蒙脱石对不同施肥处理土壤胡敏酸及其级分的吸附特征Ⅰ.蒙脱石对胡敏酸的

以１７年不同施肥处理土壤胡敏酸为材料,研究不同性质胡敏酸与钙饱和蒙脱石的吸附特征。结果表明,钙饱和蒙脱石对娄土不同施肥处理胡敏酸的吸附曲线可用单表面Ｌａｎｇｍｕｉｒ方程、双表面Ｌａｎｇｍｕｉｒ方程以及Ｆｒｅｕｎｄｉｃｈ方程来描述。由单表面Ｌａｎｇｍｕｉｒ方程计算的有机肥处理（厩肥、秸秆）胡敏酸的吸附量和吸附强度大于无肥、化肥处理。温度升高各处理胡敏酸吸附量增加,但吸附强度下降。双表面Ｌａｎｇｍｕｉｒ揭示,蒙脱石对胡敏酸的吸附呈现高低两种能位的吸附。高能点位的吸附以化学吸附为主,是吸热反应,低能点位的吸附以物理吸附为主,是放热反应。有机肥处理和无肥、化肥处理相比,高能点位吸附相对减弱,低能点位吸附相对增强。     

腐殖物质特异性及其产生机制

腐殖物质(HS)是天然有机质的主体,其组成、结构十分复杂。之所以称其为一类物质,就是基于他们具有不同于其形成前体的化学组成与结构特征的共性,或称"特异性",即在腐殖化过程中形成新的化学组合,甚至是"特异的"结合方式。但经历近200年的探索,人们对这种"特异性"的认识仍然不清楚,并缺少实验上的证据。加之近几年,一些研究结果被不适当的推演,HS的"特异性"更加受到质疑。HS到底有无"特异性"?"特异性"是什么?这涉及HS生物化学的根基,必须进行深入研究和回答。本文对已有的一些研究报道,包括HS的特异性、生物分子单体与HS结构特征的比较、基于生物多样性(进化)的天然生物材料与HS形成、HS形成机理及胡敏酸(HA)、富里酸(FA)形成顺序、矿物黏粒催化与HS形成、异核单量子相干谱(HSQC)和总相关谱(TOCSY)、傅里叶变换离子回旋共振质谱(FT-ICR-MS)和C1s软X射线近边吸收精细结构(NEXAFS)同步辐射技术应用等进行综合评述,并提出HS化学进一步研究的方向。     

长期施肥对黑土团聚体中腐殖物质组成的影响

腐殖物质(HS)是土壤有机质的主体,在土壤固碳方面具有重要作用[1],近些年来,在土壤有机质化学研究中越来越受到重视。团聚体是土壤有机质(SOM)分解转化和HS形成的最主要“场所”,土壤中的一切生物化学活动均在这一骨架内进行(包括土壤腐殖化作用)。在正常的或特定的条件下,不仅微生物主导的腐殖化作用需要合适的“场所”,而且所形成的HS也只有在合适的“场所”或者说与土壤矿质部分相结合才能长时间保存[2-3]。这种“场所”或者说有机无机结合状况,是制约整个土壤固碳反应的关键。但至今为止关于这种“场所”(团聚体)的固碳机制尚不清楚,特别是很少注重HS化学方面。团聚体和HS二者关系密切,不可分割。可以假     

