土壤腐殖质氮结构的X-光电能谱研究

X－ray photoelectron spectroscopy(XPS) was applied to examine the N structures of soil humic substances and some of their analogues.It was found that for soil humic substances XPS method gave similar results as those obtained by ^15N CPMAS NMR (cross-polarization magic-angle spinning nuclear magnetic resonance) method.70%-86% of total N in soil humic substances was in the form of amide,and 6%-13% was presented as ammes,with the remaining part as heterocyclic N.There was no difference in the distribution of the forms of N between the humic substances from soils formed over hundreds or thousands of years and the newly formed ones.For fulvic acid from weathered coal and benzoquinone-(NH4)2SO4 polymer the XPS results deviated significantly from the ^15N CPMAS NMR data.     

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。     

Effects of fractions of coal-derived humic substances on seed germination and growth of seedlings (Lactuga sativa and Lycopersicum esculentum)

Summary Lettuce and tomato seeds were treated in Petri dishes with a humic acid derived from an oxidized coal and with fractions of the same humic acid obtained by ultrafiltration through membranes of known molecular cutoff and by extracting with buffers set at pH 4 and pH 5. The unfractionated humic acid was applied at 40, 100, 1000, and 5000 mg l^-1 whereas the humic fractions were applied at 40, 100, and 200 mg l^-1. Germination parameters such as the number of total germinated seeds, the velocity of seed germination, the fresh weight and dry weight of total seedlings were measured and related to the chemical and physicochemical properties of the humic material. No increase in the germination percentage or the germination rate was observed for either lettuce or tomato seeds. The fresh weight of total seedlings and per seedling increased in treatments with unfractionated humic acid with increasing concentrations for both lettuce and tomato plants without showing signs of growth inhibition up to 5000 mg l^-1. This was attributed to cell elongation and more efficient water uptake. For the lettuce, the fresh weight both of total seedlings and per seedling was enhanced by treating the seeds with fractions of low molecular weight and high content of acidic functions, whereas the dry weight both of total seedlings and per seedling did not change with the humic fraction used. For the tomato seeds in contrast, the dry weight both of total seedlings and per seedling was increased by the use of unfractionated humic acid and by some of the humic fractions. An uptake of humic material by growing tomato seedlings was inferred.     

Responses of phyto- and zooplankton to liming in a small acidified humic lake

Liming resulted in an immediate and transitory decrease of plankton biomass and phytoplankton primary production in the limed part of an acidified humic lake. In the longer term liming has changed species composition and dominance of phyto- and zooplankton. Due to increased transparency and improved oxygen conditions plankton biomass peaked deeper in the water column after liming. During the three years post-liming period phyto- and zooplankton communities have changed less than reported in several other studies. This is largely because liming was carried out well before the collapse of perch population, which has controlled zooplankton both in the pre- and post-treatment period.     

几种有机物对紫色土镉的溶出效应与吸附-解吸行为影响的研究

研究了天然有机物胡敏酸和富里酸 ,螯合剂EDTA和DTPA和四种简单有机酸对紫色土镉的溶出效应和吸附解吸行为的影响。结果表明 ,供试八种有机物均能显著促进镉从紫色土中的溶出。作用大小顺序为 :EDTA≥DTPA >柠檬酸 >胡敏酸 >草酸 >富里酸 >酒石酸≥水杨酸。有机物对土壤镉溶出和迁移的影响是其对土壤镉吸附和解吸综合作用的结果。有机物显著降低了紫色土对镉的吸附 ,其作用大小顺序与其对镉的溶出能力的相对大小顺序一致 ,同时也改变了吸附镉的解吸特性。有机物影响下 ,紫色土镉的吸附动力学模型以双常数方程拟合最佳。而吸附等温曲线以Freundlich方程拟合最好 ,吸附常数n与有机物对土壤镉的溶出率之间存在良好的相关性。     

