连续淹水培养条件下沉积物和土壤的氮素矿化过程

在淹水条件下,采用连续培养法研究了后海沉积物(HH)、环科院沉积物(HK)和土壤(TR)的氮素矿化过程。结果表明:三个处理矿化趋势基本相同,都是培养前期矿化量迅速升高并达到峰值,之后逐渐降低,最后回到培养前的氨氮含量水平。两种沉积物的矿化高峰出现时间在培养的第4天,要早于TR的第7天;污染严重HH的矿化最大累积量远大于污染较轻的HK和TR。培养过程中各处理各层次有机质、总氮和固定态铵含量都表现为降低趋势。说明培养过程中,开始占主导地位的氨化微生物被其它土壤微生物所代替,这些微生物大量繁殖,生物固持作用逐渐强于矿化作用,造成矿化氮和固定态铵含量迅速下降。     

Overwinter Mineralization of a Biosolid and Composted Banana Residues in Humid Mediterranean Conditions

The objectives of this work were to study nitrogen (N) release from a biosolid and a compost of banana wastes. The overwinter N decomposition was evaluated as the uptake by a cereal cover crop and the in situ losses from buried bags in a loamy sand (site 1) and in a calcareous silty clay loam (site 2). Organic materials were applied in two rates as sludge (1, 3.75 Mg ha^?1; 2, 7.5 Mg ha^?1) and compost (1, 3.29 Mg ha^?1; 2, 6.58 Mg ha^?1). Immediately after their incorporation in October, barley was planted as a cover crop. Its growth was negatively affected by the slow drainage of the silty clay loam, leading to greater N concentration in site 1 (21.18 g kg^?1 of barley versus 14.35 g kg^?1 of barley in site 2). Yet only 10% of the added N was intercepted by the cover crop in the fast-draining site 1. The ash-rich compost (N: 21.1 g kg^?1; ash: 467 g kg^?1) was comparable to the control. Within site 2, the biosolid treatments had a residual effect on a second barley crop, as N uptake was 1.99–2.13 times that of the control. The approach of in situ loss from bags incorporated in bare soil was repeated in two successive seasons. Nitrogen losses (% input) during the fall and winter months were comparable between sites 31.9 % (site 1) and 28.6 % (site 2). When the N fate was studied during the winter months only, the loss decreased slightly, suggesting the presence of a fraction liable to decomposition overwinter in Mediterranean conditions. Soil nitrate was determined 1 month after the incorporation of the cover crop in late spring. In the first season, only the sludge 2 treatment generated more nitrate than the control, whereas 19 months after the application of the organic products both sludge treatments had a positive effect. The soil properties influenced the amounts of N mineralized with site 1, yielding twice that of site 2. In the fast-draining soils, the presence of an active cover crop overwinter is necessary, while the N level of sludge 1 (164 kg N ha^?1) was more acceptable.     

Mineralization of Three Organic Manures Used as Nitrogen Source in a Soil Incubated under Laboratory Conditions

