溶解性有机质对紫色土中锌形态分布的影响

溶解性有机质(Dissolved Organic Matter)作为有机质中生物活性和物理化学反应活性较为活跃的重要组成部分,对土壤中锌的形态分布有着重要影响,本文采用室内培养的方法,在相同的温度和湿度条件下,分析了两种不同来源的DOM在不同浓度梯度下对紫色土外源锌形态分布的影响,得出以下结论:(1)紫色土在添加DOM后,显著地促进了外源锌各形态之间的相互转化分布,酸性紫色土中DOM促进了外源锌由EX-Zn向其它形态转化,这对于减少土壤锌污染的植物毒性有一定的作用。石灰性紫色土中主要促进RES-Zn向其它形态转化,提高了锌对植物的有效性;(2)两种DOM对酸性紫色土的影响优于石灰性紫色土,影响效果DOM2>DOM1;(3)酸性紫色土形态间的相关关系程度显著,石灰性紫色土形态间的相关关系程度不显著。     

风沙土不同有机组分对磷的吸附特征影响

采用平衡吸附法研究了风沙土不同有机组分对磷的吸附特征影响,可为有机组分吸附态磷携载量估算提供依据。结果表明：去除有机质后的风沙土对磷的吸附能力大大降低,其碳标化饱和吸附量（Гmo）c和吸附分配系数（ko）c分别只能达到重组的27.76%和8.45%,说明有机质是影响磷在风沙土上吸附特征的重要因素;磷在轻组有机组分上的吸附以分配作用为主（koc=51.02）;风沙土有机组分中的重组有机质对磷的吸附起主导作用（Гmoc=388.35mg.kg-1）,重组有机组分中的紧结态腐殖质（胡敏素）对磷的吸附起关键作用（Гmoc=1007.96mg.kg-1）,影响机制主要为稳、紧结态腐殖质是形成土壤疏松多孔团聚体结构的重要胶结物质。在其所形成的有机矿质复合体中除分配作用吸附外,还存在着孔隙填充方式的磷吸附;考查土壤对磷的吸附能力不但要考虑有机质的含量,更要考虑有机质的存在形态,它也是影响土壤对磷吸附特征的重要因素。以重组为基准,轻组有机组分以及重组有机组分中稳结态腐殖质和紧结态腐殖质携载的吸附态磷分别可按0.69倍以及1.37、2.75倍估算。     

Copper Tolerance and Accumulation of Elsholtzia splendens Nakai in a Pot Environment

ABSTRACT

Elsholtzia splendens Naki has been identified as a copper (Cu) geobotanical indicator. In this study, the effects of Cu supply levels (control, 100, 200, 400, 600, 800, 1000, 1200 mg kg¹) on the growth and Cu accumulation in E. splendens were studied in one pot experiment. The results showed that no reduction in shoot height and dry weight was noted when the plants were grown at Cu supply levels up to 1000 mg kg^?1 in soil. Slight stimulation on shoot growth was noted at Cu levels ≥ 100 mg kg^?1. Copper concentration in shoots and roots increased with increasing Cu levels, and reached a maximum of 1751 and 9.45 mg kg^?1 (DW) at 1200 mg Cu kg^?1. The amount of Cu accumulated in the roots and shoots were 313 and 22 μ g plant^?1 at external Cu levels of 1000 and 800 mg kg^?1, respectively. The shoot/root Cu ratios ranged from 0.005 to 0.008 and more than 92% of the total Cu taken up by E. splendens was accumulated in roots. Furthermore, Cu concentrations in roots and shoots were significant and positively correlated with total soil Cu, water, ammonium nitrate (NH₄NO₃), ammonium (NH₄)-acetate, and ethylenediaminetetraacetic acid (EDTA) extractable Cu. These results indicate that E. splendens can considered as a Cu tolerant and accumulated plant, and root is the major part for accumulation of Cu in E. splendens.     

