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Sample records for adjusting soil ph

  1. Growth and Cadmium Phytoextraction by Swiss Chard, Maize, Rice, Noccaea caerulescens, and Alyssum murale in Ph Adjusted Biosolids Amended Soils.

    PubMed

    Broadhurst, C Leigh; Chaney, Rufus L; Davis, Allen P; Cox, Albert; Kumar, Kuldip; Reeves, Roger D; Green, Carrie E

    2015-01-01

    Past applications of biosolids to soils at some locations added higher Cd levels than presently permitted. Cadmium phytoextraction would alleviate current land use constraints. Unamended farm soil, and biosolids amended farm and mine soils were obtained from a Fulton Co., IL biosolids management facility. Soils contained 0.16, 22.8, 45.3 mg Cd kg(-1) and 43.1, 482, 812 mg Zn kg(-1) respectively with initial pH 6.0, 6.1, 6.4. In greenhouse studies, Swiss chard (Beta vulgaris var. cicla), a Cd-accumulator maize (inbred B37 Zea mays) and a southern France Cd-hyperaccumulator genotype of Noccaea caerulescens were tested for Cd accumulation and phytoextraction. Soil pH was adjusted from ∼5.5-7.0. Additionally 100 rice (Oryza sativa) genotypes and the Ni-hyperaccumulator Alyssum murale were screened for potential phytoextraction use. Chard suffered phytotoxicity at low pH and accumulated up to 90 mg Cd kg(-1) on the biosolids amended mine soil. The maize inbred accumulated up to 45 mg Cd kg(-1) with only mild phytotoxicity symptoms during early growth at pH>6.0. N. caerulescens did not exhibit phytotoxicity symptoms at any pH, and accumulated up to 235 mg Cd kg(-1) in 3 months. Reharvested N. caerulescens accumulated up to 900 mg Cd kg(-1) after 10 months. Neither Alyssum nor 90% of rice genotypes survived acceptably. Both N. caerulescens and B37 maize show promise for Cd phytoextraction in IL and require field evaluation; both plants could be utilized for nearly continuous Cd removal. Other maize inbreds may offer higher Cd phytoextraction at lower pH, and mono-cross hybrids higher shoot biomass yields. Further, maize grown only for biomass Cd maximum removal could be double-cropped. PMID:25174422

  2. Biochar's effect on soil nitrous oxide emissions from a maize field with lime-adjusted pH treatment

    NASA Astrophysics Data System (ADS)

    Hüppi, R.; Felber, R.; Neftel, A.; Six, J.; Leifeld, J.

    2015-07-01

    Biochar, a carbon-rich, porous pyrolysis product of organic residues may positively affect plant yield and can, owing to its inherent stability, promote soil carbon sequestration when amended to agricultural soils. Another possible effect of biochar is the reduction in emissions of nitrous oxide (N2O). A number of laboratory incubations have shown significantly reduced N2O emissions from soil when mixed with biochar. Emission measurements under field conditions however are more scarce and show weaker or no reductions, or even increases in N2O emissions. One of the hypothesized mechanisms for reduced N2O emissions from soil is owing to the increase in soil pH following the application of alkaline biochar. To test the effect of biochar on N2O emissions in a temperate maize system, we set up a field trial with a 20 t ha-1 biochar treatment, a limestone treatment adjusted to the same pH as the biochar treatment, and a control treatment without any addition. An automated static chamber system measured N2O emissions for each replicate plot (n = 3) every 3.6 h over the course of 8 months. The field was conventionally fertilised at a rate of 160 kg-N ha-1 in 3 applications of 40, 80 and 40 kg-N ha-1. Cumulative N2O emissions were 53 % smaller in the biochar compared to the control treatment. However, the effect of the treatments overall was not statistically significant (p = 0.26) because of the large variability in the dataset. Limed soils emitted similar mean cumulative amounts of N2O as the control. This indicates that the observed N2O reduction effect of biochar was not caused by a pH effect.

  3. Biochar's effect on soil nitrous oxide emissions from a maize field with lime adjusted pH treatment

    NASA Astrophysics Data System (ADS)

    Hüppi, Roman; Leifeld, Jens; Felber, Raphael; Neftel, Albrecht; Six, Johan

    2015-04-01

    Biochar is a carbon-rich, porous product from pyrolysis of organic residues. Especially tropical soils have shown positive response in yield to biochar addition. Its high stability in soil makes biochar a potent carbon sequestration option at the same time. A number of laboratory incubations have shown significantly reduced nitrous oxide (N2O) emissions from soil when mixed with biochar. Emission measurements from the field show the same trend but are much more scarce. One of the hypothesized mechanisms for reduced N2O emissions from soil is owing to the increase in soil pH from the application of alkaline biochar. To test the effect of biochar on N2O emissions from a temperate maize system, we set up a field trial with a 20 t/ha biochar treatment, a limestone treatment adjusted to the same pH as with biochar and a control without addition. An automated static chamber greenhouse gas measurement system measured N2O emissions for each replicated (n=3) every 3.6 hours. The field was conventionally fertilised at a rate of 160 kg-N/ha in 3 doses of 40, 80 and 40 kg-N/ha. Cumulative emissions show a significant reduction for N2O in the biochar treatment by about 55 % relative to the control. The limed treatment shows similar emissions than control but with higher variability. This suggests that the N2O reduction effect of biochar is not mainly due to its liming effect. In conclusion, we confirm that biochar is a promising material to reduce N2O emissions from intensively managed agricultural soils.

  4. Growth and cadmium uptake of Swiss chard, Thlaspi caerulescens and corn in pH adjusted biosolids amended soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Before regulations were established, some biosolids applications added higher Cd levels than presently permitted. Cadmium phytoextraction from such soils would alleviate constraints on land use. Unamended farm soil, and biosolids amended farm soil and mine soil were obtained from Fulton County, Il...

  5. MRF with adjustable pH

    NASA Astrophysics Data System (ADS)

    Jacobs, Stephen D.

    2011-10-01

    Deterministic final polishing of high precision optics using sub-aperture processing with magnetorheological finishing (MRF) is an accepted practice throughout the world. A wide variety of materials can be successfully worked with aqueous (pH 10), magnetorheological (MR) fluids, using magnetic carbonyl iron (CI) and either ceria or nanodiamond nonmagnetic abrasives. Polycrystalline materials like zinc sulfide (ZnS) and zinc selenide (ZnSe) are difficult to polish at pH 10 with MRF, due to their grain size and the relatively low stiffness of the MR fluid lap. If microns of material are removed, the grain structure of the material begins to appear. In 2005, Kozhinova et al. (Appl. Opt. 44 4671-4677) demonstrated that lowering pH could improve MRF of ZnS. However, magnetic CI particle corrosion rendered their low pH approach unstable and unsuitable for commercial implementation. In 2009, Shafrir et al. described a sol-gel coating process for manufacturing a zirconia-coated CI particle that protects the magnetic core from aqueous corrosion (Appl. Opt .48 6797-6810). The coating process produces free nanozirconia polishing abrasives during the coating procedure, thereby creating an MR polishing powder that is "self-charged" with the polishing abrasive. By simply adding water, it was possible to polish optical glasses and ceramics with good stability at pH 8 for three weeks. The development of a corrosion resistant, MR polishing powder, opens up the possibility for polishing additional materials, wherein the pH may be adjusted to optimize effectiveness. In this paper we describe the CI coating process, the characterization of the coated powder, and procedures for making stable MR fluids with adjustable pH, giving polishing results for a variety of optical glasses and crystalline ceramics.

  6. 27 CFR 19.386 - Adjusting pH of denatured spirits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Adjusting pH of denatured... of Articles Rules for Denaturing Spirits and Testing Denaturants § 19.386 Adjusting pH of denatured... neutralize the pH of denatured spirits. However, a proprietor may not adjust the pH with any substance...

  7. 27 CFR 19.386 - Adjusting pH of denatured spirits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Adjusting pH of denatured... of Articles Rules for Denaturing Spirits and Testing Denaturants § 19.386 Adjusting pH of denatured... neutralize the pH of denatured spirits. However, a proprietor may not adjust the pH with any substance...

  8. 27 CFR 19.386 - Adjusting pH of denatured spirits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Adjusting pH of denatured... of Articles Rules for Denaturing Spirits and Testing Denaturants § 19.386 Adjusting pH of denatured... neutralize the pH of denatured spirits. However, a proprietor may not adjust the pH with any substance...

  9. 27 CFR 19.386 - Adjusting pH of denatured spirits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Adjusting pH of denatured... of Articles Rules for Denaturing Spirits and Testing Denaturants § 19.386 Adjusting pH of denatured... neutralize the pH of denatured spirits. However, a proprietor may not adjust the pH with any substance...

  10. Influence of soil pH on properties of the soil-water interface

    NASA Astrophysics Data System (ADS)

    Diehl, Doerte

    2010-05-01

    Surface characteristics of soils are one of the main factors controlling processes at the soil-water interface like wetting, sorption or dissolution processes and, thereby, have a high impact on natural soil functions like habitat, filter, buffer, storage and transformation functions. Since surface characteristics, like wettability or repellency, are not static soil properties but continuously changing, the relevant processes and mechanisms are in the focus of the presented study. These mechanisms help to gain further insight into the behaviour of soil and its dynamics under changing environmental conditions. The influence of water content, relative air humidity and drying temperature on soil water repellency has been investigated in many studies. In contrast, few studies have systematically investigated the relationship between soil water repellency (SWR) and soil pH. Several studies found alkaline soils to be less prone to SWR compared to acidic soils (e.g., Cerdà, and Doerr 2007; Mataix-Solera et al. 2007). Furthermore, SWR has been successfully reduced in acidic soils by increasing soil pH via liming (e.g., Karnok et al. 1993; Roper 2005). However, SWR has also been reported in calcareous soils in the Netherlands (Dekker and Jungerius 1990), California, USA (Holzhey 1968) and Spain (Mataix-Solera and Doerr 2004). The hypothesis that the pH may control repellency via changes in the variable surface charge of soil material has not yet been tested. Previously it has been shown that it is necessary to eliminate the direct influence of changes in soil moisture content so that the unique relationship between pH and SWR can be isolated (Bayer and Schaumann 2007). A method has been developed which allows adjustment of the pH of soils with low moisture content via the gas phase with minimal change in moisture content. The method was applied to 14 soil samples from Germany, Netherlands, the UK and Australia, using the water drop penetration time (WDPT) as the indicator

  11. Effects of pH adjustment with phosphates on attributes and functionalities of normal and high pH beef.

    PubMed

    Young, O A; Zhang, S X; Farouk, M M; Podmore, C

    2005-05-01

    Longissimus dorsi muscles from six normal- and six high-ultimate pH bulls were selected for fine mincing and subsequent pH adjustment with acid and alkaline pyrophosphate. Four pH treatments were prepared: initially high remains high (mean of pH 6.37), high becomes normal (5.62); initially normal remains normal (5.65), and normal becomes high (6.21). The addition level of phosphate as P(2)O(5) was the same in all replicates. Before pH adjustment, colour and water holding capacity (WHC) values were strongly affected by higher (initial) pH in expected ways: darker, lower chroma, higher capacity. After pH adjustment, these values were affected only by the final pH, not the initial pH (the pH history). Total protein solubility was likewise affected by final pH but not initial pH. In contrast, the combination high initial pH-high final pH improved sarcoplasmic protein solubility by 20% over the combination normal initial pH-high final pH. Sarcoplasmic protein solubility is an indicator of strain required to fracture cooked batters made from the minced meats; in the event, the rank order of the four treatments for strain-to-fracture matched that of sarcoplasmic protein solubility. Statistically, sarcoplasmic protein solubility and strain-to-fracture were both affected by initial pH (P<0.01) and final pH (P<0.001). However, stress required to fracture cooked batters was entirely controlled by initial pH (P<0.01). In other words, the stress-to-fracture advantage of initially high pH meat was not matched by upward pH adjustment of initially normal pH meat. Emulsion stability, which is better with higher pH meat, was affected by initial and final pH (both P<0.01). Cook yield, like WHC of pH-adjusted raw meat, was more due to final pH than initial pH, similarly cooked batter colour, whereas final pH had a significant effect on quality attributes (generally better when higher). An initially high pH history conferred an enduring advantage on three important batter attributes

  12. Soil phosphorus and pH influence the growth of mycorrhizal sweetgum. [Liquidambar styraciflua; Gigaspora margarita

    SciTech Connect

    Yawney, W.J.; Schultz, R.C.; Kormanik, P.P.

    1982-01-01

    The response of sweetgum (Liquidambar styraciflua L.) seedlings grown either without or inoculated with the vesicular-arbuscular mycorrhizal (VAM) fungus Gigaspora margarita to 25, 50, and 100 ppm soil phosphorus (P) and adjusted soil pHs of 4.5, 5.5, 6.5, and 7.8 was observed during the first growing seasons. The best seedling growth for both VAM and noninoculated seedlings occurred at soil pH 4.5 and 100 ppm of soil P where mean heights and top dry weights average > 28 cm and 8 g, respectively. As soil pH increased, seedling growth decreased significantly and at pH 7.8 the seedlings average < 4 cm in height regardless of the soil P level or mycorrhizal condition. Seedling growth at all pH levels, except pH 7.8, decreased with decreasing soil P. Inoculated seedlings were significantly larger than noninoculated seedlings at 25 ppm soil P and pHs 4.5 and 5.5. Soil P, soil pH, and mycorrhizal condition significantly influenced nutrient levels in plant parts. Soil nutrient levels varied significantly with soil pH. 26 references, 1 figure, 6 tables.