Abstract

The rate and timing of manure application when used as nitrogen (N) fertilizer depend on N‐releasing capacity (mineralization) of manures. A soil incubation study was undertaken to establish relative potential rates of mineralization of three organic manures to estimate the value of manure as N fertilizer. Surface soil samples of 0–15 cm were collected and amended with cattle manure (CM), sheep manure (SM), and poultry manure (PM) at a rate equivalent to 200 mg N kg^?1 soil. Soil without any amendment was used as a check (control). Nitrogen‐release potential of organic manures was determined by measuring changes in total mineral N [ammonium‐N+nitrate‐N (NH₄ ⁺–N+NO₃ ^?–N)], NH₄ ⁺–N, and accumulation of NO₃ ^?–N periodically over 120 days. Results indicated that the control soil (without any amendment) released a maximum of 33 mg N kg^?1soil at day 90, a fourfold increase (significant) over initial concentration, indicating that soil had substantial potential for mineralization. Soil with CM, SM, and PM released a maximum of 50, 40, and 52 mg N kg^?1 soil, respectively. Addition of organic manures (i.e., CM, SM, and PM) increased net N released by 42, 25, and 43% over the control (average). No significant differences were observed among manures. Net mineralization of organic N was observed for all manures, and the net rates varied between 0.01 and 0.74 mg N kg^?1 soil day^?1. Net N released, as percent of organic N added, was 9, 10, and 8% for CM, SM, and PM. Four phases of mineralization were observed; initial rapid release phase in 10–20 days followed by slow phase in 30–40 days, a maximum mineralization in 55–90 days, and finally a declined phase in 120 days. Accumulation of NO₃ ^?–N was 13.2, 10.6, and 14.6 mg kg^?1 soil relative to 7.4 mg NO₃ ^?–N kg^?1 in the control soil, indicating that manures accumulated NO₃ ^?–N almost double than the control. The proportion of total mineral N to NO₃ ^?–N revealed that a total of 44–61% of mineral N is converted into NO₃ ^?–N, indicating that nitrifiers were unable to completely oxidize the available NH₄ ⁺. The net rates of mineralization were highest during the initial 10–20 days, showing that application of manures 1–2 months before sowing generally practiced in the field may cause a substantial loss of mineralized N. The rates of mineralization and nitrification in the present study indicated that release of inorganic N from the organic pool of manures was very low; therefore, manures have a low N fertilizer effect in our conditions.     

Organic Carbon and Nitrogen Amendment Prevents Oxidation of Subsurface of Sulfidic Soil under Aerobic Conditions

Eurasian Soil Science - Managing the surface soil (0−10 mm) is important for microbes and benthic organisms that regulate various ecological services, e.g. regulation of soil or water...     

Mineralization of Nitrogen and N2O Production Potentials in Acid Forest Soils under Controlled Aerobic Conditions

Some acid surface mineral soils from different forest vegetations and sites in central Japan were taken during April and October in 2003 to study the net N mineralization and N₂O production potentials in the laboratory. Under the controlled aerobic conditions, 50 Pa C₂H₂ in the headspace can be used to study total gaseous-N losses during the aerobic mineralization and heterotrophic N₂O production in acid forest soils. The net N mineralization of these acid forest soils and N₂O-N production was variable with forest stands and with seasons, probably because of the quality of the litters and the variations of soil attributes. Three deciduous forest soils during two sampling reveal a higher potential for the total gaseous-N loss during the aerobic mineralization as compared with two coniferous forest soils. Heterotrophic nitrification among these acid forest soils accounted for the range from 37.0 to 76.3% of the total N₂O production under the experimental conditions, and was variable with forest stands and with seasons. Some factors regulating the net N mineralization and N₂O-N production were discussed in these acid forest soils.     

The Influence of Heavy Metals on Carbon Dioxide Evolution from a Typic Xerochrept Soil

In a laboratory study the effects on soil respiration of trace metals (Ni, Cd, Cu, Mn, Pb, Zn)added at loading rates ranging from 0 to 1000 µg g-1 were determined. Differences intoxicity with respect to the type of metal salt added were also evaluated. The inhibitory effect onsoil respiration differed considerably among the heavy metals and increased with the increasingloading rate. No linear relationships were found between the degree of inhibition and the levels oftotal and available metals. Toxicity evaluation at 20 and 50% inhibition of soil respiration showedCu as the most toxic and Mn as the most tolerable metal. A ‘metal equivalent’ was calculated asthe sum of the amounts of the available metals weighted to their relative toxicity with respect tothe least toxic one: Mn equivalent = Mn + 1.9Pb + 2.1Ni + 2.5Zn + 6.7Cd + 6.7Cu. The ionicpotential of the heavy metals was found to be positively related to the percent inhibition of soilrespiration. Chlorides and sulphates appeared to depress soil respiration more than nitrates, thelatter counter-balancing the toxic effect of the heavy metals.     