风沙土不同有机组分对氨氮的吸附特征影响

采用平衡吸附法研究了风沙土不同有机组分对氨氮的吸附特征影响。结果表明,去除腐殖质后的风沙土对氨氮的吸附能力大大降低,其碳标化饱和吸附量Гmoc和吸附分配系数Koc分别只能达到原样的68.58%和28.24%,说明腐殖质是影响氨氮在风沙土上吸附特征的主要因素;轻组有机质是一类橡胶态胶体,氨氮在橡胶态胶体上的吸附以分配作用为主,其碳标化吸附分配系数为81.58;重组有机质对氨氮的吸附起主导作用,其碳标化饱和吸附量为3350.55mg.kg-1;重组有机质是一类玻璃态胶体,氨氮在玻璃态胶体上的吸附除分配作用外,还存在孔隙填充方式的吸附;重组有机组分中的紧结态腐殖质（胡敏素）对氨氮的吸附起关键作用,其碳标化饱和吸附量可达6626.30mg.kg-1,影响机制主要为稳、紧结态腐殖质是形成土壤疏松多孔团聚体结构的重要胶结物质。在其所形成的有机-无机复合体中存在着孔隙填充方式的氨氮吸附。考查土壤对氨氮的吸附能力不但要考虑有机质的含量,更要考虑有机质的存在形态,它也是影响土壤对氨氮吸附特征的重要因素。以重组为基准,轻组有机质、稳结态腐殖质和紧结态腐殖质携载吸附态氨氮可分别按重组的0.59、1.05倍和2.50倍估算。     

植草恢复对侵蚀红壤重组有机质的影响

在福建中亚热带红壤区,将侵蚀经济林(油茶)改造成人工草地(人工植草)、封山育林(自然恢复)进行生态恢复,11a后,分析A-C层土壤的常规理化性质、土壤复合量、原土复合度、腐殖质结合形态用以评价土壤肥力变化。结果表明:不同土层各指标有明显差异,其中土壤速效养分、有机质、土壤复合量表现为A层B层C层,原土复合度则表现为C层B层A层。土壤腐殖质在C层呈松结合态向紧结合态转变的趋势,其中在自然恢复区B、C层土壤的松/紧比值较A层分别下降0.149,0.458个单位,人工植草区C层土壤的松/紧比值较A层下降0.292个单位,松结合态向紧结合态转变速度较自然恢复区有所减缓。人工植草区A层土壤的有机质及有机碳总量虽低于自然恢复区,但重组有机碳含量相近,其它测定指标亦无明显差异。     

Characterization of Organic Matter in Compost Produced with Municipal Solid Wastes: An Italian Approach

Stabilization of the organic matter of a static pile of compost from municipal solid wastes (MSW) under a forced-pressure ventilation composting system was followed for 55 days during winter season. The materials were analyzed according to the official methodologies required by Italian regulations regarding the quality of composts from MSW. The stabilization process of the organic matter was monitored using both the degree of humification (DH), i.e. the ratio between the humified fractions (HA + FA) and the total extractable carbon (TEC), and the electrofocusing technique (EF). The DH increased steadily in compost during stabilization process and converged asymptotically at the end of the period of composting. The EF analyses of the organic extracts of compost from MSW showed a definite trend in the humification process and confirmed the actual evolution of the organic matter composted.     

Microbiological Transformation of Organic Matter in Oil-Polluted Tundra Soils after Their Reclamation

Eurasian Soil Science - The influence of oil pollution caused by the accident of 1994 on the biological activity of Histic Cryosols is considered. Despite the use of complex mechanical (oil...     

Markers of Soil Organic Matter Transformation in Permafrost Peat Mounds of Northeastern Europe

For the paleoreconstruction of permafrost peat mounds and the identification of plant communities participating in the formation of peat, the contents of n-alkanes (C₂₀–C₃₃) have been determined, and relative changes in the stable isotope compositions of carbon and nitrogen and the C/N ratio have been analysed. Several indices (CPI_alkanes, P_aq, P_wax) have been calculated to assess the degree of decomposition of the peats studied and the contributions of different plant species to their formation. It has been found that shortand long-chain n-alkanes are concentrated in high-moor peat, while medium-chain alkanes are typical for transitional peat. Integrated analysis of the studied markers has shown that the botanical and material composition of peat, anaerobic conditions of bog formation, and permafrost play an important role in the preservation of organic carbon in permafrost peat mounds. Alternation of plant associations is the main reason for changes in n-alkane concentrations, C/N ratios, and δ13C values.     