雪被斑块对高山森林凋落叶腐殖化过程中胡敏酸和富里酸累积的影响

高山森林凋落叶腐殖化过程中胡敏酸(Humic acid,HA)、富里酸(Fulvic acid,FA)等腐殖物质的累积是土壤形成和碳吸存的重要途径,并可能受到冬季不同厚度雪被斑块的影响,但一直缺乏必要关注。本文采用凋落物网袋法,于2012/2013年冬季研究了川西高山森林天然形成的不同厚度雪被斑块(厚雪被、中雪被、薄雪被和无雪被)下优势树种岷江冷杉(Abies faxoniana)、方枝柏(Sabina saltuaria)、四川红杉(Larix mastersiana)、红桦(Betula albo-sinensis)、康定柳(Salix paraplesia)和高山杜鹃(Rhododendron lapponicum)凋落叶在不同雪被关键期(雪被形成期、雪被覆盖期和雪被融化期)腐殖化过程中胡敏酸和富里酸累积特征。结果表明:经过一个冬季,6种凋落叶胡敏酸碳和富里酸碳含量在各雪被关键期均表现出随雪被厚度减少而增加的趋势,而净累积量表现出在雪被形成期和融化期随雪被厚度减少而增加、在雪被覆盖期随雪被厚度减少而减少的趋势,且均受到凋落叶初始酸不溶性组分含量的影响。同时,不同雪被斑块下6种凋落叶胡敏酸碳均累积且净累积量为四川红杉康定柳岷江冷杉高山杜鹃红桦方枝柏,而除红桦外的其他5种凋落叶富里酸碳均出现不同程度的降解且降解量为四川红杉高山杜鹃康定柳方枝柏岷江冷杉红桦。这些结果清晰地表明,未来气候变暖情景下冬季雪被的减少可能促进高山森林凋落叶腐殖质累积,但在雪被覆盖不同时期受到雪被斑块特征和凋落叶基质质量的调控。     

人工腐殖化及产品在农业增产中的应用

腐殖质（humic substance,HS）作为农业生产中土壤养分组成的重要指标,在维护土壤地力、碳储存、植物营养及生态环境稳定性等方面具有重大战略意义。然而,由于HS的天然提取源不足,导致HS市场供给需求逐年攀升。鉴于木质素与HS的结构相似,能否采用人工腐殖化方法,精准调控大分子木质素的氧化分解或其小分子衍生物的自由基耦合,生成可媲美甚至超越商业HS作用和功效的类HS产品？该创造性思路对实现我国农业连续增产增收具有极大的经济价值和应用前景。本文简述了天然HS的结构特征和多功能属性,探讨了人工腐殖化的最新理念、方式和机理,对比了人工腐殖化产物与天然HS的差异性,并总结了人工腐殖化产品在农业实践中的潜在应用和价值,旨在为研究者攻克木质素及其衍生物人工腐殖化的科技瓶颈提供理论支撑和技术指导。     

干旱地区有机肥料腐解及腐殖化系数的研究

新疆农田主要施用的三种秸秆肥和三种厩肥,在一年内的腐解率分别平均为71 84%和43 22%,绿肥(油葵)腐解率高达95%～97%;有机肥料的腐殖化系数在18%～27%,平均21 5%;土壤有机质年矿化率一般在4%～12%,平均5%～6%。表明土壤有机质矿化率较高,而有机肥料的腐殖化系数较低,这是新疆农田土壤有机质含量难于提高的两个很重要的原因。     

酸性二甲基亚砜和碱混液提取土壤胡敏酸效率及其特性的比较研究

土壤中的腐殖物质大多数是同无机成分相结合以复合体形式存在，大部分不溶于水。为了研究腐殖物质的本质和特征，需要将腐殖物质同无机成分分离开来。目前最常用的提取剂是NaOH和Na4P2O7或其混合液。含强碱的提取剂虽具有提取效率高等优点，但也存在提取过程中腐殖物质被氧化变性，以及一     

盐含量对餐厨垃圾好氧堆肥腐殖化过程及微生物演变的影响

含盐量过高会对堆肥有机质腐殖化过程产生抑制作用,但作用规律仍不清楚。该研究以餐厨垃圾为研究对象,以不添加盐分的处理为对照,设置添加食用盐的处理作为试验组（添加质量分数分别为0.5%、1%和1.5%）,进行好氧堆肥,研究不同盐分含量对基本腐熟度指标、有机质组成、腐殖质（Humus,HS）的影响,并结合微生物群落结构和相关性统计分析阐明其作用规律。结果表明,4个处理温度、碳氮比（C/N）、有机质组成等达到腐熟要求,但盐分添加提高了堆体电导率（Electrical Conductivity,EC）,添加比例达到1.5%时,高温期缩短至13 d,种子发芽指数（seed Germination Index,GI）降低至65.5%,总有机物降解率降低6.5%,有机质腐殖化过程受到限制。高通量测序和相关性分析的结果表明,添加1.5%盐分主要通过抑制高温双岐菌（Thermobifida）、糖单孢菌（Saccharomonospora）和曲霉（Aspergillus）、毛孢子菌（Trichosporon）的活性,降低总糖、木质纤维素等有机物质的降解和后续HS形成,从而限制餐厨垃圾堆肥过程中腐殖化效果的提升。该研究将为餐厨垃圾等农村有机废弃物处理技术应用提供理论指导。     