  13. Nanomaterials for the cleaning and pH adjustment of vegetable-tanned leather

    NASA Astrophysics Data System (ADS)

    Baglioni, Michele; Bartoletti, Angelica; Bozec, Laurent; Chelazzi, David; Giorgi, Rodorico; Odlyha, Marianne; Pianorsi, Diletta; Poggi, Giovanna; Baglioni, Piero

    2016-02-01

    Leather artifacts in historical collections and archives are often contaminated by physical changes such as soiling, which alter their appearance and readability, and by chemical changes which occur on aging and give rise to excessive proportion of acids that promote hydrolysis of collagen, eventually leading to gelatinization and loss of mechanical properties. However, both cleaning and pH adjustment of vegetable-tanned leather pose a great challenge for conservators, owing to the sensitivity of these materials to the action of solvents, especially water-based formulations and alkaline chemicals. In this study, the cleaning of historical leather samples was optimized by confining an oil-in-water nanostructured fluid in a highly retentive chemical hydrogel, which allows the controlled release of the cleaning fluid on sensitive surfaces. The chemical gel exhibits optimal viscoelasticity, which facilitates its removal after the application without leaving residues on the object. Nanoparticles of calcium hydroxide and lactate, dispersed in 2-propanol, were used to adjust the pH up to the natural value of leather, preventing too high alkalinity which causes swelling of fibers and denaturation of the collagen. The treated samples were characterized using scanning electron microscopy, controlled environment dynamic mechanical analysis, and infrared spectroscopy. The analytical assessment validated the use of tools derived from colloid and materials science for the preservation of collagen-based artifacts.

  14. SOIL REDOX AND PH EFFECTS ON METHANE PRODUCTION IN A FLOODED RICE SOIL

    EPA Science Inventory

    Methane formation in soil is a microbiological process controlled by many factors. f them soil redox potential (Eh) and soil pH are considered as critical controls. aboratory incubation experiment was conducted to study the critical initiation soil Eh, the optimum soil pH and the...

  15. Mapping Soil pH Buffering Capacity of Selected Fields

    NASA Technical Reports Server (NTRS)

    Weaver, A. R.; Kissel, D. E.; Chen, F.; West, L. T.; Adkins, W.; Rickman, D.; Luvall, J. C.

    2003-01-01

    Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One hundred thirty six soil samples (0 to 15 cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b (slope of pH vs. lime added) = 0.00029 - 0.00003 * % clay + 0.00135 * % O/C, r(exp 2) = 0.68. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(exp 2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities.

  16. Effects of Soil pH on Reproduction of Pratylenchus penetrans and Forage Yield of Alfalfa

    PubMed Central

    Willis, C. B.

    1972-01-01

    'Vernal' alfalfa was grown for 30 weeks in nematode-free soil and in soil infested with Pratylenchus penetrans. Charlottetown fine sandy loam soil was used at its pH of 4.4 and at adjusted reactions of 5.2, 6.4 and 7.3. Nematode reproduction was significantly greater at pit 5.2 and 6.4 and was not related to alfalfa root production over the full pH range studied. A significant nematode infestation X soil pit interaction on forage yield was recorded. Nematode infestation significantly decreased forage yields at ptt 5.2 and 6.4 but not at pH 4.4 and 7.3. PMID:19319283

  17. Effects of pH adjustment and sodium ions on sour taste intensity of organic acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Protonated organic acid species have been shown to be the primary stimuli responsible for sour taste of organic acids. However, we have observed that sour taste may be modulated when the pH of acid solutions is raised using sodium hydroxide. Objectives were to evaluate the effect of pH adjustment on...

  18. Biochar contribution to soil pH buffer capacity

    NASA Astrophysics Data System (ADS)

    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

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

    SciTech Connect

    Singh, B.R.; Almas, A.; Narwal, R.P.; 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.

  20. Does pH influence soil hydro-mechanical properties?

    NASA Astrophysics Data System (ADS)

    Chaplain, V.; Défossez, P.; Delarue, G.; Dexter, A. R.; Richard, G.; Tessier, D.

    2009-04-01

    Does pH influence soil hydro-mechanical properties ? V. Chaplain1, P. Défossez2, G. Delarue1, A.R. Dexter3, G. Richard3 and D. Tessier1. 1 UR INRA PESSAC RD 10, F-78026 Versailles cedex 2 UMR INRA/URCA FARE, 2 Esplanade Roland Garros, BP 224 F-51686 Reims cedex 2 3 UR INRA Sols 2163 Avenue de la Pomme de Pin - CS 40001 ARDON F-45075 Orléans Cedex 2 Corresponding author : chaplain@versailles.inra.fr Structure of soils and its dynamic, physico-chemistry of the interface are of a great importance in the fate of organic pollutants because it governs the accessibility of pollutants to micro-organisms. The soil structure of soils is related to physical parameters (texture, density, water content) but the physico-chemical properties of the interface is not considered. In this study we performed hydro-mechanical measurements on soil samples taken from the 42-plot long-term experiment in Versailles. Indeed six plots were selected to cover a large range of pH values from acid (3.5) to alkaline (8.2) due to the repeated application of fertilizers. Soils were taken in the 0-20 cm and in the 30-35 cm layer out of the ploughed zone. All soils had similar texture and composition with low organic carbon. Therefore pH changes the surface charges and hydrophobicity that are implied in aggregation process. The two layers had the same pH values. The precompression stress Pc and the compression index Cc were derived from confined compression tests performed on remoulded soil samples (density 1.45 g/cm3) at saturation. Results shows that the precompression stress increased at pH lower than 4. In acid case, precompression stress was higher in subsoil. This increase of Pc was attributed to the hydrophobicity due in part to the condensation of charges probably sensitive to the humectation/dessication processes.

  1. Designing a generalized soil-adjusted vegetation index (GESAVI)

    NASA Astrophysics Data System (ADS)

    Gilabert, M. A.; Gonzalez Piqueras, Jose; Garcia-Haro, Joan; Melia, J.

    1998-12-01

    Operational monitoring of vegetative cover by remote sensing currently involves the utilization of vegetation indices (VIs), most of them being functions of the reflectance in red (R) and near-infrared (NIR) spectral bands. A generalized soil-adjusted vegetation index (GESAVI), theoretically based on a simple vegetation canopy model, is introduced. It is defined in terms of the soil line parameters (A and B) as: GESAVI equals (NIR-BR-A)/(R + Z), where Z is related to the red reflectance at the cross point between the soil line and vegetation isolines. Z can be considered as a soil adjustment coefficient which let this new index be considered as belonging to the SAVI family. In order to analyze the GESAVI sensitivity to soil brightness and soil color, both high resolution reflectance data from two laboratory experiments and data obtained by applying a radiosity model to simulate heterogeneous vegetation canopy scenes were used. VIs (including GESAVI, NDVI, PVI and SAVI family VIs) were computed and their correlation with LAI for the different soil backgrounds was analyzed. Results confirmed the lower sensitivity of GESAVI to soil background in most of the cases, thus becoming the most efficient index. This good index performance results from the fact that the isolines in the NIR-R plane are neither parallel to the soil line (as required by the PVI) nor convergent at the origin (as required by the NDVI) but they converge somewhere between the origin and infinity in the region of negative values of both NIR and R. This convergence point is not necessarily situated on the bisectrix, as required by other SAVI family indices.

  2. Fertigation with micronized sulfur rapidly reduces soil pH in highbush blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blueberry is adapted to low soil pH in the range of 4-5.5. At higher pH, soil is often modified with elemental sulfur (S) prior to planting. A 2-year study was conducted to determine the potential of applying micronized wettable S by fertigation through the drip system to reduce soil pH in highbush ...

  3. Application of Acetate Buffer in pH Adjustment of Mash and its Influence on Fuel Ethanol Fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A 2M sodium acetate buffer at pH 4.2 was used to adjust pH of liquefied mashes in a simultaneous saccharification and fermentation (SSF) procedure. Although 5 mL of the buffer did not bring the pH values of the mashes (~100 mL) from a sorghum hybrid to 4.2, it kept the system stable (pH from 4.7 to ...

  4. Soil calcium and pH monitoring sensor system.

    PubMed

    Lemos, Sherlan G; Nogueira, Ana Rita A; Torre-Neto, André; Parra, Aleix; Alonso, Julian

    2007-06-13

    An agrarian sensorial system based on temperature, moisture, and all solid-state ion-selective potentiometric sensors was developed with the objective of monitoring the behavior of H+ and Ca2+ ions in soil and in real conditions, contributing with a new tool that tries to complement the current precision agriculture technology. The evaluation of the sensorial system to pH monitoring presented a good correlation between the results obtained by the system and the standard methodology, allowing us to notice the soil buffer capacity at different soil depths. With regard to calcium, the sensor system also presented an agreement between its results and those obtained by flame atomic absorption spectrometry, using a calibration model based on multiple linear regressions that allows the correct determination of Ca2+ concentrations in soil depths where the relative moisture is different. In this way, using well-known potentiometric sensors in a complex, discontinued, and heterogeneous matrix, such as soil, the sensorial system proved to be a useful task for agrochemical field applications. PMID:17500528

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

    PubMed

    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

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

    PubMed

    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

  7. Effect of Soil pH on Nematicide Efficacy on Soybean

    PubMed Central

    Schmitt, D. P.

    1989-01-01

    To determine the efficacy of selected nematicides under different soil pH regimes in a sandy soil, soil pH ranges were achieved by adding lime or sulfur. Nematicides increased soybean yields, and their efficacy was generally not influenced by soil pH. Belonolaimus longicaudatus was negatively correlated (r = -0.58, P = 0.01) with yield in 1977. PMID:19287658

  8. Integrating pH, substrate, and plant regrowth effects on soil nitrogen cycling after fire

    NASA Astrophysics Data System (ADS)

    Hanan, E. J.; Schimel, J.; Tague, C.; D'Antonio, C. M.

    2014-12-01

    Mediterranean-type ecosystems are structured by fire. In California chaparral, fires uncouple N production and consumption by enhancing nitrification and reducing plant uptake. NO3- that accumulates after fire is vulnerable to leaching. However, the extent to which fires decouple N fluxes can vary spatially and with timing of fire, and the specific mechanisms controlling N metabolism in recovering chaparral are not well understood. We combined empirical analysis and modeling in two chaparral watersheds to better understand how these systems recover from fire, and to explore their sensitivity to changing climate and fire regimes. To evaluate how pH, charcoal, and NH4+ supply influence N cycling, we measured mineralization and nitrification rates in chaparral soils that burned 1, 4, 20 and 40 years prior to sampling. We then experimentally adjusted pH, charcoal, and NH4+ concentrations for all soils in a factorial design, and incubated them for 8 weeks. Each week, we measured respiration, exchangeable NH4+ and NO3- content, nitrification potential, microbial biomass, and pH. Then to project the effects of altered precipitation patterns and fire timing on nitrogen dynamics and recovery, we used the hydro-biogeochemical model RHESSys. Fires were imposed at the beginning and end of the growing season under various climates. NO3- production was highest in soils collected from the most recently burned sites. Also, NO3- concentrations increased over the course of incubation in soils from all sites, especially at high pH, and with NH4+ addition. Charcoal slightly augmented the effects of elevated pH and NH4+ on NO3- production iduring the early stages of incubation in 1 and 4-year old sites, while it slightly dampened their effects by week 8. However, in 20 and 40-year old sites, charcoal had no effect. Overall, nitrification was most powerfully constrained by NH4+ supply. However, increases in pH that occur after fire may enhance nitrification rates when substrate is

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

    PubMed

    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 (<3.5) and sites with higher pH values. The major OTUs from soil samples with low pH could be detected at each site with a soil pH <3.5 but not at sites with 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

  10. Effect of oxygen amendments and soil pH on bioremediation of industrially contaminated soils

    SciTech Connect

    Joshi, M.M.; Lee, S.

    1996-04-01

    Polynuclear aromatic hydrocarbons (PAHs), by-products of coal conversion processes, have contaminated soils near coal plant sites either through accidental spills or systematic discharge. Because these compounds are carcinogenic, mutagenic, and teratogenic, remediation of such sites is a legitimate concern. For this study, contaminated soil samples were obtained from the Alberta Research Council (ARC) primary clean-up facility. Preliminary analysis of the soil was done for contaminant characterization and determination of initial contamination levels. Acinetobacter sp. was used for aerobic treatment of soil over a five-week period under optimum conditions. Because the rate of biodegradation is influenced by the pH, it is of interest to study the effect of pH on remediation efficiency in the physiological pH range of 5.0 to 9.0. Also, oxygen amendment via hydrogen peroxide solution was used to improve remediation in a packed bed, and the results were compared with those obtained under completely mixed conditions.

  11. [Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types].

    PubMed

    Ji, Gang; Xu, Ming-gang; Wen, Shi-lin; Wang, Bo-ren; Zhang, Lu; Liu, Li-sheng

    2015-09-01

    The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica

  12. Urea Hydrolysis Rate in Soil Toposequences as Influenced by pH, Carbon, Nitrogen, and Soluble Metals.

    PubMed

    Fisher, Kristin A; Meisinger, John J; James, Bruce R

    2016-01-01

    A simultaneous increase in the use of urea fertilizer and the incidence of harmful algal blooms worldwide has generated interest in potential loss pathways of urea from agricultural areas. The objective of this research was to study the rate of urea hydrolysis in soil profile toposequences sampled from the Coastal Plain (CP) and Piedmont (PM) regions of Maryland to understand native urea hydrolysis rates (UHRs) as well as the controls governing urea hydrolysis both across a landscape and with depth in the soil profile. A pH-adjustment experiment was conducted to explore the relationship between pH and urea hydrolysis because of the importance of pH to both agronomic productivity and microbial communities. Soils were sampled from both A and B horizons along transects containing an agricultural field (AG), a grassed field border (GB), and a perennially vegetated zone adjacent to surface water. On average, the A-horizon UHRs were eight times greater than corresponding B-horizon rates, and within the CP, the riparian zone (RZ) soils hydrolyzed urea faster than the agricultural soils. The pH adjustment of these soils indicated the importance of organic-matter-related factors (C, N, extractable metals) in determining UHR. These results suggest that organic-matter-rich RZ soils may be valuable in mitigating losses of urea from neighboring fields. Additional field-scale urea hydrolysis studies would be valuable to corroborate the mechanisms described herein and to explore the conditions affecting the fate and transport of urea in agroecosystems. PMID:26828191

  13. Activities of Cu/sup 2 +/ and Cd/sup 2 +/ in soil solutions as affected by pH

    SciTech Connect

    Cavallaro, N.; McBride, M.B.