Changes in the Apolar Organic Fraction Through The Composting Process

The organic fraction soluble in different organic solvents with increasing polarity was studied during the composting process, following its transformation from raw material until the stable final product with the aim to establish new quality indices of compost maturity. All apolar fractions during the composting process had a reduction higher than 50%. Part of the compounds have been utilized by the microflora as energetic material and to perform the biotransformations, and part has been transformed in molecule like the humic molecules. However, in our conditions a relevant part (36%) of apolar material is recovered at the end of the biotransformation. The spectroscopic analysis indicates in the final product an increase of lipidic compounds, as esters or acids as well as hydrocarbons with longer linear aliphatic chain.     

施用生物炭对白菜根际土壤中有机质含量及酶活性的影响

为研究生物炭土壤有机质及白菜叶片中糖含量的影响。试验采用盆栽方法共设4个处理:不施用生物炭为对照(CK);施用1%,3%,5%生物炭等4个处理。结果表明,随着生物炭施用量的增加,白菜根际土壤蔗糖酶活性和有机质含量显著增加。同时施用3%和5%生物炭提高了白菜叶片中糖含量,根际土壤中多酚氧化酶,纤维素酶以及EC值显著提高,而土壤pH的变化并不明显。综上,土壤中施用生物炭提高了白菜根际土壤有机质含量和土壤酶的活性,促进了白菜生长并提高叶片中可溶性糖含量,施用3%生物炭改善效果较为明显,相当于在每公顷农田施入10 t的生物炭,可以在白菜生产上试用推广。     

Partitioning of Hg Between Solid and Dissolved Organic Matter in the Humus Layer of Boreal Forests

The mobility of mercury (Hg) deposited on soils controls the concentration and toxicity of Hg within soils and in nearby streams and lakes, but has rarely been quantified under field conditions. We studied the in situ partitioning of Hg in the organic top layer (mor) of podsols at two boreal forest sites differing in Hg deposition and climatic regime (S. and N. Sweden, with pollution declining to the north). Soil solution leaching from the mor layer was repeatedly sampled using zero-tension lysimeters over 2 years, partly in parallel with tension lysimeters. Concentrations of Hg and dissolved organic carbon (DOC) were higher while pH was lower at the southern site (means ± SD: Hg?=?44?±?15 ng L^?1, DOC?=?63.0?±?31.3 mg L^?1, pH?=?4.05?±?0.53) than at the northern site (Hg?=?22?±?6 ng L^?1, DOC?=?41.8?±?12.1 mg L^?1, pH?=?4.28?±?0.43). There was a positive correlation over time between dissolved Hg and DOC at both sites, even though the DOC concentration peaked during autumn at both sites, while the Hg concentration remained more constant. This correlation is consistent with the expected strong association of Hg with organic matter and supports the use of Hg/C ratios in assessments of Hg mobility. In the solid phase of the overlying O_f layer, both Hg concentrations and Hg/C ratios were higher at the southern site (means ± SD: 0.34?±?0.06 μg g^?1 dw and 0.76?±?0.14 μg g^?1 C, respectively) than at the northern site (0.31?±?0.05 μg g^?1 dw and 0.70?±?0.12 μg g^?1 C, respectively). However, concentrations in the solid phase differed less than might be expected from the difference in current atmospheric input, suggesting that the fraction of natural Hg is still substantial. At both sites, Hg/C ratios in the upper half of the mor layer were only about two thirds of those in the lower half, suggesting that the recent decrease in anthropogenic Hg deposition onto the soil is offset by a natural downward enrichment of Hg due to soil decomposition or other processes. Most interestingly, comparison with soil leachate showed that the average Hg/C ratios in the dissolved phase of the mor layers at both sites did not differ from the average Hg/C ratios in the overlying solid organic matter. These results indicate a simple mobilisation with negligible fractionation, despite differences in Hg deposition patterns, soil chemistry and climatic regimes. Such a straight-forward linkage between Hg and organic matter greatly facilitates the parameterisation of watershed models for assessing the biogeochemical fate, toxic effect and critical level of atmospheric Hg input to forest soils.     