苜蓿根际土壤化感潜力的初步研究

通过盆栽试验和发芽实验初步研究了4个生长年限(处理)的苜蓿地土壤化感作用强弱,其抑制活性强弱依次为:三年生苜蓿地>二年生苜蓿地>一年生苜蓿地>休闲地;在相同处理条件下,苜蓿对其他作物的化感作用强于其自毒效应。在一定年限内,苜蓿化感物质通过根系分泌、残茬分解和地上部分淋溶等途径进入土壤中,呈现出逐年富集的趋势。     

农林废弃物对厨余垃圾堆肥腐殖化的影响与微生物驱动机制

高碳源农林辅料复配是实现厨余垃圾好氧堆肥促腐提质的关键技术,但不同辅料对厨余垃圾堆肥过程腐殖化的影响及其相应的微生物驱动机制仍不清楚,从而限制了对辅料的有效筛选与利用。为此,该研究选用园林废弃物、玉米秸秆和西瓜秧3种典型高碳源农林废弃物为辅料,探究其对厨余垃圾堆肥过程有机质腐殖化的调控效果与机制。研究结果表明：相较于园林废弃物和西瓜秧,添加15%玉米秸秆（湿质量）作为辅料,能够有效调节堆体物料结构,富集功能微生物,促进厨余垃圾堆肥产物腐熟度提升,种子发芽指数可达139%。具体而言,西瓜秧蛋白质含量较高,作为辅料能够在堆肥初期促进堆体快速升温,但不利于高温期延续,且产物腐殖化程度较低。相比之下,园林废弃物和玉米秸秆添加可以在高温期和降温腐熟期富集更多Ureibacillus、Bacillus Oceanobacillus和Flavobacterium等具有木聚糖降解和纤维素降解功能的细菌,促进有机质转化为多酚、氨基酸等腐殖质前驱物,进而推动稳定的腐殖酸生成。特别是玉米秸秆作为辅料时有效增加了具有木质纤维素降解功能的细菌,从而能够加速有机质的降解,促进腐殖化提升75%,研究结果为选取适宜的辅料强化厨余垃圾堆肥产品品质提供参考。     

Isoelectric focusing of humic substances on ultrathin polyacrylamide gels: evidence of fingerprint performance

Differentiated interactions between humic substances and isoelectric focusing-carrier ampholytes were demonstrated by comparing specific absorption ratios from the supernatant after precipitation with 2 M HCl and with acid ampholytes (pH 2–4) containing both carboxylic and sulphate groups. An increasingly stronger interaction was observed when comparing soil humic substances to those of synthetic origin or those extracted from young reclaimed soil material. Electrofocusing of the humic substances under study revealed a fingerprint-like quality; the band patterns observed were consistent with the concept of three main fractions.     

Assessment of biogeochemical trends in soil organic matter sequestration in Mediterranean calcimorphic mountain soils (Almería, Southern Spain)

Total soil organic matter levels and humic acid formation processes in mountain calcimorphic soils from Sierra María-Los Vélez Natural Park (Almería, Southern Spain) were found to differ depending on soil use (pine and oak forests, and cleared areas either cultivated or affected by bush encroachment). Biogeochemical indicators such as the concentration of exchangeable cations, or the concentration of the different types of humic substances were neither influenced by the type of vegetation nor soil use. In fact, multidimensional scaling and multiple correlations suggest that soil carbon sequestration processes are controlled by small-scale topographical features and their impact on water holding capacity. From a qualitative viewpoint, there were two more or less defined sets of soils: one set consisted of soils with humic acids with marked aliphatic character, displayed intense 2920 cm⁻¹ infrared band, and had low optical density. The resolution-enhanced infrared spectra suggested typical lignin patterns and well-defined amide bands, which point to a selective preservation of comparatively young organic matter. This situation contrasts with that in other set of soils with low C levels (<20 g kg⁻¹) where humic acids with featureless infrared spectra showed high aromaticity and were associated with perylenequinonic chromophors of fungal origin: this is considered the consequence of overlapping biogeochemical mechanisms involving both microbial synthesis and condensation processes. The results from visible and infrared derivative spectroscopies suggest that the reliability of statistically assessing the biogeochemical performance of the different uses on the site studied in terms of the intensity of the prevailing humic acid formation mechanisms, i.e., accumulation of inherited macromolecular substances in the former set, vs. microbial synthesis including the condensation of precursors of low molecular weight substances in the latter.     