Influence of Soil Granulometry on Pyrene Desorption in Groundwater Using Surfactants

The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) is the main limiting factor for the remediation of soils and aquifers. Surfactants are amphiphilic substances which encourage the transfer of hydrophobic compounds from the solid to the liquid phase. While the interaction between organic matter and surfactants has been widely studied, there is a lack of knowledge concerning the relationship between surfactant efficiency and the granulometry of soil and/or geologic material. In this paper, three non-ionic surfactants (Tween 80, Gold Crew, and BS-400) were used to study the desorption of pyrene, chosen as a representative PAH, in soils with different grain size proportions (1%, 5%, 10%, and 20% of clay and silt) and no organic matter (<0.1%). The best quantity of surfactant to apply is closely related to the proportion of fine materials. Tween 80 gave better maximum desorption than Gold Crew and BS-400 (89%, 40%, and 36%, respectively). As an important proportion of aquifers show fine material above 1%, the effective critical micellar concentration obtained when applying surfactants to this type of geologic materials has to be higher than 150 mg L⁻¹ for Tween 80, and higher than 65 mg L⁻¹, and 100 mg L⁻¹ for Golf Crew and BS 400, respectively. Furthermore, results indicate that carrying out simple laboratory tests before the use of surfactants on a field scale is necessary to improve the efficiency and minimize the financial and environmental impact of its application.     

制备条件对生物质炭特性及修复重金属污染农田土壤影响研究进展

生物质炭是生物质废弃物在限氧条件下热解产生的多孔、低密度的富碳材料。前体物质和热解条件在很大程度上决定了生物质炭的表面积和阳离子交换量,影响生物质炭将重金属污染物吸附到其表面的能力,从而影响重金属在农田土壤中的迁移。本文从生物质炭的前体物质种类及热解条件对生物质炭的特性、改良土壤以及修复重金属污染农田土壤的影响等方面进行综述,并提出生物质炭修复重金属污染农田土壤研究的未来发展趋势。     

Dynamics of Organic C Mineralization and the Mobile Fraction of Heavy Metals in a Calcareous Soil Incubated with Organic Wastes

Organic wastes such as sewage sludge and compost increase the input of carbon and nutrients to the soil. However, sewage sludge-applied heavy metals, and organic pollutants adversely affect soil biochemical properties. Therefore, an incubation experiment lasting 90 days was carried out to evaluate the effect of the addition of two sources of organic C: sewage sludge or composted turf and plant residues to a calcareous soil at three rates (15, 45, and 90 t of dry matter ha^–1) on pH, EC, dissolved organic C, humic substances C, organic matter mineralization, microbial biomass C, and metabolic quotient. The mobile fraction of heavy metals (Zn, Cd, Cu, Ni, and Pb) extracted by NH₄NO₃ was also investigated.The addition of sewage sludge decreased soil pH and increased soil salinity to a greater extent than the addition of compost. Both sewage sludge and compost increased significantly the values of the cumulative C mineralized, dissolved organic C, humic and fulvic acid C, microbial biomass C, and metabolic quotient (qCO₂), especially with increasing application rate. Compared to compost, the addition of sewage sludge caused higher increases in the values of these parameters. The values of dissolved organic C, fulvic acid C, microbial biomass C, metabolic quotient, and C/N ratio tended to decrease with time. The soil treated with sewage sludge showed a significant increase in the mobile fractions of Zn, Cd, Cu, and Ni and a significant decrease in the mobile fraction of Pb compared to control. The high application rate of compost resulted in the lowest mobility of Cu, Ni, and Pb. The results suggest that biochemical properties of calcareous soil can be enhanced by both organic wastes. But, the high salinity and extractability of heavy metals, due to the addition of sewage sludge, may limit the application of sewage sludge.     

Soil arthropod abundance under conventional and no tillage in a Mediterranean climate

We have studied the impact on arthropod populations of conventional tillage and no-tillage systems in maize. Two different corn–weed control programs were assayed: NT, direct drilling of seed genetically modified to tolerate herbicide plus a combination of two pre-emergence and post-emergence herbicides; CT, conventional drilling with an isogenic corn variety plus a pre-emergence herbicide. Management system affected the soil arthropod community, based on major groups. Lower number of arthropods occurred in CT than in NT. Spider and hymenopteran parasitoids, especially those belonging to the families Lycosidae and Diapriidae were the groups that were most clearly affected. The natural field environment seems to favour the presence of Diapriidae. Spiders, in addition to being abundant, behaved in a similar way during both years of each treatment and might therefore be considered as reliable indicator families of the effects of different soil managements on the arthropod population in corn crops. Management system implies alterations on abundance of arthropods populations and natural enemies present in the crop.     