    1980-07-01

    The concentrations of free copper and cadmium ions in soil suspensions were measured by an ion-selective electrode as a function of pH after equilibrating metal salt solutions with the soils. Similar experiments were done with water-extractable organic matter. Free (uncomplexed) Cu/sup 2 +/ concentrations were strongly pH-dependent in the soil systems, but well below the level where precipitation could have occurred. Free Cd/sup 2 +/ concentrations were much less affected by pH adjustment, and the nonacid soil systems approached saturation or oversaturation with respect to CdCO/sub 3/ precipitation at high pH. Similar dependence of the free metal ion concentration on pH was found in water extracted organic matter solutions. Precipitation of CdCO/sub 3/ in oversaturated solutions containing the extracted organic matter was slow, while none of the copper-organic matter solutions attained oversaturation with respect to Cu(OH)/sub 2/ or Cu/sub 2/(OH)/sub 2/CO/sub 3/.

  14. Biochar effects on soil-resident ligninolytic fungi: in vitro growth response and its pH dependence

    NASA Astrophysics Data System (ADS)

    Taskin, Eren; Loffredo, Elisabetta

    2016-04-01

    Ligninolytic fungi play an essential role on soil fertility because of their decomposing activity that allows nutrients inside biomasses to be released back into the soil. Their enzymes are able to degrade lignin which is otherwise recalcitrant to microbial and chemical degradation. Biochar (BC) has been recently proposed as a soil amendment that may contribute to climate change mitigation via carbon sequestration in soil. Pyrolysis conditions, feedstock and several other factors affect BC characteristics which in turn may influence BC impact on soil microorganisms and terrestrial ecosystems. However, limited information is available in the literature about BC's impact on ligninolytic fungi. The objective of this in vitro study was to assess the impact of BC and pH change caused by BC addition on three soil-resident ligninolytic fungi, Pleurotus ostreatus, Trametes versicolor and Bjerkandera adusta. The BC sample used in this study was obtained from 100% red spruce pellets pyrolysed at a temperature of 550 °C, and it was added to PDA medium directly as solid BC at the doses of 2 g L-1 (BC-LD) and 10 g L-1 (BC-HD). pH values were determined and the experiments were conducted either adjusting the pH of the controls either without pH adjustment. The fungi were inoculated separately in Petri dishes filled with the various media and the radial mycelial growth was measured at several sampling times. Results obtained showed a fungal growth response clearly dependent on the species and the BC dose. BC-LD stimulated the growth of P. ostreatus and T. versicolor, whereas it inhibited that of B. adusta. BC-HD stimulated the growth of P. ostreatus and inhibited that of T. versicolor and B. adusta. Similar responses were obtained with or without pH adjustment for P. ostreatus and T. versicolor, whereas a pH dependency was found for B. adusta. The effects of these and other pertinent treatments on fungal enzymes of the fungi are currently under investigation.

  15. Soil pH determines microbial diversity and composition in the park grass experiment.

    PubMed

    Zhalnina, Kateryna; Dias, Raquel; de Quadros, Patricia Dörr; Davis-Richardson, Austin; Camargo, Flavio A O; Clark, Ian M; McGrath, Steve P; Hirsch, Penny R; Triplett, Eric W

    2015-02-01

    The Park Grass experiment (PGE) in the UK has been ongoing since 1856. Its purpose is to study the response of biological communities to the long-term treatments and associated changes in soil parameters, particularly soil pH. In this study, soil samples were collected across pH gradient (pH 3.6-7) and a range of fertilizers (nitrogen as ammonium sulfate, nitrogen as sodium nitrate, phosphorous) to evaluate the effects nutrients have on soil parameters and microbial community structure. Illumina 16S ribosomal RNA (rRNA) amplicon sequencing was used to determine the relative abundances and diversity of bacterial and archaeal taxa. Relationships between treatments, measured soil parameters, and microbial communities were evaluated. Clostridium, Bacteroides, Bradyrhizobium, Mycobacterium, Ruminococcus, Paenibacillus, and Rhodoplanes were the most abundant genera found at the PGE. The main soil parameter that determined microbial composition, diversity, and biomass in the PGE soil was pH. The most probable mechanism of the pH impact on microbial community may include mediation of nutrient availability in the soil. Addition of nitrogen to the PGE plots as ammonium sulfate decreases soil pH through increased nitrification, which causes buildup of soil carbon, and hence increases C/N ratio. Plant species richness and plant productivity did not reveal significant relationships with microbial diversity; however, plant species richness was positively correlated with soil microbial biomass. Plants responded to the nitrogen treatments with an increase in productivity and a decrease in the species richness. PMID:25395291

  16. Site-specific management of soil pH and nutrients in blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Site-specific management of soil pH and fertilizers is one of the most promising strategies in precision agriculture and is potentially applicable to many horticultural crops, including blueberry. Unlike most fruit crops, blueberry is adapted to low soil pH conditions in the range of 4-5.5 and has ...

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

    ERIC Educational Resources Information Center

    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…

  18. Temporal Adjustment in Academic Labor Markets: Time to Ph.D. AIR Forum Paper 1978.

    ERIC Educational Resources Information Center

    Kuh, Charlotte V.

    A research project is described that concerns "temporal adjustment" as one form of a non-wage adjustment in the academic labor market. Receipt of the doctorate, the number and length of post-doctoral fellowships, and the achievement of tenure are temporal factors in academic careers. The change in timing of these factors is a form of adjustment to…

  19. Nicotine Absorption from Smokeless Tobacco Modified to Adjust pH

    PubMed Central

    Pickworth, Wallace B.; Rosenberry, Zachary R.; Gold, Wyatt; Koszowski, Bartosz

    2014-01-01

    Introduction Nicotine delivery from smokeless tobacco (ST) products leads to addiction and the use of ST causes pathology that is associated with increased initiation of cigarette smoking. The rapid delivery of nicotine from ST seems to be associated with the pH of the aqueous suspension of the products - high pH is associated with high nicotine absorption. However, early studies compared nicotine absorption from different commercial products that not only differed in pH but in flavoring, nicotine content, and in format-pouches and loose tobacco. Methods The present study compared nicotine absorption from a single unflavored referent ST product (pH 7.7) that was flavored with a low level of wintergreen (2 mg/g) and the pH was amended to either high (8.3) or low (5.4) pH with sodium carbonate or citric acid, respectively. Results In a within-subject clinical study, the higher pH products delivered more nicotine. No significant differences were seen between perceived product strengths and product experience in all conditions. Heart rate increased by 4 to 6 beats per minute after the high pH flavored and the un-amended product but did not change after the low pH flavored product. Conclusions These results indicate that pH is a primary determinant of buccal nicotine absorption. The role of flavoring and other components of ST products in nicotine absorption remain to be determined. PMID:25530912

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Effect of Cadmium on Fungi and on Interactions Between Fungi and Bacteria in Soil: Influence of Clay Minerals and pH

    PubMed Central

    Babich, H.; Stotzky, G.

    1977-01-01

    Fungi (Rhizopus stolonifer, Trichoderma viride, Fusarium oxysporum f. sp. conglutinans, Cunninghamella echinulata, and several species of Aspergillus and Penicillium) tolerated higher concentrations of cadmium (Cd) when grown in soil than when grown on laboratory media, indicating that soil mitigated the toxic effects of Cd. In soil amended with clay minerals, montmorillonite provided partial or total protection against fungistatic effects of Cd, whereas additions of kaolinite provided little or no protection. Growth rates of Aspergillus niger were inhibited to a greater extent by 100 or 250 μg of Cd per g in soil adjusted to pH 7.2 than in the same soil at its natural pH of 5.1. However, there were no differences in the growth rates of Aspergillus fischeri with 100 or 250 μg of Cd per g in the same soil, whether at pH 5.1 or adjusted to pH 7.2. Growth of A. niger and A. fischeri in a soil contaminated with a low concentration of Cd (i.e., 28 μg/g), obtained from a site near a Japanese smelter, did not differ significantly from growth in a soil collected some distance away and containing 4 μg of Cd per g. Growth of A. niger in sterile soil amended with 100 μg of Cd per g and inoculated with Bacillus cereus or Agrobacterium tumefaciens was reduced to a greater extent than in the same soil containing 100 μg of Cd per g but no bacteria. The inhibitory effects of Agrobacterium radiobacter to A. niger were slightly reduced in the presence of 100 μg of Cd per g, whereas the inhibitory effects of Serratia marcescens were enhanced. PMID:18085

  2. Ammonia volatilization from soils amended with biochars of different pH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A significant amount of nitrogen fertilizer applied to agricultural land is in the form of ammonium. Ammonium nitrogen can be lost through volatilization if applied under certain conditions, mainly to soils with a pH greater than 8. The pH of biochar varies from slightly acidic to highly alkaline ...

  3. Influence of pH and electrolyte composition on adsorption of poliovirus by soils and minerals.

    PubMed Central

    Taylor, D H; Moore, R S; Sturman, L S

    1981-01-01

    The pH and the nature an concentration of simple electrolytes influenced the interaction of poliovirus type 2 with three soils, a sand, and a clay mineral. In electrolytes above pH 9 the virus was not adsorbed extensively to the substrates, but below pH 7 almost all virus was bound. For each adsorbent there was a characteristic pH region of transition from strong to weak uptake. Differences between the soils in virus uptake were shown to parallel their pH-dependent mineral. In electrolytes above pH 9 the virus was not adsorbed extensively to the substrates, but below pH 7 almost all virus was bound. For each adsorbent there was a characteristic pH region of transition from strong to weak uptake. Differences between the soils in virus uptake were shown to parallel their pH-dependent mineral. In electrolytes above pH 9 the virus was not adsorbed extensively to the substrates, but below pH 7 almost all virus was bound. For each adsorbent there was a characteristic pH region of transition from strong to weak uptake. Differences between the soils in virus uptake were shown to parallel their pH-dependent charge properties, as determined by whole-particle microelectrophoresis. Only when the pH was close to or above the critical region was uptake increased with electrolyte concentration. The transition region for all substrates was above pH 7.5 the isoelectric point of the virus. Thus, it appears that when both the virus and substrate are highly negative charged, repulsive electrostatic effects may exceed inherent attractive interactions, thereby inhibiting adsorption. PMID:6274260

  4. Effects of soil oxygen conditions and soil pH on remediation of DDT-contaminated soil by laccase from white rot fungi.

    PubMed

    Zhao, Yuechun; Yi, Xiaoyun

    2010-04-01

    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 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. PMID:20617049

  5. Effect of fertilizers on faba bean (V. faba) growth and soil pH

    NASA Astrophysics Data System (ADS)

    Angel, C.

    2013-12-01

    The purpose of this experiment was to see the effect of fertilizers on faba bean (V. faba) growth and soil pH. This experiment is important because of the agriculture here in California and the damage fertilizers are doing to the soil. Three Broad Fava Windsor beans (Vicia faba) were planted per pot, with at least three pots per treatment. There were four treatments: soil with phosphorus (P) fertilizer, soil with nitrogen (N) fertilizer, soil with both N and P fertilizer, and soil without any fertilizers (control). The soil pH was 7.7, and it had 26.6mg/kg Olsen-P, 2.2mg/kg ammonium-N and no nitrate-N (Data from UCD Horwath Lab). All pots were put in a greenhouse with a stable temperature of 80 degrees. I watered them 2-3 times a week. After two months I measured the soil pH using a calibrated pHep HI 98107 pocket-sized pH meter. After letting the plants dry I weighed the shoots and roots separately for dry biomass. From testing pH of the soil of the faba bean plants with and without fertilizer I found that only the nitrogen fertilizer made the soil more acidic than the other ones. The other ones became more basic. Also the N-fertilized plants weighed more than the other ones. This shows how the nitrogen fertilizer had a greater impact on the plants. I think the reason why the nitrogen and the phosphorus fertilizers didn't work as well is because there was an interaction between the fertilizers and the nitrogen one made the soil more acidic because of the way nitrogen is made.

  6. PH adjustment of power plant cooling water with flue gas/fly ash

    DOEpatents

    Brady, Patrick V.; Krumhansl, James L.

    2015-09-22

    A system including a vessel including a heat source and a flue; a turbine; a condenser; a fluid conduit circuit disposed between the vessel, the turbine and the condenser; and a diverter coupled to the flue to direct a portion of an exhaust from the flue to contact with a cooling medium for the condenser water. A method including diverting a portion of exhaust from a flue of a vessel; modifying the pH of a cooling medium for a condenser with the portion of exhaust; and condensing heated fluid from the vessel with the pH modified cooling medium.

  7. Composition and Flow Behavior of F-Canyon Tank 804 Sludge following Manganese Addition and pH Adjustment

    SciTech Connect

    Poirier, M. R.; Stallings, M. E.; Burket, P.R.; Fink, S. D.

    2005-11-30

    The Site Deactivation and Decommissioning (SDD) Organization is evaluating options to disposition the 800 underground tanks (including removal of the sludge heels from these tanks). To support this effort, SDD requested assistance from Savannah River National Laboratory (SRNL) personnel to examine the composition and flow characteristics of the Tank 804 sludge slurry after diluting it 10:1 with water, adding manganese nitrate to produce a slurry containing 5.5 wt % manganese (40:1 ratio of Mn:Pu), and adding sufficient 8 M caustic to raise the pH to 7, 10, and 14. Researchers prepared slurries containing one part Tank 804 sludge and 10 parts water. The water contained 5.5 wt % manganese (which SDD will add to poison the plutonium in Tank 804) and was pH adjusted to 3, 7, 10, or 14. They hand mixed (i.e., shook) these slurries and allowed them to sit overnight. With the pH 3, 7, and 10 slurries, much of the sludge remained stuck to the container wall. With the pH 14 slurry, most of the sludge appeared to be suspended in the slurry. They collected samples from the top and bottom of each container, which were analyzed for plutonium, manganese, and organic constituents. Following sampling, they placed the remaining material into a viscometer and measured the relationship between applied shear stress and shear rate. The pH 14 slurry was placed in a spiral ''race track'' apparatus and allowed to gravity drain.

