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Sample records for acids soils ph

  1. Soil sorption of acidic pesticides: modeling pH effects.

    Spadotto, Claudio A; Hornsby, Arthur G

    2003-01-01

    A model of acidic pesticide sorption in soils was developed from theoretical modeling and experimental data, which initially considered a combination of a strongly acidic pesticide and a variable-charge soil with high clay content. Contribution of 2,4-D [(2,4-dichlorophenoxy) acetic acid] anionic-form sorption was small when compared with molecular sorption. Dissociation of 2,4-D was not sufficient to explain the variation in Kd as a function of pH. Accessibility of soil organic functional groups able to interact with the pesticide (conformational changes) as a function of organic matter dissociation was proposed to explain the observed differences in sorption. Experimental 2,4-D sorption data and K(oc) values from literature for flumetsulam [N-(2,6-difluorophenyl)-5-methyl [1,2,4] triazolo [1,5-a] pyrimidine-2-sulfonamide] and sulfentrazone [N-[2,4-dichloro-5-[4-(difluromethyl)-4,5-dihydro-3-methyl-5-oxo-1H-1,2,4-triazol-1-yl] phenyl] methanesulfonamide] in several soils fit the model. PMID:12809295

  2. pH effects of the addition of three biochars to acidic Indonesian mineral soils

    Martinsen, V; Alling, V; Nurida, N L;

    2015-01-01

    Soil acidity may severely reduce crop production. Biochar (BC) may increase soil pH and cation exchange capacity (CEC) but reported effects differ substantially. In a systematic approach, using a standardized protocol on a uniquely large number set of 31 acidic soils, we quantified the effect of...... increasing amounts (0–30%; weight:weight) of three types of field-produced BCs (from cacao (Theobroma cacao. L.) shell, oil palm (Elaeis guineensis. Jacq.) shell and rice (Oryza sativa. L.) husk) on soil pH and CEC. Soils were sampled from croplands at Java, Sumatra and Kalimantan, Indonesia. All BCs caused...... a significant increase in mean soil pH with a stronger response and a greater maximum increase for the cacao shell BC addition, due to a greater acid neutralizing capacity (ANC) and larger amounts of extractable base cations. At 1% BC addition, corresponding to about 30 tons ha−1, the estimated...

  3. Effects of pH, organic acids, and inorganic ions on lead desorption from soils

    The desorption characteristics of lead in two variable charge soils (one developed from Arenaceous rock (RAR) and the other derived from Quaternary red earths (REQ)) were studied, and the effects of pH value, organic acid, and competitive ions were examined. Desorption of Pb2+ decreased from nearly 100.0 to 20.0% within pH 1.0-4.0 in both soils, and then the decrease diminished at pH > 4.0. Organic ligands at relatively low concentrations (≤10-3 mol L-1) slightly inhibited Pb2+ desorption, but enhanced Pb2+ desorption at higher concentrations. In this study, citric acid or acetic acid at higher concentrations (>10-3 mol L-1) had the greatest improvement of Pb2+ desorption, followed by malic acid; and the smallest was oxalic acid. Desorption of the adsorbed Pb2+ increased greatly with increasing concentrations of added Cu2+ or Zn2+. Applied Cu2+ increased Pb2+ desorption more than Zn2+ at the same loading. - The adsorption-desorption process is a basic and important reaction in soils controlling Pb2+ mobility and bioavailability

  4. Removal of Radium-226 from Radium-contaminated soil using distilled water and humic acid: Effect of pH

    Effect of washing solutions pH on removal of radium-226 from radium-contaminated soil using distilled water and humic acid extracted from Malaysian peat soil was studied by a single batch washing method. The study encompassed the extraction of humic acid and the washing of radium-contaminated soil using distilled water and humic acid solutions of varying pH in the range between 3 to 11. Activity of radium-226 was determined by gamma spectrometer. In the pH range studied, the removal of radium-226 was greater when humic acid solutions were used compared to distilled water. Greater removal of radium-226 was obtained using highly basic pH washing solutions compared to neutral and acidic solutions. (author)

  5. Removal of Radium-226 from Radium-Contaminated Soil using Distilled Water and Humic Acid: Effect of pH

    Effect of washing solutions' pH removal of radium-226 from radium-contaminated soil using distilled water and humic acid extracted from Malaysian peat soil was studied by batch washing method. The study encompassed the extraction of humic acid and the washing of radium-contaminated soil using distilled water and humic acid solutions of 100 ppm, both with varying pHs in the range of 3 to 11. The radioactivity concentration of radium-226 was determined by gamma spectrometer.The removal of radium-226 was greater when humic acid solutions were used compared to distilled water at the pH range studied and both washing solutions showed greater removal of radium-226 when basic solutions were used. Nevertheless, comparable removal efficiencies were observed when neutral and highly basic humic acid solutions were used. (author)

  6. Effects of Humic Acid and Solution pH on Dispersion of Na—and Ca—Soil Clays

    LANYEQING; HUQIONGYING; 等

    1996-01-01

    Dispersed soil clays have a negative impact on soil structure and contribute to soil erosion and contaminant movement.In this study,two typical soils from the south of China were chosen for investigating roles of pH and humic acid(HA) on dispersion of soil clays.Critical flocculation concentration (CFC) of the soil clay suspension was determined by using light transmission at a wavelength of 600 nm.The results indicated that effects of pH and HA on dispersion of the soil clays were closely related to the type of the major minerals makin up the soil and to the valence of the exchangeable cations as well.At four rates of pH(4,6,8and 10),the CFC for the Na-yellow-brown soil treated with H2O2 was increased from 0.32 to 0.56,6.0 to 14.0,10.0 to 24.6 and 26.0 to 52.0mmol L-1 NaCl,respectively when Na-HA was added at the rate of from 0 to 40mgL-1,With the same Na-HA addition and three pH(6,8and 10)treatments,the CFC for the Na-red soil was incresed from 0.5 to 20.0,1.0 to 40.0 and 6.0 to 141.0mmol L-1 NaCl,respectively.Obviously,pH and HA has greater effects on clay dispersion of the red soil(dominated by 1:1 minerals and oxides) than on that of the yellow-brown soil(dominated by 2:1minerals).However,at three rates of pH(6,8and 10) and with the addition of Ca-HA from 0 to 40mg L-1,the CFC of the Ca-yellow-brown soil and Ca-red soil treated with H2O2 was increased from 0.55 to 0.81,0.75 to 1.28,0.55 to 1.45and 0.038 to 0.266.0.25 to 0.62,0.7to 1.6mmol CaCl2 L-1,respectively.So,Na-soil claye are more sensitive to pH and HA than Ca-soil clays.

  7. PH BUFFERING IN FOREST SOIL ORGANIC HORIZONS: RELEVANCE TO ACID PRECIPITATION

    Samples of organic surface horizons (Oi, Oe, Oa) from New York State forest soils were equilibrated with 0 to 20 cmol HNO3 Kg(-1) soil in the laboratory by a batch technique designed to simulate reactions of acid precipitation with forest floors. Each organic horizon retained a c...

  8. ALUMINUM SOLUBILITY, CALCIUM-ALUMINUM EXCHANGE, AND PH IN ACID FOREST SOILS

    Important components in several models designed to describe the effects of acid deposition on soils and surface waters are the pH-A1 and Ca-A1 exchange relationships. f A1 solubility is controlled by A1 trihydroxide minerals, the theoretical pH-A1 relationship can be described by...

  9. Urea Fertilizer and pH Influence on Sorption Process of Flumetsulam and MCPA Acidic Herbicides in a Volcanic Soil.

    Palma, Graciela; Jorquera, Milko; Demanet, Rolando; Elgueta, Sebastian; Briceño, Gabriela; de la Luz Mora, María

    2016-01-01

    The aim of this study was to evaluate the influence of urea fertilizer and pH on the sorption process of two acidic herbicides, flumetsulam (2',6'-difluoro-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonanilide) and MCPA (4-chloro--tolyloxyacetic acid), on an Andisol. Urea reduced the adsorption of MCPA but not that of flumetsulam. The Freundlich parameter of MCPA decreased from 8.5 to 5.1 mg L kg. This finding could be attributed to an increase in dissolved organic C due to an initial increase in soil pH for urea application. The higher acidic character of MCPA compared with that of flumetsulam produced a greater hydrolysis of urea, leading to a further pH increase. A marked effect of pH on the adsorption of both herbicides was observed. The organic C distribution coefficient () values for flumetsulam were in the range of 74 to 10 L kg, while those of MCPA were in the range of 208 to 45 L kg. In the kinetic studies, the pseudo-second-order model appeared to fit the data best ( > 0.994). The initial adsorption rates () ranged from 20.00 to 4.59 mg kg h for flumetsulam and from 125.00 to 25.60 mg kg hfor MCPA. Both herbicides were adsorbed rapidly during the first stage of the sorption process, and the rates of sorption were dependent on pH. The application of the Elovich and Weber-Morris models led us to conclude that mass transfer through the boundary layer and, to a lesser degree, intraparticle diffusion were influenced by the chemical character of the herbicide. These results suggest that urea application could increase leaching of acid herbicides in soils. PMID:26828188

  10. The geochemistry during management of lake acidification caused by the rewetting of sulfuric (pH < 4) acid sulfate soils

    Highlights: • The dynamic geochemistry of a lake acidification event and its management was assessed. • Sulfate complexes dominated the aqueous metal speciation at low pH. • Iron oxydroxysulfate minerals (schwertmannite, jarosite) were identified. • Aerial additions of limestone to the acidic water slowly returned the pH to near neutral. • Coating of the limestone with gypsum and metal precipitates limited its neutralisation efficiency. - Abstract: Understanding the geochemistry and kinetics of acidification events arising from acid sulfate soils is important to enable effective management and risk assessment. Large-scale exposure and oxidation of acid sulfate soils occurred during a drought in the Lower Lakes (Murray–Darling Basin) of South Australia. We examined the geochemical changes that occurred in one region (Boggy Lake) that experienced surface water acidification and was subsequently neutralised via aerial limestone (CaCO3) dosing and dilution via natural lake refill. Very low pH (< 3) and high concentrations (≈10–1000 mg/L Fe, Al, Mn) of dissolved metals were initially found in surface water. The water chemistry exhibited pH-dependent enhancement of constituents typically associated with acid sulfate soils (SO4, Al and Fe). Geochemical speciation calculations indicated that most (60–80%) of the acidity was present as dissolved metal-sulfate complexes at low pH. X-ray diffraction (XRD) analyses showed that the orange-brown precipitates present after an initial limestone dosing were secondary oxyhydroxysulfate minerals (schwertmannite, jarosite). Further limestone dosing resulted in neutralisation of the pH, reduction in dissolved metal concentrations, dissolution of jarosite and schwertmannite precipitates, and formation of other metal oxyhydroxide phases. The results were consistent with a pE-pH diagram constructed for metal-sulfur geochemistry. Assessment of the measured and simulated (using PHREEQC) pH and Ca/Cl ratio during limestone

  11. Effect of pH Value on Stress Corrosion Cracking of X70 Pipeline Steel in Acidic Soil Environment

    Zhiyong LIU; Cuiwei DU; Xin ZHANG; Fuming WANG; Xiaogang LI

    2013-01-01

    The effect of pH value on the stress corrosion cracking (SCC) of API X70 pipeline steel in simulated acidic soil solutions was investigated by using slow strain rate test,electrochemical polarization curves,electrochemical impedance spectroscopy,and scanning electron microscopy.pH plays an important role in the susceptibility and electrochemical mechanism of SCC.The pH higher than 5 has no significant effect on electrochemical processes.By contrast,the pH lower than 5 intensifies cathodic hydrogen evolution reactions,thus increasing the cathodic current and corrosion potential.Under different pH values,the SCC mechanism of X70 pipeline steel varies among anodic dissolution (AD),hydrogen embrittlement (HE),and the combination of AD and HE (AD + HE) with variations of applied potential.At-850 mVSCE,the SCC mechanism is HE if pH is less than 4 or AD + HE if pH value is more positive.

  12. Copper availability and bioavailability are controlled by rhizosphere pH in rape grown in an acidic Cu-contaminated soil

    Chaignon, Valerie; Quesnoit, Marie [INRA, UMR 1222 Eco and Sols Ecologie fonctionnelle and Biogeochimie des Sols (INRA-IRD-SupAgro), Place Viala, F-34060 Montpellier (France); Hinsinger, Philippe, E-mail: philippe.hinsinger@supagro.inra.f [INRA, UMR 1222 Eco and Sols Ecologie fonctionnelle and Biogeochimie des Sols (INRA-IRD-SupAgro), Place Viala, F-34060 Montpellier (France)

    2009-12-15

    We evaluated how root-induced changes in rhizosphere pH varied and interacted with Cu availability and bioavailability in an acidic soil. Rape was grown on a Cu-contaminated acidic soil, which had been limed at 10 rates. Soil Cu bioavailability was not influenced by liming. However, liming significantly decreased CaCl{sub 2}-extracted Cu for pH between 3.7 and 5.1. Little effect was found for pH above 5.1. For soil pH < 4.4, CaCl{sub 2}-Cu contents were smaller in rhizosphere than uncropped soil. Rhizosphere alkalisation occurred at pH < 4.8, while acidification occurred at greater pH. This explained the changes of CaCl{sub 2}-Cu in the rhizosphere at low pH and the absence of pH dependency of Cu bioavailability to rape. In addition, apoplastic Cu in roots increased with increasing soil pH, most probably as a result of increased dissociation and affinity of cell wall compounds for Cu. - Root-induced increase in pH reduces Cu availability in the rhizosphere and Cu bioavailability to rape.

  13. A review of metal (Pb and Zn) sensitive and pH tolerant bioassay organisms for risk screening of metal-contaminated acidic soils

    To improve risk estimates at the screening stage of Ecological Risk Assessment (ERA), short duration bioassays tailored to undisturbed soil cores from the contaminated site could be useful. However, existing standardized bioassays use disturbed soil samples and often pH sensitive organisms. This is a problem as naturally acidic soils are widespread. Changing soil properties to suit the test organism may change metal bioavailability, leading to erroneous risk estimates. For bioassays in undisturbed soil cores to be effective, species able to withstand natural soil properties must be identified. This review presents a critical examination of bioassay species' tolerance of acidic soils and sensitivity to metal contaminants such as Pb and Zn. Promising organisms include; Dendrobaena octaedra, Folsomia candida, Caenorhabditis elegans, Oppia nitens, Brassica rapa, Trifolium pratense, Allium cepa, Quercus rubra and Acer rubrum. The MetSTICK test and the Bait lamina test were also identified as suitable microorganism tests. -- Highlights: •Risk screening of metal contaminated soils should consider metal bioavailability. •Metal bioavailability is dependent on soil properties such as pH. •Many standardized bioassay organisms are sensitive to acidic soils. •This review identifies acid tolerant and metal sensitive bioassays and species. •The identified tests can improve risk screening of acidic metal contaminated soil. -- This review identifies bioassay species able to withstand naturally acidic soils while being sensitive to metal contaminants

  14. Copper availability and bioavailability are controlled by rhizosphere pH in rape grown in an acidic Cu-contaminated soil

    We evaluated how root-induced changes in rhizosphere pH varied and interacted with Cu availability and bioavailability in an acidic soil. Rape was grown on a Cu-contaminated acidic soil, which had been limed at 10 rates. Soil Cu bioavailability was not influenced by liming. However, liming significantly decreased CaCl2-extracted Cu for pH between 3.7 and 5.1. Little effect was found for pH above 5.1. For soil pH 2-Cu contents were smaller in rhizosphere than uncropped soil. Rhizosphere alkalisation occurred at pH 2-Cu in the rhizosphere at low pH and the absence of pH dependency of Cu bioavailability to rape. In addition, apoplastic Cu in roots increased with increasing soil pH, most probably as a result of increased dissociation and affinity of cell wall compounds for Cu. - Root-induced increase in pH reduces Cu availability in the rhizosphere and Cu bioavailability to rape.

  15. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils.

    Obia, Alfred; Cornelissen, Gerard; Mulder, Jan; Dörsch, Peter

    2015-01-01

    Biochar (BC) application to soil suppresses emission of nitrous- (N2O) and nitric oxide (NO), but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2) were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH) were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH. PMID:26397367

  16. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils.

    Alfred Obia

    Full Text Available Biochar (BC application to soil suppresses emission of nitrous- (N2O and nitric oxide (NO, but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2 were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH.

  17. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils

    Obia, Alfred; Cornelissen, Gerard; Mulder, Jan; Dörsch, Peter

    2015-01-01

    Biochar (BC) application to soil suppresses emission of nitrous- (N2O) and nitric oxide (NO), but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2) were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH) were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH. PMID:26397367

  18. Effecf of pH and some cations on activity of acid phosphatase secreted from Ustilago sp. isolated from acid sulphate soil

    Chairatana Nilnond

    2007-03-01

    Full Text Available Acid phosphatase secreted from Ustilago sp. is able to hydrolyze organic phosphorus. These soil yeast microorganisms were isolated from rice roots grown in acid sulphate soil that generally contains highamount of aluminum (Al, iron (Fe and manganese (Mn ions. Therefore, the objectives of this study were to examine the effect of pH and some cations on acid phosphatase activity. Two isolates of Ustilago sp., AR101and AR102, were cultured in 100 mL of modified Pikovskaya's broth containing Na-phytate, pH 4, and acid phosphatase activity was determined at pH 2.0-7.0. Effect of Al, Fe, and Mn, including calcium (Ca ions,on growth of AR101 and AR102, secreted acid phosphatase activity, and the ability of acid phosphatase on the phosphorus release from Na-phytate by Ustilago sp. were investigated. It was found that the optimum pH for acid phosphatase activity was 3.5-4.5. The activity of acid phosphatase secreted from AR101 (3,690nmol min-1 mL-1 was remarkably higher than that from AR102 (956 nmol min-1 mL-1. Aluminum, iron, manganese and calcium ions in the medium did not affect the growth of either isolate. The activity of secretedacid phosphatase of AR101 was inhibited by Al and Ca ion, and synthesis of acid phosphatase of Ustilago sp. AR102 was possibly stimulated by Fe ion. Both AR101 and AR102 solubilized Na-phytate, resulting in therelease of P. However, some amount of released P was then precipitated with Al and Fe ions as the highly insoluble Fe- or Al- phosphate.

  19. Aluminium uptake and translocation in Al hyperaccumulator Rumex obtusifolius is affected by low-molecular-weight organic acids content and soil pH.

    Stanislava Vondráčková

    Full Text Available High Al resistance of Rumex obtusifolius together with its ability to accumulate Al has never been studied in weakly acidic conditions (pH > 5.8 and is not sufficiently described in real soil conditions. The potential elucidation of the role of organic acids in plant can explain the Al tolerance mechanism.We established a pot experiment with R. obtusifolius planted in slightly acidic and alkaline soils. For the manipulation of Al availability, both soils were untreated and treated by lime and superphosphate. We determined mobile Al concentrations in soils and concentrations of Al and organic acids in organs.Al availability correlated positively to the extraction of organic acids (citric acid < oxalic acid in soils. Monovalent Al cations were the most abundant mobile Al forms with positive charge in soils. Liming and superphosphate application were ambiguous measures for changing Al mobility in soils. Elevated transport of total Al from belowground organs into leaves was recorded in both lime-treated soils and in superphosphate-treated alkaline soil as a result of sufficient amount of Ca available from soil solution as well as from superphosphate that can probably modify distribution of total Al in R. obtusifolius as a representative of "oxalate plants." The highest concentrations of Al and organic acids were recorded in the leaves, followed by the stem and belowground organ infusions.In alkaline soil, R. obtusifolius is an Al-hyperaccumulator with the highest concentrations of oxalate in leaves, of malate in stems, and of citrate in belowground organs. These organic acids form strong complexes with Al that can play a key role in internal Al tolerance but the used methods did not allow us to distinguish the proportion of total Al-organic complexes to the free organic acids.

  20. Interactions of Zn(II) Ions with Humic Acids Isolated from Various Type of Soils. Effect of pH, Zn Concentrations and Humic Acids Chemical Properties

    Boguta, Patrycja; Sokołowska, Zofia

    2016-01-01

    The main aim of this study was the analysis of the interaction between humic acids (HAs) from different soils and Zn(II) ions at wide concentration ranges and at two different pHs, 5 and 7, by using fluorescence and FTIR spectroscopy, as well as potentiometric measurements. The presence of a few areas of HAs structures responsible for Zn(II) complexing was revealed. Complexation at α-sites (low humified structures of low-molecular weight and aromatic polycondensation) and β-sites (weakly humified structures) was stronger at pH 7 than 5. This trend was not observed for γ-sites (structures with linearly-condensed aromatic rings, unsaturated bonds and large molecular weight). The amount of metal complexed at pH5 and 7 by α and γ-structures increased with a decrease in humification and aromaticity of HAs, contrary to β-areas where complexation increased with increasing content of carboxylic groups. The stability of complexes was higher at pH 7 and was the highest for γ-structures. At pH 5, stability decreased with C/N increase for α-areas and -COOH content increase for β-sites; stability increased with humification decrease for γ-structures. The stability of complexes at α and β-areas at pH 7 decreased with a drop in HAs humification. FTIR spectra at pH 5 revealed that the most-humified HAs tended to cause bidentate bridging coordination, while in the case of the least-humified HAs, Zn caused bidentate bridging coordination at low Zn additions and bidentate chelation at the highest Zn concentrations. Low Zn doses at pH 7 caused formation of unidentate complexes while higher Zn doses caused bidentate bridging. Such processes were noticed for HAs characterized by high oxidation degree and high oxygen functional group content; where these were low, HAs displayed bidentate bridging or even bidentate chelation. To summarize, the above studies have showed significant impact of Zn concentration, pH and some properties of HAs on complexation reactions of humic

  1. Past and future seasonal variation in pH and metal concentrations in runoff from river basins on acid sulphate soils in Western Finland.

    Saarinen, Tuomas S; Kløve, Bjørn

    2012-01-01

    Drainage of acid sulphate soils (ASS) increases oxidation, leading to extensive leaching of acidity and metals to rivers (Al, Cd, Cr, Fe, Ni and Zn). This is often apparent during high runoff periods in spring and autumn after long dry periods with low groundwater levels and associated ASS oxidation. Regression models were used to study changes in these water quality variables according to various discharge scenarios. The knowledge of seasonal patterns of water quality variables in future is important for planning land use of the catchments in relation to WFD of European Union. The data showed that river water acidity (pH and metals) increased with discharge, with the correlation being strongest in low runoff periods in winter and summer and less clear in spring. With future climate change, river acidity can increase radically, especially during winters following extremely dry summers, and pH and metal peaks may occur even during winter. PMID:22702821

  2. Remediation of grey forest soils heavily polluted with heavy metals by means of their leaching at acidic pH followed by the soil reclamation by means of neutralization and bacterial manure addition

    Georgiev, Plamen; Groudev, Stoyan; Spasova, Irena; Nicolova, Marina

    2014-05-01

    Some grey forest soils in Western Bulgaria are heavily polluted with heavy metals (copper, lead, and zinc), arsenic, and uranium due to the infiltration of acid mine drainage generated at the abandoned uranium mine Curilo. This paper presents some results from a study about soil remediation based on the contaminants leaching from the topsoil by means of irrigation with solutions containing sulphuric acid or its in situ generation by means of sulphur-oxidizing chemolithotrophic bacteria in or without the presence of finely cut straw. These methods were tested in large scale zero suction lysimeters. The approaches based on S° and finely cut straw addition was the most efficient amongst the tested methods and for seven months of soil remediation the concentration of all soil contaminants were decreased below the relevant Maximum Admissible Concentration (MAC). Neutralization of the soil acidity was applied as a next stage of soil reclamation by adding CaCO3 and cow manure. As a result, soil pH increased from strongly acidic (2.36) to slightly acidic (6.15) which allowed subsequent addition of humic acids and bacterial manure to the topsoil. The soil habitat changed in this way facilitated the growth of microorganisms which restored the biogeochemical cycles of nitrogen and carbon to the levels typical for non-polluted grey forest soil.

  3. Determining Critical Soil pH for Grain Sorghum Production

    Katy Butchee

    2012-01-01

    Full Text Available Grain sorghum (Sorghum bicolor L. has become a popular rotation crop in the Great Plains. The transition from conventional tillage to no-tillage production systems has led to an increase in the need for crop rotations. Some of the soils of the Great Plains are acidic, and there is concern that grain sorghum production may be limited when grown on acidic soils. The objective of this study was to evaluate the effect of soil pH for grain sorghum production. Potassium chloride-exchangeable aluminum was also analyzed to determine grain sorghum’s sensitivity to soil aluminum (Al concentration. The relationship between relative yield and soil pH was investigated at Lahoma, Perkins, and Haskell, Oklahoma, USA with soil pH treatments ranging from 4.0–7.0. Soil pH was altered using aluminum sulfate or hydrated lime. Soil acidity reduced grain sorghum yield, resulting in a 10% reduction in yield at soil pH 5.42. Potassium chloride-exchangeable aluminum levels above 18 mg kg−1 resulted in yield reductions of 10% or greater. Liming should be considered to increase soil pH if it is below these critical levels where grain sorghum will be produced.

  4. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils

    Obia, Alfred; Cornelissen, Gerard; Mulder, Jan; Dörsch, Peter

    2015-01-01

    Biochar (BC) application to soil suppresses emission of nitrous- (N2O) and nitric oxide (NO), but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitri...

  5. Determining Critical Soil pH for Sunflower Production

    Apurba Sutradhar

    2014-01-01

    Full Text Available Soil acidity has become a major yield-limiting factor in cropping systems of the Southern Great Plains, in which winter wheat (Triticum aestivum L. is the predominant crop. Sunflower (Helianthus annuus L. is a strong rotational crop with winter wheat due to its draught and heat tolerance. However, the effects of low soil pH on sunflower productivity have not been explored. The objective of this study was to determine the critical soil pH and aluminum concentration (AlKCl for sunflower. Sunflower was grown in a randomized complete block design with three replications of a pH gradient ranging from 4.0 to 7.0 at three locations with varying soil types. Soil pH was altered using aluminum sulfate (Al2(SO43 and hydrated lime (Ca(OH2. Plant height, vigor, and survivability were all negatively affected by soil acidity. Sunflower yield was reduced by 10% at or below soil pH 4.7 to 5.3 dependent upon location and soil type. Levels of AlKCl above 6.35 mg kg−1 reduced seed yield by 10% or greater. We concluded that sunflower may serve as a better rotational crop with winter wheat under acidic conditions when compared to other adaptable crops.

  6. Impact of pH on Microbial Biomass Carbon and Microbial Biomass Phosphorus in Red Soils

    CHEN Guo-Chao; HE Zhen-Li; WANG Yi-Jun

    2004-01-01

    The impact of pH changes on microbial biomass carbon (Cmic) and microbial biomass phosphorus (Pmic)were examined for 3 red soils under citrus production with different lengths of cultivation. Soil pH significantly affected Cmic and Pmic. The Cmic and Pmic changes, as a function of soil pH, appeared to follow a normal distribution with the original soil pH value at the apex and as pH increased or decreased compared to the original soil pH, Cmic and Pmic declined. Moreover, there were critical pH values at both extremes (3.0 on the acidic side and 8.0 to 8.5 on the alkaline side), beyond which most of microorganisms could never survive.The effect of pH on Cmic and Pmic was also related to the original soil pH. The higher the original soil pH was, the less Cmic or Pmic were affected by pH change. It is suggested that soil microorganisms that grow in a soil environment with a more neutral soil pH range (I.e. pH 5.5-7.5) may have a greater tolerance to pH changes than those growing in more acidic or more alkaline soil pH conditions.

  7. Observation of pH Value in Electrokinetic Remediation using various electrolyte (MgSO4, KH2PO4 and Na(NO3)) for Barren Acidic Soil at Ayer Hitam, Johor, Malaysia

    Norashira, J.; Zaidi, E.; Aziman, M.; Saiful Azhar, A. T.

    2016-07-01

    Barren acidic soil collected at Ayer Hitam, Johor Malaysia was recorded at pH value of 2.36 with relative humidity of 86%. This pH value is not suitable for the growth of any plants especially for the soil stabilization purposes. Gradation weathering within the range of 4 to 6 indicates an incomplete/partial weathering process. The soil grade in this range is known as a black shale mudstone. Beside, this also influences to a factor of the high surface water runoff at this particular soil species. As the acidic pH become a major problem for soil fertilizing hence an appropriate technique was implemented known as using ‘Electrokinetic Remediation’, EKR. This technique has a great potential in changing the soil pH value from acidic to less acidic and also kept maintain the pH at the saturated rate of electrochemical process. This research study presents the monitoring data of pH value due to the effect of various electrolyte consist of 0.5M of MgSO4, KH2PO4, and Na(NO3). Here, the distilled water (DW) was used as reference solution. The electric field was provided by dipping two pieces of identical rectangular aluminum foil as anode and cathode. The EKR was conducted under a constant voltage gradient of 50 V/m across the sample bulk at 0.14 m length measured between both electrodes. The data collection was conducted during the total period of 7 days surveillance. The variation of pH values at the remediation area between anode and cathode for various type of electrolyte indicates that there are a significant saturated value as it reaches 7 days of treatment. During the analysis, it is found that the highest pH value at the remediation area after 7 days treatment using Na(NO3), KH2PO4 and MgSO4 was 3.93, 3.33 and 3.39 respectively. Hence from the last stage of pH value observation, it can be conclude that the best electrolyte for barren soil treatment is Na(NO3) whereby it contribute to highest pH value and turn the soil to be less acidic.

  8. Acid Rain, pH & Acidity: A Common Misinterpretation.

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  9. Biochar contribution to soil pH buffer capacity

    Tonutare, Tonu; Krebstein, Kadri; Utso, Maarius; Rodima, Ako; Kolli, Raimo; Shanskiy, Merrit

    2014-05-01

    Biochar as ecologically clean and stable form of carbon has complex of physical and chemical properties which make it a potentially powerful soil amendment (Mutezo, 2013). Therefore during the last decade the biochar application as soil amendment has been a matter for a great number of investigations. For the ecological viewpoint the trend of decreasing of soil organic matter in European agricultural land is a major problem. Society is faced with the task to find possibilities to stabilize or increase soil organic matter content in soil and quality. The availability of different functional groups (e.g. carboxylic, phenolic, acidic, alcoholic, amine, amide) allows soil organic matter to buffer over a wide range of soil pH values (Krull et al. 2004). Therefore the loss of soil organic matter also reduces cation exchange capacity resulting in lower nutrient retention (Kimetu et al. 2008). Biochar can retain elements in soil directly through the negative charge that develops on its surfaces, and this negative charge can buffer acidity in the soil. There are lack of investigations about the effect of biochar to soil pH buffering properties, The aim of our investigation was to investigate the changes in soil pH buffer capacity in a result of addition of carbonizated material to temperate region soils. In the experiment different kind of softwood biochars, activated carbon and different soil types with various organic matter and pH were used. The study soils were Albeluvisols, Leptosols, Cambisols, Regosols and Histosols . In the experiment the series of the soil: biochar mixtures with the biochar content 0 to 100% were used. The times of equiliberation between solid and liquid phase were from 1 to 168 hours. The suspension of soil: biochar mixtures was titrated with HCl solution. The titration curves were established and pH buffer capacities were calculated for the pH interval from 3.0 to 10.0. The results demonstrate the dependence of pH buffer capacity from soil type

  10. Silicate weathering in soils: A solution for soil pH management?

    Soldal, Jostein

    2015-01-01

    N2O released form agricultural soils is mainly a product of denitrification; a key microbial process in the N cycle. The relative rate of N2O released from this process depends of the soil pH, where the relative amount of N2O to denitrified N (N2O/N2+N2O) increase in more acidic soils. pH management in soils is mainly based on carbonate based liming, which will release CO2 to the atmosphere during dissolution or at later acidification. Use of non-carbonate rock p...

  11. Adaptation of Denitrifying Populations to Low Soil pH

    Parkin, Timothy B.; Sexstone, Alan J.; Tiedje, James M.

    1985-01-01

    Natural denitrification rates and activities of denitrifying enzymes were measured in an agricultural soil which had a 20-year past history of low pH (pH ca. 4) due to fertilization with acid-generating ammonium salts. The soil adjacent to this site had been limed and had a pH of ca. 6.0. Natural denitrification rates of these areas were of similar magnitude: 158 ng of N g−1 of soil day−1 for the acid soil and 390 ng of N g−1 of soil day−1 at the neutral site. Estimates of in situ denitrifyin...

  12. pH as a Driver for Ammonia-Oxidizing Archaea in Forest Soils.

    Stempfhuber, Barbara; Engel, Marion; Fischer, Doreen; Neskovic-Prit, Ganna; Wubet, Tesfaye; Schöning, Ingo; Gubry-Rangin, Cécile; Kublik, Susanne; Schloter-Hai, Brigitte; Rattei, Thomas; Welzl, Gerhard; Nicol, Graeme W; Schrumpf, Marion; Buscot, Francois; Prosser, James I; Schloter, Michael

    2015-05-01

    In this study, we investigated the impact of soil pH on the diversity and abundance of archaeal ammonia oxidizers in 27 different forest soils across Germany. DNA was extracted from topsoil samples, the amoA gene, encoding ammonia monooxygenase, was amplified; and the amplicons were sequenced using a 454-based pyrosequencing approach. As expected, the ratio of archaeal (AOA) to bacterial (AOB) ammonia oxidizers' amoA genes increased sharply with decreasing soil pH. The diversity of AOA differed significantly between sites with ultra-acidic soil pH (4.5, regardless of geographic position and vegetation. These OTUs could be related to the Nitrosotalea group 1.1 and the Nitrososphaera subcluster 7.2, respectively, and showed significant similarities to OTUs described from other acidic environments. Conversely, none of the major OTUs typical of sites with a soil pH >4.6 could be found in the ultra- and extreme acidic soils. Based on a comparison with the amoA gene sequence data from a previous study performed on agricultural soils, we could clearly show that the development of AOA communities in soils with ultra-acidic pH (<3.5) is mainly triggered by soil pH and is not influenced significantly by the type of land use, the soil type, or the geographic position of the site, which was observed for sites with acido-neutral soil pH. PMID:25501889

  13. Some negative chemical properties of acid soils

    SVETLANA ANTIC-MLADENOVIC; SRDJAN BLAGOJEVIC; MIRJANA KRESOVIC; MIODRAG JAKOVLJEVIC

    2005-01-01

    Some important chemical properties of various samples of two types of acid soil fromWestern Serbia (pseudogley and brown forest) are presented in this paper.Mobile Al was found in elevated and toxic quantities (10–30 mg/100 g) in the more acid samples of pseudogley soil. All samples of brown forest soil were very acid and the quantities ofmobile Al were in the range from 12.8 to 90.0mg/100 g. In a selected number of pseudogley soils, the influence of pH and other soil properties on the minera...

  14. Teaching Plant-Soil Relationships with Color Images of Rhizosphere pH.

    Heckman, J. R.; Strick, J. E.

    1996-01-01

    Presents a laboratory exercise that uses a simple imaging technique to illustrate the profound effects that living roots exert on the pH of the surrounding soil environment. Achieves visually stimulating results that can be used to reinforce lectures on rhizosphere pH, nutrient availability, plant tolerance of soil acidity, microbial activity, and…

  15. Effect of the Soil pH on the Alkaloid Content of Lupinus angustifolius

    Gisela Jansen; Hans-Ulrich Jürgens; Edgar Schliephake; Frank Ordon

    2012-01-01

    Field studies were conducted in growing seasons 2004, 2005, and 2010 to investigate the effect of different soil pH values on the alkaloid content in seeds of Lupinus angustifolius. Two-year experiments with eleven cultivars were carried out in acid soils with an average of pH=5.8 (Mecklenburg-Western Pomerania) and on calcareous soils with an average pH of 7.1 (Bavaria), respectively. In addition, in 2010, eight cultivars were grown in field experiments in soils with pH values varying betwee...

  16. Degradation of [14C]isofenphos in soil in the laboratory under different soil pH's, temperatures, and moistures

    The effects of three soil pH's, three soil temperatures, and three soil moistures on [14C]isofenphos degradation were investigated. All three factors interacted strongly and significantly affected the persistence of isofenphos as well as the formation of the degradation products (p less than 1%). Isofenphos degradation was greatest at the higher temperatures 350C greater than 250C greater than 150C (except under alkaline pH's), medium moisture 25% greater than 30% greater than 15%, and in both alkaline (pH = 8) and acidic soils (pH = 6) compared with neutral soil (pH = 7). Isofenphos oxon formation was greatest at higher temperatures 350C compared with 250C and 150C, in acidic soil greater than neutral soil greater than alkaline soil, and under high moisture (30%) compared with the 15% and 22.5% moistures. The formation of soil-bound residues was greatest at higher temperatures 350C greater than 250C greater than 150C, higher moisture 30% compared with 15% and 22.5%, and in alkaline soil compared with neutral and acidic soils

  17. Higher pH acid stimulation systems

    Abrams, A.; Richardson, E.A.; Scheuerman, R.F.; Templeton, C.C.