施用猪粪对棕壤胡敏酸和富里酸热力学参数的影响

应用Vodyanitsky提出的方法，根据元素组成数据，计算了施用猪粪对棕壤胡敏酸(HA)、富里酸(FA)热力学参数的影响。结果表明，HA、FA的形成都是自发进行的放热反应；与HA相比，FA的能态较低，分子结构有序度和热稳定性较高；FA在土壤中比HA更容易形成。施用猪粪后，HA、FA的能态降低，分子结构有序度和热稳定性也降低，形成的自发性减弱且放热量减少，这些与它们元素组成的变化有关。     

山地土壤坡向性分异的研究概况

综述了山地土壤坡向性分异的研究概况,包括土壤生物积累和盐基淋溶的坡向差异,以及坡向对土壤垂直带谱结构的影响。已有研究大多集中在山地土壤垂直带谱的坡向分异,可将其归纳为山地迎风坡与背风坡和阴、阳坡分异两种主要情况。同时,针对目前有关山地土壤坡向性研究的不足,提出了今后研究的重点:从山体不同坡向的对应高度出发,运用现代地理研究方法,研究山地土壤多种属性的坡向性分异及其生产生态意义。     

Bound amino acids in humic acids from arable cropping systems

We investigated the varying concentrations of bound amino acids in humic acids (HA) extracted from soils under both crop rotation and continuous cropping of rye. The experiment was created in 1957. Since then, winter rye had been grown continuously and also the sequence of the 7 yr rotation had been started: potato, spring barley, alfalfa, alfalfa, oil seed rape, winter rye, and winter rye. Soils were fertilized with NPK and manure. Continuous cropping of rye increased total acidity of soils and the contents of carboxylic and phenolic groups in HA. The total amounts of the bound amino acids in HA from soils under crop rotation were higher than from continuous cropping of rye. Fertilization with NPK increased the contents of bound amino acids more than manure. Neutral amino acids dominated in all samples of HA, and basic amino acids had the lowest concentrations. In both types of cultivation, glutamic acids, glycine, alanine, valine, and lysine dominated. The proline contents in HA from continuous rye cropping were higher than in HA from soils under crop rotation. The concentrations of β‐alanine and lysine were higher in HA from crop rotation indicating a higher microbial biomass since these compounds are typical constituents of bacteria cell walls.     

重金属影响下有机物料分解与转化的研究

通过室内培养实验，初步研究了重金属Cd、Pb影响下。猪粪和玉米秸秆在土壤中的分解与转化规律。结果表明；添加重金属后。有机物料的分解与转化和有机物料种类、用量以及重金属类型有关。一般来看，与不添加重金属的非污染土相比。有机物料低用量（1％用量）条件下。单加Cd有抑制其分解的趋势，单加Pb则有促进其分解的趋势．同时加Cd、Pb也有抑制其分解的趋势；而高用量（5％用量）条件下，无论单加还是同时加Cd、Pb都有抑制其分解的趋势。有机物料低用量时更有利于胡敏酸（HA）形成，而高用量时则更有利于富里酸（FA）形成。有机物料低用量使HA、FA的分子结构都变得复杂化。从环境保护和提高经济效益两方面综合考虑，重金属污染土壤中有机物料施用量不宜过高。     

Characterization of fungal melanins and soil humic acids by chemical analysis and infrared spectroscopy

Summary Humic acids from two Brazilian topsoils under savanna grassland and five soil fungal melanins were characterized by elemental, functional group and infrared analysis. C, N, total acidity, COOH, and phenolic OH contents were within the ranges reported for several other fungal melanins and soil humic acids. Compared with the soil humic acids, the infrared spectra of the fungal melanins showed greater detail, indicative of higher aliphaticity. They were similar to the type III infrared spectra of humic acids, which are characteristically high in proteinaceous material and polysaccharides. The infrared spectra of the humic acids from the two Brazilian soils studied were classified as type I, which includes most soil humic acids. Notwithstanding the greater detail, in some areas the fungal melanin spectra were similar to those reported for other fungal melanins and humic acids of different origins. The probable contribution of the melanic fungi to the formation of soil humic polymers is discussed.