艾比湖地区典型乔灌群落水盐胁迫下土壤重金属对酶活性的影响

为探讨自然水盐胁迫下土壤重金属对酶活性的影响,对艾比湖国家级自然保护区内3种典型植被群落水盐胁迫下土壤Cd,Cr,Cu等5种重金属和过氧化氢酶、磷酸酶、脲酶等4种酶活性进行了研究。结果表明:不同群落类型土壤水盐、酶活性和重金属含量方面具有各自特征,典型群落中土壤重金属含量对过氧化氢酶活性的影响更为强烈,而这种现象在耐旱植物梭梭中尤为明显,土壤水分受限情况下,以Cd,Cr和Zn为代表的土壤重金属对土壤酶活性有一定影响。在水盐环境较好、重金属含量较少的自然土壤中,土壤重金属对酶活性具有较高的促进作用;重金属含量较少,盐胁迫对酶活性抑制作用明显;水分胁迫对酶活性限制较小,土壤重金属对酶活性的影响小于土壤可溶性总盐,说明自然条件下土壤盐胁迫对土壤酶活性具有强烈的抑制作用;研究区Cd和Cr对土壤酶表现出激活作用,Cu对土壤酶活性的影响不明显,Mn和Zn对土壤酶则多表现出抑制效应。     

Influence of Reducing Conditions on Solubility of Trace Metals in Contaminated Soils

Dissolved trace metals Cd, Pb, Zn, andother solutes were determined after reducingconditions have been imposed to samples of anagricultural polluted soil. The ploughed layer wassampled as undisturbed blocks for floodingexperiments, and sieved samples were incubated inaqueous suspensions at controlled pH (pH 6.2) underdifferent redox conditions. Redox potential and pH,concentrations of major and trace elements, andorganic and inorganic ligands, were measured in thesolutions. Their chemical speciation was calculated byusing the programme Soilchem.These experiments and calculations have shown that pHvariations definitively influence trace metalsolubility, whatever they are induced by reductivedissolution, organic acid formation, or otherprocesses, and that strong acidification can beobtained with well buffered soil when about 1%available carbon is anaerobically transformed intoorganic acids. The organic acids also intervene bycomplexation, particularly for Pb. On another hand,denitrification can limit these effects by consumingprotons and organic substances. Given a steady pH,reducing conditions enhance the mobility of tracemetals, at first by dissolution of manganic and ferricoxides; Pb appeared more sensitive to these processesthan Zn, and finally Cd. As a general rule,hydromorphy in a well-buffered contaminated soil at afirst step should increase the mobility of divalenttrace metals, by decreasing pH and reducing Mn and Feoxides, but prolonged flooding can lead to fix tracemetals again, rather by re-adsorption or precipitationphenomena than by formation of insoluble sulphides.     