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

    NASA Astrophysics Data System (ADS)

    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

  9. Commentary: Attitude Adjustment--Educating PhD Scientist for Business Careers

    ERIC Educational Resources Information Center

    Schuster, Sheldon M.

    2011-01-01

    The PhD graduate from a US research academic institution who has worked 5-7 years to solve a combination of laboratory and computational problems after an in-depth classroom experience is likely superbly trained in at least a subset of the life sciences and the underlying methodology and thought processes required to perform high level research.…

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

    PubMed

    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

  11. Effect of redox potential and pH on TNT transformation in soil-water slurries

    SciTech Connect

    Price, C.B.; Brannon, J.M.; Hayes, C.A.

    1997-10-01

    The presence of 2,4,6-trinitrotoluene (TNT) and its transformation products in surface soil, the vadose zone, and ground water can present serious environmental problems. This situation is exacerbated because the processes that control the mobility and transformation of TNT are not well understood. The objective of this study was to determine the effects of redox potential (Eh) and pH on the fate and transformation of TNT in soil. An initial investigation of soil components responsible for the observed TNT transformation was also conducted. Laboratory investigations consisted of testing at four separate redox potentials and four pH levels. An 18:1 (water:soil) suspension spiked with 100 {micro}g/g TNT was used. Results indicated that TNT was unstable under all redox and pH conditions, and was least stable under highly reducing conditions at all four pH values. Greater amounts of TNT were incorporated into soil organic matter under anaerobic than under aerobic conditions. Results of the soil component study indicated that the presence of Fe{sup +2} sorbed to clay surfaces may account for the rapid disappearance of TNT at reduced redox potentials. TNT in ground water moving into areas of intense reduction would not persist for long, but would undergo transformation and binding by soil organic matter.

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

    PubMed Central

    Chu, Linlin; Kang, Yaohu; Wan, Shuqin

    2014-01-01

    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. PMID:25147843

  13. Separation of switchgrass bio-oil by water/organic solvent addition and pH adjustment

    DOE PAGESBeta

    Park, Lydia Kyoung-Eun; Ren, Shoujie; Yiacoumi, Sotira; Ye, X. Philip; Borole, Abhijeet P.; Tsouris, Costas

    2016-01-29

    Applications of bio-oil are limited by its challenging properties including high moisture content, low pH, high viscosity, high oxygen content, and low heating value. Separation of switchgrass bio-oil components by adding water, organic solvents (hexadecane and octane), and sodium hydroxide may help to overcome these issues. Acetic acid and phenolic compounds were extracted in aqueous and organic phases, respectively. Polar chemicals, such as acetic acid, did not partition in the organic solvent phase. Acetic acid in the aqueous phase after extraction is beneficial for a microbial-electrolysis-cell application to produce hydrogen as an energy source for further hydrodeoxygenation of bio-oil. Organicmore » solvents extracted more chemicals from bio-oil in combined than in sequential extraction; however, organic solvents partitioned into the aqueous phase in combined extraction. When sodium hydroxide was added to adjust the pH of aqueous bio-oil, organic-phase precipitation occurred. As the pH was increased, a biphasic aqueous/organic dispersion was formed, and phase separation was optimized at approximately pH 6. The neutralized organic bio-oil had approximately 37% less oxygen and 100% increased heating value than the initial centrifuged bio-oil. In conclusion, the less oxygen content and increased heating value indicated a significant improvement of the bio-oil quality through neutralization.« less

  14. Fluctuations in Ammonia Oxidizing Communities Across Agricultural Soils are Driven by Soil Structure and pH

    PubMed Central

    Pereira e Silva, Michele C.; Poly, Franck; Guillaumaud, Nadine; van Elsas, Jan Dirk; Salles, Joana Falcão

    2012-01-01

    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 toward defining a NOR for soil nitrification. The sensitivity of the process and organisms to impacts from the milieu support their use as proxies in the

  15. Bacterial Chitinolytic Communities Respond to Chitin and pH Alteration in Soil

    PubMed Central

    Kielak, Anna M.; Cretoiu, Mariana Silvia; Semenov, Alexander V.; Sørensen, Søren J.

    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 rRNA 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 by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one of Actinobacteria in the immediate response to the added chitin (based on 16S rRNA gene abundance and chiA gene types) was indicated. The results of this study enhance our understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes. PMID:23104407

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

    PubMed

    Kielak, Anna M; Cretoiu, Mariana Silvia; Semenov, Alexander V; Sørensen, Søren J; van Elsas, Jan Dirk

    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 rRNA 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 by the addition of chitin at different prevailing soil pH values. Interestingly, a major role of Gram-negative bacteria versus a minor one of Actinobacteria in the immediate response to the added chitin (based on 16S rRNA gene abundance and chiA gene types) was indicated. The results of this study enhance our understanding of the response of the soil bacterial communities to chitin and are of use for both the understanding of soil suppressiveness and the possible mining of soil for novel enzymes. PMID:23104407

  17. Soil pH Mapping with an On-The-Go Sensor

    PubMed Central

    Schirrmann, Michael; Gebbers, Robin; Kramer, Eckart; Seidel, Jan

    2011-01-01

    Soil pH is a key parameter for crop productivity, therefore, its spatial variation should be adequately addressed to improve precision management decisions. Recently, the Veris pH Manager™, a sensor for high-resolution mapping of soil pH at the field scale, has been made commercially available in the US. While driving over the field, soil pH is measured on-the-go directly within the soil by ion selective antimony electrodes. The aim of this study was to evaluate the Veris pH Manager™ under farming conditions in Germany. Sensor readings were compared with data obtained by standard protocols of soil pH assessment. Experiments took place under different scenarios: (a) controlled tests in the lab, (b) semicontrolled test on transects in a stop-and-go mode, and (c) tests under practical conditions in the field with the sensor working in its typical on-the-go mode. Accuracy issues, problems, options, and potential benefits of the Veris pH Manager™ were addressed. The tests demonstrated a high degree of linearity between standard laboratory values and sensor readings. Under practical conditions in the field (scenario c), the measure of fit (r2) for the regression between the on-the-go measurements and the reference data was 0.71, 0.63, and 0.84, respectively. Field-specific calibration was necessary to reduce systematic errors. Accuracy of the on-the-go maps was considerably higher compared with the pH maps obtained by following the standard protocols, and the error in calculating lime requirements was reduced by about one half. However, the system showed some weaknesses due to blockage by residual straw and weed roots. If these problems were solved, the on-the-go sensor investigated here could be an efficient alternative to standard sampling protocols as a basis for liming in Germany. PMID:22346591

  18. Microbial colonisation of sterilised soils across a pH gradient in a full factorial re-inoculation experiment

    NASA Astrophysics Data System (ADS)

    Barcenas Moreno, Gema; Bååth, Erland; Rousk, Johannes

    2015-04-01

    We compared the influence of community and environmental conditions for the functioning (fungal and bacterial growth and respiration) and trait distribution (bacterial pH-tolerance) of soil microorganisms across a pH gradient. A reciprocal inoculation experiment, including pHs 4.1, 5.2, 6.7, and 8.3, was used. Sterilised soil microcosms with added plant material were inoculated with fresh soil (communities) and monitored for two months. Respiration was dominated by bacteria at high and by fungi at low pHs. The bacterial pH-tolerance of all inoculated communities (initial trait distribution) converged with the pH of the soil (environment). There were also differences between inocula, resulting in suboptimal pH-tolerance when the inoculum pH did not correspond to soil pH; low pH inocula had lower than optimal pH-tolerance in high pH soils and vice versa. Bacterial communities misaligned to their environment had impaired functioning (growth in all soils and respiration in high pH soils). The inoculum effect on bacterial pH tolerance and functioning could be detected within one week and remained for two months. Fungal communities emanating from low pH inocula consistently resulted in higher fungal growth and biomass (all soils) and respiration (low pH soils). This suggested that variation in fungal pH-tolerance did not influence their performance, in contrast with bacteria. It is likely that a larger fungal sample in low pH inocula explained these results. Consequently, respiration was characterised by the alignment of the bacterial trait distribution to the environment for high pH soils, while it was characterised by larger fungal inoculum for low pH soils.

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

    PubMed

    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. Interactive Effects of Soil ph, Halosulfuron Rate, and Application Method on Carryover to Turnip Green and Cabbage.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted in 2006 and 2007 to evaluate the tolerance of autumn-planted cabbage and turnip green to halosulfuron applied the previous spring to cantaloupe. Main plots were three levels of soil pH; maintained at a natural pH level, pH raised with Ca(OH)2, and pH lowered with Al2(SO...

  1. Effect of Soil Temperature and pH on Resistance of Soybean to Heterodera glycines

    PubMed Central

    Anand, S. C.; Matson, K. W.; Sharma, S. B.

    1995-01-01

    Soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a major pest of soybean, Glycine max L. Merr. Soybean cultivars resistant to SCN are commonly grown in nematode-infested fields. The objective of this study was to examine the stability of SCN resistance in soybean genotypes at different soil temperatures and pH levels. Reactions of five SCN-resistant genotypes, Peking, Plant Introduction (PI) 88788, Custer, Bedford, and Forrest, to SCN races 3, 5, and 14 were studied at 20, 26, and 32 C, and at soil pH's 5.5, 6.5, and 7.5. Soybean cultivar Essex was included as a susceptible check. Temperature, SCN race, soybean genotype, and their interactions significantly affected SCN reproduction. The effect of temperature on reproduction was quadratic with the three races producing significantly greater numbers of cysts at 26 C; however, reproduction on resistant genotypes remained at a low level. Higher numbers of females matured at the soil pH levels of 6.5 and 7.5 than at pH 5.5. Across the ranges of temperature and soil pH studied, resistance to SCN in the soybean genotypes remained stable. PMID:19277315

  2. Changes in soil pH across England and Wales in response to decreased acid deposition

    NASA Astrophysics Data System (ADS)

    Kirk, G. J. D.; Bellamy, P. H.

    2009-04-01

    In our recent analysis of data from the National Soil Inventory of England and Wales, we found widespread changes in soil pH across both countries between the two samplings of the Inventory. In general, soil pH increased - i.e. soils became less acid - under all land uses. The Inventory was first sampled in 1978-83 on a 5-km grid over the whole area. This yielded about 6,000 sites of which 5,662 could be sampled for soil. Roughly 40% of the sites were re-sampled at intervals from 12 to 25 years after the original sampling - in 1994/96 for agricultural land and in 2002/03 for non-agricultural. Exactly the same sampling and analytical protocols were used in the two samplings. In arable soils, the increase in pH was right across the range, whereas in grassland soils the main increase was at the acid end of the scale (pH < 5.5) with a small increase above pH 7. Some part of the change is likely to have been due to changes in land management. This includes better targeting of agricultural lime on acid soils; changes in nitrogen fertilizer use; deeper ploughing bringing up more calcareous subsoil on soils on calcareous materials; and so forth. However a major driver appears to have been decreased acid deposition to land. The total amounts of nitrogen compounds deposited were relatively unchanged over the survey period, but the amounts of acidifying sulphur compounds decreased by approximately 50%. We constructed a linear regression model to assess the relation between the rate of change in pH (normalised to an annual basis) and the rate of change in acid deposition, as modified by soil properties (pH, clay content, organic matter content), rainfall and past acid deposition. We used data on rainfall and acid deposition over the survey period on the same 5-km grid as the NSI data. We fitted the model separately for each land use category. The results for arable land showed a significant effect of the change in rate of acid deposition, though a significant part of the

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

    PubMed

    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

  4. Effects of solution pH and complexing reagents on the desorption of radionuclides in soil

    SciTech Connect

    Wang, Yug-Yea; Yu, C.

    1992-01-01

    In contaminated soils, radionuclides such as uranium and/or thorium may be associated with different chemical species on soil surfaces or inside soil grains with consequent differences in leachability and mobility. Chemical species in contacting solutions can react with soil contaminants by dissolution, ion exchange, or complexation to release contaminants from the soil to the solution. It is important to understand the effect of chemical species in solution for investigating the distribution of uranium and thorium between the soil and the solution under desorption conditions. In this work, the effects of the solution pH and the complexing reagents on the desorption of uranium and thorium under saturated equilibrium conditions were investigated.

  5. Effects of solution pH and complexing reagents on the desorption of radionuclides in soil

    SciTech Connect

    Wang, Yug-Yea; Yu, C.

    1992-05-01

    In contaminated soils, radionuclides such as uranium and/or thorium may be associated with different chemical species on soil surfaces or inside soil grains with consequent differences in leachability and mobility. Chemical species in contacting solutions can react with soil contaminants by dissolution, ion exchange, or complexation to release contaminants from the soil to the solution. It is important to understand the effect of chemical species in solution for investigating the distribution of uranium and thorium between the soil and the solution under desorption conditions. In this work, the effects of the solution pH and the complexing reagents on the desorption of uranium and thorium under saturated equilibrium conditions were investigated.

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

    PubMed

    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

  7. The influence of soil pH on the diversity, abundance and transcriptional activity of ammonia oxidizing archaea and bacteria.