    1979-01-01

    Two types of high pH (4 to 6), mild acting acidizing systems developed for in-depth rock matrix stimulation for both sandstone and carbonate reservoirs are described. With these systems, in-depth stimulation capability is available from ambient to about 280 F (138 C). Buffer regulated (BR) systems also have application for near well-bore stimulation at temperatures of up to at least 365 F (185 C). The self-generating systems based on methyl formate (MF), the ammonium salt of monochloroacetic acid (CA), and methyl acetate (MA), have sandstone application ranges and are described. Three BR systems have been developed, based on formic, acetic, and citric acids. Included in the study is a brief review of the theory involved, experimental techniques for measuring acid reaction rates, and discussions of clay dissolution and carbonate acidization mechanisms. 16 references.

  18. Estimativa da acidez potencial pelo método do pH SMP em solos da formação Caiuá: noroeste do estado do Paraná Estimation of potential acidity by the pH SMP method in soils of the Caiuá formation: northwest of the State of Paraná

    J. A. Sambatti

    2003-04-01

    Full Text Available A utilização do pH SMP na estimativa da acidez potencial tem vantagens em relação ao método do acetato de cálcio 0,5 mol L-1, pH 7, mas requer regionalização edafológica prévia para estimar, com segurança, os valores de H + Al. Na região noroeste do Paraná, encontram-se solos originários de uma rocha sedimentar arenosa da Formação Caiuá, denominada Arenito Caiuá, do período Cretáceo. Esses solos são caracterizados pelos baixos teores de argila, matéria orgânica e baixo tamponamento, diferindo da maioria dos solos existentes no estado. Este estudo teve por objetivo comparar os métodos do pH SMP e o do acetato de cálcio 0,5 mol L-1, pH 7, visando estabelecer uma equação que estime a acidez potencial dos solos dessa área, por meio da obtenção do pH de equilíbrio da suspensão com a solução SMP. Cento e cinqüenta amostras de solos daquela área foram submetidas a análises de regressão, utilizando três modelos que foram avaliados, quanto à qualidade das estimativas, pelas estatísticas dos seus coeficientes e pelo comportamento dos seus resíduos (medido-estimado. A equação linear H + Al = 20,1925 - 2,6484 pH SMP (R² = 0,9051 foi a que melhor estimou a acidez potencial dos solos pertencentes à Formação Caiuá.The use of the pH SMP to estimate the potential acidity has advantages in relation to the 0.5 mol L-1, pH 7, calcium acetate method, but it requires previous edaphic regionalization to estimate the H + Al values with safety. In the northwestern region of the State of Paraná there are soils originally developed from sandy sedimentary rock of the Caiuá Formation, called Caiuá Sandstone, of the Cretaceous period. These soils are characterized by low contents of clay and organic matter, and a low buffer capacity, differing from most of the other soils in the state. The objective of this research was to compare the pH SMP and the 0.5 mol L-1, pH 7 calcium acetate methods, in order to establish an

  19. Long-term changes in soil pH across major forest ecosystems in China

    Yang, Yuanhe; Li, Pin; He, Honglin; Zhao, Xia; Datta, Arindam; Ma, Wenhong; Zhang, Ying; Liu, Xuejun; Han, Wenxuan; Wilson, Maxwell C.; Fang, Jingyun

    2015-02-01

    Atmospheric acidic deposition has been a major environmental problem since the industrial revolution. However, our understanding of the effect of acidic deposition on soil pH is inconclusive. Here we examined temporal variations in topsoil pH and their relationships with atmospheric sulfur and nitrogen deposition across China's forests from the 1980s to the 2000s. To accomplish this goal, we conducted artificial neural network simulations using historical soil inventory data from the 1980s and a data set synthesized from literature published after 2000. Our results indicated that significant decreases in soil pH occurred in broadleaved forests, while minor changes were observed in coniferous and mixed coniferous and broadleaved forests. The magnitude of soil pH change was negatively correlated with atmospheric sulfur and nitrogen deposition. This relationship highlights the need for stringent measures that reduce sulfur and nitrogen emissions so as to maintain ecosystem structure and function.

  20. Reversibility of soil solution acidity and of sulfate retention in acid forest soils

    Alewell, C.; Matzner, E. (Universitaet Bayreuth, Bayreuth (Germany). Lehrstuhl fuer Bodenoekologie)

    1993-11-01

    To quantify the effects of reduced sulfate input on the chemistry of soil solution and soil S storage in acid forest soils, an experiment with undisturbed soil columns from two different sites was implemented. The acid cambisol of the Solling is subjected to a high sulfate input and especially the B-horizon has a high sulfate content. On the contrary, the podzol of the Fuhrberg site is subjected to low input and has low sulfate content. Undisturbed soil columns were taken from both sites and were irrigated at 6[degree]C with a precipitation rate of 3 mmd[sup -1] over 10 mo. In treatment No. 1, an artificial throughfall with pH 5.2 and reduced sulfate load (45[mu]mol L[sup -1]) was applied. In treatment No. 2, an artificial throughfall representing a high sulfate deposition (427 [mu]mol L[sup -1], pH 3.2) was used. In the case of the Solling soil, the pH of soil solution was unaffected by treatments during the entire experiment. Alkalinity of the soil solution was slightly increased in treatment No. 1 at a depth of 20 cm. While treatment No. 1 resulted in a reduction of the sulfate concentrations of the soil solution in the top soil, sulfate concentrations were unaffected at a depth of 40 cm. The B-horizon of the Solling soil prevented deacidification of the soil solution by desorption of previously stored sulfate. In the case of the Fuhrberg soil, treatment No. 1 resulted in reduced sulfate concentrations of the soil solution even in deeper soil layers with concentrations approaching input levels. The pH of the solution was slightly elevated and the alkalinity of the solution increased. Organic S compounds in the soil seemed to have no influence on sulfate release in either soils. 37 refs., 3 figs., 1 tab.

  1. Fixation Status of Acid Soils

    Six acid soil series from different benchmark sites; Rangsit soil (Sulfic Tropaquepts) (two acid sulfate soils), Pakchong soil (Oxic Paleustults) Korat soil (Oxic Paleustults), Warin soil (Oxic Paleustults), Mae Taeng soil (Typic paleustults) and Boundary grey soil and two Thai phosphate rocks (P R) (Lampun P R and Ratchabuie P R) had been characterized in the laboratory by isotope techniques (E, value Part 1). Triple superphosphate (TSP) was used as a standard fertilizer. R P and TSP with 50 mg P Kg-1 soil were incubated for 30 days to examine the fixing capacity of the acid soils. The results showed that Rangsit Soil which is acid sulfate had high fixing capacity. Pakchong soil retained higher P fixation ability than Korat and Warin soil series. The highest fixation capacity among 7 acid soils were Grey Soil and Mae Taeng soil series. The solubility of TSP was decreased when incorporated with soil after incubation for 30 days. P R from Ratchaburi showed higher effectiveness than Lamphun P R

  2. Brown coal derived products ameliorating soil acidity

    Issa, J.; Patti, A.F.; Jackson, W.R. [Monash University, Clayton, Vic. (Australia). Centre for Green Chemistry

    2000-07-01

    Humic acid derived from brown coal, with added calcium, when applied to the soil surface, can increase pH deeper into the soil profile. The humates can move down with water percolating the soil. As they move down the added calcium bound to the humate's cation exchange sites (the acidic oxygen functional groups) can exchange with toxic aluminium ions and ions on exchange sites in the soil. Thus the soil pH is buffered, nutrient transport to plants assisted, and phytotoxic aluminium bound and rendered harmless to plants. K Humate is a commercially available source of humate (ex HRL Agriculture Pty Ltd Australia) derived from brown coal. It can be obtained by the treatment of brown coal with potassium hydroxide. Calsulmag is a commercial treated coal fly ash (also ex HRL Agriculture Pty Ltd) which can be used instead of lime due to its high inorganic calcium and magnesium content. When K humate and Calsulmag are combined in an aqueous mixture, and applied to the surface of an acidic soil, pH is increased (from 3.8 to 4.5) as is exchangeable calcium (30-50%), while exchangeable aluminium is decreased (30-50%), down to a 5 cm depth.

  3. ACID RAIN AND SOIL MICROBIAL ACTIVITY: EFFECTS AND THEIR MECHANISMS

    In the investigation, our aim was to determine if acid rain affects soil microbial activity and to identify possible mechanisms of observed effects. A Sierran forest soil (pH 6.4) planted with Ponderosa pine seedlings was exposed to simulated rain (pH 2.0, 3.0, 4.0 and 5.6) with ...

  4. Determination of Soil pH in Dominant Soil Types in the Republic of Croatia

    Darija Čapka; Ivica Kisić; Željka Zgorelec; Milan Mesić; Aleksandra Jurišić

    2009-01-01

    Soil pH is a basic soil parameter, since many processes in the soil depend on it, such as the growth and development of plants. Therefore, the monitoring of soil pH is very important. In this paper the values of soil pH are obtained by measurement of the samples in three media: H2O, KCl and CaCl2. The sampling was conducted at 18 locations on 11 soil types and 15 lower systematic units. The aim of this work was to establish functional connections between the pH values in all three media. R...

  5. Electrokinetic remediation of a Cu-Zn contaminated red soil by controlling the voltage and conditioning catholyte pH.

    Zhou, Dong-Mei; Deng, Chang-Fen; Cang, Long; Alshawabkeh, Akram N

    2005-10-01

    Electrokinetics is an innovative technique for treating heavy metals contaminated soil, especially low pH soils such as the Chinese red soil (Udic Ferrisols). In this paper, a Cu-Zn contaminated red soil is treated by electrokinetics. When the Cu-Zn contaminated red soil was treated without control of catholyte pH during the electrokinetic treatment, the soil pH in the soil sections near cathode after the experiment was high above 6, which resulted in accumulation of large amounts of Cu and Zn in the soil sections with such high pH values. Compared to soil Cu, soil Zn was more efficiently removed from the soil by a controlled electrokinetic method. Application of lactic acid as catholyte pH conditioning solution caused an efficient removal of Cu and Zn from the soil. Increasing the electrolyte strength (salt concentration) of the conditioning solution further increased Cu removal, but did not cause a significant improvement for soil Zn. Soil Cu and Zn fractions after the electrokinetic treatments were analyzed using sequential extraction method, which indicated that Cu and Zn precipitation in the soil section closest to the cathode in the treatments without catholyte pH control limited their removal from the soil column. When the catholyte pH was controlled by lactic acid and CaCl(2), the soil Cu and Zn removal percentage after 554 h running reached 63% and 65%, respectively. Moreover, both the residual soil Cu and Zn concentrations were lower than 100 mg kg(-1), which is adequate and meets the requirement of the Chinese soil environmental quality standards. PMID:16202805

  6. Designer, acidic biochar influences calcareous soil characteristics.

    Ippolito, J A; Ducey, T F; Cantrell, K B; Novak, J M; Lentz, R D

    2016-01-01

    In a proof-of-concept study, an acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 °C) and steam activation (800 °C) to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0%, 1%, 2%, and 10% (by wt.) and soils were destructively sampled at 1, 2, 3, 4, 5, and 6 month intervals. Soil was analyzed for gravimetric water content, pH, NO3-N, plant-available Fe, Zn, Mn, Cu, and P, organic C, CO2 respiration, and microbial enumeration via extractable DNA and 16S rRNA gene copies. Gravimetric soil water content increased with biochar application regardless of rate, as compared to the control. Soil pH decreased between 0.2 and 0.4 units, while plant-available Zn, Mn, and P increased with increasing biochar application rate. Micronutrient availability decreased over time likely due to insoluble mineral species precipitation. Increasing biochar application raised the soil organic C content and remained elevated over time. Increasing biochar application rate also increased respired CO2, yet the CO2 released decreased over time. Soil NO3-N concentrations significantly decreased with increasing biochar application rate likely due to microbial immobilization or denitrification. Depending on application rate, biochar produced a 1.4 to 2.1-fold increase in soil DNA extracted and 1.4- to 2.4-fold increase in 16S rRNA gene abundance over control soils, suggesting microbial stimulation and a subsequent burst of activity upon biochar addition. Our results showed that there is promise in designing a biochar to improve the quality and water relations of eroded calcareous soils. PMID:26077798

  7. 种植紫花苜蓿对云南酸性土壤酸碱性和土壤成分的影响%Effects on Soil pH and Soil Composition in Acid Soil in Yunnan by Planting Alfalfa

    孙仕仙; 杨思林; 李永梅; 陶瑞

    2012-01-01

    [目的]探讨利用石灰调节酸性土壤pH后,不同播种量、施磷量和行距对土壤成分的影响以及种植不同作物对土壤成分的影响.[方法]采用二次饱和D-最优设计和随机区组设计.[结果]紫花苜蓿不同播种量、施磷量和行距对土壤pH没有显著的影响,土壤有机质含量随播种量和施磷量的增加有不同程度的增加,而与行距的变化呈负相关关系,但均未达到显著水平;土壤速效氮含量与播种量和施磷量呈不显著正相关,与行距呈0.01水平显著的负相关;种植不同作物1年后土壤有机质含量增加,且差异达到0.05显著水平.种植苜蓿和三叶草能在0.05水平显著增加土壤全氮含量,但种植小麦和南瓜对全氮含量没有影响.种植豆科牧草(苜蓿和三叶草)均在0.01水平显著增加土壤碱解氮含量,而种植小麦和南瓜对碱解氮含量没有显著影响.[结论]该研究可为云南酸性土壤引进种植紫花苜蓿提供基础依据.%[ Objective ] The research aimed to study the influence of different seeding rate, amount of phosphate and row spacing of alfafa on soil nutrient after adjusting the soil pH using lime, and the influence of planting different crops on soil nutrient. [ Method]The two times satu-rated D-the optimal design and randomized design were adopted. [ Result ] Different seeding rate, amount of phosphate and row spacing of alfafa had no significant effects on soil pH. The content of soil organic matter increased in different level with the increase of seeding rate and amount of phosphate, while soil pH was inversely related with the change of the row spacing, but the influence wasn't significant. The content of soil nitrogen positively correlated with seeding rate and amount of phosphate, but negatively correlated with row spacing. The content of soil organic matter increased by planting different crops after a year and the difference was significant. The content of soil total nitrogen

  8. Mycorrhizal Response to Experimental pH and P Manipulation in Acidic Hardwood Forests

    Kluber, Laurel A.; Carrino-Kyker, Sarah R; Coyle, Kaitlin P.; DeForest, Jared L.; Charlotte R Hewins; Shaw, Alanna N.; Kurt A Smemo; David J. Burke

    2012-01-01

    Many temperate forests of the Northeastern United States and Europe have received significant anthropogenic acid and nitrogen (N) deposition over the last century. Although temperate hardwood forests are generally thought to be N-limited, anthropogenic deposition increases the possibility of phosphorus (P) limiting productivity in these forest ecosystems. Moreover, inorganic P availability is largely controlled by soil pH and biogeochemical theory suggests that forests with acidic soils (i.e.,

  9. Organic Ligand, Competing Cation, and pH Effects on Dissolution of Zinc in Soils

    2008-01-01

    A series of experiments were conducted to examine the interactive effects of an organic ligand,a competing cation,and pH on the dissolution of zinc(Zn)from three California soils,Maymen sandy loam,Merced clay,and Yolo clay loam.The concentrations of soluble Zn of the three soils were low in a background solution of Ca(NO3)2.Citric acid,a common organic ligand found in the rhizosphere,was effective in mobilizing Zn in these soils; its presence enhanced the concentration of Zn in soil solution by citrate forming a complex with Zn.The ability of Zn to form a complex with citric acid in the soil solution was dependent on the concentration of citric acid,pH,and the concentration of the competing cation Ca2+.The pH of the soil solution determined the extent of desorption of Zn in solid phase in the presence of citric acid.The amounts of Zn released from the solid phase were proportional to the concentration of citric acid and inversely proportional to the concentration of Ca(NO3)2 background solution,which supplied the competing cation Ca2+ for the formation of a complex with citrate.When the soil suspension was spiked with Zn,the adsorption of Zn by the soils was retarded by citric acid via the formation of the soluble Zn-citrate complex.The dissolution of Zn in the presence of citric acid was pH dependent in both adsorption and desorption processes.

  10. Amendment of Acid Soils with Crop Residues and Biochars

    YUAN Jin-Hua; XU Ren-Kou; WANG Ning; LI Jiu-Yu

    2011-01-01

    The liming potential of some crop residues and their biochars on an acid Ultisol was investigated using incubation experiments. Rice hulls showed greater liming potential than rice hull biochar, while soybean and pea straws had less liming potential than their biochars. Due to their higher alkalinity, biochars from legume materials increased soil pH much compared to biochars from non-legume materials. The alkalinity of biochars was a key factor affecting their liming potential,and the greater alkalinity of biochars led to greater reductions in soil acidity. The incorporation of biochars decreased soil exchangeable acidity and increased soil exchangeable base cations and base saturation, thus improving soil fertility.

  11. Influence of soil pH on the sorption of ionizable chemicals

    Franco, Antonio; Fu, Wenjing; Trapp, Stefan

    2009-01-01

    The soil-water distribution coefficient of ionizable chemicals (K-d) depends on the soil acidity, mainly because the pH governs speciation. Using pH-specific K-d values normalized to organic carbon (K-OC) from the literature, a method was developed to estimate the K-OC of monovalent organic acids...... and bases. The regression considers pH-dependent speciation and species-specific partition coefficients, calculated from the dissociation constant (pK(a)) and the octanol-water partition coefficient of the neutral molecule (log P-n). Probably because of the lower pH near the organic colloid-water...... impact of pH on the total sorption is contrasting. In fact, the shortcomings of the model assumptions affect the predictive power for acids and for bases differently. We evaluated accuracy and limitations of the regressions for their use in the environmental fate assessment of ionizable chemicals....

  12. Influence of soil pH on the sorption of ionizable chemicals

    Franco, Antonio; Fu, Wenjing; Trapp, Stefan

    2009-01-01

    The soil-water distribution coefficient of ionizable chemicals (K-d) depends on the soil acidity, mainly because the pH governs speciation. Using pH-specific K-d values normalized to organic carbon (K-OC) from the literature, a method was developed to estimate the K-OC of monovalent organic acids...... and bases. The regression considers pH-dependent speciation and species-specific partition coefficients, calculated from the dissociation constant (pK(a)) and the octanol-water partition coefficient of the neutral molecule (log P-n). Probably because of the lower pH near the organic colloid......-water interface, the optimal pH to model dissociation was lower than the bulk soil pH. The knowledge of the soil pH allows calculation of the fractions of neutral and ionic molecules in the system, thus improving the existing regression for acids. The same approach was not successful with bases, for which the...

  13. Changes in ph, ec and concentration of phosphorus in soil solution during submergence and rice growth period in some paddy soils of north of Iran

    Nosratollah NAJAFI; Towfighi, Hassan

    2008-01-01

    Changes in pH, EC and concentration of phosphorus in soil solution during submergence and rice growth period were studied in three paddy soils of North of Iran (one acid and two alkaline-calcareous soils). Also, changes in pH, EC and concentration of phosphorus in soil solution of an alkaline-calcareous soil after addition of 40 mg P/ kg of soil during submergence and rice growth period were studied. The experiment was performed in a set of specially fabricated pots equipped with ...

  14. Contrasting Soil pH Effects on Fungal and Bacterial Growth Suggest Functional Redundancy in Carbon Mineralization▿ †

    Rousk, Johannes; Brookes, Philip C.; Bååth, Erland

    2009-01-01

    The influence of pH on the relative importance of the two principal decomposer groups in soil, fungi and bacteria, was investigated along a continuous soil pH gradient at Hoosfield acid strip at Rothamsted Research in the United Kingdom. This experimental location provides a uniform pH gradient, ranging from pH 8.3 to 4.0, within 180 m in a silty loam soil on which barley has been continuously grown for more than 100 years. We estimated the importance of fungi and bacteria directly by measuri...

  15. Interaction of Cd and citric acid, EDTA in red soil

    2001-01-01

    Adsorption and desorption process of cadmium in redsoil(Ferrisols) as well as the influence by media's pH were investigated in detail with and without citric acid and EDTA. Experimental results clearly showed that Cd adsorption in red soil was affected significantly by the coexisted organic chemicals. In the presence of citric acid and EDTA, Cd adsorption in red soil increased with pH in acid media but decreased in high pH one. Further studies placed stress on the adsorbed Cd in red soil which was found to be existed mainly as exchangeable one at pH<5.5, and desorption rate by 0.10 mol/L NaNO3 gave a peak-shaped curve due to the difference of specifically and nonspecifically adsorbed Cd with pH's change.

  16. Intracellular pH of acid-tolerant ruminal bacteria.

    Russell, J B

    1991-01-01

    Acid-tolerant ruminal bacteria (Bacteroides ruminicola B1(4), Selenomonas ruminantium HD4, Streptococcus bovis JB1, Megasphaera elsdenii B159, and strain F) allowed their intracellular pH to decline as a function of extracellular pH and did not generate a large pH gradient across the cell membrane until the extracellular pH was low (less than 5.2). This decline in intracellular pH prevented an accumulation of volatile fatty acid anions inside the cells.

  17. 鼎湖山不同演替阶段森林土壤pH值和土壤微生物量碳氮对模拟酸雨的响应%Responses of Soil pH Value and Soil Microbial Biomass Carbon and Nitrogen to Simulated Acid Rain in Three Successional Subtropical Forests at Dinghushan Nature Reserve

    梁国华; 吴建平; 熊鑫; 吴小映; 褚国伟; 周国逸; 曾任森; 张德强

    2015-01-01

    开展酸雨增加对森林土壤酸化和土壤微生物活性的影响,可以为正确评估森林生态系统碳氮过程及其对全球气候变化的响应提供依据。以鼎湖山处于不同演替阶段的3种森林类型(马尾松Pinus massoniana)针叶林、针阔叶混交林和季风常绿阔叶林)为研究对象,从2009年6月开始,在自然林里喷施4个不同处理水平的模拟酸雨,即CK(pH=4.5左右的天然湖水)、T1(pH=4.0)、T2(pH=3.5)和T3(pH=3.0);2009年12月─2013年3月对模拟酸雨下土壤pH值和土壤微生物量碳、氮含量进行长期观测研究。重复测量方差分析表明,观测周期内,模拟酸雨没有显著影响松林的土壤pH值和土壤微生物量碳、氮含量,但却显著地降低了阔叶林的这3个指标(P0.05), but it significantly reduced soil pH value and soil microbial biomass carbon and nitrogen in the BF (P<0.05), and the reduction was marginally significant in the MF. Compared with the CK treatment, mean rate of soil pH valuewere 0.01~0.04, 0.01~0.07, and 0.04~0.10 lower in the acid treatment plots in the PF, MF, and BF, respectively; similarly, mean rate of soil microbial biomass carbon were -1.0%~0.4%, 4.2%~13.6%, and 12.3%~18.4% lower, and mean rate of soil microbial biomass nitrogen were 0.8%~9.7%, 5.4%~17.4%, and 12.3%~25.1% lower in the acid treatment plots in the PF, MF, and BF, respectively. These results indicated the aggravation of soil acidification and the inhibition of soil microbial activity under the SAR in our forests, and more over, the sensitivity of the response of soil acidification and soil microbial activity to the SAR showed an increasing trend with the progressive succession of three forests. In addition, by analyzing the responses of soil pH value and soil microbial biomass carbon and nitrogen of each year, we found that these negative effects had been strengthened over time with significant difference among treatments

  18. Characteristics of Phosphorus in Some Eastern Australian Acid Sulfate Soils

    2002-01-01

    Forty-five acid sulfate topsoil samples (depth < 0.5 m) from 15 soil cores were collected from 11 locations along the New South Wales coast, Australia. There was an overall trend for the concentration of the HC1extractable P to increase along with increasing amounts of organic C and the HCl-extractable trivalent metals in the topsoils of some less-disturbed acid sulfate soils (pH <4.5). This suggests that inorganic P in these soils probably accumulated via biological cycling and was retained by complexation with trivalent metals or their oxides and hydroxides. While there was no clear correlation between pH and the water-extractable P, the concentration of the water-extractable P tended to increase with increasing amounts of the HCl-extractable P. This disagrees with some established models which suggest that the concentration of solution P in acid soils is independent of total P and decreases with increasing acidity. The high concentration of sulfate present in acid sulfate soils appeared to affect the chemical behavior of P in these soil systems. Comparison was made between a less disturbed wetland acid sulfate soil and a more intensively disturbed sugarcane acid sulfate soil.The results show that reclamation of wetland acid sulfate soils for sugarcane production caused a significant decrease in the HCl-extractable P in the topsoil layer as a result of the reduced bio-cycling of phosphorus following sugarcane farming. Simulation experiment shows that addition of hydrated lime had no effects on the immobilization of retained P in an acid sulfate soil sample within a pH range 3.5~4.6. When the pH was raised to above 4.6, soluble P in the soil extracts had a tendency to increase with increasing pH until the 15th extraction (pH 5.13). This, in combination with the poor pH-soluble P relationship observed from the less-disturbed acid sulfate soils, suggests that soluble P was not clearly pH-dependent in acid sulfate soils with pH < 4.5.

  19. Alleviating aluminium toxicity on an acid sulphate soils in Peninsular Malaysia with application of calcium silicate

    A. A. Elisa; Ninomiya, S.; J. Shamshuddin; Roslan, I.

    2015-01-01

    A study was conducted to alleviate Al toxicity of an acid sulphate soils collected from paddy cultivation area in Kedah, Peninsular Malaysia. For this purpose, the collected acid sulphate soils were treated with calcium silicate. The treated soils were incubated for 120 days in submerged condition in a glasshouse. Subsamples were collected every 30 days throughout the incubation period. Soil pH and exchangeable Al showed positive effect; soil pH increased from ...

  20. Bioamendment of petroleum contaminated ultisol:effect on oil content, heavy metals and pH of tropical soil

    2001-01-01

    The effect of organic amendments on the oil content,heavy metals concentration and pH of petroleum contaminated sandy loam ultisol obtained from Rumuekpe oil field in Emohua Local Government Area of Rivers State, Nigeria was determined. Petroleum contaminated soils were treated with wood ash, compost and sawdust. The addition of organic amendments resulted in a significant(at 95% probability level) decrease in oil content by 92% for composting,81% for soil treated with sawdust and 58% for soil with ash supplementation, over 6 months. The effect of treatments on the iron(Fe), copper(Cu) and lead(Pb) concentration was significant at P<0.001. The remediation also affected the pH of soil. This initial pH of 5.6 was depressed by the application of compost and sawdust supplements respectively to a final pH of 5.2 and 5.3. On the other hand, amending the soil with wood ash raised the pH from 5.6 to 6.2. Increased acidity caused a decrease in the heavy metals concentration in the contaminated soil. Soil treatment with compost generally gave the best remediation results, followed by sawdust and then ash. Adjusting the pH of oil contaminated soil to high acidic levels may promote the availability and migration of heavy metals in remediated soils and not necessarily the rate of oil mineralization.

  1. Bacterial chitinolytic communities respond to chitin and pH alteration in soil

    Kielak, Anna; Cretoiu, Mariana; Semenov, Alexander; Sørensen, Søren Johannes; van Elsas, Jan

    2013-01-01

    Chitin amendment is a promising soil management strategy that may enhance the suppressiveness of soil toward plant pathogens. However, we understand very little of the effects of added chitin, including the putative successions that take place in the degradative process. We performed an experiment...... in moderately acid soil in which the level of chitin, next to the pH, was altered. Examination of chitinase activities revealed fast responses to the added crude chitin, with peaks of enzymatic activity occurring on day 7. PCR-denaturing gradient gel electrophoresis (DGGE)-based analyses of 16S r......RNA and chiA genes showed structural changes of the phylogenetically and functionally based bacterial communities following chitin addition and pH alteration. Pyrosequencing analysis indicated (i) that the diversity of chiA gene types in soil is enormous and (i) that different chiA gene types are selected...

  2. Simulated acid rain effects on soil chemistry and microbiology

    A research study was carried out regarding the effects of artificial rains at different pH's (3.1, 4.0, 5.6) on soil samples from Appiano Gentile pinewood. Chemical parameters, biological activities and microbiological groups, particularly sensitive to possible variations in the presence of pH changes, were monitored after 2, 4 and 6 months of treatment of the soil on eluate obtained from treatment with artificial acid rains. The paper reports the results research

  3. Effect of pH on boron adsorption in some soils of Paraná, Brazil

    Fábio Steiner

    2013-06-01

    Full Text Available Temporary B deficiency can be triggered by liming of acid soils because of increased B adsorption at higher soil pH. Plants respond directly to the activity of B in soil solution and only indirectly to B adsorbed on soil constituents. Because the range between deficient and toxic B concentration is relatively narrow, this poses difficulty in maintaining appropriate B levels in soil solution. Thus, knowledge of the chemical behavior of B in the soil is particularly important. The present study investigated the effect of soil pH on B adsorption in four soils of Paraná State, and to correlate these values with the physical and chemical properties of the soils. Surface samples were taken from a Rhodic Hapludox, Arenic Hapludalf, Arenic Hapludult, and one Typic Usthorthent. To evaluate the effect of pH on B adsorption, subsamples soil received the application of increasing rates of calcium carbonate. Boron adsorption was accomplished by shaking 2.0 g soil, for 24 h, with 20 mL of 0.01 mol L¹ NaCl solution containing different concentrations (0.0, 0.1, 0.2, 0.4, 0.8, 1.2, 1.6, 2.0, and 4.0 mg B L-1. Sorption was fitted to non-linear form of the Langmuir adsorption isotherm. Boron adsorption increased as concentration increased. Boron adsorption was dependent on soil pH, increasing as a function of pH in the range between 4.6 and 7.4, although the bonding energy has decreased. Maximum adsorption capacity (MAC of B was observed in the Arenic Hapludalf (49.8 mg B kg-1 soil followed by Arenic Hapludult (22.5 mg kg-1, Rhodic Hapludox (17.4 mg kg-1, and Typic Usthorthent (7.0 mg kg-1. The organic matter content, clay content, and aluminum oxide content (Al2O3 were the soils properties that affecting the B adsorption on Paraná soils.

  4. Mycorrhizal fungal communities respond to experimental elevation of soil pH and P availability in temperate hardwood forests.

    Carrino-Kyker, Sarah R; Kluber, Laurel A; Petersen, Sheryl M; Coyle, Kaitlin P; Hewins, Charlotte R; DeForest, Jared L; Smemo, Kurt A; Burke, David J

    2016-03-01

    Many forests are affected by chronic acid deposition, which can lower soil pH and limit the availability of nutrients such as phosphorus (P), but the response of mycorrhizal fungi to changes in soil pH and P availability and how this affects tree acquisition of nutrients is not well understood. Here, we describe an ecosystem-level manipulation in 72 plots, which increased pH and/or P availability across six forests in Ohio, USA. Two years after treatment initiation, mycorrhizal fungi on roots were examined with molecular techniques, including 454-pyrosequencing. Elevating pH significantly increased arbuscular mycorrhizal (AM) fungal colonization and total fungal biomass, and affected community structure of AM and ectomycorrhizal (EcM) fungi, suggesting that raising soil pH altered both mycorrhizal fungal communities and fungal growth. AM fungal taxa were generally negatively correlated with recalcitrant P pools and soil enzyme activity, whereas EcM fungal taxa displayed variable responses, suggesting that these groups respond differently to P availability. Additionally, the production of extracellular phosphatase enzymes in soil decreased under elevated pH, suggesting a shift in functional activity of soil microbes with pH alteration. Thus, our findings suggest that elevating pH increased soil P availability, which may partly underlie the mycorrhizal fungal responses we observed. PMID:26850158

  5. Factors Affecting Sensitivity of Variable Charge Soils to Acid Rain

    WANGJING-HUA

    1995-01-01

    The sensitivity of a large number of variable charge soils to acid rain was evaluated through examining pH-H2SO4 input curves.Two derivative parameters,the consumption of hydrogen ions by the soil and the acidtolerant limit as defined as the quantity of sulfuric acid required to bring the soil to pH 3.5 in a 0.001mol L-1 Ca(NO3)2 solution,were used.The sensitivity of variable charge soils was higher than that of constant charge soils,due to the predominance of kaolinite in clay mineralogical composition.Among these soils the sensitivity was generally of the order lateritic red soil>red soil> latosol.For a given type of soil within the same region the sensitivity was affected by parent material,due to differences in clay minerals and texture.The sensitivity of surface soil may be lower or higher than that of subsiol,depending on whether organic matter or texture plays the dominant role in determining the buffering capacity.Paddy soils consumed more acid within lower range of acid input when compared with upland soils,due to the presence of more exchangeable bases,but consumed less acid within higher acid input range,caused by the decrease in clay content.

  6. Alleviating soil acidity through plant organic compounds

    Anderson R. Meda

    2001-06-01

    Full Text Available A laboratory experiment was conducted to evaluate the effects of water soluble plant extracts on soil acidity. The plant materials were: black oat, oil seed radish, white and blue lupin, gray and dwarf mucuna, Crotalaria spectabilis and C. breviflora, millet, pigeon pea, star grass, mato grosso grass, coffee leaves, sugar cane leaves, rice straw, and wheat straw. Plant extracts were added on soil surface in a PVC soil column at a rate of 1.0 ml min-1. Both soil and drainage water were analyzed for pH, Ca, Al, and K. Plant extracts applied on the soil surface increased soil pH, exchangeable Ca ex and Kex and decreased Al ex. Oil seed radish, black oat, and blue lupin were the best and millet the worst materials to alleviate soil acidity. Oil seed radish markedly increased Al in the drainage water. Chemical changes were associated with the concentrations of basic cations in the plant extract: the higher the concentration the greater the effects in alleviating soil acidity.Foram conduzidos experimentos de laboratórios para avaliar os efeitos de extratos de plantas solúveis em água na acidez do solo. Os materiais de plantas foram: aveia preta, nabo, tremoço branco e azul, mucuna cinza e anã, Crotalaria spectabilis e C. breviflora, milheto, guandu, grama estrela, grama mato grosso, folhas de café, folhas de cana-de-açúcar, palhada de arroz e palhada de trigo. Foi utilizado o seguinte procedimento para o extrato da planta solúvel em água: pesar 3g de material de planta, adicionar 150 ml de água, agitar por 8h e filtrar. Os extratos de plantas foram adicionados na superfície do solo em uma coluna de PVC (1 ml min-1. Após, adicionou-se água deionizada em quantidade equivalente a três volumes de poros. Os extratos de plantas aumentaram o pH, Ca e K trocável e diminuíram Al. Nabo, aveia preta e tremoço azul foram os melhores e milheto o pior material para amenizar a acidez do solo. Nabo aumentou Al na água de drenagem. As altera

  7. Contrasting pH buffering patterns in neutral-alkaline soils along a 3600 km transect in northern China

    W. Luo

    2015-08-01

    Full Text Available Soil pH buffering capacity (pHBC plays a crucial role in predicting acidification rates, yet its large-scale patterns and controls are poorly understood, especially for neutral-alkaline soils. Here, we evaluated the spatial patterns and drivers of pHBC along a 3600 km long transect (1900 km sub-transect with carbonate containing soils and 1700 km sub-transect with non-carbonate containing soils across northern China. Soil pHBC was greater in the carbonate containing soils than in the non-carbonate containing soils. Acid addition decreased soil pH in the non-carbonate containing soils more markedly than in the carbonate containing soils. Within the carbonate soil sub-transect, soil pHBC was positively correlated with cation exchange capacity (CEC, carbonate content and exchangeable sodium (Na concentration, but negatively correlated with initial pH and clay content, and not correlated with soil organic carbon (SOC content. Within the non-carbonate sub-transect, soil pHBC was positively related to initial pH, clay content, CEC and exchangeable Na concentration, but not related to SOC content. Carbonate content was the primary determinant of pHBC in the carbonate containing soils and CEC was the main determinant of buffering capacity in the non-carbonate containing soils. Soil pHBC was positively related to aridity index and carbonate content across the carbonate containing soil sub-transect. Our results indicated that mechanisms controlling pHBC differ among neutral-alkaline soils of northern China, especially between carbonate and non-carbonate containing soils, leading to different rates, risks, and impacts of acidification. This understanding should be incorporated into the acidification risk assessment and landscape management in a changing world.

  8. Interaction of NPK Fertilizers During Their Transformation in Soils:I.Dynamic Changes of Soil pH

    WANG HUOYAN; ZHOU JIANMIN; CHEN XIAOQIN; LI SHOUTIAN; DU CHANGWEN; DONG CAIXIA

    2003-01-01

    Dynamic changes of soil pH as influenced by ammonium sulfate (AS), monocalcium phosphate (MCP),potassium chloride (KCl) and their interaction in soils were evaluated in incubation experiments. Applyingthese fertilizers significantly reduced soil pH values in all cases and followed sequences of AS > MCP >KCl, MCP > KCl > AS and KCl > AS > MCP for the paddy, calcareous and red soils, respectively. TheAS-induced reduction of pH in the three soils followed the sequence of red soil > paddy soil > calcareous soil,while in MCP and KCl systems the reduction of pH followed the sequences of calcareous soil > paddy soil >red soil and red soil > calcareous soil > paddy soil, respectively. The interactions of the NPK fertilizers on pHwere significant. MCP plus KCl or MCP plus AS reduced pH values more than the fertilizers applied solelyin the paddy soil, but AS partly counteracted the effect of MCP on pH in the 1 d sample of the calcareoussoil. The effect of MCP on pH was trivial when MCP was applied in combination with KCl or AS in the redsoil. When applied in combination with AS, KCl did not affect soil pH initially, but suppressed the reductionof pH at the later incubation stage, which was related to inhibition of nitrification by KCl in the soils.