牛粪配施生物质炭的土壤碳净变化率和腐殖物质组成研究

牛粪是农业生产中常用的有机肥,牛粪配施生物质炭是否会提高有机物料在土壤中的碳净变化率是高效利用有机物料重要问题。通过1年田间试验施用常量(M1)和倍量(M2)牛粪、常量(CBM1)和倍量(CBM2)牛粪配施生物质炭对比了短期腐殖物质碳净变化率差异和结构特征。结果表明,与单施牛粪(M1和M2)相比,牛粪配施生物质炭(CBM2)土壤胡敏酸、富里酸和胡敏素的含量增至1.36g·kg~(–1)、2.50g·kg~(–1)和5.03g·kg~(–1);土壤胡敏酸和富里酸碳净变化率分别提高1.18%和3.67%。与施用牛粪相比,牛粪配施生物质炭胡敏酸、富里酸和胡敏素脂族碳和多糖相对含量增加;CBM2处理胡敏酸和胡敏素芳香碳相对含量增加,CBM1处理富里酸芳香碳相对含量增加。表明牛粪配施生物质炭在土壤固碳效果上优于单施牛粪,可形成更多的腐殖物质,提高胡敏酸和富里酸的碳净变化率;同时也有利于腐殖物质脂族碳和多糖相对含量的增加,而生物质炭用量不变的情况下,配施更多的牛粪可增加胡敏酸和胡敏素芳香碳相对含量。施用牛粪或牛粪配施低量生物质炭可使Hu和FA的缩合度增加,氧化度降低,而HA则相反。     

Evaluation of soil quality parameters in a tropical paddy soil amended with rice residues and tree litters

Laboratory and greenhouse experiments were conducted to study the effects of applications of rice residue and Pongamia pinnata and Azadirachta indica leaf litters on biochemical properties (extraction yield of humus, composition of humus, microbial biomass carbon, activities of urease and acid phosphatase) of a lowland rice soil under flooded conditions. Bulk soil sample collected from the Mandya paddy fields was used for the green house trials and the laboratory incubation studies. The organic materials were added at three rates – zero, 25.0 g carbon kg⁻¹ (2.5% C) and 50.0 g carbon kg⁻¹ dry soil (5.0% C). Results showed that tree leaf litter and rice residue at 5.0% C rate decreased instantaneous decay constant (k), there by retarded the rate of C mineralization. Carbon contents of HA increased with the rate of C added. Study of delta–log K values and C contents of humic acids revealed that greatest molecular weight of HA was in the pongamia litter treatment, followed by neem litter and rice residue. Grain and straw yields of rice crop in the pot culture study were statistically correlated to the soil quality parameters. Neem and pongamia tree litter incorporation at 2.5% C could be considered for improving soil health and crop yields of rice under flooded conditions; however, application at higher rates significantly (P ≤ 0.05) lowered total dry matter production in rice, despite favorable soil health parameters such as humic yields, microbial biomass – C content and acid phosphatase and urease activity. Among different soil health parameters, microbial quotient was found to be more sensitive indicator of decline in soil quality.     

不同种植年限苜蓿土壤熟化过程中腐殖质性质的研究

综合研究了陇东黄土高原黄绵土不同苜蓿种植年限土壤的有机质含量、腐殖质组成、形态及胡敏酸的光学特征等.结果表明,随苜蓿种植年限延长,黄绵土土壤有机质含量逐步提高且品质得到改善,开垦地和撂荒地则相反.10～20 a苜蓿地土壤表层至下层松/紧比有升高的规律,说明种植苜蓿主要对20-40 cm土层肥力影响较大.胡敏酸的色调系数(ΔlogK)和相对色度(RF)分析结果进一步表明,苜蓿种植年限在5～15 a间,土壤胡敏酸向着品质提高的方向演化,种植苜蓿时间过长则腐殖质品质下降,胡敏酸结构趋于老化,耕地撂荒胡敏酸品质降低.     