    PubMed

    Nicol, Graeme W; Leininger, Sven; Schleper, Christa; Prosser, James I

    2008-11-01

    Autotrophic ammonia oxidation occurs in acid soils, even though laboratory cultures of isolated ammonia oxidizing bacteria fail to grow below neutral pH. To investigate whether archaea possessing ammonia monooxygenase genes were responsible for autotrophic nitrification in acid soils, the community structure and phylogeny of ammonia oxidizing bacteria and archaea were determined across a soil pH gradient (4.9-7.5) by amplifying 16S rRNA and amoA genes followed by denaturing gradient gel electrophoresis (DGGE) and sequence analysis. The structure of both communities changed with soil pH, with distinct populations in acid and neutral soils. Phylogenetic reconstructions of crenarchaeal 16S rRNA and amoA genes confirmed selection of distinct lineages within the pH gradient and high similarity in phylogenies indicated a high level of congruence between 16S rRNA and amoA genes. The abundance of archaeal and bacterial amoA gene copies and mRNA transcripts contrasted across the pH gradient. Archaeal amoA gene and transcript abundance decreased with increasing soil pH, while bacterial amoA gene abundance was generally lower and transcripts increased with increasing pH. Short-term activity was investigated by DGGE analysis of gene transcripts in microcosms containing acidic or neutral soil or mixed soil with pH readjusted to that of native soils. Although mixed soil microcosms contained identical archaeal ammonia oxidizer communities, those adapted to acidic or neutral pH ranges showed greater relative activity at their native soil pH. Findings indicate that different bacterial and archaeal ammonia oxidizer phylotypes are selected in soils of different pH and that these differences in community structure and abundances are reflected in different contributions to ammonia oxidizer activity. They also suggest that both groups of ammonia oxidizers have distinct physiological characteristics and ecological niches, with consequences for nitrification in acid soils. PMID:18707610

  8. Increasing aridity, temperature and soil pH induce soil C-N-P imbalance in grasslands

    PubMed Central

    Jiao, Feng; Shi, Xin-Rong; Han, Feng-Peng; Yuan, Zhi-You

    2016-01-01

    Due to the different degrees of controls exerted by biological and geochemical processes, climate changes are suggested to uncouple biogeochemical C, N and P cycles, influencing biomass accumulation, decomposition and storage in terrestrial ecosystems. However, the possible extent of such disruption in grassland ecosystems remains unclear, especially in China’s steppes which have undergone rapid climate changes with increasing drought and warming predicted moving forward in these dryland ecosystems. Here, we assess how soil C-N-P stoichiometry is affected by climatic change along a 3500-km temperate climate transect in Inner Mongolia, China. Our results reveal that the soil from more arid and warmer sites are associated with lower soil organic C, total N and P. The ratios of both soil C:P and N:P decrease, but soil C:N increases with increasing aridity and temperature, indicating the predicted decreases in precipitation and warming for most of the temperate grassland region could lead to a soil C-N-P decoupling that may reduce plant growth and production in arid ecosystems. Soil pH, mainly reflecting long-term climate change in our sites, also contributes to the changing soil C-N-P stoichiometry, indicating the collective influences of climate and soil type on the shape of soil C-N-P balance. PMID:26792069

  9. Increasing aridity, temperature and soil pH induce soil C-N-P imbalance in grasslands.

    PubMed

    Jiao, Feng; Shi, Xin-Rong; Han, Feng-Peng; Yuan, Zhi-You

    2016-01-01

    Due to the different degrees of controls exerted by biological and geochemical processes, climate changes are suggested to uncouple biogeochemical C, N and P cycles, influencing biomass accumulation, decomposition and storage in terrestrial ecosystems. However, the possible extent of such disruption in grassland ecosystems remains unclear, especially in China's steppes which have undergone rapid climate changes with increasing drought and warming predicted moving forward in these dryland ecosystems. Here, we assess how soil C-N-P stoichiometry is affected by climatic change along a 3500-km temperate climate transect in Inner Mongolia, China. Our results reveal that the soil from more arid and warmer sites are associated with lower soil organic C, total N and P. The ratios of both soil C:P and N:P decrease, but soil C:N increases with increasing aridity and temperature, indicating the predicted decreases in precipitation and warming for most of the temperate grassland region could lead to a soil C-N-P decoupling that may reduce plant growth and production in arid ecosystems. Soil pH, mainly reflecting long-term climate change in our sites, also contributes to the changing soil C-N-P stoichiometry, indicating the collective influences of climate and soil type on the shape of soil C-N-P balance. PMID:26792069

  10. pH affects bacterial community composition in soils across the Huashan Watershed, China.

    PubMed

    Huang, Rui; Zhao, Dayong; Zeng, Jin; Shen, Feng; Cao, Xinyi; Jiang, Cuiling; Huang, Feng; Feng, Jingwei; Yu, Zhongbo; Wu, Qinglong L

    2016-09-01

    To investigate soil bacterial richness and diversity and to determine the correlations between bacterial communities and soil properties, 8 soil samples were collected from the Huashan watershed in Anhui, China. Subsequently, 454 high-throughput pyrosequencing and bioinformatics analyses were performed to examine the soil bacterial community compositions. The operational taxonomic unit richness of the bacterial community ranged from 3664 to 5899, and the diversity indices, including Chao1, Shannon-Wiener, and Faith's phylogenetic diversity ranged from 7751 to 15 204, 7.386 to 8.327, and 415.77 to 679.11, respectively. The 2 most dominant phyla in the soil samples were Actinobacteria and Proteobacteria. The richness and diversity of the bacterial community were positively correlated with soil pH. The Mantel test revealed that the soil pH was the dominant factor influencing the bacterial community. The positive modular structure of co-occurrence patterns at the genus level was discovered by network analysis. The results obtained in this study provide useful information that enhances our understanding of the effects of soil properties on the bacterial communities. PMID:27374919

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

    NASA Astrophysics Data System (ADS)

    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 < 1.0 mm and pH was modified by NH3 and HCl gas (Diehl et al. 2010) and measured electrometrically in 0.01 M CaCl2 solution. TISED measurements (2007)were conducted at 10, 20 and 30 oC using OCA 15 Contact Angle Meter (Dataphysics, Germany) on three replications for each 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

  12. Persistence of spiromesifen in soil: influence of moisture, light, pH and organic amendment.

    PubMed

    Mate, Ch Jamkhokai; Mukherjee, Irani; Das, Shaon Kumar

    2015-02-01

    Persistence of spiromesifen in soil as affected by varying moisture, light, compost amendment, soil sterilization and pH in aqueous medium were studied. Degradation of spiromesifen in soil followed the first-order reaction kinetics. Effect of different moisture regimes indicated that spiromesifen dissipated faster in submerged soil (t 1/2 14.3-16.7 days) followed by field capacity (t 1/2 18.7-20.0 days), and dry soil (t 1/2 21.9-22.9 days). Dissipation was faster in sterilized submerged (t 1/2 17.7 days) than in sterilized dry (t 1/2 35.8 days). Photo spiromesifen metabolite was not detected under different moisture regimes. After 30 days, enol spiromesifen metabolite was detected under submerged condition and was below detectable limit (<0.001 μg g(-1)) after 90 days. Soil amendment compost (2.5 %) at field capacity enhanced dissipation of the insecticide, and half-life value was 14.3 against 22.4 days without compost amendment. Under different pH condition, residues persisted in water with half-life values 5.7 to 12.5 days. Dissipation in water was faster at pH 9.0 (t 1/2 5.7 days), followed by pH 4.0 (t 1/2 9.7 days) and pH 7.2 (t 1/2 12.5 days). Exposure of spiromesifen to different light conditions indicated that it was more prone to degradation under UV light (t 1/2 3-4 days) than sunlight exposure (t 1/2 5.2-8.1 days). Under sunlight exposure, photo spiromesifen metabolite was detected after 10 and 15 days as compared to 3 and 5 days under UV light exposure. PMID:25616783

  13. Adsorption behavior of copper and zinc in soils: Influence of pH on adsorption characteristics

    SciTech Connect

    Msaky, J.J. ); Calvet, R. )

    1990-08-01

    The authors studied adsorption of copper and zinc on three different soils: a brown silty soil, an Oxisol, and a Podzol. They determined the amounts adsorbed and the shapes of adsorption isotherms as a function of the pH of the adsorbing medium at a constant ionic strength. The adsorbed amount-pH relationship depended strongly on the natures of the metallic cation and of the soil. The pH greatly influenced the characteristics of adsorption isotherms. They based interpretation on the variations with the pH of both adsorbent affinity for the metal in relation to the surface electric charge and chemical speciation in solution. The adsorption mechanism in the Oxisol probably involves monohydroxylated cations but is more determined by bivalent cations in the brown silty soil and the Podzol. From a general point of view, adsorption of copper and zinc cannot be represented with a single adsorption constant, but should be described by adsorption isotherms obtained at various pH values.

  14. EVALUATION OF CHEMICAL AMENDMENTS FOR PH AND REDOX STABILIZTION IN AQUEOUS SUSPENSIONS OF THREE CALIFORNIA SOILS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many chemically and biologically important trace element, heavy metal, and organic contaminant reactions in soils are constrained by pH and redox conditions and changes in these conditions can significantly affect reaction rates. Although closed-system, batch methods have been used for many years to...

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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 (pH<4), but may have important biogeochemical consequences with regard to soil and water quality.

  17. Effect of adjusted pH prior to ultrafiltration of skim milk on membrane performance and physical functionality of milk protein concentrate.

    PubMed

    Luo, X; Vasiljevic, T; Ramchandran, L

    2016-02-01

    Processing conditions during ultrafiltration of skim milk influence properties of the casein micelle and thereby the physical properties of milk protein concentrate (MPC). The aim of the study was to establish the effects of pH adjustment of skim milk feed to obtain MPC with desired emulsification properties. The ultrafiltration was conducted using commercially pasteurized skim milk with the pH adjusted to 6.7 (control), 6.3, 5.9, or 5.5 at 15°C until a volume concentration factor of 5 was reached. Effects of pH adjustment on selected physico-chemical properties (Ca content, particle size, ζ-potential) and functionalities (solubility, heat stability, emulsification capacity, and stability) of MPC were determined. Lowering the feed pH solubilized colloidal calcium phosphate that substantially contributed to modifying the properties of casein. This caused a reduction in the particle size while increasing the net negative charge. The structural modifications in proteins were manifested in the Fourier transform infrared spectra. Subsequent concentration did not induce any further protein structural changes. Such modifications to the casein micelles and colloidal calcium phosphate negatively affected the solubility and heat stability of the corresponding MPC powders. However, the emulsion activity index improved only until the pH of the feed was lowered to 5.9 and declined when pH was dropped to 5.5, followed with the loss of stability. Readjusting the pH of MPC powder dispersions to 6.7 restored their surface properties and thereby their functionality. Lowering the feed pH also negatively affected the membrane performance by clogging the membrane pores and lowering the flux, particularly at pH 5.5. Adjusting pH to 5.9 produced MPC with optimum emulsifying properties with minimal influence on membrane performance. PMID:26686705

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

    NASA Astrophysics Data System (ADS)

    Luo, W. T.; Nelson, P. N.; Li, M.-H.; Cai, J. P.; Zhang, Y. Y.; Zhang, Y. G.; Yang, S.; Wang, R. Z.; Wang, Z. W.; Wu, Y. N.; Han, X. G.; Jiang, Y.

    2015-12-01

    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. Along the transect, soil pHBC was different in regions with different aridity index. 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. This understanding should be incorporated into the acidification risk assessment and landscape management in a changing world.

  19. Effect of pH and organic acids on nitrogen transformations and metal dissolution in soils

    SciTech Connect

    Fu, Minhong.

    1989-01-01

    The effect of pH (4, 6, and 8) on nitrogen mineralization was evaluated in three Iowa surface soils treated with crop residues (corn (Zea mays L.), soybean (Glycine max (L.) Merr.), and sorghum (Sorghum vulgare Pers.), or alfalfa (Medicago sativa L.)) and incubated in leaching columns under aerobic conditions at 30C for 20 weeks. In general, N mineralization was significantly depressed at soil pH 4, compared with pH 6 or 8. The types of crop residues added influenced the pattern and amount of N mineralization. A study on the effect of 19 trace elements on the nitrate red activity of four Iowa surface soils showed that most trace elements inhibited this enzyme in acid and neutral soils. The trace elements Ag(I), Cd(II), Se(IV), As(V), and W(VI) were the most effective inhibitors, with >75% inhibition. Mn(II) was the least effective inhibitor, with <10% inhibition. Other trace elements included Cu(I), Co(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), Al(III), As(III), Cr(III), Fe(III), V(IV), Mo(VI), and Se(VI). The application of high-performance liquid chromatography (HPLC) showed that, when coupled to a refractive index detector, it is a rapid, sensitive, and accurate method for determining organic acids in soils. Three organic acids, acetic (2-20 mM), propionic (0-3 mM), and n-butyric (0-1.4 mM), were identified with HPLC and confirmed by gas chromatography in crop-residue-treated soils incubated under waterlogged conditions at 25C for 72 h. No organic acids were detected under aerobic conditions. Four mineral acids and 29 organic acids were studied for their effect on N mineralization and metal dissolution in soils incubated under waterlogged conditions at 30C for 10 days.

  20. Yield and composition of soybeans as influenced by soil pH, phosphorus, zinc, and copper

    SciTech Connect

    Payne, G.G.; Summer, M.E.; Plank, C.O.

    1986-01-01

    This field study was conducted to determine the response of soybean cultivars with different tolerance to P induced growth disorders to applied P, Zn, and Cu at different soil pH levels. Both Wright (tolerant) and Hutton (sensitive) soybean cultivars showed a significant response to applied Zn. The greatest response was observed for Hutton although Wright had seed yields as great or greater than those for Hutton. Yield of both cultivars was significantly correlated with leaf Zn concentration and the P/Zn ratio. The highest yields for both cultivars were associated with leaf Zn concentrations of approximately 26 ..mu..g/g and P/Zn ratios of 115. Applied P did not affect yield or P absorption of either cultivar. Copper fertilization increased Cu concentration in plant tissue by 38% to 58% but did not influence seed yields. Seed yield and Zn absorption of both cultivars was reduced by increased pH with yield decreasing at a faster rate when Zn was not applied than when plants received Zn fertilizer. Copper Concentrations in plant tissue were not affected by increased soil pH. Zinc concentration of leaf tissue was also affected by a P-Zn interaction. Wright contained much greater concentrations of leaf Zn, Fe, Cu, and several other nutrients than did Hutton indicating a greater ability to absorb these elements under conditions of high soil pH and P levels. This ability may account for the difference in tolerance to P induced growth disorders that has been observed between these cultivars. Within each pH treatment, Zn absorption was highly correlated to extractable soil Zn.