  9. Combined Use of Alkaline Slag and Rapeseed Cake to Ameliorate Soil Acidity in an Acid Tea Garden Soil

    WANG Lei; YANG Xing-Lun; K.RACHEL; WANG Yu; TONG De-Li; YE Mao; JIANG Xin

    2013-01-01

    Rapeseed cake (RC),the residue of rapeseed oil extraction,is effective for improving tea (Camellia sinensis) quality,especially taste and aroma,but it has limited ability to ameliorate strongly acidic soil.In order to improve the liming potential of RC,alkaline slag (AS),the by-product of recovery of sodium carbonate,was incorporated.Combined effects of different levels of RC and AS on ameliorating acidic soil from a tea garden were investigated.Laboratory incubations showed that combined use of AS and RC was an effective method to reduce soil exchangeable acidity and A1 saturation and increase base saturation,but not necessarily for soil pH adjustment.The release of alkalinity from the combined amendments and the mineralization of organic nitrogen increased soil pH initially,but then soil pH decreased due to nitrifications.Various degrees of nitrification were correlated with the interaction of different Ca levels,pH and N contents.When RC was applied at low levels,high Ca levels from AS repressed soil nitrification,resulting in smaller pH fluctuations.In contrast,high AS stimulated soil nitrification,when RC was applied at high levels,and resulted in a large pH decrease.Based on the optimum pH for tea production and quality,high ratios of AS to RC were indicated for soil acidity amelioration,and 8.0 g kg-1 and less than 2.5 g kg-1 were indicated for AS and RC,respectively.Further,field studies are needed to investigate the variables of combined amendments.

  10. Effect of organic matter and pH on the adsorption of metalaxyl and penconazole by soils

    Highlights: • The adsorption of non-ionic pesticides on soils is affected by pH. • At pH sOC/Ce ratio increased as the pH of the medium decreased. • The effect of pH on adsorption is related to the ionization of carboxylic groups. • SOM charge had similar effect on CsOC/Ce in the four soils under study. -- Abstract: Soil organic matter (SOM) is considered to be the primary adsorbent of non-ionic pesticides, and it is therefore thought to determine the concentration of such pesticides in the soil solution and how they are transported throughout the medium. It is generally assumed that the sorption capacity of different soils is the same per unit mass of SOM; however, the reactivity also depends on the SOM composition and the pH of the medium. We carried out experiments to study the effects of pH and ionic strength on the adsorption of the non-ionic fungicides metalaxyl and penconazole on four soils containing different amounts of organic carbon. The adsorption isotherms fitted a Freundlich equation. For pH > 5, partitioning of the fungicides between the solid phase and the soil solution did not vary with the pH, while at lower pH, the fraction adsorbed on the solid phase increased as the pH decreased. The response was related to the effect of pH on the ionization of the carboxylic groups of the SOM and therefore to the hydrophilic nature of the SOM. Analysis of the charge effect on the partitioning of both fungicides revealed a common response in all four soils. Adsorption appears to be related to the magnitude of the charge developed at the SOM due to ionization of the carboxylic acid groups

  11. Effect of organic matter and pH on the adsorption of metalaxyl and penconazole by soils

    Gondar, Dora; López, Rocío [Departamento de Química Física, Facultad de Química, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Antelo, Juan [Departamento de Edafología y Química Agrícola, Facultad de Biología, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Fiol, Sarah, E-mail: sarah.fiol@usc.es [Departamento de Química Física, Facultad de Química, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Arce, Florencio [Departamento de Química Física, Facultad de Química, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

    2013-09-15

    Highlights: • The adsorption of non-ionic pesticides on soils is affected by pH. • At pH < 5, the C{sub s}{sup OC}/C{sub e} ratio increased as the pH of the medium decreased. • The effect of pH on adsorption is related to the ionization of carboxylic groups. • SOM charge had similar effect on C{sub s}{sup OC}/C{sub e} in the four soils under study. -- Abstract: Soil organic matter (SOM) is considered to be the primary adsorbent of non-ionic pesticides, and it is therefore thought to determine the concentration of such pesticides in the soil solution and how they are transported throughout the medium. It is generally assumed that the sorption capacity of different soils is the same per unit mass of SOM; however, the reactivity also depends on the SOM composition and the pH of the medium. We carried out experiments to study the effects of pH and ionic strength on the adsorption of the non-ionic fungicides metalaxyl and penconazole on four soils containing different amounts of organic carbon. The adsorption isotherms fitted a Freundlich equation. For pH > 5, partitioning of the fungicides between the solid phase and the soil solution did not vary with the pH, while at lower pH, the fraction adsorbed on the solid phase increased as the pH decreased. The response was related to the effect of pH on the ionization of the carboxylic groups of the SOM and therefore to the hydrophilic nature of the SOM. Analysis of the charge effect on the partitioning of both fungicides revealed a common response in all four soils. Adsorption appears to be related to the magnitude of the charge developed at the SOM due to ionization of the carboxylic acid groups.

  12. Titratable acidity of beverages influences salivary pH recovery

    Livia Maria Andaló TENUTA

    2015-01-01

    Full Text Available A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conducted in vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and < 0.005 mmols OH- to reach pH 5.5, respectively. Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH.

  13. Soil Quality Assessment of Acid Sulfate Paddy Soils with Different Productivities in Guangdong Province, China

    LIU Zhan-jun; ZHOU Wei; SHEN Jian-bo; LI Shu-tian; LIANG Guo-qing; WANG Xiu-bin; SUN Jing-wen; AI Chao

    2014-01-01

    Land conversion is considered an effective measure to ensure national food security in China, but little information is available on the quality of low productivity soils, in particular those in acid sulfate soil regions. In our study, acid sulfate paddy soils were divided into soils with high, medium and low levels based on local rice productivity, and 60 soil samples were collected for analysis. Twenty soil variables including physical, chemical and biochemical properties were determined. Those variables that were signiifcantly different between the high, medium and low productivity soils were selected for principal component analysis, and microbial biomass carbon (MBC), total nitrogen (TN), available silicon (ASi), pH and available zinc (AZn) were retained in the minimum data set (MDS). After scoring the MDS variables, they were integrated to calculate a soil quality index (SQI), and the high, medium and low productivity paddy soils received mean SQI scores of 0.95, 0.83 and 0.60, respectively. Low productivity paddy soils showed worse soil quality, and a large discrepancy was observed between the low and high productivity paddy soils. Lower MBC, TN, ASi, pH and available K (AK) were considered as the primary limiting factors. Additionally, all the soil samples collected were rich in available P and AZn, but deifcient in AK and ASi. The results suggest that soil AK and ASi deifciencies were the main limiting factors for all the studied acid sulfate paddy soil regions. The application of K and Si on a national basis and other sustainable management approaches are suggested to improve rice productivity, especially for low productivity paddy soils. Our results indicated that there is a large potential for increasing productivity and producing more cereals in acid sulfate paddy soil regions.

  14. TRPV1 senses both acidic and basic pH

    Dhaka, Ajay; Uzzell, Valerie; Dubin, Adrienne; Mathur, Jayanti; Petrus, Matt; Bandell, Michael; Patapoutian, Ardem

    2009-01-01

    Maintaining physiological pH is required for survival, and exposure to alkaline chemicals such as ammonia (smelling salts) elicits severe pain and inflammation through unknown mechanisms. TRPV1, the capsaicin receptor, is an integrator of noxious stimuli including heat and extracellular acidic pH. Here we report that ammonia activates TRPV1, TRPA1 (another polymodal nocisensor), and other unknown receptor(s) expressed in sensory neurons. Ammonia and intracellular alkalization activate TRPV1 t...

  15. Isolation and Characterization of Soil Fulvic Acid

    Mir Munsif Ali Talpur

    2016-06-01

    Full Text Available Fulvic acid was isolated from the agriculture soil of District Naushahro Feroz, Sindh, Pakistan by International Humic Substances Society (IHSS method. The nutrient contents of the soil like N. P, K, Ca, Mg, Fe and Zn were determined by using the Atomic Absorption spectrophotometer (AAS. The Spectroscopic analysis was carried out by studying the UV-Vis, FT-IR and NIR spectra of isolated compounds. The data has been compared with the literature and correlated. Moisture as well as texture shows good water holding capacity and silt- loam type of soil. pH and EC are indicators of the fertility of soil to be beneficial for plantation. The spectral data (UV-Visible, FTIR and NIR supports the characteristic functional groups (-COOH, C=O, -OH, -NH2, C=C, CH2 and Polysaccharides present in Fulvic acid. E4/E6 values depict its hydrophilic nature, having less aromatic and more aliphatic groups. The presence of metal ions indicates its chelating ability.

  16. Effect of organic matter and pH on the adsorption of metalaxyl and penconazole by soils.

    Gondar, Dora; López, Rocío; Antelo, Juan; Fiol, Sarah; Arce, Florencio

    2013-09-15

    Soil organic matter (SOM) is considered to be the primary adsorbent of non-ionic pesticides, and it is therefore thought to determine the concentration of such pesticides in the soil solution and how they are transported throughout the medium. It is generally assumed that the sorption capacity of different soils is the same per unit mass of SOM; however, the reactivity also depends on the SOM composition and the pH of the medium. We carried out experiments to study the effects of pH and ionic strength on the adsorption of the non-ionic fungicides metalaxyl and penconazole on four soils containing different amounts of organic carbon. The adsorption isotherms fitted a Freundlich equation. For pH>5, partitioning of the fungicides between the solid phase and the soil solution did not vary with the pH, while at lower pH, the fraction adsorbed on the solid phase increased as the pH decreased. The response was related to the effect of pH on the ionization of the carboxylic groups of the SOM and therefore to the hydrophilic nature of the SOM. Analysis of the charge effect on the partitioning of both fungicides revealed a common response in all four soils. Adsorption appears to be related to the magnitude of the charge developed at the SOM due to ionization of the carboxylic acid groups. PMID:23827731

  17. Mechanisms of soil pH regulation by biochar amendments and consequences for biochar long-term effects

    Rees, Frédéric; Morel, Jean-Louis

    2015-01-01

    Soil amendments of biochar, i.e. the solid product of biomass pyrolysis, have been increasingly investigated over the last few years as a way to store stable C in soils, to improve crop production and to remediate degraded and contaminated land. Many short-term effects of biochar on soil chemical and biological properties may be explained by the observed increase of soil pH, largely reported in the recent scientific literature for acid or neutral soils. However, both the mechanisms by which b...

  18. Succession of Soil Acidity Quality and its Influence on Soil Phosphorus Types

    DUANWenbiao; CHENLixin

    2004-01-01

    Succession rules of soil acidity quality of larch plantations in first rotation at different development stages, succession rules of soil acidity quality of young stand of larch plantations in second rotation and the relationship between soil acidity and various forms of organic phosphorus and inorganic phosphorus were studied in mountainous area of eastern part of Northeastern China. The results showed that active acidity (pH value) inrhizosphere soil decreased continually with stand age increasing from young stand, half-mature stand, near mature stand to mature stand, but active acidity (pH value) in non-rhizosphere soil, exchange acidity, exchangeable aluminium, total hydrolytic acidity, and the ratio of exchange acidity and total hydrolytic acidity in rhizosphere soil and in non-rhizosphere soil increased apparently; total organic P, moderately resistant organic P, and highly resistant organic P in soil decreased at all age stages in larch plantations when soil acidity added. For rhizosphere soil of all stands of larch plantations at different development stages,there was positive correlation between Ca-P (except in young stand), Al-P(except in half-mature stand), Fe-P (except in near mature stand and mature stand), O-P (except in young stand), and soil active acidity,respectively; For rhizosphere soil, there was negative correlation between Ca-P (except in half-mature stand), Al-P(except in young stand), O-P, and exchange acidity, exchangeable aluminium, there was also negative correlation between Ca-P, Al-P(except in young stand and half-mature stand), Fe-P, O-P, and total hydrolytic acidity respectively. For rhizosphere soil, the correlation coefficient between Ca-P, O-P and total hydrolytic aciditydecreased, respectively, as stand ages up and that between Fe-P and exchange acidity,exchangeable aluminium increased, respectively, as stand ages grew. For non-rhizosphere soil, there was not significant correlation between soil acidity and various forms of

  19. 不同母质和植被类型下红壤pH和交换性酸的剖面特征%Changes in pH and Exchangeable Acidity at Depths of Red Soils Derived from 4 Parent Materials Under 3 Vegetations

    赵凯丽; 蔡泽江; 王伯仁; 石林; 周晓阳; 孙楠

    2015-01-01

    性酸的变化较小。在3种植被类型下,0—40 cm土层以第四纪红土红壤酸化最为严重,其次为红砂岩红壤和花岗岩红壤,再次为板页岩红壤;湿地松林的酸化效果最强,其次为阔叶林,以马尾松林的酸化效果最弱。%[Objective]Soil parent materials and vegetation types are two main factors that affect soil acidification. To investigate changes in pH and soil exchangeable acidity at different depths of red soil derived from different soil parent materials and different vegetations will be significant for preventing soil acidification in regions with red soil.[Method]A series of soil samples at depths of 0-20, 20-40, 40-60, 60-80 and 80-100 cm were collected from 11 sites with 4 parent materials (Quaternary red earth, Red sandstone, Plate shale, and Granite) under 3 vegetations (masson pine forest, slash pine forest, and broadleaf forest), in Qiyang County, Hunan province. Soil pH and soil exchangeable acidity were determined, and soil acidification was estimated by the difference in soil pH between 0-40 cm and 60-100 cm layers.[Result] The pH of red soils derived from the 4 parent materials was below 6.0. For the 4 parent materials, the average pH of red soils at 0-40 cm layers were following the orders: Granite red soil>Red sandstone red soil>Quaternary red earth red soil>Plate shale red soil; the average pH of red soils under the 3 vegetations were following the orders: masson pine forest>slash pine forest>broadleaf forest. But exchangeable acidity showed the opposite trend. For Quaternary red earth, soil pH significantly increased with soil depths increasing at 0-40 cm layers, but the pH of red soils derived from other parent materials decreased; soil exchangeable acidity had the opposite change trend as compared with soil pH. At layers of 40-100 cm, the average pH of red soils derived from the 4 parent materials werein the following order: Granite red soil>Quaternary red earth red soil>Red sandstone red soil>Plate shale red soil

  20. The solubility of aluminum in acidic forest soils: Long-term changes due to acid deposition

    Mulder, Jan; Stein, Alfred

    1994-01-01

    Despite the ecological and pedogenic importance of Al, its solubility control in acidic forest soils is poorly understood. Here we discuss the solubility of Al and its development with time in three acid brown forest soils in The Netherlands, which are under extreme acidification from atmospheric deposition. All soil solutions (to a 60 cm depth) were undersaturated with respect to synthetic gibbsite (Al(OH) 3; log K = 9.12 at 8°C), with the highest degree of undersaturation occurring in the surface soil. In about one third of the individual soil layers a significant positive correlation existed between the activity of Al 3+ and H +, but this relationship was far less than cubic. Kinetically constrained dissolution of Al is unlikely to explain the disequilibrium with respect to gibbsite, because undersaturation was highest through summer when water residence times were longest and temperatures greatest. Time series analysis of six year data sets for several soil layers revealed a significant annual decline in soil solution pH and Al solubility (defined as log Al + 3 pH) despite a constant concentration of strong acid anions. The annual decline of both pH and Al solubility was greatest in the surface soil and was positively correlated with the relative depletion of reactive organically bound soil Al. The results support our earlier hypothesis that in strongly acidified forest soils complexation by solid phase organics controls the solubility of Al even in mineral soil layers, relatively low in organic C. The data lend no support to the current widespread and often uncritical use of gibbsite as a model for the Al solubility in highly acidic forest soils (pH temperate zone.

  1. Effect of pH and soil structure on transport of sulfonamide antibiotics in agricultural soils.

    Park, Jong Yol; Huwe, Bernd

    2016-06-01

    We investigated the effect of solution pH and soil structure on transport of sulfonamide antibiotics (sulfamethoxazole, sulfadimethoxine and sulfamethazine) in combination with batch sorption tests and column experiments. Sorption isotherms properly conformed to Freundlich model, and sorption potential of the antibiotics is as follows; sulfadimethoxine > sulfamethoxazole > sulfamethazine. Decreasing pH values led to increased sorption potential of the antibiotics on soil material in pH range of 4.0-8.0. This likely resulted from abundance of neutral and positive-charged sulfonamides species at low pH, which electrostatically bind to sorption sites on soil surface. Due to destruction of macropore channels, lower hydraulic conductivities of mobile zone were estimated in the disturbed soil columns than in the undisturbed soil columns, and eventually led to lower mobility of the antibiotics in disturbed column. The results suggest that knowledge of soil structure and solution condition is required to predict fate and distribution of sulfonamide antibiotics in environmental matrix. PMID:26995452

  2. Soil water repellency and pH soil change under tropical pine plantations compared with native tropical forest

    Lebron, Inma; Robinson, David A.; Oatham, Mike; Wuddivira, Mark N.

    2012-01-01

    SummaryIn temperate climates, soil water repellency (SWR) has been documented to develop with land-use change from native forest to pine plantations. In the tropics a sparse evidence base has been documented for the observation of SWR, but no investigation has been conducted to determine the consequences of changing land-use from native forest to pine plantations with regard to SWR. In our research we broaden the evidence base for tropical SWR by comparing the SWR behavior of seven tropical pine plantations in Trinidad with co-located native forest. We found that SWR occurred under both pine and native forest, but was more persistent and less heterogeneous under pine. The SWR was water content dependent with a threshold ˜0.2 m 3 m -3, it showed a linear dependence with litter depth, and it was also found to be higher in more acidic soils. The forest floor pH, contrary to convention for temperate climates, was observed to increase under some pine plantations, as compared with native tropical forest. This only occurred in the very acidic tropical soils (pH soil and water quality.

  3. Mycorrhizal response to experimental pH and P manipulation in acidic hardwood forests.

    Laurel A Kluber

    Full Text Available Many temperate forests of the Northeastern United States and Europe have received significant anthropogenic acid and nitrogen (N deposition over the last century. Although temperate hardwood forests are generally thought to be N-limited, anthropogenic deposition increases the possibility of phosphorus (P limiting productivity in these forest ecosystems. Moreover, inorganic P availability is largely controlled by soil pH and biogeochemical theory suggests that forests with acidic soils (i.e., <pH 5 are particularly vulnerable to P limitation. Results from previous studies in these systems are mixed with evidence both for and against P limitation. We hypothesized that shifts in mycorrhizal colonization and community structure help temperate forest ecosystems overcome an underlying P limitation by accessing mineral and organic P sources that are otherwise unavailable for direct plant uptake. We examined arbuscular mycorrhizal (AM and ectomycorrhizal (EcM communities and soil microbial activity in an ecosystem-level experiment where soil pH and P availability were manipulated in mixed deciduous forests across eastern Ohio, USA. One year after treatment initiation, AM root biomass was positively correlated with the most available P pool, resin P, while AM colonization was negatively correlated. In total, 15,876 EcM root tips were identified and assigned to 26 genera and 219 operational taxonomic units (97% similarity. Ectomycorrhizal richness and root tip abundance were negatively correlated with the moderately available P pools, while the relative percent of tips colonized by Ascomycetes was positively correlated with soil pH. Canonical correspondence analysis revealed regional, but not treatment, differences in AM communities, while EcM communities had both treatment and regional differences. Our findings highlight the complex interactions between mycorrhizae and the soil environment and further underscore the fact that mycorrhizal communities do

  4. Characteristics of Soluble and Exchangeable Acidity in an Extremely Acidified Acid Sulfate Soil

    C.Lin; M.D.MELVILLE; 等

    1999-01-01

    An extremely acidified acid sulfate soil(ASS) was investigated to characterise its soluble and exchangeable acidity,The results showed that soluble acidity of a sample dtermined by titration with a KOH soulution was much significantly greater than that indicated by pH measured using a pH meter,paricularly for the extremely acidic soil samples,This is because the total soluble acidity of the extremely acidic soil samples was mainly composed of various soluble Al and Fe species,possibly in forms of Al sulfate complexes(e.g.,AlSO4+) and feerous Fe(Fe2+)_,It is therefore suggested not to use pH alone as an indicator of soluble acidity in ASS,particularly for extremely acidic ASS,It is also likely that AlSO4+ actively participated in cation exchange reactions.It appears that the possible involvement of this Al sulfate cation in the cation adsorption has significant effect on increasing the amount of acidity being adsorbed by the soils.

  5. THE RELATIONSHIP BETWEEN pH VALUE AND MAGNETIC SUSCEPTIBILITY OF KUNMING RED LIMESTONE SOIL BY ACID- ALKALI DISPOSED%昆明红色石灰土经酸碱处理后的pH值与磁化率的关系研究

    钟望春; 苏怀; 张丹

    2012-01-01

    土壤磁性变化机制的研究中,越来越多的证据指示成壤作用的影响,而土壤理化性质是其分类的主要因素,却很少有关于土壤理化性质与磁化率关系的研究报道。通过对碳酸盐岩上覆红色石灰土的酸碱处理实验,探究土壤pH值与其磁化率的影响。研究结果表明:酸碱处理前,红色石灰土的磁化率集中在3000~4500×10m^3/kg,pH值在7~8,为碱性土壤;经HCI溶液处理后,pH值下降到1~4,磁化率下降到250—4000×10^-8m^3/kg,pH值与磁化率呈现正相关关系;经NaOH溶液处理后,pH值上升到8~13,磁化率反而下降到2500-4000×10^-8m^3/kg,pH值与磁化率呈现负相关关系。上述现象的产生,与酸和强碱所分别带来的还原和氧化环境有关,改变了弱磁性矿物和强磁性矿物之间的转化方向,抑制了趋磁细菌作用,最终引起土壤磁化率的变化。%About the research of soil magnetic change mechanism, more and more evidences indicate the impact of pedogenesis. The physical and chemical properties of soil decided soil classification, rarely reported on he relationship between soil properties and magnetic susceptibility. Based on studied the red limestone soil Acid - Alkali disposed, try to analysis the relationship between soil pH and the Magnetic susceptibility. Our result indicate that the magnetic susceptibility of the soils changes from 3 000 -4 500 × 10^ -8m^3/kg before disposing and the pH value of the soil stays from 7 -8, belongs to alkaline soil. After disposing the soil samples with HCl, the magnetic susceptibility changes from 250 -4 000 × 10^-8m^3/kg and the pH value drops tol -4, the pH value and the magmefic susceptibility are positive correlation. After disposing the soil samples with NaOH, the magnetic susceptibility changes form 2 500 - 4 000 × 10^-8m^3/kg and the pH value rises to 8 - 13, the pH value and the magnetic susceptibility are negative

  6. Soil Components Affecting Phosphate Sorption Parameters of Acid Paddy Soils in Guangdong Province

    2000-01-01

    Soil components affecting phosphate sorption parameters were studied using acid paddy soils derived from basalt, granite, sand-shale and the Pearl River Delta sediments, respectively, in Guangdong Province.For each soil, seven 2.50 g subsamples were equilibrated with 50 mL 0.02 mol L-1 (pH=7.0) of KCl containing 0, 5, 10, 15, 25, 50 and 100 ng P kg-1, respectively, in order to derive P sorption parameters (P sorption maximum, P sorption intensity factor and maximum buffer capacity) by Langmuir isotherm equation. It was shown that the main soil components influencing phosphate sorption maximum (Xm) included soil clay, pH,amorphous iron oxide (Feo) and amorphous aluminum oxide (Alo), with their effects in the order of Alo >Feo > pH > clay. Among these components, pH had a negative effect, and the others had a positive effect.Organic matter (OM) was the only soil component influencing P sorption intensity factor (K). The main components influencing maximum phosphate buffer capacity (MBC) consisted of soil clay, OM, pH, Feo and Alo, with their effects in the order of Alo > OM > pH > Feo > clay. Path analysis indicated that among the components with positive effects on maximum phosphate buffer capacity (MBC), the effect was in the order of Alo > Feo > Clay, while among the components with negative effects, OM > pH. OM played an important role in mobilizing phosphate in acid paddy soils mainly through decreasing the sorption intensity of phosphate by soil particles.

  7. Observation of Soil Water Repellency and pH soil change under Tropical Pine Plantations Compared with Native Tropical Forest

    Robinson, D. A.; Lebron, I.; Oatham, M. P.; Wuddivira, M. N.

    2011-12-01

    In temperate climates, soil water repellency (SWR) has been documented to develop with land-use change from native forest to pine plantations. In the tropics a sparse evidence base has been documented for the observation of SWR, but no investigation has been conducted to determine the consequences of changing land-use from native forest to pine plantations with regard to SWR. In our research we broaden the evidence base for tropical SWR by comparing the SWR behavior of seven tropical pine plantations in Trinidad with co-located native forest. We found that SWR occurred under both pine and native forest, but was more persistent and less heterogeneous under pine. The SWR was water content dependent with a threshold ~0.2 m3m-3, it showed a linear dependence with litter depth, and it was also found to be pH dependent, being higher in more acidic soils. The forest floor pH, contrary to convention for temperate climates, was observed to increase under some pine plantations, as compared with native tropical forest. This only occurred in the very acidic tropical soils (pHsoil and water quality.

  8. Tolerance of VA Mycorrhizal Fungi to Soil Acidity

    2001-01-01

    A 45-day greenhouse experiment was carried out to determine effect of vesicular-arbuscular (VA) mycorrhizai fungi on colonization rate,plant height, plant growth,hyphae length,total Al in the plants,exchangeable A1 in the soil and soil pH by comparison at soil pH 3.5,4.5 and 6.0.Plant mung bean (Phaseolus radiatus L.) and crotalaria (Crotalaria mucronata Desv.) were grown with and without VA mycorrhizal fungi in pots with red soil.Ten VA mycorrhizal fungi strains were tested,including Glomus epigaeum (No.90001),Glomus caledonium (No.90036),Glomus mosseae (No.90107), Acaulospora spp.(No.34),Scutellospora heterogama (No.36),Scutellospora calospora (No. 37),Glomus manihotis (No.38),Gigaspora spp.(No.47),Glomus manihotis (No.49),and Acaulospora spp.(No.53).Being the most tolerant to acidity,strain 34 and strain 38 showed quicker and higher-rated colonization without lagging,three to four times more in number of nodules,two to four times more in plant dry weight,30% to 60% more in hyphae length,lower soil exchangeable Al,and higher soil pH than without VA mycorrhizal fungi (CK).Other strains also could improve plant growth and enhance plant tolerance to acidity,but their effects were not marked.This indicated that VA mycorrhizal fungi differed in the tolerance to soil acidity and so did their inoculation effects.In the experiment,acidic soil could be remedied by inoculation of promising VA mycorrhizal fungi tolerant of acidity.

  9. Soil acidity and mobile aluminum status in pseudogley soils in Čačak-Kraljevo basin

    Đalović Ivica G.; Jocković Đorđe S.; Dugalić Goran J.; Bekavac Goran F.; Purar Božana; Šeremešić Srđan I.; Jocković Milan Đ.

    2012-01-01

    Soil acidity and aluminum toxicity are considered most damaging soil conditions affecting the growth of most crops. This paper reviews the results of tests of pH, exchangeable acidity and mobile aluminum (Al) concentration in profiles of pseudogley soils from Čačak-Kraljevo basin. For that purpose, 102 soil pits were dug in 2009 in several sites around Čačak- Kraljevo basin. The tests encompassed 54 field, 28 meadow, and 20 forest soil samples. Samples of soil in the disturbed state wer...

  10. Biochar impacts soil microbial community composition and nitrogen cycling in an acidic soil planted with rape.

    Xu, Hui-Juan; Wang, Xiao-Hui; Li, Hu; Yao, Huai-Ying; Su, Jian-Qiang; Zhu, Yong-Guan

    2014-08-19

    Biochar has been suggested to improve acidic soils and to mitigate greenhouse gas emissions. However, little has been done on the role of biochar in ameliorating acidified soils induced by overuse of nitrogen fertilizers. In this study, we designed a pot trial with an acidic soil (pH 4.48) in a greenhouse to study the interconnections between microbial community, soil chemical property changes, and N2O emissions after biochar application. The results showed that biochar increased plant growth, soil pH, total carbon, total nitrogen, C/N ratio, and soil cation exchange capacity. The results of high-throughput sequencing showed that biochar application increased α-diversity significantly and changed the relative abundances of some microbes that are related with carbon and nitrogen cycling at the family level. Biochar amendment stimulated both nitrification and denitrification processes, while reducing N2O emissions overall. Results of redundancy analysis indicated biochar could shift the soil microbial community by changing soil chemical properties, which modulate N-cycling processes and soil N2O emissions. The significantly increased nosZ transcription suggests that biochar decreased soil N2O emissions by enhancing its further reduction to N2. PMID:25054835

  11. Influence of Soil and Irrigation Water pH on the Availability of Phosphorus in Struvite Derived from Urine through a Greenhouse Pot Experiment.

    Liu, Xiaoning; Tao, Yi; Wen, Guoqi; Kong, Fanxin; Zhang, Xihui; Hu, Zhengyi

    2016-05-01

    One greenhouse pot experiment was used to investigate the availability of phosphorus in struvite derived from urine affected by soil pH (cinnamon soil, pH 7.3; paddy soil, pH 5.3) and irrigation water (pH 6.0 and 7.5) with bird rapeseed (Brassica campestris L.). The biomass of applied struvite in paddy soil was significantly greater than that of applied calcium superphosphate. However, statistically significant differences were not observed in cinnamon soil. Soil-applied struvite had a higher Olsen P compared to soil-applied calcium superphosphate irrespective of soil type. The biomass of applied struvite and irrigation with pH 6.0 water was greater compared to that with irrigation with pH 7.3 water irrespective of soil type, accompanied with significantly higher leaf chlorophyll concentration. Therefore, struvite has the potential to be an effective P fertilizer, and acidic irrigation water has greater influence on the availability of phosphorus in struvite than does acidic soil. PMID:27078189

  12. Effect of acid rain on soil microbial processes

    Acid rain is real; the pH of precipitation in many areas of the world is below its normal equilibrium value, and concentrations of inorganic N and S are elevated above background. The impact of acid rain on soil microbial processes is less clear. This is largely because of the chemical buffering of the soil ecosystem and the inherent resiliency and redundancy of soil microorganisms. Microorganisms have an amazing capacity to adapt to new situations, which is enhanced by their ability to evolve under selection pressure. Their resilience is a function of both the large number of microorganisms present in a given volume of soil and their high growth rate relative to macroorganisms. This suggests that microorganisms are likely to be able to adapt more quickly to acidification than plants or animals, which may be one reason why symbiotic associations, such as ectomycorrhizae, are more susceptible to acid inputs than their saprophytic counterparts

  13. Chemical Species of Aluminum Lons in Acid Soils

    XURENKOU; JIGUOLIANG

    1998-01-01

    Soil samples collected from several acid soils in Guangdong,Fujian,Zhejiang and Anhui provinces of the southern China were employded to characterize the chemical species of aluminum ions in the soils.The proportion or monoeric inorganic Al to total Al in soil solution was in the range of 19% to 70%,that of monomeric organlic Al (Al-OM) to total Al ranged from 7.7% to 69%,and that of the acid-soluble Al to total Al was generally smaller and was lower than 20% in most of the acid soils studied ,The Al-OM concentration in soil solution was postively correlated with the content of dissolved organic carbon(DOC) and aslo affected by the concentration of Al3+,The complexes of aluminum with fluoride(Al-F) were the predominant forms of inorganic Al,and the proportion of Al-F compexes to total inorganic Al increased with pH.Under strongly acid ondition,Al3+ was also a mjaor form of inorganic Al,and the proportio of Al3+ to total inorganic Al decreased with increasing pH.The,proportions of Al-OH and Al-SO4 complexes to total inorganic Al were small and were not larger than 10% in the most acid soils.The concentration of inorganic Al in solution depended largely on pH and the concentration of total F in soil solution,The concentrations of Al-OM,Al3+,Al-F and Al-OH complexes in topsoil were higher than those in subsoil and decreased with the increase in soil depth,The chemical species of aluminum ions were influenced by pH,The concentrations of Al-OM, Al3+,Al-F complexes and Al-OH complexes decreased with the increase in pH.

  14. Determination of amino acids in industrial effluents contaminated soil

    38 samples of soil for 19 locations partially irrigated on the effluents of sugar mill and oil andghee mill, bottom sediments of evaporation ponds of sugar and fertilizer industries were collected and analyzed for amino acids after acid digestion by gas chromatography using pre column derivatization with trifluroacetyleacetone and ethyl chloroformate. The results obtained were compared with the soil samples irrigated with fresh water. The soil samples were also analyzed for pH, total nitrogen contents and organic carbon. Nine essential (leucine (Leu), threonine (Thr), lysine (Lys), L-phenylalanine (Phe), tryptophan (Trp), histadine (His), L-valine (Val), methionine (Met) and isoleucine Ile) and ten non-essential ( alanine (Ala), cysteine (Cys), asparagine (Asn), glutamic acid (Glu), serine (Ser), glycine (Gly), proline (Pro), Glutamine (Gln), aspartic acid (Asp), tyrosine (Tyr)) amino acids were analyzed 13-15 amino acids were identified and determined quantitatively from soil samples. Amino acids Met, Asn, Gln and Trp were observed absent from all the samples. The variation in the amino acids contents in soil with the industrial effluents added and total nitrogen and organic carbon is discussed. (author)

  15. Acidification of Forest Soils: A Model for Analyzing Impacts of Acidic Deposition in Europe - Version II

    Kauppi, P.; Kaemaeri, J.; Posch, M; Kauppi, L.; Matzner, E.

    1985-01-01

    Acidification is an unfavorable process in forest soils. Timber logging, natural accumulation of biomass in the ecosystem, and acidic deposition are sources of acidification. Acidification causes a risk of damage to plant roots and a subsequent risk of a decline in ecosystem productivity. A dynamic model is introduced for describing the acidification of forest soils. In one-year time steps the model calculates the soil pH as function of acid stress and the buffer mechanisms of the soil. ...

  16. Effect of Oxalic Acid on Potassium Release from Typical Chinese Soils and Minerals

    TU Shu-Xin; GUO Zhi-Fen; SUN Jin-He

    2007-01-01

    Oxalic acid plays an important role in improving the bioavailability of soil nutrients. Batch experiments were employed to examine the influences of oxalic acid on extraction and release kinetics of potassium (K) from soils and minerals along with the adsorption and desorption of soil K+. The soils and minerals used were three typical Chinese soils, black soil (Mollisol), red soil (Ultisol), and calcareous alluvial soil (Entisol), and four K-bearing minerals, biotite, phlogopite, muscovite, and microcline. The results showed that soil K extracted using 0.2 mol L-1 oxalic acid was similar to that using 1 mol L-1 boiling HNO3. The relation between K release (y) and concentrations of oxalic acid (c) could be best described logarithmically as y=a+blogc, while the best-fit kinetic equation of K release was y=a +b√t, where a and b are the constants and t is the elapsed time. The K release for minerals was ranked as biotite> phlogopite>> muscovite> microcline and for soils it was in the order: black soil> calcareous alluvial soil> red soil. An oxalic acid solution with low pH was able to release more K from weathered minerals and alkaline soils. Oxalic acid decreased the soil K+ adsorption and increased the soil K+ desorption, the effect of which tended to be greater at lower solution pH, especially in the red soil.