~(14)C-环氧虫啶光学异构体在不同土壤中的矿化、结合残留及其在腐殖质中的分布

环氧虫啶是我国自主创制的手性新烟碱类杀虫剂,从对映体层面研究其环境行为和归趋对科学使用手性农药及其风险评估有着重要意义。本文采用~(14)C标记技术,研究了环氧虫啶2个对映异构体(1S2R-环氧虫啶,1R2S-环氧虫啶)和外消旋混合物(RM)在酸性红砂土S1、中性黄松土S2及碱性滨海盐土S3好氧和淹水培养中的矿化、结合残留形成及其在腐殖质中的分布规律。结果表明:土壤施药后培养100 d,环氧虫啶的异构体在3种土壤2种培养方式中的矿化、结合残留形成及在腐殖质中的分布均无明显差异;环氧虫啶在好氧和淹水培养的3种土壤中矿化量均有显著差异,在好氧的S1中矿化量最低(占引入量的0.21%~0.23%),S3中矿化量最高(占引入量的16.45%~17.06%),淹水的3种土壤中矿化均小于1%;环氧虫啶在好氧和淹水的S2和S3中结合残留量有显著差异,在S1中结合残留量差异不显著且残留量最小(56.84%~64.38%),好氧的S2中结合残留量最大(占引入量的79.55%~82.99%),淹水的S3中结合残留量最大(占引入量的73.85%~84.11%);环氧虫啶2种光学异构体和外消旋混合物在3种土壤2种培养方式下,结合残留在土壤腐殖质中的分布均呈现富啡酸胡敏素胡敏酸的规律。因此,手性杀虫剂环氧虫啶在土壤中的行为归趋不存在对映体选择性。     

不同土层水稻土培养条件下有机碳矿化规律研究

以湖南省桃源县水稻土为研究对象,基于土壤有机碳三库一级动力学理论,从垂直变化角度研究水稻土总有机碳(Ct)、活性碳(Ca)、缓效性碳(Cs)、惰性碳(Cp)的含量及有机碳矿化特征的相关规律。研究结果表明:1总有机碳、活性碳、缓效性碳、惰性碳含量分别与土层深度成负相关,相关系数分别为0.8431、0.8516、0.8320、0.7734(P0.01),土层越深活性碳占总有机碳比例越小,惰性碳占总有机碳比例越大。2按照CO2-C释放速率变化程度,将矿化曲线划分为快速矿化(平均约7.94 d)、缓慢矿化(平均约28 d)和平衡矿化三个阶段,其中快速矿化阶段主要为活性碳矿化。3土壤有机碳矿化速率、累积矿化量、矿化比例等都随土层加深而减小,但30~60 cm土层有机碳总量大,其有机碳矿化总量的变化对1 m深有机碳矿化总量变化的影响大。4偏相关分析表明不同土层土壤有机碳各组分含量、有机碳矿化总量与土壤全氮含量和土壤p H相关,即土壤性质影响有机碳矿化特征。由此得出,深层土壤有机碳也参与全球碳循环,并且全氮含量和p H会影响深层碳库成为碳源或是碳汇,在研究全球碳循环时应给予充分重视。     

Effects of Changed Soil Conditions on the Mobility of Trace Metals in Moderately Contaminated Urban Soils

Changes in the soil chemical environment can be expected to increase the leaching of trace metals bound in soils. In this study the mobility of trace metals was monitored in a column experiment for two contaminated urban soils. Four different treatments were used (i.e. rain, acid rain, salt and bark). Leachates were analysed for pH, dissolved organic carbon (DOC) and for seven trace metals (cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn)). The salt treatment produced the lowest pH values (between 5 and 6) in the effluent whereas the DOC concentration was largest in the bark treatment (40–140 mg L^?1) and smallest in the salt and acid treatments (7–40 mg L^?1). Cadmium, Ni and Zn were mainly mobilised in the salt treatment, whereas the bark treatments produced the highest concentrations of Cu and Pb. The concentrations of Cu, Cr, and Hg were strongly correlated with DOC (r ²?=?0.90, 0.91 and 0.96, respectively). A multi-surface geochemical model (SHM-DLM) produced values for metal dissolution that were usually of the correct magnitude. For Pb, however, the model was not successful indicating that the retention of this metal was stronger than assumed in the model. For all metals, the SHM-DLM model predicted that soil organic matter was the most important sorbent, although for Pb and Cr(III) ferrihydrite was also important and accounted for between 15 and 50% of the binding. The results confirm the central role of DOC for the mobilization of Cu, Cr, Hg and Pb in contaminated soils.     