特定培养条件下土壤有机质分解转化规律的研究

通过室内培养实验,应用δ~(13)C方法研究了玉米秸秆分解期间,土壤固有及新形成有机质的分解转化规律。结果表明:玉米秸秆分解期间,土壤固有及新形成的有机质都逐渐分解,但前者的分解速度较慢。第360 d时,玉米秸秆和土壤固有有机质的残留率分别为30.0％和92.2％;720 d时分别为25.3％和78.8％。培养初期,富里酸的形成速度大于胡敏酸,而后富里酸转化为胡敏酸或相互转化;与新形成有机质相比,固有有机质中胡敏酸、富里酸的转化速度相对较慢。     

Importance of Organic Matter to the Retention and Transport of Bisphenol A and Bisphenol S in Saturated Soils

Water, Air, & Soil Pollution - Our goal was to reconstruct soil recovery from Acid Rain based upon removal of stemflow at beech (Fagus sylvatica) stands of known historic and recent soil...     

Variation in community structure of arbuscular mycorrhizal fungi associated with a Cu tolerant plant—Elsholtzia splendens

Little is known about the characteristics of arbuscular mycorrhizal fungi (AMF) community in the roots of host plants growing on heavy metal contaminated sites. The objectives of this study were to examine the community structure of AMF associated with the roots of a copper (Cu) tolerant plant—Elsholtzia splendens in a Cu mining area in southeastern Anhui Province, China. Molecular techniques were used to analyze AMF community composition and phylogenetic relationship in E. splendens roots sampled from three Cu mine spoils and two adjacent reference areas. Results obtained showed that root colonization and AMF diversity were very low and negatively correlated with total and extractable Cu concentrations. All the DNA sequences recovered belonged to the genus of Glomus. The principal component analysis (PCA) revealed that the AMF community composition varied remarkably among different sites and was related closely to soil properties, especially Cu concentrations. The distribution pattern of AMF species in various sites suggested the degree of AMF tolerance to Cu contamination. The unique AMF species that presented exclusively in heavily contaminated sites need to be further examined for potential application in phytoremediation of metal contaminated soils.     

Predicting the Concentration of Total Mercury in Mineral Horizons of Forest Soils Varying in Organic Matter and Mineral Fine Fraction Content

In this study, an artificial neural networks (ANN) model was developed to predict the removal of a polycyclic aromatic hydrocarbon (PAH), namely, naphthalene from marine oily wastewater by using UV irradiation. The removal rate was used as model output and simulated as a function of five independent input variables, including fluence rate, salinity, temperature, initial concentration and reaction time. The configuration of the ANN model was optimized as a three-layer feed-forward Levenberg–Marquardt backpropagation network with log-sigmoid and linear transfer functions at the hidden (12 hidden neurons) and output layers, respectively. By considering goodness-of-fit and cross validated predictability, the ANN model was trained to provide good overall agreement with experimental results with a slope of 0.97 and a correlation of determination (R ²) of 0.943. Sensitivity analysis revealed that fluence rate and temperature were the most influential variables, followed by reaction time, salinity and initial concentration. The findings of this study showed that neural network modeling could effectively predict the behavior of the photo-induced PAH degradation process.     

Influence of Organic Manure on Organic Phosphorus Fraction in Soils

The transformation of organic P(Po) from organic manures in two types of soils (ultisol and entisol) and the influences of external addition of organic substance or inorganic P(Pi) on Po under the condition of the 60% maximum water capacity were investigated.The results obtained from Po fractionation experiments indicated that all the Po fractions except for the highly resistant Po fraction decreased during incubation.Application of pig feces and cow feces could largely increase each fraction of Po in the soils.Immediately after application of organic manure into the soils a large part of labile and moderately labile Po from organic manure was transferred into moderately resistant Po,which might be due to the fact that Ca-or Mg-inositol P was precipitated into Fe-inositol P.However,the availability of Po from organic manure in the soils would increase again after incubation because of the transformation of moderately labile and resistant Po fractions into labile Po fractions.Addition of cellulose or Pi into the soils showed a good effect on increasing all the Po fractions except for the highly resistant Po,and this effect was much more pronounced when cellulose was applied in combination with Pi.Therefore,in view of the effect of organic manure on improving P nutrition to plant,attention should be paid to both the Po and the organic substances from organic manure,It is suggested that application of Pi fertilizer combined with organic manure may be referred to as an effective means of protecting Pi from chemical fixation in soil.     