  17. Impact of tree species on soil carbon stocks and soil acidity in southern Sweden

    The impact of tree species on soil carbon stocks and acidity in southern Sweden was studied in a non-replicated plantation with monocultures of 67-year-old ash (Fraxinus excelsior L.), beech (Fagus silvatica L.), elm (Ulmus glabra Huds.), hornbeam (Carpinusbetulus L.), Norway spruce (Picea abies L.) and oak (Quercus robur L.). The site was characterized by a cambisol on glacial till. Volume-determined soil samples were taken from the O-horizon and mineral soil layers to 20 cm. Soil organic carbon (SOC), total nitrogen (TN), pH (H2O), cation-exchange capacity and base saturation at pH 7 and exchangeable calcium, magnesium, potassium and sodium ions were analysed in the soil fraction hornbeam > oak > beech > ash > elm. The pH in the O-horizon ranged in the order elm > ash > hornbeam > beech > oak > spruce. In the mineral soil, SOC and TN ranged in the order elm > oak > ash = hornbeam > spruce > beech, i.e. partly reversed, and pH ranged in the same order as for the O-horizon. It is suggested that spruce is the best option for fertile sites in southern Sweden if the aim is a high carbon sequestration rate, whereas elm, ash and hornbeam are the best solutions if the aim is a low soil acidification rate

  18. Acid soils of western Serbia and their further acidification

    Mrvic, Vesna

    2010-05-01

    Acid soils cause many unfavorable soil characteristics from the plant nutrition point of view. Because of increased soil acidity the violation of buffering soil properties due to leaching of Ca and Mg ions is taking place that also can cause soil physical degradation via peptization of colloids. Together with increasing of soil acidity the content of mobile Al increases that can be toxic for plants. Easily available nutritive elements transforms into hardly avaialble froms. The process of deactivation is especially expressed for phosphorous that under such conditions forms non-soluble compounds with sesqui-oxides. From the other hand the higher solubility of some microelements (Zn and B) can cause their accelerated leaching from root zone and therefore, result in their deficiency for plant nutrition. Dangerous and toxic matters transforms into easly-available forms for plants, especially, Cd and Ni under the lower soil pH. The studied soil occupies 36675 hectare in the municipality of Krupan in Serbia, and are characterized with very unfavorable chemical properties: 26% of the territory belongs to the cathegory of very acidic, and 44 % belongs to the cathegory of acidic. The results showed that the soil of the territory of Krupan is limited for agricultural land use due to their high acidity. Beside the statement of negative soil properties determined by acidity, there is a necessity for determination of soil sensitivity for acidification processes toward soil protection from ecological aspect and its prevention from further acidification. Based on such data and categorization of soils it is possible to undertake proper measures for soil protection and melioration of the most endangered soil cover, where the economic aspect of these measures is very important. One of the methods of soil classification based on sensitivity for acidification classification the determination of soil categories is based on the values of soil CEC and pH in water. By combination of these

  19. The relationship between N mineralization or microbial biomass N with micromorphological properties in beech forest soils with different texture and pH

    Kooijman, A.M.; Mourik, van, J.A.; Schilder, M.L.M.

    2009-01-01

    To test relationships between net N-mineralization, organic matter and soil organisms, we combined micromorphology with laboratory incubation experiments over a soil gradient. Microbial biomass N generally increased with pH, and from sandy to loamy soil, but net N-mineralization showed the opposite, and was highest in acid, sandy soil. Twenty-two micromorphological characteristics were analyzed with principal component analysis. PC1 had high eigenvalue (0.70), and clearly separated fungi from...

  20. EFFECT OF SIMULATED ACID RAIN ON NITRIFICATION AND NITROGEN MINERALIZATION IN FOREST SOILS

    To determine the possible microbiological changes in soil resulting from acid rain, columns containing samples of forest soils were leached with either a continuous application of 100cm of simulated acid rain (pH3.2-4.1) at 5 cm/hour or an intermittent 1.5-hour application of 1.2...

  1. Organic amendments increase soil solution phosphate concentrations in an acid soil: A controlled environment study

    Schefe, C.R.; Patti, A.F.; Clune, T.S.; Jackson, R. [Rutgers Centre, Rutherglen, Vic. (Australia)

    2008-04-15

    Soil acidification affects at least 4 million hectares of agricultural land in Victoria, Australia. Low soil pH can inhibit plant growth through increased soluble aluminum (Al) concentrations and decreased available phosphorus (P). The addition of organic amendments may increase P availability through competition for P binding sites, solubilization of poorly soluble P pools, and increased solution pH. The effect of two organic amendments (lignite and compost) on P solubility in an acid soil was determined through controlled environment (incubation) studies. Three days after the addition of lignite and compost, both treatments increased orthophosphate and total P measured in soil solution, with the compost treatments having the greatest positive effect. Increased incubation time (26 days) increased soil solution P concentrations in both untreated and amended soils, with the greatest effect seen in total P concentrations. The measured differences in solution P concentrations between the lignite- and compost-amended treatments were likely caused by differences in solution chemistry, predominantly solution pH and cation dynamics. Soil amendment with lignite or compost also increased microbial activity in the incubation systems, as measured by carbon dioxide respiration. Based on the results presented, it is proposed that the measured increase in soil solution P with amendment addition was likely caused by both chemical and biological processes, including biotic and abiotic P solubilization reactions, and the formation of soluble organic-metal complexes.

  2. Leachability and desorption of PCBs from soil and their dependency on pH and dissolved organic matter

    Badea, Silviu-Laurentiu, E-mail: badeasilviu@gmail.com; Mustafa, Majid; Lundstedt, Staffan; Tysklind, Mats

    2014-11-15

    pH affects both soil–water partitioning coefficient (K{sub d}) of polychlorinated biphenyls (PCBs) and dissolved organic matter (DOM), thereby influencing PCBs' leachability from contaminated soils. To explore these incompletely understood interactions, the leachability of 11 selected PCBs in a naturally aged soil was investigated in pH static leaching tests spanning a wide pH range (2 to 9). The K{sub d} was calculated for each of the PCBs, based on their observed concentrations in the soil and leachates obtained from each test. The concentration and composition of DOM in each leachate were also determined, the latter using FTIR spectroscopy. Correlations between the DOM's FTIR spectra and K{sub d} values were investigated by orthogonal projections to latent structures. The log K{sub d}-values varied among the PCB congeners and were most variable at low pH, but the values for all studied congeners decreased with increasing pH, by up to 3 log units (for PCB 187). In the pH 5–7 interval, an abrupt decrease in log K{sub d} values with increases in pH was observed, although the total organic carbon content remained relatively stable. The FTIR data indicate that fulvic and humic acids in DOM partially deprotonate as the pH rises from 5 to 7. - Highlights: • The log K{sub d}-values of 11 selected PCBs were investigated in pH static leaching tests • The log K{sub d}-values of all PCBs decreased with increasing pH, by up to 3 log units • The de-protonation of humics may explain why K{sub d}-values fell as pH rose from 5 to 7.

  3. Short-term effects of human urine fertiliser and wood ash on soil pH and electrical conductivity

    Dora Neina

    2014-03-01

    Full Text Available The fertiliser value of human urine has been examined on several crops, yet little is known about its effects on key soil properties of agronomic significance. This study investigated temporal soil salinization potential of human urine fertiliser (HUF. It further looked at combined effects of human urine and wood ash (WA on soil pH, urine-NH_3 volatilisation, soil electrical conductivity (EC, and basic cation contents of two Acrisols (Adenta and Toje series from the coastal savannah zone of Ghana. The experiment was a factorial design conducted in the laboratory for 12 weeks. The results indicated an increase in soil pH by 1.2 units for Adenta series and 1 unit for Toje series after one week of HUF application followed by a decline by about 2 pH units for both soil types after twelve weeks. This was attributed to nitrification of ammonium to nitrate leading to acidification. The EC otherwise increased with HUF application creating slightly saline conditions in Toje series and non-saline conditions in Adenta series. When WA was applied with HUF, both soil pH and EC increased. In contrast, the HUF alone slightly salinized Toje series, but both soils remained non-saline whenWA and HUF were applied together. The application ofWA resulted in two-fold increase in Ca, Mg, K, and Na content compared to HUF alone. Hence, WA is a promising amendment of acid soils and could reduce the effect of soluble salts in human urine fertilizer, which is likely to cause soil salinity.

  4. Impacts of soil organic matter, pH and exogenous copper on sorption behavior of norfloxacin in three soils

    ZHANG Jie; LI Zhaojun; GE Gaofei; SUN Wanchun; LIANG Yongchao; WU Laosheng

    2009-01-01

    Norfloxacin (Nor) sorption and the factors (soil organic matter (SOM), pH, and exogenous copper (Cu) influencing the sorption were investigated in a black soil (soil B), a fluvo-aquic soil (soil F), and a red soil (soil R). With increasing of Nor concentrations, sorption amount of norfloxacin increased in both the bulk soils and their SOM-removed soils, but the sorption capacity in SOM-removed soils was higher than that of their corresponding bulk soils, indicating that the process of norfloxacin sorption in soil was influenced by the soil properties including SOM. The sorption data in all bulk soils and SOM-removed soils were fitted to Freundlich and Langmuir models. The correlation coefficients suggested that the experimental data fitted better to Freundlich equation than to Langmuir equation. Furthermore, the data from soil F and SOM-removed F could not be described by Langmuir equation. The norfloxacin sorption amount decreased in soil B and soil F, whereas it increased in soil R as solution pH increased. The maximum KD and KOC were achieved in soil R when the equilibrium solution pH was 6. And the norfloxacin sorption was also influenced by the exogenous Cu2+ ions, which depended on the soil types and Cu2+ concentrations. With increasing of Cu2+ concentrations in solution, generally, sorption amount, KD and KOC for norfloxacin in soils increased and were up to a peak at 100 mg/L Cu2+, and then the sorption amount decreased regardless of norfloxacin levels.

  5. The effect of acidity on the distribution and symbiotic efficiency of rhizobia in Lithuanian soils

    Lapinskas, E. B.

    2007-04-01

    The distribution and symbiotic efficiency of nodule bacteria Rhizobium leguminosarum_bv. trifolii F., Sinorhizobium meliloti D., Rhizobium galegae L., and Rhizobium leguminosarum bv. viciae F. in Lithuanian soils as dependent on the soil acidity were studied in the long-term field, pot, and laboratory experiments. The critical and optimal pH values controlling the distribution of rhizobia and the symbiotic nitrogen fixation were determined for every bacterial species. The relationship was found between the soil pH and the nitrogen-fixing capacity of rhizobia. A positive effect of liming of acid soils in combination with inoculation of legumes on the efficiency of symbiotic nitrogen fixation was demonstrated.

  6. Responses of soil buffering capacity to acid treatment in three typical subtropical forests.

    Jiang, Jun; Wang, Ying-Ping; Yu, Mengxiao; Li, Kun; Shao, Yijing; Yan, Junhua

    2016-09-01

    Elevated anthropogenic acid deposition can significantly affect forest ecosystem functioning by changing soil pH, nutrient balance, and chemical leaching and so on. These effects generally differ among different forests, and the dominant mechanisms for those observed responses often vary, depending on climate, soil conditions and vegetation types. Using soil monoliths (0-40cm) from pine forest (pioneer), coniferous and broadleaved mixed forest (transitional) and broadleaved forest (mature) in southern China, we conducted a leaching experiment with acid treatments at different pH levels (control: pH≈4.5; pH=3.5; pH=2.5). We found that pH3.5 treatment significantly reduced dissolved organic carbon (DOC) concentrations in leachate from the pioneer forest soil. pH2.5 treatment significantly increased concentrations of NO3(-), SO4(2-), Ca(2+), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the pioneer forest soil, and also concentrations of NO3(-), SO4(2-), Mg(2+), Al(3+), Fe(3+) and DOC in leachate from the transitional forest soil. All acid treatments had no significant effects on concentrations of these chemicals in leachate from the mature forest soil. The responses can be explained by the changes in soil pH, acid neutralizing capacity (ANC) and concentrations of Al and Fe. Our results showed that acid buffering capacity of the pioneer or transitional forest soil was lower than that of the mature forest soil. Therefore preserving mature forests in southern China is important for reducing the adverse impacts of high acid deposition on stream water quality at present and into the future. PMID:27185346

  7. Effects of Electrolyte Anions and pH on Adsortpion of Sulfate by Variable Charge Soils

    ZHANGGANGYA; G.M.BRUEMMER; 等

    1996-01-01

    The effects of three electrolyte anions,ionic strength and pH on the adsorption of sulfate by two variable charge soils,with different surface charge properties were studied.Under the conditions of the same pH and ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of Cl->NO3->ClO4-,indicating the difference of the nature among these three anions.For ferralsol in the same concentration of chloride and perchloride solutions,the two sulfate adsorption-pH curves could intersect at certain pH value.When pH was higher than the intersecting point.more sulfate was adsorbed in the perchloride solution,while when it was lower than the intersecting point,more sulfate was adsorbed in the chloride solution.In different concentratioins of electrolyte solution,the curves of the amount of oxy-acid anion adsorbed,which changed with pH,could intersect at a certain pH,which is termed point of zero salt effect(PZSE) on adsortpion.The nature of electrolyte anions influenced obviously the appearace of PZSE for sulfate adsorption.For ferralsol the curves of adsorption converged to about pH 7 in NaCl solution seemed to intersect in NaNO3 solution and to have a typical PZSE for sulfate adsorption in NaClO4 solution,For Acrisol the three curves of adsorption were nearly parallel in NaCl and NaNO3 solutions and converged to pH 6.5 in NaClO4 solution.

  8. Variation in pH Optima of Hydrolytic Enzyme Activities in Tropical Rain Forest Soils

    Turner, Benjamin L.

    2010-01-01

    Extracellular enzymes synthesized by soil microbes play a central role in the biogeochemical cycling of nutrients in the environment. The pH optima of eight hydrolytic enzymes involved in the cycles of carbon, nitrogen, phosphorus, and sulfur, were assessed in a series of tropical forest soils of contrasting pH values from the Republic of Panama. Assays were conducted using 4-methylumbelliferone-linked fluorogenic substrates in modified universal buffer. Optimum pH values differed markedly am...

  9. The effect of soil pH on N2O/(N2O+N2) product ratio of denitrification depends on soil NO3- concentration

    Senbayram, Mehmet; Dittert, Klaus; Well, Reinhard; Lewicka-Szczebak, Dominika; Lammel, Joachim; Bakken, Lars

    2015-04-01

    Globally, agricultural soils account for about 60% of the atmospheric N2O emissions and denitrification in soil is the major source of atmospheric N2O, which contributes to global warming and destruction of stratospheric ozone. Denitrification is the microbially mediated process of dissimilatory nitrate reduction that may produce not only N2O but also nitric oxide (NO), and molecular nitrogen (N2). The major controls on denitrification rates are soil NO3, O2, and labile C levels. Typically, when soils become more anoxic, larger proportions of N2O produced in denitrification are further reduced to N2 before leaving the soil. Microbial ecology may possibly find solutions to this major environmental problem of agricultural systems once mechanisms controlling the product ratio of denitrification (N2O/N2O+N2) are better understood. Recent investigations of these gaseous microbial products provided the evidence for a negative effect of soil acidity on the N2O/N2O+N2 product ratio. However, in an earlier study, we showed that, regardless of soil type, higher NO3- concentrations in soil may also retard the reduction of N2O to N2. In this context, the positive effect of higher soil pH on the N2O/(N2O+N2) product ratio in soils with high NO3- content is still poorly understood. Therefore, we set up a number of incubation experiments in order to test short-term and long-term effects of soil pH and NO3- concentration on denitrification rates and the product stoichiometry of denitrification. We measured N2O, NO as well as elemental N2 in soils with pH levels ranging 4.1 to pH 6.9 collected from a long-term liming experiment. In a continuous flow incubation system we evacuated and flushed all vessels with He. Then, fresh He was directed through an inlet in the lid at a flow rate of 15-30 ml min-1. Gas samples were analyzed twice a day for N2O by ECD and for N2 by TCD detectors. Denitrification rates increased significantly with increasing soil pH, however, during the initial

  10. Insights into the Effect of Soil pH on N2O and N2 Emissions and Denitrifier Community Size and Activity ▿

    Čuhel, Jiří; Šimek, Miloslav; Laughlin, Ronnie J.; Bru, David; Chèneby, Dominique; Watson, Catherine J.; Philippot, Laurent

    2010-01-01

    The objective of this study was to investigate how changes in soil pH affect the N2O and N2 emissions, denitrification activity, and size of a denitrifier community. We established a field experiment, situated in a grassland area, which consisted of three treatments which were repeatedly amended with a KOH solution (alkaline soil), an H2SO4 solution (acidic soil), or water (natural pH soil) over 10 months. At the site, we determined field N2O and N2 emissions using the 15N gas flux method and...

  11. Effects of simulated acid rain on microbial characteristics in a lateritic red soil.

    Xu, Hua-qin; Zhang, Jia-en; Ouyang, Ying; Lin, Ling; Quan, Guo-ming; Zhao, Ben-liang; Yu, Jia-yu

    2015-11-01

    A laboratory experiment was performed to examine the impact of simulated acid rain (SAR) on nutrient leaching, microbial biomass, and microbial activities in a lateritic red soil in South China. The soil column leaching experiment was conducted over a 60-day period with the following six SAR pH treatments (levels): 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0 and one control treatment (pH = 7). Compared with the control treatment, the concentrations of soil organic matter, total nitrogen, total phosphorus, total potassium, soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), and average well color density (AWCD) in the Ecoplates were all significantly decreased by leaching with SAR at different pH levels. The decrease in MBC and MBN indicated that acid rain reduced the soil microbial population, while the decrease in AWCD revealed that acid rain had a negative effect on soil bacterial metabolic function. Soil basal respiration increased gradually from pH 4.0 to 7.0 but decreased dramatically from pH 2.5 to 3.0. The decrease in soil nutrient was the major reason for the change of soil microbial functions. A principal component analysis showed that the major carbon sources used by the bacteria were carbohydrates and carboxylic acids. PMID:26201661

  12. Soil organic matter, soil pH and soil nutrient dynamics in forest stands after fire

    Altun, Lokman; Bilgili, Ertuğrul; SAĞLAM, Bülent; KÜÇÜK, Ömer; Yılmaz, Murat; Tüfekçioğlu, Aydın

    2004-01-01

    Fires burn, spread and release energy. The process of burning not only helps increase the decomposition of organic matters but also causes the plant nutrients bound to vegetation and organic dead material to get into soil and inflicts changes on the physical and chemical properties of soil. Changes taken place in soils and their status over time are extremely important for the success of the vegetation that will establish on the site after fire. This study presents the results of a study cond...

  13. Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

    Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China. PMID:26657252

  14. Effects of Multiple Soil Conditioners on a Mine Site Acid Sulfate Soil for Vetiver Growth

    LIN Chu-Xia; LONG Xin-Xian; XU Song-Jun; CHU Cheng-Xing; MAI Shao-Zhi; JIANG Dian

    2004-01-01

    A pot experiment was conducted to investigate the effects of various soil treatments on the growth of vetiver grass ( Vetiveria zizanioides (L.) Nash) with the objective of formulating appropriate soil media for use in sulfide-bearing mined areas. An acidic mine site acid sulfate soil (pH 2.8) was treated with different soil conditioner formula including hydrated lime, red mud (bauxite residues), zeolitic rock powder, biosolids and a compound fertilizer. Soils treated with red mud and hydrated lime corrected soil acidity and reduced or eliminated metal toxicity enabling the establishment of vetiver grass.Although over-liming affected growth, some seedlings of vetiver survived the initial strong alkaline conditions. Addition of appropriate amounts of zeolitic rock powder also enhanced growth, but over-application caused detrimental effects. In this experiment, soil medium with the best growth performance of vetiver was 50 g of red mud, 10 g of lime, 30 g of zeolitic rock powder and 30 g of biosolids with 2000 g of mine soils (100% survival rate with the greatest biomass and number of new shoots), but adding a chemical fertilizer to this media adversely impacted plant growth. In addition, a high application rate of biosolids resulted in poorer growth of vetiver, compared to a moderate application rate.

  15. Application of Ground Phosphate Rock to Diminish the Effects of Simulated Acid Rain of Soil Properties

    DONGYUAN-YAN; LIXUE-YUAN

    1992-01-01

    The effects of simulated acid rain retained in soil on the properties of acid soil and its diminishing by application of ground phosphate rock were investigated by using the sorption method.Results show as follows:(1)For yellow brown soil,the effect of simulated acid rain on the properties of soil with a pH value of 5.9 was relatively small,except a great quantity of acid rain deposited on it.(2) for red soil,the effect of simulated acid rain on the properties of soil was significant.With the increase of the amount of acid deposition,the pH value of soil was declined,but the contents of exchangeable H+,Al3+ and Mn2+ and the amount of SO41- retention were increased.(3) Many properties of acid soils could be improved by applying ground phosphate rock.For example,pH value of soils and the amounts of available P and exchangeable Ca2+ and Mg2+ were increased,and the amounts of exchangeable H+ and Al3+ and SO42- retained was reduced.The application of ground posphate rock could effctively diminish the pollution of acid rain to soil.

  16. pH Effect on kinetics of Heavy Metal Sorption in Soils

    LINYU-SUO; XUEJIA-HUA

    1994-01-01

    The pH effect on the sorption kinetics of heavy metals in soils was studied using a constant flow leaching method.The soil samples were red soil collected from Yingtan,Jiangxi,and yellow-brown soil from Nanjing,Jiansu,The heavy metals tested were zinc and cadmium.Assuming that the experimental data diffed to the following kinetic rate equation:1/c.dx/dt=kx∞-kx,the rate constant k of sorption could be determined from the slope of the straight line by plotting of 1/c,dx/dt vs.x.The results showed that the pH effect on the rate constants of heavy mental sorption in soils was very significant.The values of k decreased with increasing pH.The sorptions were more sensitive to pH in red soil than in yellow-brown soil.

  17. Forest-soil response to acid and salt additions of sulfate. 2. Aluminum and base cations

    Reconstructed spodosol and intact alfisol soil columns were used to examine the effects of 52 weeks of additions of various simulated throughfall solutions on base cation, Al, acid neutralizing capacity, and pH levels in soil leachates. The work illustrates the importance of soil cation exchange (especially in the forest floor), anion concentrations, and pCO2 levels in controlling the leachate chemistry in response to acidic and 'seasalt' deposition events

  18. Acidification of Forest Soils: Model Development and Application for Analyzing Impacts of Acidic Deposition in Europe

    P. E. Kauppi; KÀmÀri, J.; Posch, M; Kauppi, L.; Matzner, E.

    1984-01-01

    Acidification is considered as an unfavorable process in forest soils. Timber logging, natural accumulation of biomass in the ecosystem, and acidic deposition are known as sources of acidification. Acidification causes the risk of damage to plant roots and subsequent risk of a decline in ecosystem productivity. A dynamic model is introduced for describing the acidification of forest soils. In one-year time steps the model calculates the soil pH as function of the acid stress and the buff...

  19. Studies on distribution and residue of sulfur in simulated acid rain in vegetable and soil by using 35S

    Distribution and residue of sulfur in simulated acid rain in two kinds of vegetables (lettuce and Chinese cabbage) and three types of soils (acid yellow earth, acid and neutral purple soils) were studied by using 35S tracer method. The results showed that the higher concentration of acid rain was sprayed, the more residue of sulfur in vegetable there would be. The residue of sulfur in vegetable varied with the different physical and chemical properties of soils, the order of sulfur residue in vegetable was: acid purple soil>acid yellow earth>neutral purple soil. In the same soil, the residue of sulfur in lettuce was higher than that in Chinese cabbage, for the same vegetable, the residue of sulfur in leaves were higher than that in stems. The order of sulfur residue in different soils was acid purple soil>acid yellow earth>neutral purple soil. The higher concentration of acid rain was sprayed, the more residue of sulfur in soil surface there would be. The sulfur residue varied with the depth of soil and the pH value of acid rain. With the increase of soil depth, a slight increase of sulfur residue with rain of ph 6 and a slight decrease with rain of pH 4.0 and 2.5 were found

  20. Optimizing Available Phosphorus in Calcareous Soils Fertilized with Diammonium Phosphate and Phosphoric Acid Using Freundlich Adsorption Isotherm

    Asif Naeem; Muhammad Akhtar; Waqar Ahmad

    2013-01-01

    In calcareous soils, phosphorus (P) retention and immobilization take place due to precipitation and adsorption. Since soil pH is considered a major soil variable affecting the P sorption, an acidic P fertilizer could result in low P adsorption compared to alkaline one. Therefore, P adsorption from DAP and phosphoric acid (PA) required to produce desired soil solution P concentration was estimated using Freundlich sorption isotherms. Two soils from Faisalabad and T. T. Singh districts were sp...

  1. Effects of Soil Oxygen Conditions and Soil pH on Remediation of DDT-contaminated Soil by Laccase from White Rot Fungi

    Yuechun Zhao; Xiaoyun Yi

    2010-01-01

    High residues of DDT in agricultural soils are of concern because they present serious threats to food security and human health. This article focuses on remediation of DDT-contaminated soil using laccase under different soil oxygen and soil pH conditions. The laboratory experiment results showed significant effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase at the end of a 25-d incubation period. This study found the positive correlation between ...

  2. Self-assembly of humic acid: influence of pH and chemical composition

    Chilom, G.; Nagy, Z.; Delp, S.; Huff, G.; Rice, J. A.

    2010-12-01

    Interest in enhancing the residence time of soil organic matter (SOM) through natural or engineered mechanisms as a possible means of sequestering organic carbon to mitigate the impacts of carbon-dioxide induced global warming effects has steadily increased over the last decade. Humic substances are major organic constituents of SOM and were recently shown that can self-organize or self-assemble into a composite material with different characteristics than those of the starting materials, and the organized state controls its mineralization by microorganisms. This study examines the role of pH and the relative concentration of humic-like amphiphilic (HA2) and lipid-like (L1) components in the self-assembly of the lipid-humic composite (L0). The L0, L1 and HA2 fractions were isolated using a combination of organic solvent and aqueous alkaline extractions from two humic acid samples at various pH values. HA2 and L1 isolated at low pH were mixed in various mass ratios in organic solvent in order to “reassemble” L0. The data show that the amount of L0 decreased with increasing the pH and reached a constant value from pH 6 to pH 11, and the proportion of L1 increased with the pH. Comparative measurements of the specific heat capacity as a function of temperature of the recombined L0 reveal differences when compared to the physical mixture of the HA2 and L1 depending on the ratio of the components. These differences are an indication that the recombined L0’s solid-state structure is more than just a mixture of components and is determined by specific interactions between its components.

  3. Alleviating aluminum toxicity in an acid sulfate soil from Peninsular Malaysia by calcium silicate application

    A. A. Elisa; Ninomiya, S.; J. Shamshuddin; Roslan, I.

    2016-01-01

    In response to human population increase, the utilization of acid sulfate soils for rice cultivation is one option for increasing production. The main problems associated with such soils are their low pH values and their associated high content of exchangeable Al, which could be detrimental to crop growth. The application of soil amendments is one approach for mitigating this problem, and calcium silicate is an alternative soil amendment that could be used. Therefore, the ma...

  4. Soil acidity as affecting micronutrients concentration, nitrato reductase enzyme activity and yield in upland rice plants

    Edemar Moro; Carlos Alexandre Costa Crusciol; Heitor Cantarella; Adriano Stephan Nascente; Adriana Lima Moro; Fernando Broetto

    2013-01-01

    The lowest grain yield of rice under no-tillage system (NTS) in relation to the conventional system may be due to the predominance nitrate in the soil and the low nitrate reductase activity. Another reason may be caused by micronutrient deficiency because of superficially soil acidity corrections. Therefore, the objective of this study was to evaluate the changes caused by soil pH in the N forms in the soil, micronutrients concentration in rice plants, nitrate reductase activity, yield of ric...

  5. Soil pH management by calcareous and siliceous minerals: effect on N2O yield in nitrification and denitrification

    Nadeem, Shahid; Bakken, Lars; Dörsch, Peter

    2016-04-01

    Amelioration of soil pH by liming is necessary and common practice in vast areas of crop production. It is well known that pH is one of the most pervasive factors controlling rates and product stoichiometries in microbially mediated N transformations, including N2O emissions. While liming of acid soils appears to increase N2O reductase activity in denitrification (resulting in less N2O relative to N2), sudden pH raise may boost nitrification and hence N2O emission from ammonia oxidation. Thus, the net effect of liming on N2O emissions is not straightforward, which probably explains why soil pH management has not been embraced as a strategy for mitigating N2O emissions so far. Here we report laboratory incubations in which we determined potential rates and N2O yields in soils from an ongoing field experiment, comparing traditional calcareous limes (calcite, dolomite) with mafic minerals (olivine, different types of plagioclase). The experiment is in its second year, and shows strong pH increase (0.7-1.5, units) in plots with calcareous limes, a weak pH increase (~ 0.2 unit) in the olivine treatment and no measurable pH increase with the plagioclases. Potential nitrification rates correlated positively with effective soil pH as did the N2O yield, measured as N2O accumulation rate over NO2- + NO3- accumulation rate. The N2O yield increased in the order, control soils. Overall, the N2O yield from nitrification was quite low (0.09 - 0.17%). Potential denitrifications rates showed little response to pH increase (no C source added) but significantly lower N2O product ratios (N2O/(N2O + N2) with increasing pH in the order, calcite < dolomite < olivine < plagioclase < control. Given the overall low N2O yield of nitrification as compared to that of denitrification (10 - 100%), the observed increases in N2O yields of nitrification are unlikely to override a significant reduction in N2O production by denitrification under fluctuating oxic-anoxic conditions. The results will be

  6. Reduction of exchangeable calcium and magnesium in soil with increasing pH

    Miyazawa Mário

    2001-01-01

    Full Text Available A laboratory study was conducted with soil samples and synthetic solutions to investigate possible mechanisms related with reduction in KCl exchangeable Ca and Mg with increasing pH. Increasing soil pH over 5.3 with CaCO3 added to the soil and with NaOH solution added to soil/KCl suspension increased adsorptions of Ca and Mg. The reduction of Mg was greater than Ca and was related to the concentration of soil exchangeable Al. The decreases of soluble Ca and Mg following addition of Al in synthetic solution were at pH > 7.5. The isomorphic coprecipitation reaction with Al compounds may be the most possible mechanism responsible for the decrease of exchangeable Ca and Mg with increasing pH. Possible chemical reactions are presented.

  7. Specific transformations of mineral forms of nitrogen in acid soils

    MIRJANA KRESOVIC

    2009-01-01

    Full Text Available Investigations were performed on soils of different acidity, ranging in the pH interval 4.65–5.80 (in water. Changes of the mineral nitrogen forms in the examined soils were studied by applying short-term incubation experiments performed under aerobic conditions, with a humidity of 30 % and a temperature of 20 °C, both with and without the addition of 100 and 300 ppm NH4–N. The results of the incubation experiments showed that retarded nitrification was present in all the examined soils. Increased and toxic quantities of nitrites (35.7 ppm were formed during the incubation, which remained in the soil solution for several days, and even weeks, in spite of favorable conditions of moisture, aeration and temperature for the development of the process of chemo-autotrophic nitrification. Decelerated chemoautotrophic nitrification was the source of the occurrence of nitrite in the examined less acid soil (soil 1, while in soils of higher acidity (soils 2 and 3 after addition of 100 and 300 ppm NH4–N, nitrite occurred due to chemical denitrification (chemodenitrification. Nitrites formed in the process of chemodenitrification underwent spontaneous chemical oxidation resulting in nitrate formation (chemical nitrification. The content of mineral nitrogen (NH4 + NO3 + NO2–N decreased during the incubation period, proving gaseous losses from the examined soils. Application of lower doses of nitrogen fertilizers could decrease nitrogen losses by denitrification as well as the occurrence of nitrite in toxic quantities in the investigated pseudogley soil.

  8. Influence of acid rain and organic matter on the adsorption of trace elements on soil

    Acid rain has become one of the most serious environmental problems. Soil loses its buffering capacity by long exposure to acid rain, and the soil pH value decreases significantly. The acidification of the soil disturbs the adsorption equilibrium of many elements in the soil-water system. Soil is a very complex heterogeneous system, primarily consisting of clay minerals, hydrous oxides and polymeric organic substances, which possess their own characteristic element-adsorbing properties. On the other hand, the intrinsic properties of elements are reflected in their adsorption process as a matter of course. Therefore, both the effects of the pH of acid rain and that of the components of the soil on the adsorption of different elements should be studied when the adsorption process in acid soils is to be clarified. Although leaching of major cations in soil, such as Ca2+, Mg2+ and Al3+, by acid rain, has been extensively studied, relatively little attention has been focused on trace elements which can also seriously affect the ecological system. We studied the acid rain effects on element adsorption by kaolin, forest soil, black soil, and also these soils with Fe- and Mn-oxides or organic matter selectively removed by using the radioactive multitracer technique. (author)

  9. Seasonal Belowground Ecosystem and Eco-enzymatic Responses to Soil pH and Phosphorus Availability in Temperate Hardwood Forests

    Smemo, K. A.; Deforest, J. L.; Petersen, S. L.; Burke, D.; Hewins, C.; Kluber, L. A.; Kyker, S. R.

    2013-12-01

    Atmospheric acid deposition can increase phosphorus (P) limitation in temperate hardwood forests by increasing N availability, and therefore P demand, and/or by decreasing pH and occluding inorganic P. However, only recently have studies demonstrated that P limitation can occur in temperate forests and very little is known about the temporal aspects of P dynamics in acidic forest soils and how seasonal shifts in nutrient availability and demand influence microbial investment in extracellular enzymes. The objectives of this study were to investigate how P availability and soil pH influence seasonal patterns of nutrient cycling and soil microbial activity in hardwood forests that experience chronic acid deposition. We experimentally manipulated soil pH, P, or both for three years and examined soil treatment responses in fall, winter, spring, early summer, and late summer. We found that site (glaciated versus unglaciated) and treatment had the most significant influence on nutrient pools and cycling. In general, nutrient pools were higher in glaciated soils than unglaciated for measured nutrients, including total C and N (2-3 times higher), extractable inorganic nitrogen, and readily available P. Treatment had no impact on total C and N pools in either region, but did affect other measured nutrients such as ammonium, which was greatest in the elevated pH treatment for both sites. As expected, readily available P pools were highest in the elevated P treatments (3 fold increase in both sites), but raising pH decreased available P pools in the glaciated site. Raising soil pH increased both net N mineralization rates and net P mineralization rates, regardless of site. Nitrification responses were complex, but we observed an overall significant nitrification increase under elevated pH, particularly in the growing season. Extracellular enzyme activity showed more seasonal patterns than site and treatment effects, exhibiting significant growing season activity reductions for

  10. Model study of acid rain effect on adsorption of trace elements on soils using a multitracer

    Using a radioactive multitracer and model acid rain (HCl or H2SO4 solution), batch experiments were performed to examine the pH effect on the adsorption-desorption equilibrium of 16 elements on soils as a model study of an acid rain effect. Kaolin, black soil (original and with organic matter almost removed) and Kureha soil (original and with organic matter almost removed) were used as adsorbents. Characteristic dependence on the pH value of the suspension was observed for the adsorption of the elements on kaolin and the soils. The results of this model study indicate that acid rain decreases the retention of cations, while it increases or does not change the adsorption of anions on soils. Organic matter in soils has a positive effect on the extent of adsorption of most elements investigated. (author)

  11. Spontaneous aggregation of humic acid observed with AFM at different pH.

    Colombo, Claudio; Palumbo, Giuseppe; Angelico, Ruggero; Cho, Hyen Goo; Francioso, Ornella; Ertani, Andrea; Nardi, Serenella

    2015-11-01

    Atomic force microscopy in contact (AFM-C) mode was used to investigate the molecular dynamics of leonardite humic acid (HA) aggregate formed at different pH values. HA nanoparticles dispersed at pH values ranging from 2 to 12 were observed on a mica surface under dry conditions. The most clearly resolved and well-resulted AFM images of single particle were obtained at pH 5, where HA appeared as supramolecular particles with a conic shape and a hole in the centre. Those observations suggested that HA formed under these conditions exhibited a pseudo-amphiphilic nature, with secluded hydrophobic domains and polar subunits in direct contact with hydrophilic mica surface. Based on molecular simulation methods, a lignin-carbohydrate complex (LCC) model was proposed to explain the HA ring-like morphology. The LCC model optimized the parameters of β-O-4 linkages between 14 units of 1-4 phenyl propanoid, and resulted in an optimized structure comprising 45-50 linear helical molecules looped spirally around a central cavity. Those results added new insights on the adsorption mechanism of HA on polar surfaces as a function of pH, which was relevant from the point of view of natural aggregation in soil environment. PMID:26295541

  12. Transcription of denitrification genes and kinetics of NO, N2O and N2 by soil bacteria as affected by pH

    Liu, B.; Bakken, L. R.; Frostegard, A.