Relationship between Metals Leached and Soil Type from Potential Acid Sulphate Soils under Acidic and Neutral Conditions in Western Australia

Metal contaminants are likely to be mobilised from soil when in contact with acidic drainage. Soils containing sulphide are often associated with significant quantities of trace metals. Understanding the source of metal pollution is of significant concern for management because sulphide-containing soils are found in close proximity to estuaries, lowland rivers and lakes. This study focuses on Western Australian soils, which are typically sandy and well weathered. Two leachate trials, a batch and a column method, investigated the possibility of characteristic leachate signatures with respect to future traceability of metal contamination from soil drainage. Leaching signatures were assessed for four soil types (grey sand (GS), iron-rich sand (FeRS), silty sand (SS) and peat) found coastally between Perth and Albany, in Western Australia. Trace metals leached from the four soil types showed significant differences for both the metals leached and the concentrations for the column leaching trial. No nickel (<1.0 µgL^?1) but relatively high concentrations of arsenic were leached from the peat site. The FeRS leachates contained chromium, copper, high aluminium and relatively high iron. The GS leached extremely high iron and relatively high manganese concentrations. In comparison, only small concentrations of nickel, iron, aluminium, arsenic and manganese leached from the SS columns. Selenium did not leach above reporting limits (<1.0 µg L^?1) from any of the soil types. This work suggests that leachate signatures from different soil types exist and that soil type should be considered when determining the risk of aquatic impact associated with acidic drainage.     

不同水肥条件下硝态氮在土壤剖面中垂直分布规律研究

试验选择2块不同肥力的地块来研究冬小麦收获后硝态氮在1m土壤剖面中累积状况。研究结果表明:有机无机肥料配合使用能有效地降低硝态氮在土壤中的累积;硝态氮在肥力高的地块比在肥力低的地块累积量小;只有综合考虑施肥,灌溉等影响因子才能降低硝态氮在土壤中的累积。     

Changes of Redox and pH Conditions in a Flooded Soil Amended with Glucose and Nitrate under Laboratory Conditions

The changes of soil Eh and pH during decomposition of nitrates at different levels of glucose (0%; 0, 5% and 1.0%) and nitrates (0%; 0,5%; 1% and 2% KNO₃) in water saturated soil samples (Ah horizon of a Mollic Gleysol) were examined. It was found that in the presence of 0–2% nitrates and 0,5–1% glucose in the soil with 1–2 days anaerobiosis at 20°C resulted in the increase of reduction processes and a decrease of redox potential up to 500 mV (Eh). Soil pH increased in the range of 2.5 units. The results from the model experiment - implying Eh > 200 mV and pH < 6.5 as range of nitrate stability in the soil studied - can be useful for field conditions both to predict the stability of nitrates in the soil environment and to create proper conditions for the effective use of carbon sources as a main factor of redox transformations.     

增加降水对四川干旱河谷区云南松人工林土壤有机碳矿化的影响

2014年6月至2015年5月,对四川干旱河谷区云南松(Pinusyunnanensis)人工林进行增加降水试验,试验设置对照(CK,0 mm m~(-2) a~(-1))、增水10%(A1,80 mm m~(-2) a~(-1))、增水20%(A2,160 mm m~(-2) a~(-1))和增水30%(A3,240 mm m~(-2) a~(-1))4个处理水平。分别于干、湿季结束取土样,通过室内土壤培养法和氯仿熏蒸法,研究了增加降水对云南松人工林土壤有机碳矿化和土壤微生物生物量碳的影响。结果表明:4个处理云南松人工林土壤有机碳矿化均呈明显的湿季低,干季高的季节特征。土壤培养过程中,A1、A2和A3处理的土壤有机碳累积矿化量较CK有明显升高,到30 d培养结束,各处理的土壤有机碳累积矿化总量大小表现为A2A3A1CK。同时培养期间,4个处理土壤有机碳矿化速率随时间变化呈由高到低的变化趋势,整体速率变化快慢表现为A2A3A1CK。湿季增加降水利于土壤微生物生物量碳(SMBC)含量升高,但并不随降水量增加而升高,干季增加降水则会导致SMBC含量降低;相关分析显示,湿季土壤有机碳矿化与SMBC含量呈较高的正相关性,干季两者呈相对较低的负相关性。