施加有机物料对土壤有机质影响的研究

研究结果证明,有机物料的矿化速度在绵土中,牛粪>麦草>玉米秆>草术樨;在塿土中,牛粪>玉米秆>麦草。各类还田有机物的腐殖化系数,在绵土中玉米秆为0.25,麦草为0.25,草木樨为0.26,牛粪为0.21,在塿土中玉米秆为0.35,麦草为0.37,牛粪为0.31。施入物料后土壤有机质的累积与物料的矿化速度和施后时间呈负相关,与加入有机物量呈正相关。文中计算了本地区维持土壤耕层一定的有机质水平,每亩耕地每年需加入有机物料的数量。     

有机质对红壤和黑土中外源铅镉稳定化过程的影响

采用室内培养方法研究了中国典型红壤和黑土中外源铅（Pb）、镉（Cd）在单一和复合污染下的稳定化过程,探讨了土壤有机质含量对Pb、Cd稳定化过程的影响。结果表明,加入500mg·kg-1Pb、1.0mg·kg-1Cd或1.0mg·kg-1Cd＋500mg·kg-1Pb条件下,各种土壤有效态Pb、Cd含量在培养前期迅速下降,随后变化减缓,培养30d后基本达到平衡。利用二级动力学方程对Pb、Cd稳定化过程进行拟合,在红壤和黑土上,有机质含量高的土样有效态Cd的平衡浓度比有机质含量低的土样中降低12.7%～37.3%;有效态Pb的平衡浓度比有机质含量低的土样中降低78.3%～96.2%,相关分析表明,土壤有机质含量的增加显著抑制了外源Pb、Cd的有效性（P〈0.05）。在铅镉复合污染中,Pb的存在提高了土壤中Cd的有效性,而Cd对Pb的影响较小。与黑土相比,红壤上外源Pb、Cd稳定化速率较小,达到平衡所需的时间较长,且有效态Pb、Cd的平衡浓度较高。因此,在农业生产实践中,通过提高红壤和黑土上有机质的含量能够显著降低外源重金属Pb、Cd的有效性,减少环境污染风险。     

Transformation of Fertilizer-N in Rhizosphere Soils of Wheat

INTRODUCTION There is a close relationship between the transformation of fertilizer-N and the statusof nitrogen nutrition in rhizosphere soils.Previously,Harmsen and Jager(1962)made ananalysis of N and C contents in the rhizosphere soils of upland crops and found thatclose to the root zone there was an enrichment of these substances.     

The Effect of the Organic Matter Composition on POP Accumulation in Soil

The effect of different humic fractions on polychlorinated biphenyl (PCB) contamination in soils was tested in the field by means of 53 soil samples from a high-altitude grassland plateau in the Italian Alps. Three humic fractions (humin, humic acids, and fulvic acids) were characterized in parallel by quantifying 12 PCB congeners to establish a direct relationship between PCB levels and humic fraction concentrations. Humin (the most hydrophobic fraction) appears to be the most closely correlated with the amount of PCBs in soil (R ²?=?0.83), while fulvic acid shows the lowest correlation (R ²?=?0.49). The idea of preferential sorption of hydrophobic compounds in the humin fraction is discussed, and the humin carbon content (f _huminC) is proposed as an improved parameter for evaluating the potential for POP accumulation in soils, replacing total organic carbon (f _oc). Congener studies revealed that penta- and hexa-substituted-CBs show the optimal combination of physicochemical properties for equilibrating with the humin content in soil. Moreover, f _huminC/f _oc is conceptually equivalent to the empirical coefficients used in predictive K _sa equations. In our samples, the f _huminC/f _oc was 0.55, a value in between the empirical coefficients proposed in the literature. In predictive equations, the use of f _huminC instead f _oc avoids the necessity of using an empirical parameter for a ??generic?? condition by introducing an experimental parameter (f _huminC) that takes into account local conditions (organic matter composition).