    2010-12-01

    Nitrous oxide (N2O), which is to a large part derived from denitrification in soil, is a major greenhouse gas and was also recently shown to be the single most important ozone-depleting substance. Previous studies demonstrate that the N2O/N2 product ratio of denitrification is strongly dependent on pH, increasing with decreasing soil pH. The mechanisms involved are, however, poorly understood. We here present an investigation of soils from a long-term liming experiment. Since it is difficult to control which pH is actually experienced by bacterial cells in intact soils, we extracted cells on a Nycodenz gradient and exposed them to different pH levels. Bacteria extracted from soils of 3 different pHs (4.0, 6.1 and 8.0) were incubated in minimal medium supplemented with nitrate (2mM) and glutamic acid (5 mM), buffered at three pH levels (5.7, 6.1 and 7.6). Both the pH of the medium and original soil pH showed profound effect on the denitrification activity in terms of gas emission kinetics. N2O reductase (N2OR) activity was only present when cells from the high pH soils (pH 6.1 and 8.0) were exposed to high pH medium (pH 7.6). Functional genes (nirS, nirK and nosZ) and their transcripts were quantified in the extracts from pH6.1-soil. A 10-25 fold higher expression of nosZ vs nirS was found when incubated at pH 7.6 compared to pH 6.1 and 5.7. The low but significant transcription of nosZ at pH 6.1 and 5.7 did not result in detectable N2O reduction however. Cells that had been allowed to assemble their proteome while growing in pH7 medium showed N2OR activity which was practically unaffected by pH within the range 5-7. On the contrary, no N2OR activity was detected if the proteome had been formed at pH 6. The cells extracted from acid soils (pH 5.8 and 6.1) showed very low nosZ transcritption and no N2OR activity if exposed to pH 7 during the transition from oxic to anoxic conditions, suggesting an adaptation to low pH in the sense that they do not transcribe the gene

  13. Effects of acid rain on competitive releases of Cd, Cu, and Zn from two natural soils and two contaminated soils in hunan, China

    Liao, Bo-han; Guo, Zhao-hui; Zeng, Qingru; Probst, Anne; Probst, Jean-Luc

    2007-01-01

    Leaching experiments of rebuilt soil columns with two simulated acid rain solutions (pH 4.6– 3.8) were conducted for two natural soils and two artificial contaminated soils from Hunan, southcentralChina, to study effects of acid rain on competitive releases of soil Cd, Cu, and Zn. Distilled water was used in comparison. The results showed that the total releases were Zn>Cu>Cd for the natural soils and Cd>Zn≫Cu for the contaminated soils, which reflected sensitivity of these metals to acid rai...

  14. Transformation of diphenylarsinic acid in agricultural soils.

    Maejima, Yuji; Arao, Tomohito; Baba, Koji

    2011-01-01

    We investigated the transformation and fate of diphenylarsinic acid (DPAA) during incubation in two types of soils (Entisol and Andisol) under aerobic and anaerobic conditions. Under anaerobic conditions only, DPAA was transformed into methyldiphenylarsine oxide by methylation. Under both aerobic and anaerobic conditions, DPAA was degraded to phenylarsonic acid by dephenylation, and phenylarsonic acid was subsequently methylated to form methylphenylarsinic acid and dimethylphenylarsine oxide. The degradation of DPAA in the Andisol was less extensive than in the Entisol. In autoclaved soil under anaerobic conditions, DPAA underwent little degradation during the 24-wk incubation. In unautoclaved soils, the concentration of DPAA in soil clearly decreased after 24 wk of incubation, indicating that DPAA degradation was driven by microbial activity. PMID:21488495

  15. Proton interactions with soil organic matter: the importance of aggregation and the weak acids of humin

    Cooke, J. D.; Tipping, E.; Hamilton-Taylor, J.

    2008-01-01

    Samples of three organic-rich soils (ombrotrophic peat, podzol H-horizon, humic ranker) were extensively washed with dilute nitric acid, dialysed against deionised water, and then subjected to acid-base titrations over the pH range 3 – 10, in 0.3 – 300 mM NaNO3, and with soil concentrations in the range 2 to 150 g l-1. The results for the three soils were quantitatively similar. Comparison of the titration data with previously published results for humic acids isolated from the same soils s...

  16. Utilization of maize cob biochar and rice husk charcoal as soil amendments for improving acid soil fertility and productivity

    Nurhidayati

    2014-10-01

    Full Text Available The decline in soil fertility in agricultural land is a major problem that causes a decrease in the production of food crops. One of the causes of the decline in soil fertility is declining soil pH that caused the decline in the availability of nutrients in the soil. This study aimed to assess the influence of alternative liming materials derived from maize cob biochar and rice husk charcoal compared to conventional lime to improve soil pH, soil nutrient availability and maize production. The experiment used a factorial complete randomized design which consisting of two factors. The first factor is the type of soil amendment which consists of three levels (calcite lime, rice husk charcoal and cob maize biochar. The second factor is the application rates of the soil amendment consisted of three levels (3, 6 and 9 t/ha and one control treatment (without soil amendment. The results of this study showed that the application of various soil amendment increased soil pH, which the pH increase of the lime application was relatively more stable over time compared to biochar and husk charcoal. The average of the soil pH increased for each soil amendment by 23% (lime, 20% (rice husk charcoal and 23% (biochar as compared with control. The increase in soil pH can increase the availability of soil N, P and K. The greatest influence of soil pH on nutrient availability was shown by the relationship between soil pH and K nutrient availability with R2 = 0.712, while for the N by R2 = 0.462 and for the P by R2 = 0.245. The relationship between the availability of N and maize yield showed a linear equation. While the relationship between the availability of P and K with the maize yield showed a quadratic equation. The highest maize yield was found in the application of biochar and rice husk charcoal with a dose of 6-9 t/ha. The results of this study suggested that biochar and husk charcoal could be used as an alternative liming material in improving acid soil

  17. TOLERANCE OF PEANUT GENOTYPES TO ACIDIC SOIL CONDITION

    Astanto Kasno

    2013-06-01

    Full Text Available The acidic soil is generally less productive due to soil pH ranging from 3.1 to 5.0. However, it could be solved through soil amelioration, planting tolerant varieties to acidic soil condition, and a combination of both. Twenty peanut genotypes including two check varieties (Jerapah and Talam 1 were evaluated on dolomite-ameliorated and non ameliorated soil. In the greenhouse, the treatments were laid out in factorial design with four replications, while in the field using strip plot design with three replications. Assessment of tolerance was using Stressed Tolerance Index (STI according to Fernandez (1992. Results showed that dolomite application at dose equivalent to 0.5 x exchangeable Al was optimal in improving peanut growth, and peanut yield on acidic soil. Lines of GH3 (G/92088/92088-02-B-2-8-1 and GH 4 (G/92088/ 92088-02-B-2-8-2 genotypes had high STI with average yield of 2.47 tha-1 and 2.62 t ha-1 of dry pods and potential yield of 4.05 t ha-1 and 3.73 t ha-1 of dry pods, respectively as well as check varieties (Jerapah and Talam-1. It is concluded that peanut genotype of G/92088//92088-02-B-2-8-1 and G/92088//920 88- 02-B-2-8-2 were adaptable and tolerance to acidic, and tolerance of peanuts on acidic soil condition were probably controlled by the buffering mechanisms.

  18. Exchangeable aluminum evaluation in acid soils

    Abreu Jr. Cassio Hamilton; Muraoka Takashi; Lavorante André Fernando

    2003-01-01

    One of the main factors limiting agricultural production in tropical climate regions is mainly related to the presence of exchangeable aluminum (Al3+) in highly weathered acid soils. Four methods of Al3+ determination extracted with neutral 1 mol L¹ KCl solution were evaluated: three colorimetric methods (aluminon plus ascorbic acid, and eriochrome cyanine R by FIA) and the usual titrimetric method with back-titration. Surface samples from 20 soils of different Brazilian regions, with active ...

  19. Effect of crushed mussel shell addition on bacterial growth in acid polluted soils

    Fernandez Calviño, David; Garrido-Rodríguez, B.; Arias-Estévez, M.;

    2015-01-01

    We applied three different doses of crushed mussel shell (CMS) on two Cu-polluted acid soils to study the effect of these amendments on the growth of the bacterial community during 730 days. Soil pH increased in the short and medium term due to CMS addition. In a first stage, bacterial growth was...

  20. Regulation of antigen presentation by acidic pH

    1990-01-01

    The effect of pH on functional association of peptide antigens with APC membranes was investigated by using aldehyde-fixed B cells and class II- restricted T cell hybridomas to assess antigen/MHC complex formation. The results indicated that the rate and extent of functional peptide binding was markedly increased at pH 5.0 as compared with pH 7.3. The pH dependence of binding was preserved after pretreatment of fixed APC with pH 5.0 buffer, suggesting that pH had a direct effect on the intera...

  1. Controls of Soluble Al in Experimental Acid Sulfate Conditions and Acid Sulfate Soils

    LINCHUXIA; M.D.MELVILLE

    1997-01-01

    The controls of soluble Al concentration were examined in three situations of acid sulfate conditions:1) experimental acid sulfate conditions by addition of varying amounts of Al(OH)3(gibbsite) into a sequence of H2SO4 solutions;2)experimental acid sulfate conditions by addition of the same sequence of H2SO4 solutions into two non-cid sulfacte soil samples with known amounts of acid oxalate extractable Al; and 3) actual acid sulfate soil conditions.The experiment using gibbsite as an Al-bearing mineral showed that increase in the concentration of H2SO4 solution increased the soluble Al concentration,accompanied by a decrease i the solution pH, Increasing amount of gibbsite added to the H2SO4 solutions also increased soluble Al concentration,but resulted in an increase in solution pH.Within the H2SO4 concentration range of 0.0005-0.5mol L-1 and the Al(OH)3 range of 0.01-0.5g(in 25 mL of H2SO4 solutions),the input of H2SO4 had the major control on soluble Al Concentration and pH .The availability of Al(OH)3,however,was responsible for the spread fo the various sample points,with a tendency that the samples containing more gibbsite had a higher soluble Al concentration than those containing less gibbsite at equivalent pH levels.The experimental results from treatment of soil samples with H2SO4 solutions and the analytical results of acid sulfate soils also showed the similar trend.

  2. The effect of soil pH and the fungicide 'Captan' on 134Cs transfer factors for cucumber and radish plants

    The effect of soil pH and the fungicide 'Captan' on 134Cs transfer factors (TFs) was studied in a greenhouse pot experiment with cucumber and radish plants. A soil with a low pH (4.2) was selected and its pH value has increased to 5.7, 6.5 and 7.6 by the addition of different amounts of Ca(OH)2. Liming of the soil and the subsequent increase in pH values resulted in a reduction of 134Cs TFs which was not always significant. TFs were the highest in the very acid soil (pH 4.2) and were practically the same above the pH 5.7 although they were the lowest in the calcareous soil. The ratio highest / lowest TF of each crop or plant part ranged between ∼ 2.0 for radish and 4.5 for cucumber plants and it was much lower than that previously reported and attributed to pH differences. Edible to other plant material TF ratio indicates that cucumber plant accumulates considerably more of the totally absorbed 134CS in the edible part than radish crops. When biomass production was used for excluding dilution effects, 134CS total activity (Bq/pot) was higher for both plants when grown in the intermediate soil pH (5.7 - 6.5), due to the higher yield at these pH values. The application of the fungicide 'Captan' gave no significant differences in 134Cs TFs for both plant species and in all studied soil pH. Refs. 4 (author)

  3. Influence of pH on wetting kinetics of a pine forest soil

    Amer, Ahmad; Schaumann, Gabriele; Diehl, Dörte

    2014-05-01

    Water repellent properties of organic matter significantly alter soil water dynamics. Various environmental factors control appearance and breakup of repellency in soil. Beside water content and temperature also pH exerts an influence on soil water repellency although investigations achieved partly ambiguous results; some found increasing repellency with increasing pH (Terashima et al. 2004; Duval et al. 2005), other with decreasing pH (Karnok et al. 1993; Roper 2005) and some found repellency maxima at intermediate pH and an increase with decreasing and with increasing pH (Bayer and Schaumann 2007; Diehl et al. 2010). The breakup of repellency may be observed via the time dependent sessile drop contact angle (TISED). With water contact time, soil-water contact angle decreases until complete wetting is reached. Diehl and Schaumann (2007) calculated the activation energy of the wetting process from the rate of sessile drop wetting obtained at different temperatures and draw conclusions on chemical or physical nature of repellency. The present study aims at the influence of pH on the wetting kinetics of soil. Therefore, TISED of soil was determined as a function of pH and temperature. We used upper soil samples (0 - 10 cm) from a pine forest in the southwest of Germany (Rheinland-Pfalz). Samples were air-dried, sieved soil sample. Apparent work of adhesion was calculated, plotted vs. time and mathematically fitted using double exponential function. Rate constants of wetting were used to determine the activation energy by Arrhenius equation. First results indicated that despite comparable initial contact angles, pH alteration strongly changed the wetting rate suggesting maximum wetting resistance at the natural pH of 4.3 and decreasing wetting resistance at lower and at higher pH. The poster will present further current results of the ongoing study and discuss the activation energy of the wetting process in dependence of artificially altered soil pH. References: Bayer

  4. Effect of organic matter and pH on mercury release from soils

    2007-01-01

    An investigation was conducted on the effect of organic matter (OM) and pH on mercury (Hg) release from soils. Hg release flux was measured using the dynamic flux chamber (DFC) combined with the Lumex(r) multifunctional mercury analyzer in both laboratory experiment and field monitoring. The results showed that Hg emission from the OM-added soils was apparently low because of the high affinity of OM to Hg, resulting in the reverse order as the amount of OM addition. Meanwhile, Hg release flux from different pH value soils exhibited the same trend for both Hg2+ and Hg22+ treatment, increasing the Hg flux with pH value of soils increasing. The trend of Hg release in the pH dependence experiment has been well in agreement with that from the field test. In addition, Hg release seemed to be related to its species in the soil, the flux from Hg2+-added soil was obviously higher than that of Hg22+-added soil in both the OM and pH laboratory experiment.

  5. Effect of Simulated Acid Rain on Potential Carbon and Nitrogen Mineralization in Forest Soils

    OUYANG Xue-Jun; ZHOU Guo-Yi; HUANG Zhong-Liang; LIU Ju-Xiu; ZHANG De-Qiang; LI Jiong

    2008-01-01

    Acid rain is a serious environmental problem worldwide. In this study, a pot experiment using forest soils planted with the seedlings of four woody species was performed with weekly treatments of pH 4.40, 4.00, 3.52, and 3.05 simulated acid rain (SAR) for 42 months compared to a control of pH 5.00 lake water. The cumulative amounts of C and N mineralization in the five treated soils were determined after incubation at 25 ℃ for 65 d to examine the effects of SAR treatments.For all five treatments, cumulative CO2-C production ranged from 20.24 to 27.81 mg kg-1 dry soil, net production of available N from 17.37 to 48.95 mg kg-1 dry soil, and net production of NO-3-N from 9.09 to 46.23 mg kg-1 dry soil. SAR treatments generally enhanced the emission of CO2-C from the soils; however, SAR with pH 3.05 inhibited the emission.SAR treatments decreased the net production of available N and NO3-N. The cumulative CH4 and N2O productions from the soils increased with increasing amount of simulated acid rain. The cumulative CO2-C production and the net production of available N of the soil under Acmena acuminatissima were significantly higher (P≤0.05) than those under Schima superba and Cryptocarya concinna. The mineralization of soil organic C was related to the contents of soil organic C and N, but was not related to soil pH. However, the overall effect of acid rain on the storage of soil organic matter and the cycling of important nutrients depended on the amount of acid deposition and the types of forests.

  6. Crossing the pedogenetic threshold: Apparent phosphorus limitation by soil microorganisms in unglaciated acidic eastern hardwood forests

    Deforest, J. L.; Smemo, K. A.; Burke, D. J.

    2010-12-01

    The availability of soil phosphorus (P) can significantly influence microbial community composition and the ecosystem-level processes they mediate. However, the threshold at which soil microorganisms become functionally P-limited is unclear because of soil acidity effect on P availability. We reason that acidic temperate hardwood forest ecosystems are, in fact, functionally P-limited, but compensation occur via soil microbial production of phosphatase enzymes. We tested this hypothesis in glaciated and unglaciated mature mixed-mesophytic forests in eastern Ohio where both soil pH and P availability had been experientially manipulated. We measured the activity of two P acquiring soil enzymes, phosphomonoesterase (PMono) and phosphodiesterase (PDi), to understand how soil acidity and available P influence microbial function. Our experimental treatments elevated ambient soil pH from below 4.5 to around 5.5 and increased readily available phosphate from 3 to ~25 mg P/kg on glaciated soils and from 0.5 to ~5 mg P/kg on unglaciated soils. The P treatment decreased the activity of PDi by 82% relative to the control on unglaciated soils, but we observed no P treatment effect on glaciated soils. A similar result was observed for PMono. Soil pH, alone, did not significantly influence enzyme activities. Results suggest that soil microorganisms are more likely to be P-limited in older unglaciated soils. However, dramatically higher phosphatase activity in response to very low P availability suggests that an underlying ecosystem P limitation can be ameliorated by soil microbial community dynamics. This mechanism may be more important for older, unglaciated soils that have already crossed a pedogenic threshold where P availability influences ecosystem and microbial function.

  7. Effects of Soil Oxygen Conditions and Soil pH on Remediation of DDT-contaminated Soil by Laccase from White Rot Fungi

    Yuechun Zhao

    2010-04-01

    Full Text Available High residues of DDT in agricultural soils are of concern because they present serious threats to food security and human health. This article focuses on remediation of DDT-contaminated soil using laccase under different soil oxygen and soil pH conditions. The laboratory experiment results showed significant effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase at the end of a 25-d incubation period. This study found the positive correlation between the concentration of oxygen in soil and the degradation of DDT by laccase. The residue of DDTs in soil under the atmosphere of oxygen decreased by 28.1% compared with the atmosphere of nitrogen at the end of the incubation with laccase. A similar pattern was observed in the remediation of DDT-contaminated soil by laccase under different flooding conditions, the higher the concentrations of oxygen in soil, the lower the residues of four DDT components and DDTs in soils. The residue of DDTs in the nonflooding soil declined by 16.7% compared to the flooded soil at the end of the incubation. The residues of DDTs in soils treated with laccase were lower in the pH range 2.5–4.5.

  8. Alleviating aluminum toxicity in an acid sulfate soil from Peninsular Malaysia by calcium silicate application

    Elisa, A. A.; Ninomiya, S.; Shamshuddin, J.; Roslan, I.

    2016-03-01

    In response to human population increase, the utilization of acid sulfate soils for rice cultivation is one option for increasing production. The main problems associated with such soils are their low pH values and their associated high content of exchangeable Al, which could be detrimental to crop growth. The application of soil amendments is one approach for mitigating this problem, and calcium silicate is an alternative soil amendment that could be used. Therefore, the main objective of this study was to ameliorate soil acidity in rice-cropped soil. The secondary objective was to study the effects of calcium silicate amendment on soil acidity, exchangeable Al, exchangeable Ca, and Si content. The soil was treated with 0, 1, 2, and 3 Mg ha-1 of calcium silicate under submerged conditions and the soil treatments were sampled every 30 days throughout an incubation period of 120 days. Application of calcium silicate induced a positive effect on soil pH and exchangeable Al; soil pH increased from 2.9 (initial) to 3.5, while exchangeable Al was reduced from 4.26 (initial) to 0.82 cmolc kg-1. Furthermore, the exchangeable Ca and Si contents increased from 1.68 (initial) to 4.94 cmolc kg-1 and from 21.21 (initial) to 81.71 mg kg-1, respectively. Therefore, it was noted that calcium silicate was effective at alleviating Al toxicity in acid sulfate, rice-cropped soil, yielding values below the critical level of 2 cmolc kg-1. In addition, application of calcium silicate showed an ameliorative effect as it increased soil pH and supplied substantial amounts of Ca and Si.

  9. The combined effects of urea application and simulated acid rain on soil acidification and microbial community structure.

    Liu, Xingmei; Zhou, Jian; Li, Wanlu; Xu, Jianming; Brookes, Philip C

    2014-05-01

    Our aim was to test the effects of simulated acid rain (SAR) at different pHs, when applied to fertilized and unfertilized soils, on the leaching of soil cations (K, Ca, Mg, Na) and Al. Their effects on soil pH, exchangeable H(+) and Al(3+) and microbial community structure were also determined. A Paleudalfs soil was incubated for 30 days, with and without an initial application of urea (200 mg N kg(-1)soil) as nitrogen (N) fertilizer. The soil was held in columns and leached with SAR at three pH levels. Six treatments were tested: SAR of pH 2.5, 4.0 and 5.6 leaching on unfertilized soil (T1, T2 and T3), and on soils fertilized with urea (T4, T5 and T6). Increasing acid inputs proportionally increased cation leaching in both unfertilized and fertilized soils. Urea application increased the initial Ca and Mg leaching, but had no effect on the total concentrations of Ca, Mg and K leached. There was no significant difference for the amount of Na leached between the different treatments. The SAR pH and urea application had significant effects on soil pH, exchangeable H(+) and Al(3+). Urea application, SAR treated with various pH, and the interactions between them all had significant impacts on total phospholipid fatty acids (PLFAs). The highest concentration of total PLFAs occurred in fertilized soils with SAR pH5.6 and the lowest in soils leached with the lowest SAR pH. Soils pretreated with urea then leached with SARs of pH 4.0 and 5.6 had larger total PLFA concentrations than soil without urea. Bacterial, fungal, actinomycete, Gram-negative and Gram-positive bacterial PLFAs had generally similar trends to total PLFAs. PMID:24488523

  10. Effects of organic acids on Cd adsorption and desorption by two anthropic soils

    Jingui WANG; Jialong LV; Yaolong FU

    2013-01-01

    The objective of this experiment was to study the effects of malic, tartaric, oxalic, and citric acid on the adsorption and desorption characteristics of Cd by two typical anthropic soils (lou soil and irrigation-silted soil) in North-west China. Cadmium adsorption and desorption were studied under a range of temperatures (25℃, 30℃, 35℃, 40℃), organic acid concentrations (0.5-5.0 mmol·L-1), and pH values (2-8). The results showed that the Cd adsorption capacity of the lou soil was significantly greater than that of the irrigation-silted soil. Generally, Cd adsorption increased as the temperature increased. In the presence of NaNO3, the adsorption of Cd was endothermic with △H values of 31.365 kJ·mo1-1 for lou soil and 28.278 kJ·mol-1 for irrigation-silted soil. The endothermic reaction indicated that H bonds were the main driving force for Cd adsorption in both soils. However, different concentrations of organic acids showed various influences on the two soils. In the presence of citric acid, chemical adsorption and van der Waals interactions were the main driving forces for Cd adsorption rather than H bonds. Although the types of organic acids and soil properties were different, the effects of the organic acids on the adsorption and desorption of Cd were similar in the two soils. The adsorption percentage of Cd generally decreased as organic acid concentrations increased. In contrast, the adsorption percentage increased as the pH of the initial solution increased. The exception was that adsorption percentage of Cd increased slightly as oxalic acid concentrations increased. In contrast, the desorption percentage of Cd increased with increasing concentrations of organic acids but decreased as the initial solution pH increased.

  11. Effects of simulated acid rain on soil and soil solution chemistry in a monsoon evergreen broad-leaved forest in southern China.

    Qiu, Qingyan; Wu, Jianping; Liang, Guohua; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

    2015-05-01

    Acid rain is an environmental problem of increasing concern in China. In this study, a laboratory leaching column experiment with acid forest soil was set up to investigate the responses of soil and soil solution chemistry to simulated acid rain (SAR). Five pH levels of SAR were set: 2.5, 3.0, 3.5, 4.0, and 4.5 (as a control, CK). The results showed that soil acidification would occur when the pH of SAR was ≤3.5. The concentrations of NO₃(-)and Ca(2+) in the soil increased significantly when the pH of SAR fell 3.5. The concentration of SO₄(2-) in the soil increased significantly when the pH of SAR was acidity of SAR. The releases of soluble Al and Fe were SAR pH dependent, and their net exports under pH 2.5 treatment were 19.6 and 5.5 times, respectively, higher than that under CK. The net export of DOC was reduced by 12-29% under SAR treatments as compared to CK. Our results indicate the chemical constituents in the soil are more sensitive to SAR than those in the soil solution, and the effects of SAR on soil solution chemistry depend not only on the intensity of SAR but also on the duration of SAR addition. The soil and soil solution chemistry in this region may not be affected by current precipitation (pH≈4.5) in short term, but the soil and soil leachate chemistry may change dramatically if the pH of precipitation were below 3.5 and 3.0, respectively. PMID:25893761

  12. Soil pH management without lime, a strategy to reduce greenhouse gas emissions from cultivated soils

    Nadeem, Shahid; Bakken, Lars; Reent Köster, Jan; Tore Mørkved, Pål; Simon, Nina; Dörsch, Peter

    2015-04-01

    For decades, agricultural scientists have searched for methods to reduce the climate forcing of food production by increasing carbon sequestration in the soil and reducing the emissions of nitrous oxide (N2O). The outcome of this research is depressingly meagre and the two targets appear incompatible: efforts to increase carbon sequestration appear to enhance the emissions of N2O. Currently there is a need to find alternative management strategies which may effectively reduce both the CO2 and N2O footprints of food production. Soil pH is a master variable in soil productivity and plays an important role in controlling the chemical and biological activity in soil. Recent investigations of the physiology of denitrification have provided compelling evidence that the emission of N2O declines with increasing pH within the range 5-7. Thus, by managing the soil pH at a near neutral level appears to be a feasible way to reduce N2O emissions. Such pH management has been a target in conventional agriculture for a long time, since a near-neutral pH is optimal for a majority of cultivated plants. The traditional way to counteract acidification of agricultural soils is to apply lime, which inevitably leads to emission of CO2. An alternative way to increase the soil pH is the use of mafic rock powders, which have been shown to counteract soil acidification, albeit with a slower reaction than lime. Here we report a newly established field trail in Norway, in which we compare the effects of lime and different mafic mineral and rock powders (olivine, different types of plagioclase) on CO2 and N2O emissions under natural agricultural conditions. Soil pH is measured on a monthly basis from all treatment plots. Greenhouse gas (GHG) emission measurements are carried out on a weekly basis using static chambers and an autonomous robot using fast box technique. Field results from the first winter (fallow) show immediate effect of lime on soil pH, and slower effects of the mafic rocks. The

  13. Laser-induced breakdown spectroscopy: Extending its application to soil pH measurements

    Ferreira, Edilene Cristina, E-mail: edilene@iq.unesp.br [São Paulo State University – UNESP, Analytical Chemistry Department, Rua Prof. Francisco Degni 55, CEP 14800-060, Araraquara, SP (Brazil); Gomes Neto, José A. [São Paulo State University – UNESP, Analytical Chemistry Department, Rua Prof. Francisco Degni 55, CEP 14800-060, Araraquara, SP (Brazil); Milori, Débora M.B.P.; Ferreira, Ednaldo José [Embrapa Agricultural Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, São Carlos, SP (Brazil); Anzano, Jesús Manuel [Laser Laboratory & Environment, Faculty of Sciences, University of Zaragoza, C/. Pedro Cerbuna 12, 50009, Zaragoza (Spain)

    2015-08-01

    Acid–base equilibria are involved in almost all the processes that occur in soil. The bioavailability of nutrients for plants, for instance, depends on the solubilization of mineral nutrients in the soil solution, which is a pH-dependent process. The determination of pH in soil solutions is usually carried out by potentiometry using a glass membrane electrode, after extracting some of the soil components with water or CaCl{sub 2} solution. The present work describes a simple method for determining the pH of soil, using laser-induced breakdown spectroscopy (LIBS). Sixty samples presenting different textural composition and pH (previously determined by potentiometry) were employed. The samples were divided into a calibration set with fifty samples and a validation set with ten samples. LIBS spectra were recorded for each pelleted sample using laser pulse energy of 115 mJ. The intensities of thirty-two emission lines for Al, Ca, H, and O were used to fit a partial least squares (PLS) model. The model was validated by prediction of the pH of the validation set samples, which showed good agreement with the reference values. The prediction mean absolute error was 0.3 pH units and the root mean square error of the prediction was 0.4. These results highlight the potential of LIBS for use in other applications beyond elemental composition determinations. For soil analysis, the proposed method offers the possibility of determining pH, in addition to nutrients and contaminants, using a single LIBS measurement. - Highlights: • Physical, chemical, and biological properties of soil are influenced by pH. • The pH of mineral soils is normally determined in slurries of water and soil sample by potentiometric measurements. • The association of LIBS elemental emissions with multivariate strategies of analysis has become LIBS a powerful technique. • LIBS was unprecedentedly applied for direct pH determination in different kinds of soil sample. • The clean and fast proposed

  14. Laser-induced breakdown spectroscopy: Extending its application to soil pH measurements

    Acid–base equilibria are involved in almost all the processes that occur in soil. The bioavailability of nutrients for plants, for instance, depends on the solubilization of mineral nutrients in the soil solution, which is a pH-dependent process. The determination of pH in soil solutions is usually carried out by potentiometry using a glass membrane electrode, after extracting some of the soil components with water or CaCl2 solution. The present work describes a simple method for determining the pH of soil, using laser-induced breakdown spectroscopy (LIBS). Sixty samples presenting different textural composition and pH (previously determined by potentiometry) were employed. The samples were divided into a calibration set with fifty samples and a validation set with ten samples. LIBS spectra were recorded for each pelleted sample using laser pulse energy of 115 mJ. The intensities of thirty-two emission lines for Al, Ca, H, and O were used to fit a partial least squares (PLS) model. The model was validated by prediction of the pH of the validation set samples, which showed good agreement with the reference values. The prediction mean absolute error was 0.3 pH units and the root mean square error of the prediction was 0.4. These results highlight the potential of LIBS for use in other applications beyond elemental composition determinations. For soil analysis, the proposed method offers the possibility of determining pH, in addition to nutrients and contaminants, using a single LIBS measurement. - Highlights: • Physical, chemical, and biological properties of soil are influenced by pH. • The pH of mineral soils is normally determined in slurries of water and soil sample by potentiometric measurements. • The association of LIBS elemental emissions with multivariate strategies of analysis has become LIBS a powerful technique. • LIBS was unprecedentedly applied for direct pH determination in different kinds of soil sample. • The clean and fast proposed

  15. Exploring links between pH and bacterial community composition in soils from the Craibstone Experimental Farm.

    Bartram, Andrea K; Jiang, Xingpeng; Lynch, Michael D J; Masella, Andre P; Nicol, Graeme W; Dushoff, Jonathan; Neufeld, Josh D

    2014-02-01

    Soil pH is an important determinant of microbial community composition and diversity, yet few studies have characterized the specific effects of pH on individual bacterial taxa within bacterial communities, both abundant and rare. We collected composite soil samples over 2 years from an experimentally maintained pH gradient ranging from 4.5 to 7.5 from the Craibstone Experimental Farm (Craibstone, Scotland). Extracted nucleic acids were characterized by bacterial and group-specific denaturing gradient gel electrophoresis and next-generation sequencing of bacterial 16S rRNA genes. Both methods demonstrated comparable and reproducible shifts within higher taxonomic bacterial groups (e.g. Acidobacteria, Alphaproteobacteria, Verrucomicrobia, and Gammaproteobacteria) across the pH gradient. In addition, we used non-negative matrix factorization (NMF) for the first time on 16S rRNA gene data to identify positively interacting (i.e. co-occurring) operational taxonomic unit (OTU) clusters (i.e. 'components'), with abundances that correlated strongly with pH, and sample year to a lesser extent. All OTUs identified by NMF were visualized within principle coordinate analyses of UNIFRAC distances and subjected to taxonomic network analysis (SSUnique), which plotted OTU abundance and similarity against established taxonomies. Most pH-dependent OTUs identified here would not have been identified by previous methodologies for microbial community profiling and were unrelated to known lineages. PMID:24117982

  16. Acidez potencial pelo método do pH SMP no Estado do Amazonas Potential acidity by pH SMP method in Amazonas State, Brazil

    Adônis Moreira

    2004-01-01

    Full Text Available O objetivo deste trabalho foi definir um modelo matemático que estime o H+Al a partir do pH SMP medido em água e em solução de CaCl2 0,01 mol L-1 nas condições edafoclimáticas locais. Foram utilizadas 246 amostras de solo provenientes de diversas localidades. Mesmo apresentando menor coeficiente da correlação (r = 0,89*, a equação H+Al = 30,646 - 3,848pH SMP obtida em H2O foi mais eficiente que a obtida em solução CaCl2 (H+Al = 30,155 - 3,834pH SMP, r = 0,91*, a qual subestima os valores da acidez potencial.The objective of this work was to determine a mathematic model that estimates the potential acidity with pH SMP measured in water and in solution of CaCl2 0.01 mol L-1. Two hundred and forty six soil samples from several localities were utilized. Despite presenting a lower correlation coefficient (r = 0.89*, the equation H+Al = 30.646 - 3.848pH SMP, obtained in H2O, was more efficient than in the CaCl2 solution (H+Al = 30.155 -3.834pH SMP, r = 0.91*, since this last one underestimates the values of the potential acidity.

  17. Effect of pH on the adsorption of carbendazim in Polish mineral soils

    The study aimed to determine the influence of pH on the adsorption of carbendazim in soil profiles of three mineral agricultural soils: Hyperdystric Arenosol, Haplic Luvisol and Hypereutric Cambisol. In the examined pH range between 3 and 7 the adsorption of carbendazim was inversely correlated to the pH of the soil. The adsorption coefficients were in the range between 0.3 and 151.8 mL g−1. Decreasing the pH in the soil suspensions from 7 to 3 increased the value of this coefficient by 3 to 70 times. A decrease in the amounts of organic matter down the soil profiles was not associated with weaker carbendazim adsorption. In the samples from all soil horizons, at pH values between 3 and 6, the predominant sorption process was carbendazim adsorption on clay minerals. The adsorption of carbendazim on organic matter prevailed over that on clays only at pH > 6 and only in the Ap horizon of the examined soils. The developed mathematical models yielded very good results when the adsorption of the protonated form of carbendazim was assumed to be the predominant adsorption process on clays together with the adsorption of neutral molecules on organic matter and clays. The results from both the model fitting and the experiments revealed the negative effect of Al oxides and hydroxides and Al cations on the adsorption of the protonated form of carbendazim on clay minerals. The developed models successfully described the pH-dependent adsorption processes of carbendazim for both data from particular soil horizons and those from all three examined soil profiles. -- Highlights: ► Adsorption of carbendazim in soils was inversely correlated to soil pH. ► At low pH carbendazim was adsorbed predominantly by clay minerals. ► Al3+ influenced adsorption of the protonated form of carbendazim on clays. ► Created models predict pH-dependent sorption processes in the whole soil profiles.

  18. Influence of soil pH in vegetative filter strips for reducing soluble nutrient transport.

    Rahmana, Atikur; Rahmana, Shafiqur; Cihacek, Larry

    2014-08-01

    Low efficacy of vegetative filter strips (VFS) in reducing soluble nutrients has been reported in research articles. Solubility of phosphorus and nitrogen compounds is largely affected by pH of soil. Changing soil pH may result in a decrease in soluble nutrient transportation through VFS. This study was conducted to evaluate the effect of pH levels of VFS soil on soluble nutrient transport reduction from manure-borne runoff. Soil (loamy sand texture; bulk density 1.3 g cm-3) was treated with calcium carbonate to change pH at different pH treatment levels (5.5-6.5, 6.5-7.5, and 7.5-8.5), soil was packed into galvanized metal boxes, and tall fescue grasses were established in the boxes to simulate VFS. Boxes were placed in an open environment, tilted to a 3.0% slope, and 44.0 L manure-amended water was applied through the VFS by a pump at a rate of 1.45 L min-1. Water samples were collected at the inlet and outlet as well as from the leachate. Samples were analysed for ortho-phosphorus, ammonium nitrogen, nitrate nitrogen, and potassium. Highest transport reductions in ortho-phosphorus (42.4%) and potassium (20.5%) were observed at pH range 7.5-8.5. Ammonium nitrogen transport reduction was the highest at pH level of 6.5-7.5 and was 26.1%. Surface transport reduction in nitrate nitrogen was 100%, but leachate had the highest concentration of nitrate nitrogen. Mass transport reduction also suggested that higher pH in the VFS soil are effective in reducing some soluble nutrients transport. PMID:24956766

  19. Adsorption-Desorption of Hexaconazole in Soils with Respect to Soil Properties, Temperature, and pH

    Maznah Zainol

    2016-07-01

    Full Text Available The effect of temperature and pH on adsorption-desorption of fungicide hexaconazole was studied in two Malaysian soil types; namely clay loam and sandy loam. The adsorption-desorption experiment was conducted using the batch equilibration technique and the residues of hexaconazole were analysed using the GC-ECD. The results showed that the adsorption-desorption isotherms of hexaconazole can be described with Freundlich equation. The Freundlich sorption coefficient (Kd values were positively correlated to the clay and organic matter content in the soils. Hexaconazole attained the equilibrium phase within 24 h in both soil types studied. The adsorption coefficient (Kd values obtained for clay loam soil and sandy loam soil were 2.54 mL/g and 2.27 mL/g, respectively, indicating that hexaconazole was weakly sorbed onto the soils due to the low organic content of the soils. Regarding thermodynamic parameters, the Gibb’s free energy change (ΔG analysis showed that hexaconazole adsorption onto soil was spontaneous and exothermic, plus it exhibited positive hysteresis. A strong correlation was observed between the adsorption of hexaconazole and pH of the soil solution. However, temperature was found to have no effect on the adsorption of hexaconazole onto the soils; for the range tested.

  20. A simple model for assessing ammonia emission from ammoniacal fertilisers as affected by pH and injection into soil

    Nyord, T.; Schelde, K. M.; Søgaard, H. T.; Jensen, L. S.; Sommer, S. G.