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

    NASA Astrophysics Data System (ADS)

    Luo, W.; Nelson, P. N.; Li, M.-H.; Cai, J.; Zhang, Y.; Zhang, Y.; Shan, Y.; Wang, R.; Han, X.; Jiang, Y.

    2015-08-01

    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.

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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 < 4), but may have important biogeochemical consequences with regard to soil and water quality.

  4. Estimation of soil pH at Mount Beigu Wetland based on visible and near infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Hu, Yongguang; Li, Pingping; Mao, Hanping; Chen, Bin; Wang, Xi

    2006-12-01

    pH of the wetland soil is one of the most important indicators for aquatic vegetation and water bodies. Mount Beigu Wetland, just near the Yangtse River, is under ecological recovery. Visible and near infrared reflectance spectroscopy was adopted to estimate soil pH of the wetland. The spectroradiometer, FieldSpec 3 (ASD) with a full spectral range (350-2500 nm), was used to acquire the reflectance spectra of wetland soil, and soil pH was measured with the pH meter of IQ150 (Spectrum) and InPro 3030 (Mettler Toledo). 146 soil samples were taken with soil sampler (Eijkelkamp) according to different position and depth, which covered the wider range of pH value from 7.1 to 8.39. 133 samples were used to establish the calibration model with the method of partial least square regression and principal component analysis regression. 13 soil samples were used to validate the model. The results show that the model is not good, but the mean error and root mean standard error of prediction are less (1.846% and 0.186 respectively). Spectral reflectancebased estimation of soil pH of the wetland is applicable and the calibration model needs to be improved.

  5. Impact of soil pH and organic matter on the chemical bioavailability of vanadium species: The underlying basis for risk assessment.

    PubMed

    Reijonen, Inka; Metzler, Martina; Hartikainen, Helinä

    2016-03-01

    The main objective of this study was to unravel the chemical reactions and processes dictating the potential bioavailability of vanadium (V). In environmental solutions V exists in two stable oxidation states, +IV and +V, of which + V is considered to be more toxic. In this study, the effect of speciation and soil pH on the chemical accessibility of V was investigated with two soils: 1) field soil rather rich in soil organic matter (SOM) and 2) coarse mineral soil low in SOM. Fresh soil samples treated with V(+V) (added as NaVO3) or V(+IV) (added as VOSO4) (pH adjusted to the range 4.0-6.9) were incubated for 3 months at 22 °C. The adsorption tendency of V species was explored by water extraction (Milli-Q water, 1:50 dw/V) and by sequential extraction (0.25 M KCl; 0.1 M KH2/K2HPO4; 0.1 M NaOH; 0.25 M H2SO4, 1:10 dw/V). The potential bioavailability of V was found to be dictated by soil properties. SOM reduced V(+V) to V(+IV) and acted as a sorbent for both species, which lowered the bioaccessibility of V. A high pH, in turn, favored the predominance of the V(+V) species and thus increased the chemical accessibility of V. PMID:26807983

  6. Fertilization and pH effects on processes and mechanisms controlling dissolved inorganic phosphorus in soils

    NASA Astrophysics Data System (ADS)

    Devau, Nicolas; Hinsinger, Philippe; Le Cadre, Edith; Colomb, Bruno; Gérard, Frédéric

    2011-05-01

    We used of a set of mechanistic adsorption models (1-pK TPM, ion exchange and Nica-Donnan) within the framework of the component additive (CA) approach in an attempt to determine the effect of repeated massive application of inorganic P fertilizer on the processes and mechanisms controlling the concentration of dissolved inorganic phosphorus (DIP) in soils. We studied the surface layer of a Luvisol with markedly different total concentrations of inorganic P as the result of different P fertilizer history (i.e. massive or no application for 40 years). Soil pH was made to vary from acid to alkaline. Soil solutions were extracted with water and CaCl 2 (0.01 M). The occurrence of montmorillonite led us to determine the binding properties of P and Ca ions for this clay mineral. Satisfactory results were obtained using generic values for model parameters and soil-specific ones, which were either determined directly by measurements or estimated from the literature. We showed that adsorption largely controlled the variations of DIP concentration and that, because of kinetic constrains, only little Ca-phosphates may be precipitated under alkaline conditions, particularly in the P fertilized treatment. The mineral-P pool initially present in both P treatments did not dissolve significantly during the course of the experiments. The adsorption of Ca ions onto soil minerals also promoted adsorption of P ions through electrostatic interactions. The intensity of the mechanism was high under neutral to alkaline conditions. Changes in DIP concentration as a function of these environmental variables can be related to changes in the contribution of the various soil minerals to P adsorption. The extra P adsorbed in the fertilized treatment compared with the control treatment was mainly adsorbed onto illite. This clay mineral was the major P-fixing constituent from neutral to alkaline pH conditions, because the repulsion interactions between deprotonated hydroxyl surface sites and P

  7. Assessment of Envi-Carb™ as a passive sampler binding phase for acid herbicides without pH adjustment.

    PubMed

    Seen, Andrew; Bizeau, Oceane; Sadler, Lachlan; Jordan, Timothy; Nichols, David

    2014-05-01

    The graphitised carbon solid phase extraction (SPE) sorbent Envi-Carb has been used to fabricate glass fibre filter- Envi-Carb "sandwich" disks for use as a passive sampler for acid herbicides. Passive sampler uptake of a suite of herbicides, including the phenoxyacetic acid herbicides 4-chloro-o-tolyloxyacetic acid (MCPA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 3,6-dichloro-2-methoxybenzoic acid (Dicamba), was achieved without pH adjustment, demonstrating for the first time a suitable binding phase for passive sampling of acid herbicides at neutral pH. Passive sampling experiments with Duck River (Tasmania, Australia) water spiked at 0.5 μg L(-1) herbicide concentration over a 7 d deployment period showed that sampling rates in Duck River water decreased for seven out of eight herbicides, and in the cases of 3,6-dichloro-2-pyridinecarboxylic acid (Clopyralid) and Dicamba no accumulation of the herbicides occurred in the Envi-Carb over the deployment period. Sampling rates for 4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid (Picloram), 2,4-D and MCPA decreased to approximately 30% of the sampling rates in ultrapure water, whilst sampling rates for 2-(4,6-dimethylpyrimidin-2-ylcarbamoylsulfamoyl) benzoic acid, methyl ester (Sulfometuron-methyl) and 3,5,6-Trichloro-2-pyridinyloxyacetic acid (Triclopyr) were approximately 60% of the ultrapure water sampling rate. For methyl N-(2,6-dimethylphenyl)-N-(methoxyacetyl)-D-alaninate (Metalaxyl-M) there was little variation in sampling rate between passive sampling experiments in ultrapure water and Duck River water. SPE experiments undertaken with Envi-Carb disks using ultrapure water and filtered and unfiltered Duck River water showed that not only is adsorption onto particulate matter in Duck River water responsible for a reduction in herbicide sampling rate, but interactions of herbicides with dissolved or colloidal matter (matter able to pass through a 0.2 μm membrane filter) also reduces the herbicide sampling

  8. [Effects of simulated acid rain on respiration rate of cropland system with different soil pH].

    PubMed

    Zhu, Xue-zhu; Zhang, Gao-chuan; Li, Hui

    2009-10-15

    To evaluate the effects of acid rain on the respiration rate of cropland system, an outdoor pot experiment was conducted with paddy soils of pH 5.48 (S1), pH 6.70 (S1) and pH 8.18 (S3) during the 2005-2007 wheat-growing seasons. The cropland system was exposed to acid rain by spraying the wheat foliage and irrigating the soil with simulated rainwater of T1 (pH 6.0), T2 (pH 6.0, ionic concentration was twice as rainwater T1), and T3 (pH 4.4, ionic concentration was twice as rainwater T1), respectively. The static opaque chamber-gas chromatograph method was used to measure CO2 fluxes from cropland system. The results showed that acid rain affected the respiration rate of cropland system through crop plant, and the cropland system could adapt to acid rain. Acid rainwater significantly increased the average respiration rate in alkaline soil (S3) cropland system, while it had no significant effects on the average respiration rate in neutral soil (S2) and acidic soil (S1) cropland systems. During 2005-2006, after the alkaline soil cropland system was treated with rainwater T3, the average respiration rate was 23.6% and 27.6% higher than that of alkaline soil cropland system treated with rainwater T1 and T2, respectively. During March to April, the respiration rate was enhanced with the increase of rainwater ionic concentration, while it was dropped with the decrease of rainwater pH value in acidic soil cropland system. It was demonstrated that soil pH and crop plant played important roles on the respiration rate of cropland system. PMID:19968099

  9. Effect of acid rain pH on leaching behavior of cement stabilized lead-contaminated soil.

    PubMed

    Du, Yan-Jun; Wei, Ming-Li; Reddy, Krishna R; Liu, Zhao-Peng; Jin, Fei

    2014-04-30

    Cement stabilization is a practical approach to remediate soils contaminated with high levels of lead. However, the potential for leaching of lead out of these stabilized soils under variable acid rain pH conditions is a major environmental concern. This study investigates the effects of acid rain on the leaching characteristics of cement stabilized lead contaminated soil under different pH conditions. Clean kaolin clay and the same soil spiked with 2% lead contamination are stabilized with cement contents of 12 and 18% and then cured for 28 days. The soil samples are then subjected to a series of accelerated leaching tests (or semi-dynamic leaching tests) using a simulated acid rain leachant prepared at pH 2.0, 4.0 or 7.0. The results show that the strongly acidic leachant (pH ∼2.0) significantly altered the leaching behavior of lead as well as calcium present in the soil. However, the differences in the leaching behavior of the soil when the leachant was mildly acidic (pH ∼4.0) and neutral (pH ∼7.0) prove to be minor. In addition, it is observed that the lead contamination and cement content levels can have a considerable impact on the leaching behavior of the soils. Overall, the leachability of lead and calcium is attributed to the stability of the hydration products and their consequent influence on the soil buffering capacity and structure. PMID:24637445

  10. Spatial variability of soil carbon, pH, available phosphorous and potassium in organic farm located in Mediterranean Croatia

    NASA Astrophysics Data System (ADS)

    Bogunović, Igor; Pereira, Paulo; Šeput, Miranda

    2016-04-01

    Soil organic carbon (SOC), pH, available phosphorus (P), and potassium (K) are some of the most important factors to soil fertility. These soil parameters are highly variable in space and time, with implications to crop production. The aim of this work is study the spatial variability of SOC, pH, P and K in an organic farm located in river Rasa valley (Croatia). A regular grid (100 x 100 m) was designed and 182 samples were collected on Silty Clay Loam soil. P, K and SOC showed moderate heterogeneity with coefficient of variation (CV) of 21.6%, 32.8% and 51.9%, respectively. Soil pH record low spatial variability with CV of 1.5%. Soil pH, P and SOC did not follow normal distribution. Only after a Box-Cox transformation, data respected the normality requirements. Directional exponential models were the best fitted and used to describe spatial autocorrelation. Soil pH, P and SOC showed strong spatial dependence with nugget to sill ratio with 13.78%, 0.00% and 20.29%, respectively. Only K recorded moderate spatial dependence. Semivariogram ranges indicate that future sampling interval could be 150 - 200 m in order to reduce sampling costs. Fourteen different interpolation models for mapping soil properties were tested. The method with lowest Root Mean Square Error was the most appropriated to map the variable. The results showed that radial basis function models (Spline with Tension and Completely Regularized Spline) for P and K were the best predictors, while Thin Plate Spline and inverse distance weighting models were the least accurate. The best interpolator for pH and SOC was the local polynomial with the power of 1, while the least accurate were Thin Plate Spline. According to soil nutrient maps investigated area record very rich supply with K while P supply was insufficient on largest part of area. Soil pH maps showed mostly neutral reaction while individual parts of alkaline soil indicate the possibility of penetration of seawater and salt accumulation in the

  11. Enhanced-electrokinetic remediation of copper-pyrene co-contaminated soil with different oxidants and pH control.

    PubMed

    Cang, Long; Fan, Guang-Ping; Zhou, Dong-Mei; Wang, Quan-Ying

    2013-02-01

    Electrokinetic (EK) remediation has potential to simultaneously remove heavy metals and organic compounds from soil, but the removal percent of these pollutants is very low in general if no enhancing treatment is applied. This study developed a new enhanced-EK remediation technology to decontaminate a heavy metal-organic compound co-contaminated soil by applying different oxidants and pH control. A red soil was used as a model clayed soil, and was spiked with pyrene and Cu at about 500 mg kg(-1) for both to simulate real situation. Bench-scale EK experiments were performed using four oxidants (H(2)O(2), NaClO, KMnO(4), and Na(2)S(2)O(8)) and controlling electrolyte pH at 3.5 or 10. After the treatments with 1.0 V cm(-1) of voltage gradient for 335 h, soil pH, electrical conductivity, and the concentrations and chemical fractionations of soil pyrene and Cu were analyzed. The results showed that there was significant migration of pyrene and Cu from the soil, and the removal percent of soil pyrene and Cu varied in the range of 30-52% and 8-94%, respectively. Low pH favoured the migration of soil Cu, while KMnO(4) was the best one for the degradation of pyrene among the tested oxidants, although it unfortunately prevented the migration of soil Cu by forming Cu oxide. Application of Na(2)S(2)O(8) and to control the catholyte pH at 3.5 were found to be the best operation conditions for decontaminating the Cu-pyrene co-contaminated soil. PMID:23177009

  12. Soil pH is a Key Determinant of Soil Fungal Community Composition in the Ny-Ålesund Region, Svalbard (High Arctic)

    PubMed Central

    Zhang, Tao; Wang, Neng-Fei; Liu, Hong-Yu; Zhang, Yu-Qin; Yu, Li-Yan

    2016-01-01

    This study assessed the fungal community composition and its relationships with properties of surface soils in the Ny-Ålesund Region (Svalbard, High Arctic). A total of thirteen soil samples were collected and soil fungal community was analyzed by 454 pyrosequencing with fungi-specific primers targeting the rDNA internal transcribed spacer (ITS) region. The following eight soil properties were analyzed: pH, organic carbon (C), organic nitrogen (N), ammonium nitrogen (NH4+-N), silicate silicon (SiO42--Si), nitrite nitrogen (NO2--N), phosphate phosphorus (PO43--P), and nitrate nitrogen (NO3--N). A total of 57,952 reads belonging to 541 operational taxonomic units (OTUs) were found. of these OTUs, 343 belonged to Ascomycota, 100 to Basidiomycota, 31 to Chytridiomycota, 22 to Glomeromycota, 11 to Zygomycota, 10 to Rozellomycota, whereas 24 belonged to unknown fungi. The dominant orders were Helotiales, Verrucariales, Agaricales, Lecanorales, Chaetothyriales, Lecideales, and Capnodiales. The common genera (>eight soil samples) were Tetracladium, Mortierella, Fusarium, Cortinarius, and Atla. Distance-based redundancy analysis (db-rda) and analysis of similarities (ANOSIM) revealed that soil pH (p = 0.001) was the most significant factor in determining the soil fungal community composition. Members of Verrucariales were found to predominate in soils of pH 8–9, whereas Sordariales predominated in soils of pH 7–8 and Coniochaetales predominated in soils of pH 6–7. The results suggest the presence and distribution of diverse soil fungal communities in the High Arctic, which can provide reliable data for studying the ecological responses of soil fungal communities to climate changes in the Arctic. PMID:26955371

  13. Potential of elemental sulfur fertigation to reduce high soil pH for production of highbush blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blueberry is adapted to acidic soil conditions but is often planted in high pH soils by adding elemental sulfur (S) prior to planting. Two pot experiments were carried out in a glasshouse to determine the potential of applying elemental S by fertigation through a drip irrigation system. In the first...

