施用是提高土壤肥力的有效措施之一.     

Characteristics of organic matter in soil surface horizons derived from calcareous and metamorphic rocks and different vegetation types from the Mediterranean high-mountains in SE Spain

A study was carried out on some basic characteristics of the organic matter in the surface horizons of soils from the two different geological (calcareous and acid metamorphic rocks) and ecological systems under a Mediterranean climate in Southeast Spain. The results show some noticeable differences in soil organic matter composition. This is likely due to typical Mediterranean climate and well adapted vegetation. There is a tendency towards a greater stability for the soil humus formed under slightly alkaline soil in comparison to the slightly acidic environment. The samples taken from the latter environment have a higher content in free organic matter, a lower content in total extractable humin and a greater relative proportion of aliphatic chains and lignin in the humic acids. The results also suggest some differences caused by the type of vegetation (forest and scrubland ecosystems) in the soil humus chemistry, with a more obvious negative effect under reforestations with species of Pinus in an acidic soil environment (a higher content in free organic matter, lesser presence of fungal-derived perylenequinonic pigments in the humic acids, and a higher content in little evolved forms of nitrogen and lignin in the humic acids). In general the organic matter under scrubland and Quercus vegetation is more decomposed and the humus is more evolved than under Pinus vegetation.     

Role of soil organic matter in stabilization of water-stable aggregates in Soils under different types of land use

Three Andosols (used as grassland, upland field, and paddy field) and two Gray Lowland soils (used as upland field and paddy field) were examined to study the role of organic matter in the stabilization of soil aggregates. It was found that prolonged use of Andosols as grassland or as upland field enabled to maintain a higher level of soil organic carbon than use as paddy field. However, paddy soil exhibited a greater aggregate stability (determined by wet-sieving procedure) than soil under upland field or grassland management. Comparison between two Gray Lowland soils also showed that aggregates in the paddy soil were more stable than in the upland field soil. Among organic constituents examined (such as sodium pyrophosphate (SPP)-extractable organic matter and carbohydrates), only the contents of hot water (HW)-extractable carbohydrates of the soils were significantly correlated with aggregate stability. Paddy soils which showed a greater aggregate stability contained a larger amount of HW -extractable carbohydrates in the soils, and a larger amount of HW -extractable carbohydrates regardless of the size of their aggregates compared with other soils. These findings suggest that HW -extractable carbohydrates which represents easily decomposable organic materials may be of special importance for the stabilization of aggregates in the soils.     

石灰性母质对土壤腐殖质组成和性质的影响

本文研究了采自泰安、南京、昆明3地在相近植被类型下的石灰性土壤和非石灰性土壤的腐殖质组成和胡敏酸的结构特征。结果表明,和同一地区的非石灰性土壤相比,石灰性土壤不但胡敏酸/富里酸比值恒较高,活性胡敏酸的相对含量显著较低,且其胡敏酸的芳化度和羧基含量较高,全氮及酰胺态氮的含量较低。看来,土壤呈微碱性反应不仅有利于有机物质腐解过程的进行,而且有利于游离基的形成,从而有利于酚类物质相互之间以及酚类物质与含氮化合物之间的缩聚反应和腐殖酸的脱胺作用的进行。     