    Ammonia (NH 3) volatilisation following the application of ammoniacal fertilisers and liquid manure to agricultural land is a significant source of atmospheric NH 3, which not only poses a risk to the environment, but may also result in a loss of plant available nitrogen (N). This study examined the potential for reducing NH 3 emission through acidifying an ammoniacal solution and by injecting the solution. The combination of the two technologies was studied and a model for predicting the most optimal treatment was developed. In the laboratory, ammonium (NH 4+) hydroxide (aqueous NH 3) was dissolved in water (pH 11) and injected into a loamy sand soil. The NH 3 emission was measured with a dynamic chamber technology. Injecting the solution to 10 mm below the soil surface reduced NH 3 emission by 10% compared to surface application, and injection to 30 mm reduced emission by 20% compared to surface application. Acidifying the ammoniacal solution by adding sulphuric acid and reducing pH to 10 reduced the emission by 60% at a 10 mm injection depth and 90% at 30 mm compared with non-acidified and surface-spread ammoniacal solution. The results show that there is an important interaction of pH and injection depth and that there is a need for models predicting a combined effect. This type of model could contribute to reduce cost and energy (traction force) by providing the optimal combination of acidifying and injection depth that gives a specific reduction in NH 3 emission, which in this study was reducing pH to 10 and inject the fertiliser to 30 mm below surface. This study showed that relatively simple models can predict the NH 3 emission from injected ammoniacal fertilisers, but that there is still a need for developing algorithms that predict the effect of pH, including the pH buffering capacity of the fertiliser and the soil.

  1. Effects of soil acidity on the uptake of trace elements in soybean and tomato plants

    The effects of soil acidity on the uptake of trace elements (Co, Zn, Se, Rb, Sr, Y, Zr, Tc, Ru, Rh and Re) in soybean and tomato were studied by a multitracer technique. The soybean and tomato plants were cultivated on soils at pH 6.4 (normal soil) and 4.2 (acid soil) and administered with a multitracer for 15-60 days. In general, the uptake of cationic elements in the leaves and stems of soybean plants cultivated on acid soil became higher than those of plants cultivated on normal soil during the late period of growth. However, the effect of soil acidification on the uptake of the anionic element, Se, was quite different from that on the cationic elements. The uptake of Se by the plants cultivated on normal soil was higher than that of the plants cultivated on acid soil at all four harvest points. The uptake behavior of these elements in soybean was discussed in relation to their adsorption behavior on the same soil as was used for soybean cultivation. The growth of tomato plants was seriously affected by the soil acidity and lowering of uptake of elements was observed for the plants cultivated on acidified soil

  2. Influence of Microsprinkler Irrigation Amount on Water, Soil, and pH Profiles in a Coastal Saline Soil

    Linlin Chu

    2014-01-01

    Full Text Available Microsprinkler irrigation is a potential method to alleviate soil salinization. After conducting a homogeneous, highly saline, clayey, and coastal soil from the Bohai Gulf in northern China in a column experiment, the results show that the depth of the wetting front increased as the water amount applied increased, low-salinity and low-SAR enlarged after irrigation and water redistribution, and the soil pH increased with an increase in irrigation amount. We concluded that a water amount of 207 mm could be used to reclaim the coastal saline soil in northern China.

  3. Total Nucleic Acid Extraction from Soil

    sprotocols

    2015-01-01

    Authors: Roey Angel ### Abstract The following protocol is intended for the simultaneous extraction of DNA and RNA from various soil samples along with suggestions on how to tweak the protocol for soil with higher humic content. The protocol has been used by many and results in very high yields of nucleic acids, typically much more than commercial kits. For buffers and solutions used in this protocol, please see accompanying document Buffers and Solutions for TNA Extractions.pdf. ...

  4. Influence of humified organic matter on copper behavior in acid polluted soils

    Fernandez-Calvino, D., E-mail: davidfc@uvigo.e [Plant Biology and Soil Science Department, University of Vigo, Ourense Campus, 32004 Ourense (Spain); Soler-Rovira, P.; Polo, A. [Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Cientificas, Serrano 115 dpdo., 28006 Madrid (Spain); Arias-Estevez, M. [Plant Biology and Soil Science Department, University of Vigo, Ourense Campus, 32004 Ourense (Spain); Plaza, C. [Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Cientificas, Serrano 115 dpdo., 28006 Madrid (Spain)

    2010-12-15

    The main purpose of this work was to identify the role of soil humic acids (HAs) in controlling the behavior of Cu(II) in vineyard soils by exploring the relationship between the chemical and binding properties of HA fractions and those of soil as a whole. The study was conducted on soils with a sandy loam texture, pH 4.3-5.0, a carbon content of 12.4-41.0 g kg{sup -1} and Cu concentrations from 11 to 666 mg kg{sup -1}. The metal complexing capacity of HA extracts obtained from the soils ranged from 0.69 to 1.02 mol kg{sup -1}, and the stability constants for the metal ion-HA complexes formed, log K, from 5.07 to 5.36. Organic matter-quality related characteristics had little influence on Cu adsorption in acid soils, especially if compared with pH, the degree of Cu saturation and the amount of soil organic matter. - The effect of organic matter quality on Cu adsorption in acid soils was low compared with other soil characteristics such as pH or degree of Cu saturation.

  5. N2O production pathways in the subtropical acid forest soils in China

    To date, N2O production pathways are poorly understood in the humid subtropical and tropical forest soils. A 15N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N2O production in four subtropical acid forest soils (pH2O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N2O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N2O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N2O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N2O product ratios from nitrification. The ratio of N2O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: → We studied N2O production pathways in subtropical acid forest soil under aerobic conditions. → Denitrification was the main source of N2O production in subtropical acid forest soils. → Heterotrophic nitrification accounted for 27.3%-41.8% of N2O production. → While, contribution of autotrophic nitrification to N2O production was little. → Ratios of N2O-N emission from nitrification were higher than those in most previous references.

  6. Behavior of Engineered Nanomaterials in Unsaturated Soil: Transport, Effects on pH, and Interactions with Phosphorous

    Conway, J.; Keller, A. A.

    2013-12-01

    Recent life cycle assessments have predicted that soils will be the primary non-landfill sink for many engineered nanomaterials (ENMs), and as their production and use increases annually it becomes increasingly relevant to understand their behavior in the unsaturated surface layers of soil. In this series of experiments, the transport and interactions of three common ENMs, TiO2, CeO2, and CuOH, were measured in an unsaturated potting soil with and without humic acid as a stabilizing agent. Transport was measured in loosely packed soil columns at two concentrations (10 and 100 ppm) with three exposure methods: through the application of contaminated biosolids to the top of the column with subsequent irrigation, by watering with an ENM suspension, and by mixing ENMs homogeneously into the soil and irrigating. Transport was also measured in soil containing intact root structures for the latter two exposure methods at 10 ppm ENM concentration. Soil columns were dried and 3 cm segments were acid digested and measured with inductively coupled plasma atomic emission spectroscopy (ICS-AES). The effect of these ENMs on soil pH was tested after mixing ENM suspensions into soil at four concentrations (0, 1, 10, and 100 mg kg-1). The bioavailability of PO4 in the presence of ENMs was measured by quantifying the soluble, bioavailable (i.e., extractable by Bray No. 1 solution), and tightly bound fractions of P in 0, 1, 10, and 100 mg kg-1 spiked soils via ICP-AES. We found that these three ENMs exhibit limited transport in all exposure scenarios and so will likely remain near the source zone in an environmental exposure. Additionally, these ENMs were seen to decrease soil pH by up to 0.5 in the highest concentrations, which has consequences for plant growth and nutrient mobility. TiO2 and CeO2 also decreased the soluble and bioavailable fractions of P, and so could inhibit the uptake of this limiting nutrient by organisms.

  7. Fluctuations in ammonia oxidizing communities across agricultural soils are driven by soil structure and pH

    Michele C ePereira e Silva

    2012-03-01

    Full Text Available The milieu in soil in which microorganisms dwell is never constant. Conditions such as temperature, water availability, pH and nutrients frequently change, impacting the overall functioning of the soil system. To understand the effects of such factors on soil functioning, proxies (indicators of soil function are needed that, in a sensitive manner, reveal normal amplitude of variation. Thus, the so-called normal operating range (NOR of soil can be defined. In this study we determined different components of nitrification by analyzing, in eight agricultural soils, how the community structures and sizes of ammonia oxidizing bacteria and archaea (AOB and AOA, respectively, and their activity, fluctuate over spatial and temporal scales. The results indicated that soil pH and soil type are the main factors that influence the size and structure of the AOA and AOB, as well as their function. The nitrification rates varied between 0.11 ± 0.03 µgN.h-1.gdw-1 and 1.68 ± 0.11 µgN.h-1.gdw-1, being higher in soils with higher clay content (1.09 ± 0.12 µgN.h-1.gdw-1 and lower in soils with lower clay percentages (0.27 ± 0.04 µgN.h-1.gdw-1. Nitrifying activity was driven by soil pH, mostly related to its effect on AOA but not on AOB abundance. Regarding the influence of soil parameters, clay content was the main soil factor shaping the structure of both the AOA and AOB communities. Overall, the potential nitrifying activities were higher and more variable over time in the clayey than in the sandy soils. Whereas the structure of AOB fluctuated more (62.7 ± 2.10% the structure of AOA communities showed lower amplitude of variation (53.65 ± 3.37%. Similar trends were observed for the sizes of these communities. The present work represents a first step towards defining a NOR for soil nitrification. Moreover, the clear effect of soil texture established here suggests that the NOR should be defined in a soil-type-specific manner.

  8. Influences of pH, Temperature, and Moisture on Gaseous Tritium Uptake in Surface Soils

    Fallon, Robert D.

    1982-01-01

    In South Carolina surface soils, the uptake of gaseous tritium (T2, HT, or both) showed a broad optimal temperature response from about 20 to 50°C, with the highest rates at 35 to 45°C. The optimal pH was in the range of 4 to 7. Uptake rates declined at the wet and dry extremes in soil moisture content. Inhibition seen upon the addition of hydrogen or carbon monoxide to the soil atmosphere suggested that hydrogenase may be responsible for T2-HT uptake in soil. During the period of most rapid ...

  9. Acidity Regimes of Soils Under Different Vegetations in the Changbai Mountains Region

    YUTIANREN; GAOZIQIN; 等

    1997-01-01

    The acidity regimes of representative soils on the north slope of the Changbai Mountains were examined through determinations of pH and pCa of the soil paste as well as in-situ determinations,For soils under broad-leaf forest or broad-leaf-Korean pine forest,the pH decreased from the litte to lower layers gradually until it did not change or decreased further slightly .For soils under coniferous of Erans birch forest,ther was a minimum in pH at a depth of 3-6 cm where the content of humus was high,The pCa increased gradually from the soil surface downward to a constant value.The lime potential(pH-0.5pCa) showed a similar trend as the pH in its distribution.For a given soil,the measured pH value of the thick paste,ranging from 4.5 to 5.5,was lower by about 0.5 units than the value determined by the conventional method with a water to soil ratio of 5:1 ,The pH determined in situ was even lower.It was found that there was a firly close relationship between soil acidity and the type of vegetation.The pH showed a trend of decreasing from soils under broda-leaf forest through broad-leaf-conifer mixed rorest and coniferos forest to Ermans birch forest,and the pCa showed an opposite trend in variation.

  10. VARIAÇÃO DE PERDA DE NITROGÊNIO COM pH DO SOLO NITROGEN VARIATION LOSS WITH SOIL pH

    Ataídes Terra Lamis

    2007-09-01

    édica, Itaguai and Piranema. Nitrogen fertilization was of 200mg of N/Kg of soil. The statistical analysis with the soils of the series Itaguai, Seropédica and Ecologia showed a significant difference at the 5% level between the treatments. It was observed in these soils that when the pH became less acid there was an increase in the losses of ammonium by volatilization. In the experiment with the soil of the series Piranema there was no significant difference in the losses of ammonium in any of the three pH levels.

  11. Chicken manure biochar as liming and nutrient source for acid Appalachian soil.

    Hass, Amir; Gonzalez, Javier M; Lima, Isabel M; Godwin, Harry W; Halvorson, Jonathan J; Boyer, Douglas G

    2012-01-01

    Acid weathered soils often require lime and fertilizer application to overcome nutrient deficiencies and metal toxicity to increase soil productivity. Slow-pyrolysis chicken manure biochars, produced at 350 and 700°C with and without subsequent steam activation, were evaluated in an incubation study as soil amendments for a representative acid and highly weathered soil from Appalachia. Biochars were mixed at 5, 10, 20, and 40 g kg into a Gilpin soil (fine-loamy, mixed, active, mesic Typic Hapludult) and incubated in a climate-controlled chamber for 8 wk, along with a nonamended control and soil amended with agronomic dolomitic lime (AgLime). At the end of the incubation, soil pH, nutrient availability (by Mehlich-3 and ammonium bicarbonate diethylene triamine pentaacetic acid [AB-DTPA] extractions), and soil leachate composition were evaluated. Biochar effect on soil pH was process- and rate-dependent. Biochar increased soil pH from 4.8 to 6.6 at the high application rate (40 g kg), but was less effective than AgLime. Biochar produced at 350°C without activation had the least effect on soil pH. Biochar increased soil Mehlich-3 extractable micro- and macronutrients. On the basis of unit element applied, increase in pyrolysis temperature and biochar activation decreased availability of K, P, and S compared to nonactivated biochar produced at 350°C. Activated biochars reduced AB-DTPA extractable Al and Cd more than AgLime. Biochar did not increase NO in leachate, but increased dissolved organic carbon, total N and P, PO, SO, and K at high application rate (40 g kg). Risks of elevated levels of dissolved P may limit chicken manure biochar application rate. Applied at low rates, these biochars provide added nutritional value with low adverse impact on leachate composition. PMID:22751051

  12. Mobility and speciation of Cd,Cu,and Zn in two acidic soils affected by simulated acid rain

    GUO Zhao-hui; LIAO Bo-han; HUANG Chang-yong

    2005-01-01

    Through a batch experiment, the mobility and speciation of heavy metals(Cd, Cu, Zn) in two acidic forest soils from Hunan Province were studied. The results showed that the release and potential active speciation of Cd, Cu, and Zn in the tested contaminated red soil(CRS) and yellow red soil(CYRS) increased significantly with pH decreasing and ion concentrations increasing of simulated acid rain, and these effects were mainly decided by the pH value of simulated acid rain. Cd had the highest potential risk on the environment compared with Cu and Zn. Cd existed mainly in exchangeable form in residual CRS and CYRS, Cu in organically bound and Mn-oxide occluded forms, and Zn in mineral forms due to the high background values.

  13. Soil degradation by sulfuric acid disposition on uranium producing sites in south Bulgaria

    This study assesses the damage of soils caused by spills of sulfuric acid solutions used for in situ leaching of uranium at eight uranium producing (by open-cast method) sites (total area of approximately 220 ha) in the region of Momino-Rakovski (South Bulgaria). The upper soil layer is cinnamonic pseudopodzolic ( or Eutric Planosols by FAO Legend, 1974). The results of the investigation show that the sulfuric acid spills caused strong acidification of upper (0-20 cm) and subsurface (20-60 cm) soil horizons which is expressed as decreasing of pH (H2O) to 2.9-3.5 and increasing of exchangeable H+ and Al3+ to 18 and 32% from CEC. Acid degradation of soils is combined with reducing of organic matter content. The average concentration of the total heavy metal content in the upper soil horizon (in ppm) is: Cd=1.5; Cu=30; Pb=25; Zn=40 and U=8. No significant differences were detected between the upper and subsurface soil layers . The heavy metal concentration did not exceed the Bulgarian standards for heavy metals and uranium content of soils. But the coarse texture of the top soil layers, the lack of carbonates, The low CEC and strong acidity determine a low buffering capacity of the investigated soils and this can be considered as hazardous for plants. This indicates that a future soil monitoring should be carried out in the region together with measures for neutralizing of soil acidity

  14. Complexation of Ni(II) by α-isosaccharinic acid and gluconic acid from pH 7 to pH 13

    Nickel reactions with gluconic acid (Gl) and a-isosaccharinic acid (ISA) have been investigated from pH 7 to pH 13.3. Measurement of the stoichiometries of the products of these reactions showed that NiGl and NiISA were formed at pH2Gl(OH)3 and Ni2ISA(OH)3 were formed at pH values between 7 and 10 and Ni2Gl(OH)4 and Ni2ISA(OH)4 were formed at pH>10. The stability constants for the formation of the soluble complexes were measured using an ion exchange resin method (Schubert method) at pH 7 and 13.3, and differential pulse polarography at pH 7. The polarographic measurements were performed in order to check the validity of the Schubert method at pH 7. This was due to the possibility of any cationic complexes that may have been formed sorbing to the resin. The importance of determining the stoichiometry of the reactions before calculating the stability constants from measurements taken using the Schubert method is emphasised

  15. Soil acidity as affecting micronutrients concentration, nitrato reductase enzyme activity and yield in upland rice plants

    Edemar Moro

    2013-12-01

    Full Text Available The lowest grain yield of rice under no-tillage system (NTS in relation to the conventional system may be due to the predominance nitrate in the soil and the low nitrate reductase activity. Another reason may be caused by micronutrient deficiency because of superficially soil acidity corrections. Therefore, the objective of this study was to evaluate the changes caused by soil pH in the N forms in the soil, micronutrients concentration in rice plants, nitrate reductase activity, yield of rice and its components. The experiment was performed in a greenhouse conditions. The experimental design was a completely randomized in a factorial three (levels of soil acidity x five (micronutrients sources with four replications. The addition of micronutrients does not affect levels of nitrate and ammonium in the soil; soil acidity significantly affects levels of nitrate and ammonium in the soil, concentration of micronutrients in rice plants and crop yield and its components; medium soil acidity (pH 5.5 result in medium to high levels of Cu and Fe, medium level of Zn and Mn, high nitrate reductase activity, resulting in higher dry matter, tillers, panicles, spikelets, weight of 100 grains and hence grain yield.

  16. Ammonia-oxidizing activity and microbial community structure in acid tea (Camellia sinensis) orchard soil

    Okamura, K.; Takanashi, A.; Yamada, T.; Hiraishi, A.

    2012-03-01

    The purpose of this study was to determine the ammonia-oxidizing activity and the phylogentic composition of microorganisms involved in acid tea (Camellia sinensis) orchard soil. All soil samples were collected from three sites located in Tahara and Toyohashi, Aichi Prefecture, Japan. The potential nitrification rate (PNR) was measured by the chlorate inhibition method. The soil pH of tea orchards studied ranged from 2.78 to 4.84, differing significantly from sample to sample, whereas that of meadow and unplanted fields ranged from 5.78 to 6.35. The PNR ranged from 0.050 to 0.193 μg NO2--Ng-1 h-1 and were positively correlated with the soil pH (r2 = 0.382, pamoA genes. The detected archaeal clones separated from the cluster of the 'Soil clones' and tightly clustered with the clones originating from other acidic soil environments including the Chinese tea orchard soil. These results suggest that the specific archaeal populations dominate as the ammonia oxidizers in acid tea-orchard soils and possibly other acid soils, independent of geographic locations, which results from the adaptation to specific ecological niches.

  17. Soil amendments modify phosphate sorption in an acid soil: the importance of P source (KH{sub 2}PO{sub 4}, TSP, DAP)

    Schefe, C.R.; Patti, A.F.; Clune, T.S.; Jackson, W.R. [Rutherglen Center, Rutherford, Vic. (Australia)

    2007-07-01

    Soil acidity is a widespread problem in Victoria, Australia, affecting at least 4 million ha of agricultural land. Soil amendments such as lime and organic materials may ameliorate acid soils, resulting in raised soil pH and increased availability of plant nutrients such as phosphorus (P). The addition of lime, lignite, and compost significantly modified P sorption in an acid soil, with the degree of change highly dependent upon the source of P applied. The application of 2.5 t/ha of lime increased P sorption for all P sources, while P sorption was decreased in the lignite and compost treatments when di-ammonium phosphate (DAP) was applied. Lime and compost addition increased the solution pH, with no change in pH in the lignite treatment. Addition of TSP decreased the pH in all treatments, while DAP addition only increased solution pH in the untreated soil and the lignite treatment. The addition of soil amendments had a significant effect on solution cation concentrations, due to both the influx of cations, and the resultant changes in solution pH. The source of P applied (KH{sub 2}PO{sub 4}, TSP (triple superphosphate), DAP) also had a significant effect due to both the counter-ions present and the pH of each P source (e. g. TSP pH 2.7; DAP pH 7.4). The lignite treatment decreased total P sorption relative to the other amendments. The combination of lignite and DAP resulted in both the greatest decrease in P sorption, and the formation of soluble Al-organic complexes. Therefore, a combination of lignite and DAP may be of use in decreasing P sorption in acid soils.

  18. Sorption of dissolved lead from shooting range soils using hydroxyapatite amendments synthesized from industrial byproducts as affected by varying pH conditions.

    Hashimoto, Yohey; Taki, Tomohiro; Sato, Takeshi

    2009-04-01

    For immobilization technologies to be successful, the use of readily available and cost advantageous amendment is important when the remediation targets vast amounts of contaminated soils. The objectives of this study were to investigate whether the byproduct-synthesized hydroxyapatite can be used as an immobilizing amendment for dissolved Pb from a shooting range soil, and to model the kinetic data collected from dissolution experiments. A soil-solution kinetic experiment was conducted under fixed pH conditions as a function of time. A Pb-contaminated soil was reacted with various hydroxyapatite amendments to determine the dissolution rate and mineral products of soil Pb. Three types of amendments used were pure hydroxyapatite (HA), and poorly crystalline hydroxyapatites synthesized from gypsum waste (CHA), and synthesized from incinerated poultry litter (PHA). The dissolved Pb concentration decreased with the addition of amendments at pH 3-7. Both CHA and PHA were more effective than HA for attenuating Pb dissolution at pH 6 and above. According to the thermodynamic calculation at pH 6, the dissolved Pb concentration for CHA and PHA treatments was predicted to be 66% and 50% lower than that of HA treatment, respectively. A better Pb immobilization effect demonstrated by CHA and PHA resulted in their greater solubility at higher pH, which may promote the formation of chloropyromorphite precipitates. Dissolution kinetics of soil Pb was adequately explained by pseudo-first order and pseudo-second order equations in acid pH ranges. According to the ion exchange model, an adequate agreement between the experimental data and regression curves was shown in the initial 40 min of the reaction process, but the accuracy of model predictability decreased thereafter. According to kinetic models and dissolution phenomena, CHA and PHA amendments had better Pb sorption capacity with rapid kinetics than pure hydroxyapatite at weak acid to neutral pH. PMID:19111967

  19. Effects of pH and manure on transport of sulfonamide antibiotics in soil.

    Strauss, Claudia; Harter, Thomas; Radke, Michael

    2011-01-01

    Sulfonamide antibiotics are a commonly used group of compounds in animal husbandry. They are excreted with manure, which is collected in a storage lagoon in certain types of confined animal feeding operations. Flood irrigation of forage fields with this liquid manure creates the potential risk of groundwater contamination in areas with shallow groundwater levels. We tested the hypothesis that-in addition to the soil characteristics-manure as cosolute and manure pH are two major parameters influencing sulfonamide transport in soils. Solute displacement experiments in repacked, saturated soil columns were performed with soil (loamy sand) and manure from a dairy farm in California. Breakthrough of nonreactive tracer and sulfadimethoxine, sulfamethazine, and sulfamethoxazole at different solution pH (5, 6.5, 8.5) with and without manure was modeled using Hydrus-1D to infer transport and reaction parameters. Tracer and sulfonamide breakthrough curves were well explained by a model concept based on physical nonequilibrium transport, equilibrium sorption, and first-order dissipation kinetics. Sorption of the antibiotics was low ( K₄ ≤ 0.7 L kg) and only weakly influenced by pH and manure. However, sulfonamide attenuation was significantly affected by both pH and manure. The mass recovery of sulfonamides decreased with decreasing pH, e.g., for sulfamethoxazole from 77 (pH 8.5) to 56% (pH 5). The sulfonamides were highly mobile under the studied conditions, but manure application increased their attenuation substantially. The observed attenuation was most likely caused by a combination of microbial transformation and irreversible sorption to the soil matrix. PMID:21869527

  20. Revegetation of extremely acid mine soils based on aided phytostabilization: A case study from southern China.

    Yang, Sheng-Xiang; Liao, Bin; Yang, Zhi-Hui; Chai, Li-Yuan; Li, Jin-Tian

    2016-08-15

    Acidification is a major constraint for revegetation of sulphidic metal-contaminated soils, as exemplified by the limited literature reporting the successful phytostabilization of mine soils associated with pHacidification potential. In this study, a combination of ameliorants (lime and chicken manure) and five acid-tolerant plant species has been employed in order to establish a self-sustaining vegetation cover on an extremely acid (pHacidification potential. The results from the first two-year data showed that the addition of the amendments and the establishment of a plant cover were effective in preventing soil acidification. Net acid-generating potential of the mine soil decreased steadily, whilst pH and acid neutralization capacity increased over time. All the five acid-tolerant plants colonized successfully in the acidic metal-contaminated soil and developed a good vegetation cover within six months, and subsequent vegetation development enhanced organic matter accumulation and nutrient element status in the mine soil. The two-year remediation program performed on this extremely acid metalliferous soil indicated that aided phytostabilization can be a practical and effective restoration strategy for such extremely acid mine soils. PMID:27100018

  1. Response of soil respiration to acid rain in forests of different maturity in southern China.

    Guohua Liang

    Full Text Available The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF, a transitional mixed conifer and broadleaf forest (MF and an old-growth broadleaved forest (BF] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0. Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types.

  2. Metsulfuron-methyl sorption/desorption behavior on volcanic ash-derived soils. effect of phosphate and pH.

    Cáceres, Lizethly; Fuentes, Roxana; Escudey, Mauricio; Fuentes, Edwar; Báez, María E

    2010-06-01

    Metsulfuron-methyl sorption/desorption behavior was studied through batch sorption experiments in three typical volcanic ash-derived soils belonging to Andisol and Ultisol orders. Their distinctive physical and chemical properties are acidic pH and variable surface charge. Organic matter content and mineral composition affected in different ways sorption of metsulfuron-methyl (K(OC) ranging from 113 to 646 mL g(-1)): organic matter and iron and aluminum oxides mainly through hydrophilic rather than hydrophobic interactions in Andisols, and Kaolinite group minerals, as major constituents of Ultisols, and iron and aluminum oxides only through hydrophilic interactions. The Freundlich model described metsulfuron-methyl behavior in all cases (R(2) > 0.992). K(f) values (3.1-14.4 microg(1-1/n) mL(1/n) g(-1)) were higher than those reported for different class of soils including some with variable charge. Hysteresis was more significant in Ultisols. A strong influence of pH and phosphate was established for both kinds of soil, intensive soil fertilization and liming being the most probable scenario for leaching of metsulfuron-methyl, particularly in Ultisols. PMID:20455566

  3. Acid sulfate soils are an environmental hazard in Finland

    Pihlaja, Jouni

    2016-04-01

    Acid sulfate soils (ASS) create significant threats to the environment on coastal regions of the Baltic Sea in Finland. The sediments were deposited during the ancient Litorina Sea phase of the Baltic Sea about 7500-4500 years ago. Finland has larger spatial extent of the ASS than any other European country. Mostly based on anthropogenic reasons (cultivation, trenching etc.) ASS deposits are currently being exposed to oxygen which leads to chemical reaction creating sulfuric acid. The acidic waters then dissolve metals form the soil. Acidic surface run off including the metals are then leached into the water bodies weakening the water quality and killing fish or vegetation. In constructed areas acidic waters may corrode building materials. Geological Survey of Finland (GTK) is mapping ASS deposits in Finland. The goal is to map a total of 5 million hectares of the potentially ASS affected region. It has been estimated that the problematic Litorina Sea deposits, which are situated 0-100 m above the recent Baltic Sea shoreline, cover 500 000 hectares area. There are several phases in mapping. The work begins at the office with gathering the existing data, interpreting airborne geophysical data and compiling a field working plan. In the field, quality of the soil is studied and in uncertain cases samples are taken to laboratory analyses. Also electrical conductivity and pH of soil and water are measured in the field. Laboratory methods include multielemental determinations with ICP-OES, analyses of grain size and humus content (LOI), and incubation. So far, approximately 60 % of the potential ASS affected regions in Finland are mapped. Over 15 000 sites have been studied in the field and 4000 laboratory analyses are done. The spatial database presented in the scale of 1: 250 000 can be viewed at the GTK's web pages (http://gtkdata.gtk.fi/hasu/index.html).

  4. Liming of acid soils in Osijek-Baranja county

    Dolijanović Željko; Andrijačić Martina; Đurđević Boris; Vukadinović Vladimir; Vukadinović Vesna; Jurišić Mladen; Bertić Blaženka; Jug Irena

    2011-01-01

    The negative trend of soil degradation process increases with intensive agricultural production. Therefore, there is a need for soil conditioning like liming, humification, fertilization, etc. to improve soil quality. One of the major problems that occur on agricultural soils of Croatia is acidification. A downward trend of soil pH is mainly present in soils of poor structure with intensive agricultural production. In agricultural practice liming often need...

  5. Correction of Excessive Soil Acidity with Different Liming Materials

    Milan Mesić

    2001-06-01

    According to the changes of soil pH, hydrolytic acidity, base saturation level and mobile aluminium content in soil for all investigation years, the differences in rapidity and duration of activity of particular liming material were recorded. Hydrated lime, sugar factory waste lime, ground soft lithothamnium limestone, hard limestone and dolomite influenced the soil chemical properties on the similar way, but not equally. When higher doses of these materials were applied the excessive soil acidity was almost completely neutralised. Compared to the other liming materials the efficacy of not ground lithothamnium limestone was somewhat lower, and that of phosphogypsum and special natural substrata was considerably lower. Winter wheat and corn were used as test crops and they were grown in the crop sequence winter wheat – corn – corn – winter wheat. According to the winter wheat and corn grain yield recorded at different trial treatments, the trial was statistically significant in all 4 years of investigation. At the first investigation year the highest yield of winter wheat was recorded at the treatment with higher dose of sugar factory waste lime. At the second, third and fourth year highest yields of test crops were obtained at trial treatment with higher dose of ground soft lithothamnium limestone.

  6. P Limitation and Microbial Biogeochemistry in Acidic Forest Soils of the Northeastern United States

    Smemo, K. A.; Deforest, J. L.; Burke, D. J.; Elliot, H. L.; Kluber, L. A.; Carrino-Kyker, S. R.

    2010-12-01

    In forest ecosystems with acidic soils, such as many hardwood forests of the Northeastern United States, net primary productivity should be limited by phosphorus (P) because P is biologically less available at pH temperate forests that have naturally acidic soil or are exposed to chronic acid deposition; such findings are contrary to biogeochemical expectations. We hypothesize that many eastern forests possess an underlying P limitation not realized at the ecosystem level. Instead, shifts in the composition, structure and function of soil microbial communities compensate by acquiring more P from organic sources and P limitation is therefore not manifested at the aboveground (plant) level. To test this hypothesis, we manipulated soil pH and P availability in 72 20 x 40 m mature hardwood forest plots across northeastern (glaciated) and southeastern (unglaciated) Ohio beginning in late summer 2009. Ten months after treatment initiation, soil pH has increased from 4.5 to 5.5 and soil P has increased from 3 to ~25 mg P/kg soil on glaciated soils and from 0.5 to ~5 mg P/kg soil on unglaciated soils. To quantify treatment responses, we measured the activity of soil extracellular enzymes associated with liberation of P, N, and C from organic matter, as well as pools of N and N cycling processes. We saw no significant effects of our treatments on pools of available ammonium or nitrate, nor did we see effects on net N mineralization and net nitrification rates. However, glaciated soils had significantly greater nitrate pools and higher N cycling rates than older unglaciated soils. Nitrogen and C cycling enzymes in treatment plots were not significantly different than control plots, but N-acetylglucosaminidase activity (N acquisition) was significantly greater in the unglaciated soils and β-glucosidase and cellobiosidase activities (C cycling) were greatest in the glaciated soils. In only the unglaciated soils was the activity of P acquisition enzymes (phosphomonoesterase

  7. pH regulates ammonia-oxidizing bacteria and archaea in paddy soils in Southern China.

    Li, Hu; Weng, Bo-Sen; Huang, Fu-Yi; Su, Jian-Qiang; Yang, Xiao-Ru

    2015-07-01

    Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrogen cycling. However, the effects of environmental factors on the activity, abundance, and diversity of AOA and AOB and the relative contributions of these two groups to nitrification in paddy soils are not well explained. In this study, potential nitrification activity (PNA), abundance, and diversity of amoA genes from 12 paddy soils in Southern China were determined by potential nitrification assay, quantitative PCR, and cloning. The results showed that PNA was highly variable between paddy soils, ranging from 4.05 ± 0.21 to 9.81 ± 1.09 mg NOx-N kg(-1) dry soil day(-1), and no significant correlation with soil parameters was found. The abundance of AOA was predominant over AOB, indicating that AOA may be the major members in aerobic ammonia oxidation in these paddy soils. Community compositions of AOA and AOB were highly variable among samples, but the variations were best explained by pH. AOA sequences were affiliated to the Nitrosopumilus cluster and Nitrososphaera cluster, and AOB were classified into the lineages of Nitrosospira and Nitrosomonas, with Nitrosospira being predominant over Nitrosomonas, accounting for 83.6 % of the AOB community. Moreover, the majority of Nitrosomonas was determined in neutral soils. Canonical correspondence analysis (CCA) analysis further demonstrated that AOA and AOB community structures were significantly affected by pH, soil total organic carbon, total nitrogen, and C/N ratio, suggesting that these factors exert strong effects on the distribution of AOB and AOA in paddy soils in Southern China. In conclusion, our results imply that soil pH was a key explanatory variable for both AOA and AOB community structure and nitrification activity. PMID:25744648

  8. Effect of lemon waste on soil ph and availability of micronutrient in calcareous soils of fars province, Southern Iran

    Gharaie, Hossienali

    2008-01-01

    Most of soils of Iran are calcareous in nature. The orchard trees are widespread in south of Iran. Sour lemon is one product of the area and is processed for lemon juice. To evaluate the effect of lemon waste on soil pH and availability of micronutrients, composite soil samples were collected from 0-40 Cm of the area and analyzed for physico- chemical properties. Lemon waste was gathered from processing factory, dried at 70 c and crushed to 1-2 mm size. A statistical complete r...

  9. Negative pH and extremely acidic mine waters from Iron Mountain, California

    Nordstrom, D.K.; Alpers, C.N.; Ptacek, C.J.; Blowes, D.W.

    2000-01-01

    Extremely acidic mine waters with pH values as low as -3.6, total dissolved metal concentrations as high as 200 g/L, and sulfate concentrations as high as 760 g/L, have been encountered underground in the Richmond Mine at Iron Mountain, CA. These are the most acidic waters known. The pH measurements were obtained by using the Pitzer method to define pH for calibration of glass membrane electrodes. The calibration of pH below 0.5 with glass membrane electrodes becomes strongly nonlinear but is reproducible to a pH as low as -4. Numerous efflorescent minerals were found forming from these acid waters. These extreme acid waters were formed primarily by pyrite oxidation and concentration by evaporation with minor effects from aqueous ferrous iron oxidation and efflorescent mineral formation.

  10. Analysis Of Soil NPK Ph And Electrical Conductivity At Adham Area- Renk Upper Nile State

    Abubaker Haroun Mohamed Adam

    2015-08-01

    Full Text Available ABSTRACT The objectives of this study were to investigate soil type potentiality and reaction in relation to the scattered remaining vegetation species and to quantify soil suitability for growing field crops. Adham area witnessed serious land degradation due to the rapid expansion of Rain-fed Mechanized Farming and overgrazing. Consequently the low crop yield enforced the local communities to shift to the alternative sources of income generating activities particularly those related to forest products like charcoal making firewood production logging and tree lobbing. By using Randomized Complete Block Design RCBD with emphasizes on Macro nutrients particularly the Nitrogen Phosphorous and potassium NPK in addition to soil pH and Electrical Conductivity EC. random soil samples each with three levels of depths 0 - 15 15 - 30 30 - 45 cm. were collected. All collected data were analyzed in the laboratory. The result of revealed several types of soils including the cracking and non -cracking clay sandy and red soils. The result of statistical analysis depicted variability in NPK pH and EC between the different locations and soil depths. Furthermore the result showed an association between some studied soil attributes and the spatial distribution of the vegetation species. Rational use through participatory approach is recommended for natural resources management conservation and sustainability. Moreover further study using space technology also recommended.

  11. Niveles de carbono orgánico y ph en suelos agrícolas de las regiones pampeana y extrapampeana argentina Organic carbon and ph levels in agricultural soils of the pampa and extra-pampean regions of argentina

    Hernán René Sainz Rozas

    2011-07-01

    second objective was to compare the prediction efficiency (EP of two interpolation methods: 1 inverse distance weighting (IDW and 2 ordinary Kriging method (KO. Both methods produced similar maps of SOM and pH, but the EP was slightly greater for the KO (65 to 80% compared to IDP (63 to 79%. Soil organic matter values ranged from 5.5 to 38.0 g kg-1, with values declining westward and northward and increasing to the southeast of the region. Soils of most of the area presented pH values that ranged from 6 to 7.5, except for some cases in northern Buenos Aires, center-southern Santa Fe and eastern Cordoba, where soil pH values ranged from 5.5 to 6. Soil organic matter showed a declining tendency which indicated the need to apply management practices to revert this degradation process. The soil pH should not be limiting for crop production, but potential problems of acidity could appear in some areas.