  14. The efficacy of 0.75% bupivacaine with pH adjustment and hyaluronidase for peribulbar blockade: the incidence of prolonged ptosis.

    PubMed

    Mather, C; Smith, J H; Bloom, P A

    1994-01-01

    A prospective, double masked, randomised study was performed to compare the speed of onset of peribulbar anaesthesia using pH adjusted 0.75% bupivacaine, with and without the addition of hyaluronidase. No significant difference in speed of onset occurred due to the addition of hyaluronidase. There were 7 cases of post operative ptosis in the study group, including 1 case of orbital apex syndrome and 2 cases of transient 3rd nerve palsy. This incidence of post operative ptosis using pH adjusted 0.75% bupivacaine was statistically significantly greater than in a matched control group who received a 50:50 mixture of 1% lignocaine and 0.5% bupivacaine with hyaluronidase (p < 0.05). The possible causes of this increased incidence of post operative ptosis are discussed. PMID:8019117

  15. Biogenic precipitation of manganese oxides and enrichment of heavy metals at acidic soil pH

    NASA Astrophysics Data System (ADS)

    Mayanna, Sathish; Peacock, Caroline L.; Schäffner, Franziska; Grawunder, Anja; Merten, Dirk; Kothe, Erika; Büchel, Georg

    2014-05-01

    The precipitation of biogenic Mn oxides at acidic pH is rarely reported and poorly understood, compared to biogenic Mn oxide precipitation at near neutral conditions. Here we identified and investigated the precipitation of biogenic Mn oxides in acidic soil, and studied their role in the retention of heavy metals, at the former uranium mining site of Ronneburg, Germany. The site is characterized by acidic pH, low carbon content and high heavy metal loads including rare earth elements. Specifically, the Mn oxides were present in layers identified by detailed soil profiling and within these layers pH varied from 4.7 to 5.1, Eh varied from 640 to 660 mV and there were enriched total metal contents for Ba, Ni, Co, Cd and Zn in addition to high Mn levels. Using electron microprobe analysis, synchrotron X-ray diffraction and X-ray absorption spectroscopy, we identified poorly crystalline birnessite (δ-MnO2) as the dominant Mn oxide in the Mn layers, present as coatings covering and cementing quartz grains. With geochemical modelling we found that the environmental conditions at the site were not favourable for chemical oxidation of Mn(II), and thus we performed 16S rDNA sequencing to isolate the bacterial strains present in the Mn layers. Bacterial phyla present in the Mn layers belonged to Firmicutes, Actinobacteria and Proteobacteria, and from these phyla we isolated six strains of Mn(II) oxidizing bacteria and confirmed their ability to oxidise Mn(II) in the laboratory. The biogenic Mn oxide layers act as a sink for metals and the bioavailability of these metals was much lower in the Mn layers than in adjacent layers, reflecting their preferential sorption to the biogenic Mn oxide. In this presentation we will report our findings, concluding that the formation of natural biogenic poorly crystalline birnessite can occur at acidic pH, resulting in the formation of a biogeochemical barrier which, in turn, can control the mobility and bioavailability of heavy metals in

  16. Relation of pH and other soil variables to concentrations of Pb, Cu, Zn, Cd, and Se in earthworms

    USGS Publications Warehouse

    Beyer, W.N.; Hensler, G.L.; Moore, J.

    1987-01-01

    Various soil treatments (clay, composted peat, superphosphate, sulfur, calcium carbonate, calcium chloride, zinc chloride, selenous acid) were added to experimental field plots to test the effect of different soil variables on the concentrations of 5 elements in earthworms (Pb, Cu, Zn, Cd, Se). Concentrations of the 5 elements were related to 9 soil variables (soil Pb, soil Cu, soil Zn, pH, organic matter, P, K, Mg, and Ca) with linear multiple regression. Lead concentrations in earthworms were positively correlated with soil Pb and soil organic matter, and negatively correlated with soil pH and soil Mg, with an R2 of 64%. Se concentrations were higher in earthworms from plots amended with Se, and Zn concentrations were higher in earthworms from plots amended with Zn. However, none of the other soil variables had important effects on the concentrations of Cu, Zn, Cd and Se in earthworms. Although some significant statistical relations were demonstrated, the values of r2 of all relations (> 20%) were so low that they had little predictive value.

  17. [Effects of solution pH and simulated acid rain on the behavior of two sulfonylurea herbicides in soil].

    PubMed

    Zhang, Wei; Wang, Jin-Jun

    2007-03-01

    By the methods of batch equilibration and leaching, this paper studied the effects of solution pH and simulated acid rain on the behavior of bensulfuron-methyl and metsulfuron-methyl in soil. The results showed that the adsorption isotherms of these two herbicides fitted Freundlich equation well, and their adsorbed amounts reduced obviously with the increasing pH of water-soil system, which in turn promoted the translocation of the herbicides in soil. The adsorption coefficient (Kf) was positively correlated with soil organic matter and clay contents, while negatively correlated with soil pH. The higher pH of simulated acid rain had a greater contribution on the leaching of the two sulfonylurea herbicides, and their leached amount was increased with increasing acid rain. There was a close relationship between the leaching of the herbicides and the properties of soil. The soils with higher contents of organic matter and clay had a greater retention capability to the herbicides. PMID:17552202

  18. Coupled effect of pH and porous media type on transport and deposition of variably-charged soil colloids in saturated sands

    NASA Astrophysics Data System (ADS)

    Sharma, A.; Kawamoto, K.; Moldrup, P.; de Jonge, L. W.; Komatsu, T.

    2011-12-01

    Understanding colloid transport and deposition in subsurface is essential for predicting colloid-associated contaminant transport and developing effective remedial strategies. Compared to numerous studies using model colloids and model porous media, limited studies have been conducted with natural soil-colloids and porous media. This study investigated transport and deposition of suspended soil-colloids with diameter less than 1 μm extracted from a volcanic ash-soil (VAS colloids) from Nishi-Tokyo, Japan and a red-yellow soil (RYS colloids) from Okinawa, Japan. The extracted soil colloids were applied to 10-cm long saturated sand columns repacked with either Narita sand (mean diameter = 0.64 mm) or Toyoura sand (mean diameter = 0.21 mm) at different flow rates, input concentrations and pH conditions. The pH was adjusted using 0.1 M HCl and 0.01 M NaBr was used as a conservative tracer. Colloid transport and deposition were studied by analyzing colloid effluent concentration breakthrough curves, corresponding deposition profiles and particle size distributions. Based on zeta potential measurements, VAS colloids and Toyoura sand were characterized as pH-dependent surface charge dominant whereas, RYS colloids and Narita sand were categorized as less pH-dependent surface charge dominant colloids and porous media. The results of column studies indicated that decreasing pH decreased the colloid breakthrough curves and increased the deposition of colloids through both porous media. The effect of pH was more significant for VAS colloids than for RYS colloids and for Toyoura sand than for Narita sand, mainly attributed to the pH-dependent surface charge characteristics of VAS colloids and Toyoura sand. The results also demonstrated that if either a colloid or a porous medium is pH-dependent, a significant decrease in breakthrough curves is accompanied by depth-dependent deposition profiles. This study indicated that surface charge properties of colloids coupled with

  19. Influence of Environmental Factors on Antagonism of Fungi by Bacteria in Soil: Clay Minerals and pH

    PubMed Central

    Rosenzweig, William D.; Stotzky, G.

    1979-01-01

    The soil replica plating technique was used to evaluate the influence of clay minerals and pH on antagonistic interactions between fungi and bacteria in soil. In general, the antagonistic activity of bacteria towards filamentous fungi was greater in soil than on agar. The spread of Aspergillus niger through soil was inhibited by Serratia marcescens when the organisms were inoculated into separate sites in soil, and this antagonistic effect was maintained when the soil was amended with 3, 6, 9, or 12% (vol/vol) montmorillonite, whereas the addition of kaolinite at a concentration of 3% reduced the antagonism and at 6, 9, or 12% totally eliminated it. Similar results were obtained with the inhibition of A. niger by Agrobacterium radiobacter and of Penicillium vermiculatum by either S. marcescens or Nocardia paraffinae. When A. niger and S. marcescens were inoculated into the same soil site, A. niger was inhibited in all soils, regardless of clay content, although the extent of inhibition was greater as the concentration of montmorillonite, but not of kaolinite, increased. A. niger was inhibited more when inoculated as spores than as mycelial fragments and when inoculated 96 h after S. marcescens, but a 1% glucose solution reduced the amount of inhibition when the fungus was inoculated 96 h after the bacterium. When the pH of the soil-clay mixtures was altered, the amount of antagonism usually increased as the pH increased. Antagonism appeared to be related to the cation-exchange capacity and the pH of the soil-clay mixtures. Bacillus cereus and another species of Bacillus showed no activity in soil towards A. niger under any of the environmental conditions tested, even though the Bacillus sp. significantly inhibited A. niger and seven other fungi on agar. PMID:16345477

  20. Iron biofortification of wheat grains through integrated use of organic and chemical fertilizers in pH affected calcareous soil.

    PubMed

    Ramzani, Pia Muhammad Adnan; Khalid, Muhammad; Naveed, Muhammad; Ahmad, Rashid; Shahid, Muhammad

    2016-07-01

    Incidence of iron (Fe) deficiency in human populations is an emerging global challenge. This study was conducted to evaluate the potential of iron sulphate combined with biochar and poultry manure for Fe biofortification of wheat grains in pH affected calcareous soil. In first two incubation studies, rates of sulfur (S) and Fe combined with various organic amendments for lowering pH and Fe availability in calcareous soil were optimized. In pot experiment, best rate of Fe along with biochar (BC) and poultry manure (PM) was evaluated for Fe biofortification of wheat in normal and S treated low pH calcareous soil. Fe applied with BC provided fair increase in root-shoot biomass and photosynthesis up to 79, 53 and 67%, respectively in S treated low pH soil than control. Grain Fe and ferritin concentration was increased up to 1.4 and 1.2 fold, respectively while phytate and polyphenol was decreased 35 and 44%, respectively than control in treatment where Fe was applied with BC and S. In conclusion, combined use of Fe and BC could be an effective approach to improve growth and grain Fe biofortification of wheat in pH affected calcareous soil. PMID:27179316

  1. Cr(VI) adsorption/desorption on untreated and mussel shell-treated soil materials: fractionation and effects of pH and chromium concentration

    NASA Astrophysics Data System (ADS)

    Otero, M.; Cutillas-Barreiro, L.; Nóvoa-Muñoz, J. C.; Arias-Estévez, M.; Fernández-Sanjurjo, M. J.; Álvarez-Rodríguez, E.; Núñez-Delgado, A.

    2014-12-01

    We used batch-type experiments to study Cr(VI) adsorption/desorption on granitic material, forest soil, pyritic material, mussel shell, and on forest soil and granitic material amended with 12 t ha-1 shell, considering the effects of varying Cr(VI) concentration and pH. Sequential extractions were carried out to fractionate adsorbed Cr(VI) and to determine the stability of Cr(VI) retention. The pyritic material had the highest Cr(VI) retention capacity, whereas the granitic material showed the lowest retention potential. When high Cr concentrations were added, some saturation of the adsorbent surfaces became apparent, but Cr release remained low. The highest Cr retention was achieved at very acid pH value, with release progressively increasing as a function of increasing pH. The amendment with 12 t ha-1 mussel shell did not cause marked changes in Cr(VI) retention. Adsorption data were satisfactory adjusted to the Freundlich model. Regarding Cr(VI) fractionation, the soluble fraction (weakly bound) was the dominant in mussel shell and in the un-amended and amended granitic material, whereas more stable fractions dominated in the pyritic material (residual fraction) and in the forest soil (oxidizable fraction). In conclusion, the pyritic material presented the highest Cr(VI) retention capacity, while the retention was low and weak on the granitic material; mussel shell was characterized by not marked Cr(VI) retention potential, and it did not cause remarkable increase in Cr(VI) retention when used to amend the granitic material or the forest soil.