不同水盐处理对苜蓿耗水、品质及产量的影响

为探索河套灌区不同盐分土壤苜蓿生长的适宜水分展开盆栽试验,设置3个水分水平、3个盐分水平和1个对照处理CK,监测不同水盐处理苜蓿现蕾期至初花期土壤贮水变化量、品质及产量。结果表明:(1)相同盐分条件下,植株株高、地上生物量、地下生物量、耗水量及干草产量随灌水量的增加而增大,但苜蓿的增产效应明显降低;相同水分条件下,随盐分增加,苜蓿耗水量及地下生物量整体呈现先增大后减小的变化趋势。土壤含盐量超过3 g/kg,土壤中剩余水分显著增加,且随灌水量增加逐渐增加。(2)土壤含盐量1～3 g/kg,水分胁迫有利于提高苜蓿粗蛋白含量;其中低水处理粗蛋白含量均显著高于中水及高水处理(p0.05);含盐量3～4 g/kg,盐分改变水分胁迫阈值,中水处理粗蛋白含量显著高于低水与高水处理(p0.05)。盐分与水分胁迫下,植株体内氨基酸含量增加,其中F_3W_1处理氨基酸含量最大,为20.90%。对各游离氨基酸及粗蛋白含量进行相关性分析,其中甘氨酸、蛋氨酸与粗蛋白相关性不显著;其他氨基酸与粗蛋白均呈显著正相关(p0.05)。(3)土壤盐分1～2 g/kg,苜蓿的水分利用效率随灌水量增加而降低,土壤盐分超过2 g/kg,苜蓿水分利用效率随灌水量呈现先增大后减小趋势。土壤含盐量1～2 g/kg,水分70%～75%θ_f,干草产量增加,水分利用效率提高;土壤含盐量2～3 g/kg,水分70%～85%θ_f,水分利用效率提高干草产量减小,但差异不显著;土壤含盐量3～4 g/kg,水分85%θ_f以上,苜蓿干草产量增加。该研究结果初步可为盐渍化农田苜蓿种植及合理灌溉提供理论依据。     

Involvement of soluble organic matter in increased plant growth in solarized soils

 Although soil solarization is used to control soil-borne pests, it also results in increased growth response (IGR) of plants, beyond the effect of pest control. IGR is attributed to various abiotic factors (e.g. increased mineral nutrient concentrations) and biotic factors. In this work, we studied the role played by dissolved organic matter (DOM) in soil extracts in the IGR. DOM concentrations were about twice as high in solarized soil than in untreated soil. In two out of three soils, solarization appeared to increase amino acid synthesis, indicating that it had a favorable effect on microbial activity. Elemental composition, carbohydrate levels, E₄ : E₆ ratios and FTIR spectra did not differentiate between DOM extracted from solarized soils and DOM extracted from untreated soils. Growth of corn plants increased with increasing concentrations of DOM. Addition to the soil of DOM extracted from leonardite increased populations of fluorescent pseudomonads, known as beneficial bacteria, and reduced fungal populations. We conclude that the increase in DOM concentration following soil solarization is a potentially positive plant-growth-enhancement factor. Received: 21 June 1999     

Influence of humic acid on water retention and nutrient acquisition in simulated golf putting greens

Humic substances are frequently applied to creeping bentgrass ( Agrostis palustris Huds.) on golf putting greens to improve turf health and are marketed to enhance nutrient acquisition and possibly aid in retaining water in drought prone environments, but information on the role of humic substances in increasing soil water retention is limited. Additionally, it is difficult to separate the beneficial effects of nutrients and other ingredients added to commercial humic formulations from the effects of the pure humic substance. In our study, pure humic acid, tannic and citric acids were added to simulated creeping bentgrass putting greens. The organic acids were applied at normalized carbon rates of 250 mg C per litre by watering solutions through an automated irrigation system. Volumetric water content (VWC) and irrigation frequency, shoot and root growth, and tissue nutrient concentration of the turf were measured. None of the organic acid treatments improved water retention in the simulated greens. The humic acid-treated greens required more frequent irrigation than the untreated greens indicating that they were drying out more quickly. In addition, the addition of humic acid did not result in an increased tissue concentration of nutrients in the creeping bentgrass, top growth or dry shoot mass compared with the other treatments. However, creeping bentgrass root length was greater in the greens treated with humic acid compared with the untreated control.