  12. Effect of Temperature, pH and Salt on Fluorescent Quality of Water Extractable Organic Matter in Black Soil

    LI Ming-tang; ZHAO Lan-po; ZHANG Jin-jing

    2013-01-01

    Water erosion is the major reason for the loss of soil organic carbon in the Northeast China, which leads to the soil quality deterioration and adjacent water pollution. In this study, the effect of extraction temperature, pH value, and salt on the water extractable organic matter (WEOM) was determined by means of the UV absorbance, fluorescence excitation-emission matrix, and derived fluorescence indexes. In general, the carbon content and aromaticity of WEOM increased with the increasing of extraction temperature, with the exception that there was no significant difference in the amount at 0 and 20°C. More fluorophores, especially microbially-derived organic matter were extracted at high temperature. The pH values of extractant, including 5, 7, and 10, showed no effect on the carbon amount of WEOM, whereas the aromaticity and microbially-derived component gradually increased with the increasing of pH values. The fluorescence intensity of humic acid-like fluorophore was stronger in neutral and alkali condition than that in acidic condition. The addition of 10 mmol L-1 CaCl2 significantly decreased the carbon amount of recovered WEOM. Moreover, it significantly decreased the aromaticity of WEOM and the quantity of fulvic acid-like and humic acid-like fluorophores, whereas increased the percentage of tyrosine-like and tryptophan-like fluorophores in the total fluorophores and the amount of microbially-derived organic matter. Generally, 10 mmol L-1 KCl showed the same influence trend, but with low influence degree.

  13. Impact of Seasalt Deposition on Acid Soils in Maritime Regions

    ZHANG Zhen-Hua

    2003-01-01

    The characteristics of seasalt deposition and its impact on acid soils in maritime regions are reviewed. It is pointed out that studies involving the impact of seasalt deposition on acid soils have been concentrated on short-term effects on soil and water acidification. A deep consideration of long-term effects on soil acidification in maritime regions is still needed.

  14. Dissolution of Aluminum in Variably Charged Soils as Affected by Low-Molecular-Weight Organic Acids

    LI Jiu-Yu; XU Ren-Kou; JI Guo-Liang

    2005-01-01

    Low-molecular-weight (LMW) organic acids exist widely in soils and play an important role in soil processes such as mineral weathering, nutrient mobilization and Al detoxification. In this research, a batch experiment was conducted to examine the effects of LMW organic acids on dissolution of aluminum in two variably charged soils, an Ultisol and an Oxisol. The results showed that the LMW organic acids enhanced the dissolution of Al in the two investigated soils in the following order: citric > oxalic > malonic > malic > tartaric > salicylic > lactic > maleic. This was generally in agreement with the magnitude of the stability constants for the Al-organic complexes. The effects of LMW organic acids on Al dissolution were greater in the Ultisol than in the Oxisol as compared to their controls. Also, the accelerating effects of citric and oxalic acids on dissolution of Al increased with an increase in pH, while the effects of lactic and salicylic acids decreased. Additionally, when the organic acid concentration was less than 0.2 mmol L-1, the dissolution of Al changed little with increase in acid concentration. However, when the organic acid concentration was greater than 0.2 mmol L-1,the dissolution of Al increased with increase in acid concentration. In addition to the acid first dissociation constant and stability constant of Al-organic complexes, the promoting effects of LMW organic acids on dissolution of Al were also related to their sorption-desorption equilibrium in the soils.

  15. Aluminum tolerance of two wheat cultivars (Brevor and Atlas66) in relation to their rhizosphere pH and organic acids exuded from roots.

    Wang, Ping; Bi, Shuping; Ma, Liping; Han, Weiying

    2006-12-27

    Phytotoxicity of aluminum (Al) has become a serious problem in inhibiting plant growth on acid soils. Under Al stress, the changes of rhizosphere pH, root elongation, absorption of Al by wheat roots, organic acids exuded from roots, and some main factors related to Al-tolerant mechanisms have been studied using hydroponics, fluorescence spectrophotometry, and high performance liquid chromatography (HPLC). Two wheat cultivars, Brevor and Atlas66, differing in Al tolerance are chosen in the study. Accordingly, the rhizosphere pH has a positive effect on Al tolerance. Atlas66 (Al-tolerant) has higher capability to maintain high rhizosphere pH than Brevor (Al-sensitive) does. High pH can reduce Al3+ activity and toxicity, and increase the efficiency of exuding organic acids from the roots. More inhibition of root elongation has been found in Brevor because of the exposure of roots to Al3+ solution at low pH. Brevor accumulate more Al in roots than Atlas66 even at higher pH. Al-induced exudation of malic and citric acids has been found in Atlas66 roots, while no Al-induced organic acids have been found in Brevor. These results indicate that the Al-induced secretion of organic acids from Atlas66 roots has a positive correlation with Al tolerance. Comprehensive treatment of Al3+ and H+ indicates that wheat is adversely influenced by excess Al3+, rather than low pH. PMID:17177538

  16. Contribution of ants in modifying of soil acidity and particle size distribution

    Morgun, Alexandra; Golichenkov, Maxim

    2015-04-01

    Being a natural body, formed by the influence of biota on the upper layers of the Earth's crust, the soil is the most striking example of biogenic-abiogenic interactions in the biosphere. Invertebrates (especially ants that build soil nests) are important agents that change soil properties in well developed terrestrial ecosystems. Impact of soil microorganisms on soil properties is particularly described in numerous literature and concerns mainly chemical properties and general indicators of soil biological activity. Influence of ants (as representatives of the soil mesofauna) mostly appears as mechanical movement of soil particles and aggregates, and chemical effects caused by concentration of organic matter within the ant's nest. The aim of this research was to evaluate the effect of ants on physical and chemical soil attributes such as particle size distribution and soil acidity. The samples were taken from aerial parts of Lasius niger nests, selected on different elements of the relief (summit position, slope, terrace and floodplain) in the Arkhangelsk region (north of the European part of Russia) and compared with the specimens of the upper horizons of the reference soils. Particle size distribution was determined by laser diffraction method using laser diffraction particle size analyzer «Analysette 22 comfort» (FRITSCH, Germany). The acidity (pH) was determined by potentiometry in water suspension. Particle size distribution of the samples from the nests is more variable as compared to the control samples. For example, the content of 5-10 μm fraction ranges from 9% to 12% in reference soils, while in the anthill samples the variation is from 8% to 15%. Similarly, for 50-250 μm fraction - it ranges from 15% to 18% in reference soils, whereas in anthills - from 6% to 29%. The results of particle size analysis showed that the reference sample on the terrace has silty loam texture and nests soil L. niger are medium loam. The reference soil on the slope is

  17. Effects of dicyandiamide and dolomite application on N2O emission from an acidic soil.

    Shaaban, Muhammad; Wu, Yupeng; Peng, Qi-An; Lin, Shan; Mo, Yongliang; Wu, Lei; Hu, Ronggui; Zhou, Wei

    2016-04-01

    Soil acidification is a major problem for sustainable agriculture since it limits productivity of several crops. Liming is usually adopted to ameliorate soil acidity that can trigger soil processes such as nitrification, denitrification, and loss of nitrogen (N) as nitrous oxide (N2O) emissions. The loss of N following liming of acidic soils can be controlled by nitrification inhibitors (such as dicyandiamide). However, effects of nitrification inhibitors following liming of acidic soils are not well understood so far. Here, we conducted a laboratory study using an acidic soil to examine the effects of dolomite and dicyandiamide (DCD) application on N2O emissions. Three levels of DCD (0, 10, and 20 mg kg(-1); DCD0, DCD10, and DCD20, respectively) were applied to the acidic soil under two levels of dolomite (0 and 1 g kg(-1)) which were further treated with two levels of N fertilizer (0 and 200 mg N kg(-1)). Results showed that N2O emissions were highest at low soil pH levels in fertilizer-treated soil without application of DCD and dolomite. Application of DCD and dolomite significantly (P ≤ 0.001) reduced N2O emissions through decreasing rates of NH4 (+)-N oxidation and increasing soil pH, respectively. Total N2O emissions were reduced by 44 and 13 % in DCD20 and dolomite alone treatments, respectively, while DCD20 + dolomite reduced N2O emissions by 54 % when compared with DCD0 treatment. The present study suggests that application of DCD and dolomite to acidic soils can mitigate N2O emissions. PMID:26620858

  18. Copper binding to soil fulvic and humic acids

    Xu, Jinling; Tan, Wenfeng; Xiong, Juan; Wang, Mingxia; Fang, Linchuan; Koopal, Luuk K.

    2016-01-01

    Binding of Cu(II) to soil fulvic acid (JGFA), soil humic acids (JGHA, JLHA), and lignite-based humic acid (PAHA) was investigated through NICA-Donnan modeling and conditional affinity spectrum (CAS). It is to extend the knowledge of copper binding by soil humic substances (HS) both in respect of

  19. Atmospheric Methane Consumption by Forest Soils and Extracted Bacteria at Different pH Values

    Amaral, John A.; Ren, Tie; Knowles, Roger

    1998-01-01

    The effect of pH on atmospheric methane (CH4) consumption was studied with slurries of forest soils and with bacteria extracted from the same soils. Soil samples were collected from a mixed hardwood stand in New Hampshire, from jackpine and aspen stands at the BOREAS (Boreal Ecosystem Atmosphere Study) site near Thompson, northern Manitoba, from sites in southern Québec, including a beech stand and a meadow, and from a site in Ontario (cultivated humisol). Consumption of atmospheric CH4 (conc...

  20. Standard test method for measuring pH of soil for use in corrosion testing

    American Society for Testing and Materials. Philadelphia

    1995-01-01

    1.1 This test method covers a procedure for determining the pH of a soil in corrosion testing. The principle use of the test is to supplement soil resistivity measurements and thereby identify conditions under which the corrosion of metals in soil may be accentuated (see G 57 - 78 (1984)). 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  1. Productivity of Calliandra calothyrsus, Indigofera zollingeriana and Gliricidia sepium on acid soil in the greenhouse

    Iwan Herdiawan; Endang Sutedi

    2015-01-01

    Acid soil which contains Al3+ and Mn2 is generally unfavorable for crop including the tree legumes. The minerals are toxic to the plants resulted minimalization of growth and crop production. Caliandra calothyrsus, Indigofera zollingeriana, and Gliricidia sepium were tree legumes those are generally used for forage.  The aim of this study was to compare their tolerancy to Al3+ and growth production on acid soil. The plants were grown in ultisol soil with 4.57 of pH collected from Palm Oil pla...

  2. Effects of organic acids on cadmium and copper sorption and desorption by two calcareous soils.

    Najafi, Sarvenaz; Jalali, Mohsen

    2015-09-01

    Low molecular weight organic acids (LMWOAs) present in soil alter equilibrium pH of soil, and consequently, affect heavy metal sorption and desorption on soil constitutes. This study was conducted to investigate the effects of different concentrations (0.1, 1, 2.5, 5, 10, 30, 40, 50, 70, and 100 mM) of citric, malic, and oxalic acids on sorption and desorption of cadmium (Cd) and copper (Cu) in two calcareous soils. Increasing the concentrations of three LMWOAs decreased the equilibrium pH of soil solutions. The results indicated that increase in organic acids concentrations generally reduced Cd and Cu sorption in soils. Increase concentrations of LMWOAs generally promoted Cd and Cu desorption from soils. A valley-like curve was observed for desorption of Cu after the citric acid concentration increment in soil 2. Increasing the concentrations of three LMWOAs caused a marked decrease in Kd(sorp) values of Cd and Cu in soils. In general, citric acid was the most effective organic acid in reducing sorption and increasing desorption of both metals, and oxalic acid had the minimal impact. The results indicated that LMWOAs had a greater impact on Cu sorption and desorption than Cd, which can be attributed to higher stability constants of organic acids complexes with Cu compared to Cd. It can be concluded that by selecting suitable type and concentration of LMWOAs, mobility, and hence, bioavailability of heavy metals can be changed. So, environmental implications concerning heavy metals mobility might be derived from these findings. PMID:26298186

  3. Effects of Composted and Thermally Dried Sewage Sludges on Soil and Soil Humic Acid Properties

    J.M.FERN(A)NDEZ; N.SENESI; C.PLAZA; G.BRUNETTI; A.POLO

    2009-01-01

    The effect of annual additions of composted sewage sludge (CS) and thermally dried sewage sludge (TS) at 80 t ha-1 on soil chemical properties was investigated for three years in a field experiment under semiarid conditions.Humie acids (HAs) isolated by conventional procedures from CS,TS,and unamended (SO) and sludge amended soils were analysed for elemental (C,H,N,S and O) and acidic functional groups (carboxylic and phenolic) and by ultraviolet-visible,Fourier transform infrared and fluorescence spectroscopies.With respect to CS,TS had similar pH and total P and K contents,larger dry matter,total organic C,total N.and C/N ratio and smaller ash content and electrical conductivity.Amendment with both CS and TS induced a number of modifications in soil properties,including an increase of pH,electrical conductivity,total organic C,total N,and available P.The CS-HA had greater O,total acidity,carboxyl,and phenolic OH group contents and smaller C and H contents than TS-HA.The CS-HA and TS-HA had larger N and S contents,smaller C,O and acidic functional group contents,and lower aromatic polycondensation and humification degrees than SO-HA.Amended soil-HAs showed C,H,N and S contents larger than SO-HA,suggesting that sludge HAs were partially incorporated into soil HAs.These effects were more evident with increasing number of sludge applications.

  4. Sustainable Soil Washing: Shredded Card Filtration of Potentially Toxic Elements after Leaching from Soil Using Organic Acid Solutions.

    Christopher Ash

    Full Text Available Shredded card (SC was assessed for use as a sorbent of potentially toxic elements (PTE carried from contaminated soil in various leachates (oxalic acid, formic acid, CaCl2, water. We further assessed SC for retention of PTE, using acidified water (pH 3.4. Vertical columns and a peristaltic pump were used to leach PTE from soils (O and A/B horizons before passing through SC. Sorption onto SC was studied by comparing leachates, and by monitoring total PTE contents on SC before and after leaching. SC buffers against acidic soil conditions that promote metals solubility; considerable increases in solution pH (+4.49 were observed. Greatest differences in solution PTE content after leaching with/without SC occurred for Pb. In oxalic acid, As, Cd, Pb showed a high level of sorption (25, 15, and 58x more of the respective PTE in leachates without SC. In formic acid, Pb sorption was highly efficient (219x more Pb in leachate without SC. In water, only Pb showed high sorption (191x more Pb in leachate without SC. In desorption experiments, release of PTE from SC varied according to the source of PTE (organic/mineral soil, and type of solvent used. Arsenic was the PTE most readily leached in desorption experiments. Low As sorption from water was followed by fast release (70% As released from SC. A high rate of Cd sorption from organic acid solutions was followed by strong retention (~12% Cd desorption. SC also retained Pb after sorption from water, with subsequent losses of ≤8.5% of total bound Pb. The proposed use of this material is for the filtration of PTE from extract solution following soil washing. Low-molecular-mass organic acids offer a less destructive, biodegradable alternative to strong inorganic acids for soil washing.

  5. Sustainable Soil Washing: Shredded Card Filtration of Potentially Toxic Elements after Leaching from Soil Using Organic Acid Solutions.

    Ash, Christopher; Drábek, Ondřej; Tejnecký, Václav; Jehlička, Jan; Michon, Ninon; Borůvka, Luboš

    2016-01-01

    Shredded card (SC) was assessed for use as a sorbent of potentially toxic elements (PTE) carried from contaminated soil in various leachates (oxalic acid, formic acid, CaCl2, water). We further assessed SC for retention of PTE, using acidified water (pH 3.4). Vertical columns and a peristaltic pump were used to leach PTE from soils (O and A/B horizons) before passing through SC. Sorption onto SC was studied by comparing leachates, and by monitoring total PTE contents on SC before and after leaching. SC buffers against acidic soil conditions that promote metals solubility; considerable increases in solution pH (+4.49) were observed. Greatest differences in solution PTE content after leaching with/without SC occurred for Pb. In oxalic acid, As, Cd, Pb showed a high level of sorption (25, 15, and 58x more of the respective PTE in leachates without SC). In formic acid, Pb sorption was highly efficient (219x more Pb in leachate without SC). In water, only Pb showed high sorption (191x more Pb in leachate without SC). In desorption experiments, release of PTE from SC varied according to the source of PTE (organic/mineral soil), and type of solvent used. Arsenic was the PTE most readily leached in desorption experiments. Low As sorption from water was followed by fast release (70% As released from SC). A high rate of Cd sorption from organic acid solutions was followed by strong retention (~12% Cd desorption). SC also retained Pb after sorption from water, with subsequent losses of ≤8.5% of total bound Pb. The proposed use of this material is for the filtration of PTE from extract solution following soil washing. Low-molecular-mass organic acids offer a less destructive, biodegradable alternative to strong inorganic acids for soil washing. PMID:26900684

  6. Changes of organic acid exudation and rhizosphere pH in rice plants under chromium stress

    The effect of chromium (Cr) stress on the changes of rhizosphere pH, organic acid exudation, and Cr accumulation in plants was studied using two rice genotypes differing in grain Cr accumulation. The results showed that rhizosphere pH increased with increasing level of Cr in the culture solution and with an extended time of Cr exposure. Among the six organic acids examined in this experiment, oxalic and malic acid contents were relatively higher, and had a significant positive correlation with the rhizosphere pH, indicating that they play an important role in changing rhizosphere pH. The Cr content in roots was significantly higher than that in stems and leaves. Cr accumulation in plants was significantly and positively correlated with rhizosphere pH, and the exudation of oxalic, malic and citric acids, suggesting that an increase in rhizosphere pH, and exudation of oxalic, malic and citric acid enhances Cr accumulation in rice plants. - Rhizosphere pH and organic acid exudation of rice roots are markedly affected by chromium level in culture solution

  7. Effects of Converter Slag on some Chemical Characteristics of Acid Soils

    H. Shariatmadari

    2005-01-01

    Full Text Available Lintz-Donawitz (LD converter slag, a by-product of the iron and steel-making industry is produced in large quantities in Isfahan, Iran. The slag contains 52.8 and 2.2% (w/w CaO and MgO, respectively. To determine the influence of LD slag on the chemical characteristics of three acid soils from Gilan, an incubation study was conducted. The soil samples were collected from 0-30 cm of rice and tobacco fields and a tea garden. Treatments were 0, 0.5, 1, 2, 4, 8 and 16 % (w/w of converter slag/kg soil. The slag was thoroughly mixed with 500g soil in plastic pots. Soil moisture content was adjusted to near field capacity and changes in pH, EC and AB-DTPA-extractable Fe, Mn, Zn, P and K were determined at 1, 10, 30 and 60 days. Results showed that soil pH increased with increasing slag rates. Slag increased AB-DTPA-extractable P and Mn, the magnitude increase depend on the amount of slag applied. However, the effect of slag on AB-DTPA-extractable Fe depended on initial pH, initially decreasing at the pH range of 7.4 - 8.5 and then increasing at higher pH levels. Slag decreased AB-DTPA-extractable K especially in highly acid soil. In the present study, soil pH and AB-DTPA-extractable Fe decreased with time, though the effect of incubation time on pH was not significant. The effect of incubation time on AB-DTPA extractable Mn and P was different. Time effect on EC and AB-DTPA-extractable K was not significant. In general, soil chemical characteristics were more affected by slag rates than by incubation time. In conclusion, it seems that converter slag is a suitable amendment for acid soils. It is suggested that the effect of LD converter slag on plant growth and chemical characteristics of acid soils be studied under field conditions.

  8. Primordial soup or vinaigrette: did the RNA world evolve at acidic pH?

    Bernhardt Harold S

    2012-01-01

    Full Text Available Abstract Background The RNA world concept has wide, though certainly not unanimous, support within the origin-of-life scientific community. One view is that life may have emerged as early as the Hadean Eon 4.3-3.8 billion years ago with an atmosphere of high CO2 producing an acidic ocean of the order of pH 3.5-6. Compatible with this scenario is the intriguing proposal that life arose within alkaline (pH 9-11 deep-sea hydrothermal vents like those of the 'Lost City', with the interface with the acidic ocean creating a proton gradient sufficient to drive the first metabolism. However, RNA is most stable at pH 4-5 and is unstable at alkaline pH, raising the possibility that RNA may have first arisen in the acidic ocean itself (possibly near an acidic hydrothermal vent, acidic volcanic lake or comet pond. As the Hadean Eon progressed, the ocean pH is inferred to have gradually risen to near neutral as atmospheric CO2 levels decreased. Presentation of the hypothesis We propose that RNA is well suited for a world evolving at acidic pH. This is supported by the enhanced stability at acidic pH of not only the RNA phosphodiester bond but also of the aminoacyl-(tRNA and peptide bonds. Examples of in vitro-selected ribozymes with activities at acid pH have recently been documented. The subsequent transition to a DNA genome could have been partly driven by the gradual rise in ocean pH, since DNA has greater stability than RNA at alkaline pH, but not at acidic pH. Testing the hypothesis We have proposed mechanisms for two key RNA world activities that are compatible with an acidic milieu: (i non-enzymatic RNA replication of a hemi-protonated cytosine-rich oligonucleotide, and (ii specific aminoacylation of tRNA/hairpins through triple helix interactions between the helical aminoacyl stem and a single-stranded aminoacylating ribozyme. Implications of the hypothesis Our hypothesis casts doubt on the hypothesis that RNA evolved in the vicinity of alkaline

  9. Transformation of acetate carbon into carbohydrate and amino acid metabilites during decomposition in soil

    Sørensen, Lasse Holst; Paul, E. A.

    1971-01-01

    Carbon-14-labelled acetate was added to a heavy clay soil of pH 7.6 to study the transformation of acetate carbon into carbohydrate and amino acid metabolites during decomposition. The acetate was totally metabolized after 6 days of incubation at 25°C when 70% of the labelled carbon had been...... evolved as CO2. Maximum incorporation of trace-C into the various organic fractions was observed after 4 days when 19% of residual, labelled carbon in the soil was located in carbohydrates, 29 % in amino acids and 21 % in the insoluble residue of the soil. The curves showing the amounts of labelled carbon...... days of incubation, 2.2% of the labelled carbon originally added to the soil was located in carbohydrate metabolites, 7% in amino acid metabolites and 5% in the insoluble residue. The carbon in these fractions accounted for 77% of the total, residual, labelled carbon in the soil; 12% in carbohydrates...

  10. Sorption of a triazol derivative by soils: importance of surface acidity

    2003-01-01

    The sorption of a triazol derivative, 1-(4-chlorophenyl)- 4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)penten-3-ol with a common name of S3307D, on fifteen soils and three H2O2-treated soils was investigated. The sorption isotherm for each untreated and treated soil was non-linear, and was best fitted to Freundlich sorption equation. Soils containing high amount of clay content or organic matter or both sorbed much higher amounts of the chemical than soils that had low contents of these soil constituents. H2O2-treated soils showed considerable sorptive affinity for S3307D. It was concluded that both organic matter and mineral fraction in natural soils contributed to the sorption of the basic compound. Sorption by the H2O2 treated soils increased as suspension pH decreased, but all suspension pHs exceeded the pKa of the compound by more than two units. This implies that organic base protonation can occur on surfaces of soil components, and surface acidity (exchangeable acidity ) is important in sorption process of the organic base rather than suspension pH.

  11. Declines in Soil pH due to Anthropogenic Nitrogen Inputs Alter Buffering and Exchange Reactions in Tropical Forest Soils

    Lohse, K. A.

    2003-12-01

    Anthropogenic nitrogen (N) inputs may alter tropical soil buffering and exchange reactions that have important implications for nutrient cycling, forest productivity, and downstream ecosystems. In contrast to relatively young temperate soils that are typically buffered from N inputs by base cation reactions, aluminum reactions may serve to buffer highly weathered tropical soils and result in immediate increases in aluminum mobility and toxicity. Increased nitrate losses due to chronic N inputs may also deplete residual base cations in already weathered base cation-poor soils, further acidify soils, and thereby reduce nitrate mobility through pH-dependent anion exchange reactions. To test these hypotheses, I determined soil pH and cation and anion exchange capacity (CEC and AEC) and measured base cation and aluminum soil solution losses following first-time and long-term experimental N additions from two Hawaiian tropical forest soils, a 300 year old Andisol and a 4.1 million year old Oxisol. I found that elevated base cation losses accompanied increased nitrate losses after first time N additions to the young Andisol whereas immediate and large aluminum losses were associated with increased nitrate losses from the Oxisol. In the long-term, base cation and aluminum losses increased in proportion to nitrate losses. Long-term N additions at both sites resulted in significant declines in soil pH, decreased CEC and increased AEC. These results suggest that even chronic N inputs resulting in small but elevated nitrate losses may deplete residual base cations, increase mobility and toxicity of aluminum, and potentially lead to declines in forest productivity and acidification of downstream ecosystems. These findings also suggest that AEC may provide a long-term mechanism to delay nitrate losses in tropical forests with significant variable charge that are experiencing chronic anthropogenic N inputs.

  12. REACTION OF APPLE-TREE VARIETIES AND STOCKS ON CHANGE OF pH OF SOIL

    Doroshenko T. N.; Buzoverov A. V.; Ryazanova L. G.; Zakharchuk N. V.

    2015-01-01

    The researches are devoted to the determination of physiological parameters of grafted apple-trees joining with the level of their resistance to the change of soil рН. The experiments were carried out in the conditions of lysimetric experience with the soils use characterizing by different value of рН. The scheme of experience included the following variants of soil medium reaction: neutral (рН 7,3), typical for black soils of plain part of the region (control); weak-acid (рН 6,2) existing in...

  13. Organic acid excretion in Penicillium ochrochloron increases with ambient pH

    PamelaVrabl

    2012-04-01

    Confirming our hypothesis, the main result demonstrated that organic acid excretion in P. ochrochloron was enhanced at high external pH levels compared to low pH levels independent of the tested strain, nutrient limitation and cultivation method. We discuss these findings against the background of three hypotheses explaining organic acid excretion in filamentous fungi, i.e. overflow metabolism, charge balance and aggressive acidification hypothesis.

  14. Swelling characteristics of hydroxyethylmethacrylate/ methacrylic acid pH -sensitive hydrogel as a drug delivery system

    M. Falamarzian- J. Varshosaz

    1996-01-01

    Hydroxyethyl methacrylate /methacrylic acid (HEMA/MAA) copolymer cross-linked with ethylenglycol dimethacrylate was prepared by a bulk.free radical polymerization method. The results indicate that this polymer is a pH -sensitive hydrogel which is collapsed in the acidic medium but completely swollen in the alkaline and neutral pH . it was determined that a proportion of 40% of MAA, the ionizing monomer of this hydrogel, was the best concentration among the different percentages used which sho...

  15. Sorption of Phenols: Influence of Groundwater pH and of Soil Organic Carbon Content

    Silvia Fiore

    2009-01-01

    Full Text Available Problem statement: Physical and chemical properties of soil, groundwater and pollutants deeply influenced the type and the strength of sorption phenomena involving hydrophobic organic contaminants: Soil fraction of organic carbon (foc and cation exchange capacity, groundwater pH and pollutants hydrophobicity were with undoubtedly the predominant issues. Approach: In this study an experimental study of the sorption of phenol and 2-nitrophenol on three soils was performed considering three initial pH values, with the aim to evaluate the soil/pollutant interactions as a function of the relative abundance of the neutral contaminants and phenolate species and of the solid phase properties. Results: The considered soil samples (a silty clay, a silt and a sand coming from northern Italy underwent to a physical and chemical characterization: Particle-size, mineralogical and chemical analyses were performed. The experimental data coming from some batch tests, carried employing aqueous phases containing different concentrations of phenol and 2-nitrophenol at initial pH values equal to 4, 7 and 10, were fitted by means of several isotherm models. Three Dual Mode Models (DMM, employing different isotherm models to represent the sorption of the neutral and the anionic species of the pollutants, were evaluated by the researchers to simulate the sorption of phenol and 2-nitrophenol in the examined conditions. Conclusion: The soil/contaminant interaction mechanisms determining the isotherm shapes were discussed: foc appeared to be the main issue, although the nitro-group was able to promote sorption. In all considered soil samples and at all initial pH values, the highest foc (found in the silty soil and the presence of the nitro-group determined the highest amounts of pollutant transferred on the solid phase. The two DMMs proposed by the researchers, implying nonlinearity, showed a higher reliability in simulating experimental data compared to a DMM based on

  16. Immobilization of Cd, Zn, and Pb from Soil Treated by Limestone with Variation of pH Using a Column Test

    Sung-Wook Yun

    2015-01-01

    Full Text Available Decades of mining in South Korea have resulted in the contamination of large amounts of soil by metals. The most feasible approach to site restoration requires the use of a stabilization agent to reduce metal mobility. This study examined the leaching characteristics of limestone used as a stabilization agent when subjected to solutions of differing pH. In a laboratory-scale column test, solutions with pH values of 3.5, 4.6, and 5.6, representing acidic to nonacidic rainfall, were applied to soil mixed with limestone. Test results indicate that metal components can be released with the addition of acidic solutions, even if the soil is highly alkaline. Cd and Zn, in particular, exhibited abrupt or continuous leaching when exposed to acid solutions, indicating the potential for contamination of water systems as metal-laden soils are exposed to the slightly acidic rainfall typical of South Korea. Treatment using stabilization agents such as limestone may reduce leaching of metals from the contaminated soil. Stabilizing metal-contaminated farmland is an economical and feasible way to reduce pollutants around abandoned metal mines.

  17. Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste

    Highlights: ► Examined the hydraulic conductivity evolution as function of dry density of Tunisian clay soil. ► Follow the hydraulic conductivity evolution at long-term of three clay materials using the waste solution (pH=2.7). ► Determined how compaction affects the hydraulic conductivity of clay soils. ► Analyzed the concentration of F and P and examined the retention of each soil. - Abstract: Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 × 10−10, 2.08 × 10−9 and 6.8 × 10−10 m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m3). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH = 2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m3) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.

  18. The effect of soil pH on photo-catalytic oxidation of polycyclic aromatic hydrocarbons (PAHs)

    Rakesh M. Pawar; Avice M. Hall; David C. Naseby

    2013-01-01

    The environmental fate of polycyclic aromatic hydrocarbons (PAH) is a significant issue, raising interest in its clean up using remediation. However, the physical, chemical, and biological properties of soils can drastically influence degradation of pollutants. The effect of soil pH on degradation of PAHs with a view to modify soil pH to enhance the degradation of PAH's was studied. The degradation rate of key model PAHs was monitored in topsoil modified to a range of pH 4 to 9 at half pH int...

  19. Nature of Soil Acidity in Relation to Properties and Lime Requirement of Some Inceptisols

    A. K. DOLUI; S. BHATTACHARJEE

    2003-01-01

    Some Inceptisols representing the Singla catchment area in Karimgaunge district of Assam, India, were studied for lime requirement as influenced by the nature of soil acidity. The electrostatically bonded (EB)-H+ and EB-Al3+ acidities constituted 33 and 67 percent of exchangeable acidity while EB-H+, EB-Al3+,exchangeable and pH-dependent acidities comprised 6, 14, 20 and 80 percent of total potential acidity. The pH-dependent acidity made a major contribution towards the total potential acidity (67%~84%). Grand mean of lime requirement determined by the laboratory incubation method and estimated by the methods of New Woodruff, Woodruff and Peech as expressed in MgCaCO3 ha-1 was in the order: Woodruff (15.6) > New Woodruff (14.9) > Peech (5.1) > incubation (5.0). Correlations analysis among different forms of acidity and lime requirement methods with selected soil properties showed that pH in three media, namely water, 1 mol L-1 KCl and 0.01 mol L-1 CaCl2, had a significant negative correlation with different forms of acidity and lime requirement methods. Exchangeable Fe and Al showed significant positive correlations with EB-Al3+ acidity, exchangeable acidity, pH-dependent acidity and total potential acidity, and also lime requirement methods. Extractable Al showed positive correlations with different forms of acidity except EB-H+ and EB-Al3+ acidities. The lime requirement by different methods depended upon the extractable aluminium.Significant positive correlations existed between lime requirements and different forms of acidity of the soils except EB-H+ acidity and incubation method. The nature of soil acidity was mostly pH-dependent. Statistically, the Woodruff method did slightly better than the New Woodruff, incubation and Peech methods at estimating lime requirement and hence the Woodruff procedure may be recommended for routine soil testing because of its speed and simplicity.

  20. Impact of mitigation strategies on acid sulfate soil chemistry and microbial community.

    Wu, Xiaofen; Sten, Pekka; Engblom, Sten; Nowak, Pawel; Österholm, Peter; Dopson, Mark

    2015-09-01

    Potential acid sulfate soils contain reduced iron sulfides that if oxidized, can cause significant environmental damage by releasing large amounts of acid and metals. This study examines metal and acid release as well as the microbial community capable of catalyzing metal sulfide oxidation after treating acid sulfate soil with calcium carbonate (CaCO3) or calcium hydroxide (Ca(OH)2). Leaching tests of acid sulfate soil samples were carried out in the laboratory. The pH of the leachate during the initial flushing with water lay between 3.8 and 4.4 suggesting that the jarosite/schwertmannite equilibrium controls the solution chemistry. However, the pH increased to circa 6 after treatment with CaCO3 suspension and circa 12 after introducing Ca(OH)2 solution. 16S rRNA gene sequences amplified from community DNA extracted from the untreated and both CaCO3 and Ca(OH)2 treated acid sulfate soils were most similar to bacteria (69.1% to 85.7%) and archaea (95.4% to 100%) previously identified from acid and metal contaminated environments. These species included a Thiomonas cuprina-like and an Acidocella-like bacteria as well as a Ferroplasma acidiphilum-like archeon. Although the CaCO3 and Ca(OH)2 treatments did not decrease the proportion of microorganisms capable of accelerating acid and metal release, the chemical effects of the treatments suggested their reduced activity. PMID:25933291

  1. Zn Adsorption by Variable Charge Soils in Relation to pH

    SUNHAN-YUAN

    1993-01-01

    Zn adsorption by pure oxides or in the presence of a high concentration of inner electrolyte has been extensively studied.But,in studies on Zn adsorption in the complicated soil system,especially in variable charge soils,profound knowledge about the absorption mechanism still lacks.In this paper,taking Zn ion adsorption by two typical variable charge soils as the object of the study,author discusses the relation between Zn adsorption and pH and possible adsorption mechanisms.The results showed that in the low pH range where the amount of Zn adsorbed did not exceed 50% of Zn added,the specific adsorption was the diminant mechanism.The species of Zn specifically adsorbed was free Zn2+ ion.In the middle and high pH ranges,the mechanisms of specific and electrostatic adsorptions co-existed,accounting for about 70% and 30%,respectively.Noteworthily,in the high pH range,the hydroxyl Zn ion (ZnOH+) from Zn2+ hydrolysis probably was a preferable species for specific absorption.

  2. Identifying sources of acidity and spatial distribution of acid sulfate soils in the Anglesea River catchment, southern Australia

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

    Globally, coastal and estuarine floodplains are frequently underlain by sulfidic sediments. When exposed to oxygen, sulfidic sediments oxidise to form acid sulfate soils, adversely impacting on floodplain health and adjacent aquatic ecoystems. In eastern Australia, our understanding of the formation of these coastal and estuarine floodplains, and hence, spatial distribution of acid sulfate soils, is relatively well established. These soils have largely formed as a result of sedimentation of coastal river valleys approximately 6000 years BP when sea levels were one to two metres higher. However, our understanding of the evolution of estuarine systems and acid sulfate soil formation, and hence, distribution, in southern Australia remains limited. The Anglesea River, in southern Australia, is subjected to frequent episodes of poor water quality and low pH resulting in closure of the river and, in extreme cases, large fish kill events. This region is heavily reliant on tourism and host to a number of iconic features, including the Great Ocean Road and Twelve Apostles. Poor water quality has been linked to acid leakage from mining activities and Tertiary-aged coal seams, peat swamps and acid sulfate soils in the region. However, our understanding of the sources of acidity and distribution of acid sulfate soils in this region remains poor. In this study, four sites on the Anglesea River floodplain were sampled, representative of the main vegetation communities. Peat swamps and intertidal marshes were both significant sources of acidity on the floodplain in the lower catchment. However, acid neutralising capacity provided by carbonate sands suggests that there are additional sources of acidity higher in the catchment. This pilot study has highlighted the complexity in the links between the floodplain, upper catchment and waterways with further research required to understand these links for targeted acid management strategies.