不同施肥制度下我国东部典型土壤易分解与耐分解碳的组分特征

【目的】土壤易分解碳库(labile organic carbon,Lab-C)和耐分解碳库(recalcitrant organic carbon,Rec-C)是土壤有机质的重要组分,其组分大小与比例可反映土壤有机碳的周转与固存特性。因此,研究长期不同施肥制度下土壤易分解碳库与耐分解碳库的大小与比例,对土壤养分管理及肥力培育具有重要的意义。【方法】利用我国东部23年长期不同施肥制度下的黑土、潮土、红壤和32年水稻土共四类土壤的典型土样为代表,以不施肥(CK)、施化肥(NPK)、化肥配施秸秆(NPKS)和化肥配施有机肥(NPKM)4个处理土壤,采用颗粒密度相结合的方法,将土壤有机碳分为易分解碳和耐分解碳2个组分,分析了其不同组分碳含量及比例的变化特征。【结果】土壤经该方法分组后,四种土壤的平均质量回收率和碳回收率均超过95%,是一种测定土壤易分解碳和耐分解碳的可行方法。旱作土壤(黑土、潮土和红壤)易分解碳的平均含量为1.91 g/kg低于水田的2.42 g/kg,而易分解碳占总有机碳的平均比例为15.4%,高于水田的9.9%。NPKM处理下,黑土、潮土和红壤易分解碳含量显著高于NPKS、NPK及CK处理(P0.05),较NPK处理增加的比例分别为98.4%、43.7%和71.2%,同时提高了易分解碳占总有机碳的比例,但无显著差异性;NPK和NPKS处理下黑土与潮土易分解碳的含量较不施肥无显著变化,而红壤易分解碳含量较不施肥显著降低(P0.05),降低的比例分别为33.1%和29.6%;水稻土4个处理间易分解碳的含量及其占全碳的比例无显著差异性。四类土壤耐分解碳的含量与总有机碳含量的变化一致,均表现为NPKMNPKSNPKCK。NPKM处理下,四种土壤耐分解碳含量显著增加(P0.05),黑土、潮土、红壤和水稻土较NPK处理增加的比例分别为68.8%、42.7%、17.6%和17.2%,同时耐分解碳占全碳的比例降低;NPKS处理下黑土、潮土和水稻土耐分解碳的含量较NPK处理也增加,对应增加的比例分别为10.9%、15.1%和18.0%。同时,易分解碳和耐分解碳的含量与土壤总有机碳含量之间有极显著的正相关关系。【结论】旱作土壤易分解碳含量比水田土壤更易受不同施肥处理的影响,有机无机配施(NPKM与NPKS)可提高旱作与水田土壤易分解碳与耐分解碳的含量,同时相对提高了易分解碳占全碳的比例,且NPKM处理的效果优于NPKS处理,更优于化肥处理。     

长期施肥红壤性稻田和旱地土壤有机碳积累差异

  【目的】  提高土壤有机碳水平对提升农田生产力有重要意义。基于长期定位施肥试验,比较施肥影响下相同成土母质发育的红壤性稻田和旱地土壤的总有机碳 (TOC) 及其组分的积累差异,以深入理解红壤有机碳的固持及稳定机制。  【方法】  稻田和旱地长期施肥试验分别始于1981和1986年,包含CK (不施肥对照)、NPK (施氮磷钾化肥) 和NPKM (有机无机肥配施) 3个处理,在2017年晚稻和晚玉米收获后,采集两个试验上述处理的耕层 (0—20 cm) 土样,通过硫酸水解法分离土壤活性与惰性有机碳,测定并计算土壤中TOC及其组分的含量及储量,并利用Jenny模型拟合试验期间耕层土壤TOC含量的变化动态,估算土壤固碳潜力。  【结果】  与CK相比,长期施肥可提高稻田和旱地土壤各有机碳组分的含量,且NPKM处理的效果优于NPK处理。相比于稻田土壤,施肥对旱地土壤各有机碳组分含量的提升更加明显。NPK和NPKM处理下,旱地土壤活性有机碳组分Ⅰ、活性有机碳组分Ⅱ、惰性有机碳含量的增幅分别是稻田土壤的2.7、2.7、5.8倍和2.0、1.4和2.5倍。不论施肥与否,稻田土壤TOC的固存量和固存潜力均显著高于旱地土壤。施肥促进土壤固碳,在稻田和旱地土壤上,NPKM处理的TOC固存量分别是NPK处理的1.7和25.5倍,TOC固存潜力则分别是NPK处理的1.4和5.8倍。长期不同施肥均显著提高稻田和旱地土壤年均碳投入量,线性拟合方程表明,随碳投入量增加,土壤活性有机碳储量的累积对稻田、旱地土壤TOC储量累积的贡献率分别达64.7%、44.6%。不同处理间稻田与旱地土壤活性有机碳 (包括活性有机碳组分Ⅰ与活性有机碳组分Ⅱ) 含量的差异可解释其TOC含量差异的52.9%～60.0%。  【结论】  与施氮磷钾化肥相比,有机无机肥配施可更好的促进土壤固碳,且在旱地土壤上的促进作用比在稻田土壤上更为明显。与稻田土壤相比,旱地土壤各有机碳组分含量的变化对长期施肥的响应更敏感,且在施氮磷钾化肥条件下表现更为明显。红壤性稻田和旱地土壤TOC积累的主要贡献组分分别为活性有机碳和惰性有机碳。红壤植稻虽有利于有机碳固持,但红壤性稻田土壤的活性碳占比较高,可能易因不当管理而发生损失。