  3. Molecular dynamics simulations capture the misfolding of the bovine prion protein at acidic pH.

    Cheng, Chin Jung; Daggett, Valerie

    2014-01-01

    Bovine spongiform encephalopathy (BSE), or mad cow disease, is a fatal neurodegenerative disease that is transmissible to humans and that is currently incurable. BSE is caused by the prion protein (PrP), which adopts two conformers; PrPC is the native innocuous form, which is α-helix rich; and PrPSc is the β-sheet rich misfolded form, which is infectious and forms neurotoxic species. Acidic pH induces the conversion of PrPC to PrPSc. We have performed molecular dynamics simulations of bovine PrP at various pH regimes. An acidic pH environment induced conformational changes that were not observed in neutral pH simulations. Putative misfolded structures, with nonnative β-strands formed in the flexible N-terminal domain, were found in acidic pH simulations. Two distinct pathways were observed for the formation of nonnative β-strands: at low pH, hydrophobic contacts with M129 nucleated the nonnative β-strand; at mid-pH, polar contacts involving Q168 and D178 facilitated the formation of a hairpin at the flexible N-terminus. These mid- and low pH simulations capture the process of nonnative β-strand formation, thereby improving our understanding of how PrPC misfolds into the β-sheet rich PrPSc and how pH factors into the process. PMID:24970211

  4. Molecular Dynamics Simulations Capture the Misfolding of the Bovine Prion Protein at Acidic pH

    Chin Jung Cheng

    2014-02-01

    Full Text Available Bovine spongiform encephalopathy (BSE, or mad cow disease, is a fatal neurodegenerative disease that is transmissible to humans and that is currently incurable. BSE is caused by the prion protein (PrP, which adopts two conformers; PrPC is the native innocuous form, which is α-helix rich; and PrPSc is the β-sheet rich misfolded form, which is infectious and forms neurotoxic species. Acidic pH induces the conversion of PrPC to PrPSc. We have performed molecular dynamics simulations of bovine PrP at various pH regimes. An acidic pH environment induced conformational changes that were not observed in neutral pH simulations. Putative misfolded structures, with nonnative β-strands formed in the flexible N-terminal domain, were found in acidic pH simulations. Two distinct pathways were observed for the formation of nonnative β-strands: at low pH, hydrophobic contacts with M129 nucleated the nonnative β-strand; at mid-pH, polar contacts involving Q168 and D178 facilitated the formation of a hairpin at the flexible N-terminus. These mid- and low pH simulations capture the process of nonnative β-strand formation, thereby improving our understanding of how PrPC misfolds into the β-sheet rich PrPSc and how pH factors into the process.

  5. Soil quality under forest compared to other landuses in acid soil of North Western Himalaya, India

    Sharmistha Pal

    2013-07-01

    Full Text Available A study was conducted to examine the impact of land?use on soil fertility in an Alfisol, at Dharamshala district of north western Himalayan region, India. Soil samples were collected from 0-15, 15-30, 30-45 and 45-60 cm soil depths of five land-uses viz. natural forest of Pinus roxburghii, grassland, horticulture, agriculture and wasteland. Soil was examined for pH, organic carbon (OC, electrical conductivity (EC, cation exchange capacity (CEC, available nitrogen (N, phosphorus (P, exchangeable calcium (Ca, magnesium (Mg, potassium (K, aluminium (Al, microbial biomass carbon (MBC, microbial biomass nitrogen (MBN, microbial biomass phosphorus (MBP, acid phosphatase activity (APHA and dehydrogenase activity (DHA. Soil pH varied from 5.22 in forest and 5.72 in grassland. OC content was higher in forest (3.01%, followed by grassland (2.16% and was least (0.36% in deeper layers of agriculture. Highest N content was found under forest (699, 654, 623 and 597 kg/ha, at 0-15, 15-30, 30-45 and 45-60 cm depth, respectively, followed by grassland, horticulture and agriculture and least in wasteland. Exchangeable Ca and Mg were higher in grassland (0.801 c mol kg-1 and 0.402 c mol kg-1, respectively. Exchangeable K and Al were higher under forest (0.231 c mol kg-1 and 1.89 c mol kg-1, respectively least in wasteland. Soil biological properties were highest under surface soil of forest (576 mg kg-1, 31.24 mg kg-1, 6.55 mg kg-1, 29.6 mg PNP g-1h-1 and 35.65 ľg TPF 24 h-1 g-1 dry soil, respectively for MBC, MBN, MBP, APHA and DHA and least in 45-60 cm layer, under wasteland. The forest had a higher fertility index and soil evaluation factor followed by grassland, horticulture, agriculture as compared to wasteland. 

  6. Remediation of metal/organic contaminated soils by combined acid extraction and surfactant washing

    Van Benschoten, J.E.; Ryan, M.E.; Huang, C.; Healy, T.C.; Brandl, P.J. [State Univ. of New York, Buffalo, NY (United States)

    1995-12-31

    The specific objectives of this research are to: (1) determine the solubilization of two polycyclic aromatic compounds (PAHs) (naphthalene and pyrene) using several surfactants at low pH conditions; (2) determine the losses of candidate surfactants due to precipitation or adsorption to a test soil as a function of pH; and (3) evaluate the performance of surfactants under acidic conditions for removal of lead and PAH compounds from a contaminated soil. In this paper, experimental results related to the first two objectives are presented.

  7. Fitting maize into sustainable cropping systems on acid soils of the tropics

    techniques for acid soil tolerance. There is a need to better characterise these properties on a molecular basis and to systematically select for them. Incorporation of soil acidity tolerant plant species and cultivars into cropping systems contribute to improved nutrient efficiency of the overall system and thus reduce fertilizer needs. The application of nuclear techniques could contribute to facilitate and enhance scientific progress especially in the following areas: - Quantification of morphological root characteristics and rooting patterns. - Studying water-use efficiency as affected by soil acidity and plant adaptation. - Establishment of carbon and nitrogen budgets of cropping systems as affected by soil pH and crop management. - Quantification of the soil/fertilizer P mobilisation capacity of crops and cropping systems. - Molecular characterisation of plant adaptation-mechanisms. (author)

  8. Multitracer studies on the effects of model acid rain on the adsorption of trace elements on soils

    Using a multitracer technique, the effects of acid rain pH on the adsorption of 15 trace elements on soil were studied. Kaolin, forest soil (original and with partially removed oxides), black soil (original and without organic matter) and Kureha soil (original, with partially removed oxides, and without organic matter) were employed as the adsorbents. Instead of H2SO4 solution, HCl solution was selected as the model acid rain based on the results of adsorption experiments on kaolin. In general, the percentage adsorption of cationic elements on three original soils and kaolin increased with increasing pH. The adsorption of oxyanionic elements, As and Se, on three soils was high over the entire pH range studied, while that on kaolin was low and decreased with an increase in pH. The differences in the physical and chemical properties of soils were reflected on the adsorption. The organic matter in soil had positive effects on the extent of adsorption of most elements studied, while the oxides apparently showed positive effects only for Fe and Se adsorption. The results indicate that acid rain decreases the retention of cations in soil and that it increases or does not change the adsorption of anions. (orig.)

  9. Using a toxicokinetics approach to explain the effect of soil pH on cadmium bioavailability to Folsomia candida

    The aim of this study was to improve our understanding of metal bioavailability in soil by linking the biotic ligand approach with toxicokinetics modelling. We determined cadmium bioaccumulation kinetics in Folsomia candida (Collembola) as a function of soil pH. Animals were exposed for 21 days to LUFA 2.2 soil at 5 or 20 μg Cd g−1 dry soil followed by 21 days elimination in clean soil. Internal cadmium concentrations were modelled using a first-order one-compartment model, relating uptake rate constants (k1) to total soil, water or 0.01 M CaCl2 extractable and porewater concentrations. Based on total soil concentrations, k1 was independent of soil pH while it strongly increased with increasing pH based on porewater concentrations explaining the reduced competition of H+ ions making cadmium more bioavailable in pore water at high pH. This shows that the principles of biotic ligand modelling are applicable to predict cadmium accumulation kinetics in soil-living invertebrates. -- Highlights: •Cadmium uptake and elimination in Folsomia candida were investigated. •Animals were exposed to LUFA 2.2 soil at different pH levels. •Langmuir isotherms were used to describe interaction of Ca and protons with Cd. •pH was the main factor affecting Cd toxicokinetics when pore water was considered. -- Integrating bioaccumulation kinetics with a BLM approach provides novel insights into the bioavailability of cadmium to springtails in soil

  10. Improving the efficiency of rock phosphate on high pH soils: Results from participatory research in India

    Andres, Christian; Mandloi, Lokendra S.; Verma, Rajeev; Gomez, Sara; Nyffenegger, Mirjam R.; Locher, Michael; Patel, Dharmendra; Forster, Dionys; Bhullar, Gurbir S; Studer, Christoph

    2014-01-01

    High soil pH levels may limit the availability of phosphorous (P) to crops. In organic farming, the use of synthetic P fertilizers is not allowed. Application of rock phosphate (RP) to crops is one of the alternatives for organic production. However, RP application shows little effect on high pH soils, because the P is not transformed into plant-available forms under alkaline soil conditions. Aiming at the development of locally adapted solutions, we followed a Participatory Technology Dev...

  11. Soil acidity and mobile aluminum status in pseudogley soils in Čačak-Kraljevo basin

    Đalović Ivica G.

    2012-01-01

    Full Text Available Soil acidity and aluminum toxicity are considered most damaging soil conditions affecting the growth of most crops. This paper reviews the results of tests of pH, exchangeable acidity and mobile aluminum (Al concentration in profiles of pseudogley soils from Čačak-Kraljevo basin. For that purpose, 102 soil pits were dug in 2009 in several sites around Čačak- Kraljevo basin. The tests encompassed 54 field, 28 meadow, and 20 forest soil samples. Samples of soil in the disturbed state were taken from the Ah and Eg horizons (102 samples, from the B1tg horizon in 39 field, 24 meadow and 15 forest pits (a total of 78 samples and from the B2tg horizon in 14 field, 11 meadow, and 4 forest pits (a total of 29 samples. Mean pH values (1M KCl of the tested soil profiles were 4.28, 3.90 and 3.80 for the Ah, Eg and B1tg horizons, respectively. Soil pH of forest samples was lower than those in meadow and arable land samples (mean values of 4.06, 3.97 and 3.85 for arable land, meadow and forest samples, respectively. Soil acidification was especially intensive in deep horizons, as 27% (Ah, 77% (Eg and 87% (B1tg soil samples had the pH value below 4.0. Mean values of total exchangeable acidity (TEA were 1.55, 2.33 and 3.40 meq 100 g-1 for the Ah, Eg and B1tg horizons, respectively. The TEA values in forest soils were considerably higher (3.39 meq 100 g-1 than those in arable soils and meadow soils (1.96 and 1.93, respectively. Mean mobile Al contents of tested soil samples were 11.02, 19.58 and 28.33 mg Al 100 g-1 for the Ah, Eg and B1tg horizons, respectively. According to the pH and TEA values, mobile Al was considerably higher in the forest soils (the mean value of 26.08 mg Al 100 g-1 than in the arable soils and meadow soils (the mean values of 16.85 and 16.00 mg Al 100 g-1, respectively. The Eg and B1tg horizons of the forest soil had especially high mobile Al contents (the mean values of 28.50 and 32.95 mg Al 100 g-1, respectively. High levels of

  12. Crop uptake and extractability of cadmium in soils naturally high in metals at different pH levels

    Singh, B.R.; Almas, A.; Narwal, R.P. [Haryana Agric. Univ., Hisar (India); Jeng, A.S.

    1995-12-01

    A greenhouse experiment was conducted for three years to study the effect of different pH levels on metal concentrations in plants and the cadmium (Cd) extractability by DTPA and NH{sub 4}NO{sub 3}. The soils used were an alum shale (clay loam) and a moraine (loam), which were adjusted to pH levels of 5.5, 6.5, 7.0, and 7.5. Wheat (Triticum aestivum), carrot (Daucus carota L.), and lettuce (Lactuca sativa) were grown as test crops. Crop yields were not consistently affected at increasing soil pH levels. The concentration of Cd in plant species decreased with increasing soil pH in both soils and in all three years. Significant concentration differences between soil pH levels were only seen in wheat and carrot crops. Increasing soil pH also decreased the nickel (Ni) and zinc (Zn) concentrations in plants in the first year crop but the copper (Cu) concentration was not consistently affected by soil pH. The effect of pH was more pronounced in the moraine then the alum shale soil. The DTPA-and NH{sub 4}NO{sub 3}-extractable Cd was decreased with the increasing soil pH and the pH effect was more pronounced with NH{sub 4}NO{sub 3} extractable Cd. Both extractants were found equally effective in relation to the Cd concentration in plants in this study. 33 refs., 2 figs., 7 tabs.

  13. Photoproduction of glyoxylic acid in model wine: Impact of sulfur dioxide, caffeic acid, pH and temperature.

    Grant-Preece, Paris; Schmidtke, Leigh M; Barril, Celia; Clark, Andrew C

    2017-01-15

    Glyoxylic acid is a tartaric acid degradation product formed in model wine solutions containing iron and its production is greatly increased by exposure to UV-visible light. In this study, the combined effect of sulfur dioxide, caffeic acid, pH and temperature on the light-induced (⩾300nm) production of glyoxylic acid in model wine containing tartaric acid and iron was investigated using a Box-Behnken experimental design and response surface methodology (RSM). Glyoxylic acid produced in the irradiated model wine was present in free and hydrogen sulfite adduct forms and the measured total, free and percentage free glyoxylic acid values were modeled using RSM. Sulfur dioxide significantly decreased the total amount of glyoxylic acid produced, but could not prevent its production, while caffeic acid showed no significant impact. The interaction between pH and temperature was significant, with low pH values and low temperatures giving rise to higher levels of total glyoxylic acid. PMID:27542478

  14. Distribution and elevated soil pools of mercury in an acidic subtropical forest of southwestern China

    Tieshanping catchment in southwest China was supposed to a large pool of atmospheric mercury. This work was aimed to examine THg (total mercury) concentrations, pools and influence factors in the acidic forest. THg concentrations were highly elevated in the study area, which was significantly depended on TOM (total organic matter) concentrations and altitudinal elevation, whereas negatively correlated with soil pH. The pools of mercury accumulated in soils were correlated strongly with the stocks of TOM and altitude, ranged from 5.9 to 32 mg m−2 and averaged 14.5 mg m−2, indicating that the acidic forest was a great sink of atmospheric mercury in southwest China. THg concentrations in stream waters decreased with altitude increasing and regression analyses showed that soil/air exchange flux would be increased with the decrease of altitude. Present results suggest that elevation increasing decreases THg losses as low THg concentrations in runoffs and volatilization from soils. - Highlights: • Soil THg pools and influence factors were studied at an acidic catchment in southwestern China. • THg concentrations was increased significantly with TOM concentrations and altitude increasing, decreased with pH. • THg pools in soils were highly elevated and deepened on TOM pools and altitude. • Difference in THg output by volatilization and runoff was a major reason for THg distribution at different altitudes. - Mercury pools increased with altitude increasing as mercury lost more at low elevation area in acidic subtropical forest

  15. Bromine accumulation in acidic black colluvial soils

    Cortizas, Antonio Martínez; Vázquez, Cruz Ferro; Kaal, Joeri; Biester, Harald; Casais, Manuela Costa; Rodríguez, Teresa Taboada; Lado, Luis Rodríguez

    2016-02-01

    Recent investigations showed that bromine is incorporated to soil organic matter (SOM), its content increasing with humification. But few research was done on its long-term accumulation and the role played by pedogenetic processes, as those involved in organic matter stabilization. We investigated bromine content and distribution in four deep, acidic, organic-rich, Holocene soils from an oceanic area of Western Europe. Bromine concentrations (93-778 μg g-1) in the silt + clay (area, and total estimated retention was low (6-16%). The degree of SOM bromination, expressed as the Br/C molar ratio, varied between 0.03 and 1.20 mmol Br/mol C. The ratio was highly correlated (n = 23, r2 0.88, p pool of metal-clay-stabilized organic matter.

  16. H-binding groups in lignite vs. soil humic acids: NICA-Donnan and spectroscopic parameters.

    Drosos, Marios; Jerzykiewicz, Maria; Deligiannakis, Yiannis

    2009-04-01

    A comparative study has been carried out for two sets of humic acids isolated from lignites and soils. H-binding data were analyzed using the NICA-Donnan model, for three Greek lignite humic acids (HA) plus IHSS Leonardite reference HA, and five Greek soil HAs plus a commercial peat HA. (13)C-CP-MAS NMR and H-binding data provide quantitative estimates for functional groups, showing that lignite HAs of diverse origin have strikingly homogeneous properties, while the H-binding structural units of soil HAs are characterized by a large degree of variability. Consistent differences between soil HA vs. lignite HA are revealed at the level of functional groups' concentrations. In the pH range 4 to 10, soil HA showed a charge variation 3.5 [equiv kg(-1)]. PMID:19144349

  17. Removal of radium-226 from radium-contaminated soil using humic acid by column leaching method

    In this study, evaluation of radium-226 removal from radium-contaminated soil using humic acid extracted from peat soil by column leaching method was carried out. Humic acid of concentration 100 ppm and pH 7 was leached through a column packed with radium-contaminated soil and leachates collected were analysed with gamma spectrometer to determine the leached radium-226. Results obtained indicated low removal of radium-226 between 1 - 4 %. Meanwhile, leaching profile revealed that radium-226 was bound to soil components with three different strength, thus resulting in three phases of radium-226 removal. It was estimated that the total removal of radium-226 from 10 g radium-contaminated soil sample studied could be achieved using approximately 31500 - 31850 ml HA solutions with leaching rate of 1 ml/ min. (author)

  18. Humic Acid Complexation of Th, Hf and Zr in Ligand Competition Experiments: Metal Loading and Ph Effects

    Stern, Jennifer C.; Foustoukos, Dionysis I.; Sonke, Jeroen E.; Salters, Vincent J. M.

    2014-01-01

    The mobility of metals in soils and subsurface aquifers is strongly affected by sorption and complexation with dissolved organic matter, oxyhydroxides, clay minerals, and inorganic ligands. Humic substances (HS) are organic macromolecules with functional groups that have a strong affinity for binding metals, such as actinides. Thorium, often studied as an analog for tetravalent actinides, has also been shown to strongly associate with dissolved and colloidal HS in natural waters. The effects of HS on the mobilization dynamics of actinides are of particular interest in risk assessment of nuclear waste repositories. Here, we present conditional equilibrium binding constants (Kc, MHA) of thorium, hafnium, and zirconium-humic acid complexes from ligand competition experiments using capillary electrophoresis coupled with ICP-MS (CE- ICP-MS). Equilibrium dialysis ligand exchange (EDLE) experiments using size exclusion via a 1000 Damembrane were also performed to validate the CE-ICP-MS analysis. Experiments were performed at pH 3.5-7 with solutions containing one tetravalent metal (Th, Hf, or Zr), Elliot soil humic acid (EHA) or Pahokee peat humic acid (PHA), and EDTA. CE-ICP-MS and EDLE experiments yielded nearly identical binding constants for the metal- humic acid complexes, indicating that both methods are appropriate for examining metal speciation at conditions lower than neutral pH. We find that tetravalent metals form strong complexes with humic acids, with Kc, MHA several orders of magnitude above REE-humic complexes. Experiments were conducted at a range of dissolved HA concentrations to examine the effect of [HA]/[Th] molar ratio on Kc, MHA. At low metal loading conditions (i.e. elevated [HA]/[Th] ratios) the ThHA binding constant reached values that were not affected by the relative abundance of humic acid and thorium. The importance of [HA]/[Th] molar ratios on constraining the equilibrium of MHA complexation is apparent when our estimated Kc, MHA values

  19. pH : a key control of the nature and distribution of dissolved organic matter and associated trace metals in soil

    Pédrot, M.; Dia, A.; Davranche, M.

    2009-04-01

    Dissolved organic matter is ubiquitous at the Earth's surface and plays a prominent role in controlling metal speciation and mobility from soils to hydrosystems. Humic substances (HS) are usually considered to be the most reactive fraction of organic matter. Humic substances are relatively small and formed by chemically diverse organic molecules, bearing different functional groups that act as binding sites for cations and mineral surfaces. Among the different environmental physicochemical parameters controlling the metal speciation, pH is likely to be the most important one. Indeed, pH affect the dissociation of functional groups, and thus can influence the HS structure, their ability to complex metals, their solubility degree allowing the formation of aggregates at the mineral surface. In this context, soil/water interactions conducted through batch system experiments, were carried out with a wetland organic-rich soil to investigate the effect of pH on the release of dissolved organic carbon (DOC) and associated trace elements. The pH was regulated between 4 and 7.5 using an automatic pH stat titrator. Ultrafiltration experiments were performed to separate the dissolved organic pool following decreasing pore sizes (30 kDa, 5 kDa and 2 kDa with 1 Da = 1 g.mol-1). The pH increase induced a significant DOC release, especially in heavy organic molecules (size >5 kDa) with a high aromaticity (>30 %). These were probably humic acids (HA). This HA release influenced (i) directly the trace element concentrations in soil solution since HA were enriched in several trace elements such as Th, REE, Y, U, Cr and Cu; and (ii) indirectly by the breaking of clay-humic complexes releasing Fe- and Al-rich nanoparticles associated with V, Pb and Ti. By contrast, at acid pH, most HS were complexed onto mineral surfaces. They also sequestered iron nanoparticles. Therefore, at low pH, most part of DOC molecules had a size heavy organic molecules considered to be flexible linear

  20. The time course of the transcriptomic response of Sinorhizobium meliloti 1021 following a shift to acidic pH

    Pühler Alfred

    2009-02-01

    Full Text Available Abstract Background The symbiotic soil bacterium Sinorhizobium meliloti often has to face low pH in its natural habitats. To identify genes responding to pH stress a global transcriptional analysis of S. meliloti strain 1021 following a pH shift from pH 7.0 to pH 5.75 was carried out. In detail, oligo-based whole genome microarrays were used in a time course experiment. The monitoring period covered a time span of about one hour after the pH shift. The obtained microarray data was filtered and grouped by K-means clustering in order to obtain groups of genes behaving similarly concerning their expression levels throughout the time course. Results The results display a versatile response of S. meliloti 1021 represented by distinct expression profiles of subsets of genes with functional relation. The eight generated clusters could be subdivided into a group of four clusters containing genes that were up-regulated and another group of four clusters containing genes that were down-regulated in response to the acidic pH shift. The respective mean expression progression of the four up-regulated clusters could be described as (i permanently and strong, (ii permanently and intermediate, (iii permanently and progressive, and (iv transiently up-regulated. The expression profile of the four down-regulated clusters could be characterized as (i permanently, (ii permanently and progressive, (iii transiently, and (iv ultra short down-regulated. Genes coding for proteins with functional relation were mostly cumulated in the same cluster, pointing to a characteristic expression profile for distinct cellular functions. Among the strongest up-regulated genes lpiA, degP1, cah, exoV and exoH were found. The most striking functional groups responding to the shift to acidic pH were genes of the exopolysaccharide I biosynthesis as well as flagellar and chemotaxis genes. While the genes of the exopolysaccharide I biosynthesis (exoY, exoQ, exoW, exoV, exoT, exoH, exoK exo

  1. Cadmium and Zn availability as affected by pH manipulation and its assessment by soil extraction, DGT and indicator plants

    Manipulation of soil pH by soil additives and / or rhizosphere processes may enhance the efficiency of metal phytoextraction. Here we report on the effect of nitric acid additions to four polluted soils on Cd and Zn concentrations in soil solution (Csoln) and 0.005 M Ca(NO3)2 extracts, and related changes in the diffusive fluxes and resupply of the metals as assessed by diffusive gradients in thin films (DGT). The responses of these chemical indicators of bioavailability were compared to metal uptake in two indicator plant species, common dandelion (Taraxacum officinale F.H. Wigg) and narrow leaf plantain (Plantago lanceolata L.) grown for 75 days in a pot experiment. Lowering soil pH increased Csoln, the 0.005 M Ca(NO3)2-soluble fractions and the DGT-measured Cd and Zn concentrations (CDGT) in the experimental soils. This was associated with enhanced uptake of Cd and Zn on soils acidified to pH 4.5 whereas plants did not survive at pH 3.5. Toxicity along with decreased kinetics of metal resupply (calculated by the 2D DIFS model) in the strong acidification treatment suggests that moderate acidification is more appropriate to enhance the phytoextraction process. Each of the chemical indicators of bioavailability predicted well (R2 > 0.70) the Cd and Zn concentrations in plantain shoots but due to metal toxicity not for dandelion. Concentration factors, i.e. the ratio between metal concentrations in shoots and in soil solution (CF) indicate that Cd and Zn uptake in plantain was not limited by diffusion which may explain that DGT did not perform better than Csoln. However, DGT is expected to predict plant uptake better in diffusion-limited conditions such as in the rhizosphere of metal-accumulating phytoextraction crops. - Highlights: ► The effect of soil acidification was assessed for four Zn and Cd polluted soils. ► For some soils moderate acidification could enhance the metal uptake efficiency. ► Chemical assessment of bioavailability using soil solution and

  2. Cadmium and Zn availability as affected by pH manipulation and its assessment by soil extraction, DGT and indicator plants

    Muhammad, Iqbal; Puschenreiter, Markus, E-mail: markus.puschenreiter@boku.ac.at; Wenzel, Walter W.

    2012-02-01

    Manipulation of soil pH by soil additives and / or rhizosphere processes may enhance the efficiency of metal phytoextraction. Here we report on the effect of nitric acid additions to four polluted soils on Cd and Zn concentrations in soil solution (C{sub soln}) and 0.005 M Ca(NO{sub 3}){sub 2} extracts, and related changes in the diffusive fluxes and resupply of the metals as assessed by diffusive gradients in thin films (DGT). The responses of these chemical indicators of bioavailability were compared to metal uptake in two indicator plant species, common dandelion (Taraxacum officinale F.H. Wigg) and narrow leaf plantain (Plantago lanceolata L.) grown for 75 days in a pot experiment. Lowering soil pH increased C{sub soln}, the 0.005 M Ca(NO{sub 3}){sub 2}-soluble fractions and the DGT-measured Cd and Zn concentrations (C{sub DGT}) in the experimental soils. This was associated with enhanced uptake of Cd and Zn on soils acidified to pH 4.5 whereas plants did not survive at pH 3.5. Toxicity along with decreased kinetics of metal resupply (calculated by the 2D DIFS model) in the strong acidification treatment suggests that moderate acidification is more appropriate to enhance the phytoextraction process. Each of the chemical indicators of bioavailability predicted well (R{sup 2} > 0.70) the Cd and Zn concentrations in plantain shoots but due to metal toxicity not for dandelion. Concentration factors, i.e. the ratio between metal concentrations in shoots and in soil solution (CF) indicate that Cd and Zn uptake in plantain was not limited by diffusion which may explain that DGT did not perform better than C{sub soln}. However, DGT is expected to predict plant uptake better in diffusion-limited conditions such as in the rhizosphere of metal-accumulating phytoextraction crops. - Highlights: Black-Right-Pointing-Pointer The effect of soil acidification was assessed for four Zn and Cd polluted soils. Black-Right-Pointing-Pointer For some soils moderate acidification could

  3. Short-column anion-exchange chromatography for soil and peat humic substances profiling by step-wise gradient of high pH aqueous sodium ethylenediaminetetraacetate.

    Hutta, Milan; Ráczová, Janka; Góra, Róbert; Pessl, Juraj

    2015-08-21

    Novel anion-exchange liquid chromatographic method with step gradient of aqueous EDTA(4-) based mobile phase elution has been developed to profile available Slovak soil humic substances and alkaline extracts of various soils. The method utilize short glass column (30mm×3mm) filled in with hydrolytically stable particles (60μm diameter) Separon HEMA-BIO 1000 having (diethylamino)ethyl functional groups. Step gradient was programmed by mixing mobile phase composed of aqueous solution of sodium EDTA (pH 12.0; 5mmolL(-1)) and mobile phase constituted of aqueous solution of sodium EDTA (pH 12.0, 500mmolL(-1)). The FLD of HSs was set to excitation wavelength 480nm and emission wavelength 530nm (λem). Separation mechanism was studied by use of selected aromatic acids related to humic acids with the aid of UV spectrophotometric detection at 280nm. The proposed method benefits from high ionic strength (I=5molL(-1)) of the end mobile phase buffer and provides high recovery of humic acids (98%). Accurate and reproducible profiling of studied humic substances, alkaline extracts of various types of soils enables straightforward characterization and differentiation of HSs in arable and forest soils. Selected model aromatic acids were used for separation mechanism elucidation. PMID:26143606

  4. Effect of reactive substrates used for the removal of phosphorus from wastewater on the fertility of acid soils.

    Cucarella, Victor; Zaleski, Tomasz; Mazurek, Ryszard; Renman, Gunno

    2008-07-01

    Reactive substrates used in filter systems can reduce phosphorus (P) pollution and, once saturated with P, may be recycled in agriculture. These substrates are usually calcium carbonate derivates with high pH values, which may be particularly beneficial for acid soils. Three reactive substrates (Filtra P, Polonite and wollastonite) saturated with P were used as amendments to an acid soil in a pot experiment. Substrate amendments tended to improve ryegrass yield and P uptake compared with control and potassium phosphate treatments. Polonite produced the highest yield/amendment ratio, while Polonite and Filtra P significantly increased the concentrations of P and Ca in the ryegrass. Addition of all three substrates increased the pH, AL-extractable P and cation exchange capacity of soils during the experiment. These substrates can therefore be applied to acid soils in order to recycle P and improve soil properties. PMID:17920265

  5. Composition of exchangeable bases and acidity in soils of the Crimean Mountains

    Kostenko, I. V.

    2015-08-01

    Acid forest and mountainous meadow soils of the Crimean Mountains were studied. The amount of hydrogen and aluminum ions extracted from these soils depended on the pH of extracting agents. The maximum values of the soil acidity were obtained upon the extraction with a strongly alkaline solution of sodium acetate in 0.05 N NaOH. The application of this extractant made it possible to determine the total exchange acidity, the total amount of extractable aluminum, and the total cation exchange capacity of the soils after the extraction of all the acidic components from them. The values of these characteristics were significantly higher than the values of the potential acidity and cation exchange capacity obtained by the routine analytical methods. Hydrogen predominated among the acidic components of the exchange acidity in the humus horizons, whereas aluminum predominated among them in the underlying mineral horizons. Hydrothermic conditions and the character of vegetation and parent materials were the major factors affecting the relationships between bases and acidic components in the soil adsorption complex.

  6. The treatments of soil Rirang by floatation and Acid leaching

    The treatments of soil Rirang by floatation and acid leaching has been carried out to increase high uranium concentrates of materials, separating associated economical minerals and to reduce the gangue minerals which bothering at chemical processing. The physical treatment has been done by ore preparation and floatation using oleic acid and pine oil, 20 % of pulp at pH 9, condition time at 5 minutes and collections of float fraction was 10 minutes. The chemical processing has been done by dynamic leaching using H2SO4 100 kg/ton, MnO2 20 kg/ton, 50 % of solid with ore size - 65 mesh, temperature at 80 oC and time of leaching was 8 hours. The result of experiments is as follows : Physical treatment by floatation shown that the concentrates of U increased at sink fraction by (1.5 - 2) times against feed sample for all the samples, and in the float fraction the recovery of molybdenite separation is 58 - 81 % and rare earths is 57 - 80 %. The result of dynamic leaching is 76 - 91 %, and recovery uranium increasing from 81.02 % (mixture samples soil before floatation) to 91.16 % ( mixture samples of float fraction)

  7. Dolomite application to acidic soils: a promising option for mitigating N2O emissions.

    Shaaban, Muhammad; Peng, Qi-An; Hu, Ronggui; Wu, Yupeng; Lin, Shan; Zhao, Jinsong

    2015-12-01

    Soil acidification is one of the main problems to crop productivity as well as a potent source of atmospheric nitrous oxide (N2O). Liming practice is usually performed for the amelioration of acidic soils, but the effects of dolomite application on N2O emissions from acidic soils are still not well understood. Therefore, a laboratory study was conducted to examine N2O emissions from an acidic soil following application of dolomite. Dolomite was applied to acidic soil in a factorial design under different levels of moisture and nitrogen (N) fertilizer. Treatments were as follows: dolomite was applied as 0, 1, and 2 g kg(-1) soil (named as CK, L, and H, respectively) under two levels of moisture [i.e., 55 and 90 % water-filled pore space (WFPS)]. All treatments of dolomite and moisture were further amended with 0 and 200 mg N kg(-1) soil as (NH4)2SO4. Soil properties such as soil pH, mineral N (NH4 (+)-N and NO3 (-)-N), microbial biomass carbon (MBC), dissolved organic carbon (DOC), and soil N2O emissions were analyzed throughout the study period. Application of N fertilizer rapidly increased soil N2O emissions and peaked at 0.59 μg N2O-N kg(-1) h(-1) under 90 % WFPS without dolomite application. The highest cumulative N2O flux was 246.32 μg N2O-N kg(-1) under 90 % WFPS without dolomite addition in fertilized soil. Addition of dolomite significantly (p ≤ 0.01) mitigated N2O emissions as soil pH increased, and H treatment was more effective for mitigating N2O emissions as compared to L treatment. The H treatment decreased the cumulative N2O emissions by up to 73 and 67 % under 55 and 90 % WFPS, respectively, in fertilized soil, and 60 and 68 % under 55 and 90 % WFPS, respectively, in unfertilized soil when compared to those without dolomite addition. Results demonstrated that application of dolomite to acidic soils is a promising option for mitigating N2O emissions. PMID:26289338

  8. Fractionation of Moderately and Highly Stable Organic Phosphorus in Acid Soil

    FANYEKUAN; LISHIJUN

    1998-01-01

    The fractionation of moderately and highly organic phosphorus(Po) in acid soil was studied by two methods .By the first method,after incubation for 40 d; the mineralization rates of eight constituents of stable Po in the soil were determined.By the second method ,five constituents of peecipitates of stable Po in the soil were separated,then the five precipiates were put back into the original soils and incubated for 40 d and 60 d .Then,mineralization rates of the five precipitates were determined.The same results were obtained by the two methods.When the pH of the alkali solution containing stable Po was adjusted from 3.00 to 3.10,the mineralization rate of moderately stable Po Was rapidly raised.Therefore,the pH 3.00 is the critical point between moderately and highly stable Po.

  9. Soil organic matter and soil acidity in Mangrove areas in the river Paraiba Estuary, Cabedelo, Paraiba, Brazil

    Renata Wilma Vasconcelos

    2014-08-01

    Full Text Available Mangrove ecosystems are of great environmental significance, because of their fragility and role in feeding and breeding various animal species. In northeastern Brazil, the disorderly occupation of estuarine areas and the urban sprawl have led to a considerable loss of the original area occupied by mangroves. In the municipality of Cabedelo, State of Paraíba, there are about 4,900 ha of remnant mangrove areas in the estuarine complex of the Paraíba River. However, information about the attributes of mangrove soils at this location is quite scarce. The aim of this study was to quantify the soil organic matter and soil acidity in mangroves located in the estuary of the Paraíba River, State of Paraíba, Brazil, in order to increase the database of soil attributes in this region. The study area is in local influence of the Restinga de Cabedelo National Forest (Flona, an environmental conservation unit of the Chico Mendes Institute for Biodiversity Conservation. For the choice of sampling points, we considered an area that receives direct influence of the eviction of domestic and industrial effluents. The soil of the study area is an “Organossolo Háplico” in Brazilian Soil Classification (Histosol, and was sampled at four point sites: one upstream of the effluent discharge (P1, one in the watercourse receiving effluent water (P2, one downstream of the effluent discharge (P3 and another near Flona (P4, at 0-20 and 20-40 cm, in four replications in time (28/08/2012 in the morning and afternoon, and 21/01/2013 in the morning and afternoon. Potential acidity, pH and soil organic matter (SOM were determined. No significant differences were detected in the potential acidity of the four collection sites, which ranged from 0.38 to 0.45 cmolc dm-3. Soil pH was greatest at point P4 (7.0 and lowest at point P1 (5.8. The SOM was highest at point P1 (86.4 % and lowest at P2 (77.9 %. The attributes related to soil acidity were not sensitive to indicate

  10. Early indications of soil recovery from acidic deposition in U.S. red spruce forests

    Lawrence, Gregory B.; Shortle, Walter C.; David, Mark B.; Smith, Kevin T.; Warby, Richard A.F.; Lapenis, Andrei G.

    2012-01-01

    Forty to fifty percent decreases in acidic deposition through the 1980s and 1990s led to partial recovery of acidified surface waters in the northeastern United States; however, the limited number of studies that have assessed soil change found increased soil acidification during this period. From existing data, it's not clear whether soils continued to worsen in the 1990s or if recovery had begun. To evaluate possible changes in soils through the 1990s, soils in six red spruce (Picea rubens Sarg.) stands in New York, Vermont, New Hampshire, and Maine, first sampled in 1992 to 1993, were resampled in 2003 to 2004. The Oa-horizon pH increased (P 42−, which decreased the mobility of Al throughout the upper soil profile. Results indicate a nascent recovery driven largely by vegetation processes.