  2. Cr(VI) sorption/desorption on untreated and mussel-shell-treated soil materials: fractionation and effects of pH and chromium concentration

    NASA Astrophysics Data System (ADS)

    Otero, M.; Cutillas-Barreiro, L.; Nóvoa-Muñoz, J. C.; Arias-Estévez, M.; Fernández-Sanjurjo, M. J.; Álvarez-Rodríguez, E.; Núñez-Delgado, A.

    2015-04-01

    We used batch-type experiments to study Cr(VI) sorption/desorption on granitic material, forest soil, pyritic material, mussel shell, and on forest soil and granitic material amended with 12 t ha-1 (1.2 kg m -2) shell, considering the effects of varying Cr(VI) concentration and pH. Sequential extractions were carried out to fractionate adsorbed Cr(VI) and to determine the stability of Cr(VI) retention. The pyritic material had the highest Cr(VI) retention capacity, whereas the granitic material showed the lowest retention potential. When high Cr concentrations were added, some saturation of the adsorbent surfaces became apparent, but Cr release remained low. The highest Cr retention was achieved at a very acid pH value, with release progressively increasing as a function of increasing pH. The amendment with 12 t ha-1 mussel shell did not cause marked changes in Cr(VI) retention. Sorption data were satisfactory adjusted to the Freundlich model. Regarding Cr(VI) fractionation, the soluble fraction (weakly bound) was dominant in mussel shell and in the unamended and amended granitic material, whereas more stable fractions dominated in the pyritic material (residual fraction) and in the forest soil (oxidizable fraction). In conclusion, the pyritic material presented the highest Cr(VI) retention capacity, while the retention was low and weak on the granitic material; mussel shell was not characterized by a marked Cr(VI) retention potential, and it did not cause remarkable increase in Cr(VI) retention when used to amend the granitic material or the forest soil.

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

    NASA Astrophysics Data System (ADS)

    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

  4. Gravity-driven transport of three engineered nanomaterials in unsaturated soils and their effects on soil pH and nutrient release.

    PubMed

    Conway, Jon R; Keller, Arturo A

    2016-07-01

    The gravity-driven transport of TiO2, CeO2, and Cu(OH)2 engineered nanomaterials (ENMs) and their effects on soil pH and nutrient release were measured in three unsaturated soils. ENM transport was found to be highly limited in natural soils collected from farmland and grasslands, with the majority of particles being retained in the upper 0-3 cm of the soil profile, while greater transport depth was seen in a commercial potting soil. Physical straining appeared to be the primary mechanism of retention in natural soils as ENMs immediately formed micron-scale aggregates, which was exacerbated by coating particles with Suwannee River natural organic matter (NOM) which promote steric hindrance. Small changes in soil pH were observed in natural soils contaminated with ENMs that were largely independent of ENM type and concentration, but differed from controls. These changes may have been due to enhanced release of naturally present pH-altering ions (Mg(2+), H(+)) in the soil via substitution processes. These results suggest ENMs introduced into soil will likely be highly retained near the source zone. PMID:27108211

  5. 1H NMR Analysis of Cerebrospinal Fluid from Alzheimer's Disease Patients: An Example of a Possible Misinterpretation Due to Non-Adjustment of pH.

    PubMed

    Cruz, Thomas; Balayssac, Stéphane; Gilard, Véronique; Martino, Robert; Vincent, Christian; Pariente, Jérémie; Malet-Martino, Myriam

    2014-01-01

    Two publications from the same research group reporting on the detection of new possible biomarkers for the early diagnosis of Alzheimer's disease (AD), based on the analysis of cerebrospinal fluid samples (CSF) with 1H Nuclear Magnetic Resonance (NMR), are at the origin of the present study. The authors observed significant differences in 1H NMR spectra of CSF from AD patients and healthy controls and, thus, proposed some NMR signals (without attribution) as possible biomarkers. However, this work was carried out in non-standardized pH conditions. Our study aims at warning about a possible misinterpretation that can arise from 1H NMR analyses of CSF samples if pH adjustment is not done before NMR analysis. Indeed, CSF pH increases rapidly after removal and is subject to changes over conservation time. We first identify the NMR signals described by the authors as biomarkers. We then focus on the chemical shift variations of their NMR signals as a function of pH in both standard solutions and CSF samples. Finally, a principal component analysis of 1H NMR data demonstrates that the same CSF samples recorded at pH 8.1 and 10.0 are statistically differentiated. PMID:24958390

  6. Soil lime level (pH) and VA-Mycorrhiza effects on growth responses of sweetgum seedlings

    SciTech Connect

    Davis, E.A.; Young, J.L.; Linderman, R.G.

    1983-01-01

    Sequential greenhouse experiments limed a strongly acid surface and subsurface horizons of phosphorus-deficient Jory clay loam with increments of calcium carbonate to attain a range in soil pH from 5.0 to 8.1. In the absence of vesicular-arbuscular mycorrhizae (VAM), neither the organic matter-rich surface nor the organic matter-poor subsurface horizon supported growth of sweetgum seedlings at any pH despite regular nutrient supplements. The effects of pH, VAM, and soil horizon on nutrient accumulation and plant nutrient concentrations were variable. Nitrogen and phosphorus concentrations were generally higher in the VAM than in control seedlings, which suggests that host plant should be matched with VAM species adapted to particular soil and climate conditions to obtain maximum benefit from a mycorrhizal association. 18 references, 2 figures, 3 tables.

  7. Removal of pollutants by enhanced coagulation combined PAC with variable charge soils: flocs' properties and effect of pH.

    PubMed

    Wang, Yu-Jie; Wu, Chun-De; Duan, Yan; Zhang, Zhi-Lin

    2016-09-01

    This study investigated the properties of flocs and effects of the solution pH on removal of representative pollutants by enhanced coagulation with variable charge soils of South China and polyaluminum chloride (PAC). The results demonstrated that the removal efficiency of turbidity was larger and the aggregated flocs had a faster growth rate, bigger size, denser structure and faster settling rate than those generated by PAC alone, when variable charge soil was used in conjunction with PAC. Additionally, initial solutions pH had meaningful effects on removal of pollutants. With the increase in the pH of the solution, the removal efficiencies of turbidity, algae and heavy metal ions significantly increased. Besides, charge neutralization together with physical entrapment of colloids was the dominant mechanism in enhanced coagulation, and variable charge soil displayed a great adsorption effect. PMID:26829123

  8. Effect of acid rain on the growth and nutrient content of two species of hardwood tree seedlings, and on the pH, microflora and nutrient content of the soil

    SciTech Connect

    Patten, D.K.

    1983-01-01

    The purpose of this study was to determine the sensitivity of two hardwood tree species and three soils to simulated acid rain. The value of infecting tree seedlings with mycorrhizal fungi before transplanting into acid-leached soils was also examined. Dundas silt loam, Hayden loam and Luther loam supporting coleus and sorghum were leached three times each week for 20 weeks with a mixture of H/sub 2/SO/sub 4/ and HNO/sub 3/ adjusted by dilution to pH 5.5, 4.0 or 2.5 Ninety seedlings each of green ash (Fraxinus pennsylvanica Marsh.) and silver maple (Acer saccharinum L.) were transplanted into the soils and were misted twice weekly with the acid solutions. Ash seedlings misted with the pH 2.5 solution were shorter, had a smaller total leaf area and produced less leaf and stem material than ash seedlings misted wth pH 5.5 solution. In contrast, the growth and weight of the maple seedlings increased in response to the pH 2.5 treatments. Leaves of the ash exposed to the pH 2.5 treatment were covered with numerous small lesions, and the cuticular wax was partially worn away. Nitrogen concentrations in the leaves, stems and roots of both species increased with increasing acidity, while phosphorus concentration in the leaves decreased. Soils became increasingly acidic as the acid treatments continued.

  9. Dual purpose recovered coagulant from drinking water treatment residuals for adjustment of initial pH and coagulation aid in electrocoagulation process.

    PubMed

    Jung, Kyung-Won; Ahn, Kyu-Hong

    2016-07-01

    The present study is focused on the application of recovered coagulant (RC) by acidification from drinking water treatment residuals for both adjusting the initial pH and aiding coagulant in electrocoagulation. To do this, real cotton textile wastewater was used as a target pollutant, and decolorization and chemical oxygen demand (COD) removal efficiency were monitored. A preliminary test indicated that a stainless steel electrode combined with RC significantly accelerated decolorization and COD removal efficiencies, by about 52% and 56%, respectively, even at an operating time of 5 min. A single electrocoagulation system meanwhile requires at least 40 min to attain the similar removal performances. Subsequently, the interactive effect of three independent variables (applied voltage, initial pH, and reaction time) on the response variables (decolorization and COD removal) was evaluated, and these parameters were statistically optimized using the response surface methodology. Analysis of variance showed a high coefficient of determination values (decolorization, R(2) = 0.9925 and COD removal, R(2) = 0.9973) and satisfactory prediction second-order polynomial quadratic regression models. Average decolorization and COD removal of 89.52% and 94.14%, respectively, were achieved, corresponding to 97.8% and 98.1% of the predicted values under statistically optimized conditions. The results suggest that the RC effectively played a dual role of both adjusting the initial pH and aiding coagulant in the electrocoagulation process. PMID:26593378

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

    NASA Astrophysics Data System (ADS)

    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 < plagioclase < olivine < dolomite < calcite and was significant for calcite and dolomite treated 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

  11. Short-range variability of soil pH in a regional geochemical survey, communicating uncertainty to the data user

    NASA Astrophysics Data System (ADS)

    Ander, Louise; Knights, Kate; Lark, Murray

    2015-04-01

    The north of Ireland is well-furnished with geochemical data after completion of the Tellus survey of Northern Ireland and the Tellus Border survey of six northern counties of the Republic of Ireland. These data are of considerable interest to the agricultural sector, in particular the data on soil pH. However, a geochemical survey at regional scale cannot resolve significant variation of soil pH, in particular effects of soil management and fine-scale variation of superficial material. This leads to uncertainties in the mapped soil pH which must be accounted for when making decisions about management interventions, including more detailed local sampling. In this poster we show how uncertainty of predicted soil pH, relative to established threshold values, can be quantified by disjunctive kriging. The uncertainty is expressed in terms of probabilities. We show how this can be communicated to the data user by means of the calibrated phrases of the IPCC, using results from recent research on its efficacy to modify its presentation.

  12. Influence of phosphorus sources and rates on soil pH, extractable phosphorus, and DTPA-extractable micronutrients

    SciTech Connect

    Al-Showk, A.M.; Westerman, R.L.; Weeks, D.L.

    1987-07-01

    Two soils (McLain sicl-fine, mixed, thermic, Pachic Argiustoll and Quinlan cl-loamy, mixed, thermic, shallow Typic Ustocrept) that differed in micronutrient content and chemical characteristics were collected from western Oklahoma. Soils were passed through a 2-mm screen and placed in plastic Petri dishes, and five P levels (0, 20, 40, 60, and 80 kg ha/sup -1/) were applied using monocalcium phosphate (MCP), monoammonium phosphate (MAP), and ammonium polyphosphate (APP); the soils were then mixed uniformly. Soils were moistened to approximately 0.33 MPa and incubated for 2 mo at room temperature. Application of P decreased soil pH in both soils, and MAP and APP had a greater effect than MCP, which was attributed to the nitrification of the added ammonium. Bray and Kurtz no. 1 P increased with P application in both soils. Monocalcium phosphate and MAP decreased DTPA-Fe, -Mn, and -Cu in McLain soil. However, high levels of P applied as APP increased DTPA-Fe, -Mn, and -Cu. Phosphorus application, regardless of source, had no effect on DTPA-Zn in McLain soil. Monocalcium phosphate and MAP decreased DTPA-Mn in the Quinlan soil; however; high levels of P applied as APP increased DTPA-Fe. Phosphorus application, regardless of source, had no effect on DTPA-Zn and -Cu in Quinlan soil.

  13. Electrokinetic remediation of a Cu contaminated red soil by conditioning catholyte pH with different enhancing chemical reagents.

    PubMed

    Zhou, Dong-Mei; Deng, Chang-Fen; Cang, Long

    2004-07-01

    The effect of enhancement reagents on the efficiency of electrokinetic remediation of Cu contaminated red soil is evaluated. The enhancement agents were a mix of organic acids, including lactic acid+NaOH, HAc-NaAc and HAc-NaAc+EDTA. The soil was prepared to an initial Cu concentration of 438 mgkg(-1) by incubating the soil with CuSO4 solution in a flooded condition for 1 month. Sequential extraction showed that Cu was partitioned in the soil as follows: 195 mgkg(-1) as water soluble and exchangeable, 71 mgkg(-1) as carbonate bound and 105 mgkg(-1) as Fe and Mn oxides. The results indicate that neutralizing the catholyte pH maintains a lower soil pH compared to that without electrokinetic treatment. The electric currents varied depending upon the conditioning solutions and increased with an increasing applied voltage potential. The electroosmotic flow rate changed significantly when different conditioning enhancing reagents were used. It was observed that lactic acid+NaOH treatments resulted in higher soil electric conductivities than HAc-NaAc and HAc-NaAc+EDTA treatments. Ultimately, enhancement by lactic acid+NaOH resulted in highest removal efficiency (81% Cu removal) from the red soil. The presence of EDTA did not enhance Cu removal efficiencies from the red soil, because EDTA complexed with Cu to form negatively charge complexes, which slowly migrated toward the anode chamber retarding Cu2+ transport towards the cathode. PMID:15172599

  14. The influence of soil pH and humus content on received by Mehlich 3 method nutrients analysis results

    NASA Astrophysics Data System (ADS)

    Tonutare, Tonu; Krebstein, Kadri; Rodima, Ako; Kõlli, Raimo; Künnapas, Allan; Rebane, Jaanus; Penu, Priit; Vennik, Kersti; Soobik, Liina

    2015-04-01

    Soils provide vital ecosystem functions, playing an important role in our economy and in healthy living environment. However, soils are increasingly degrading in Europe and at the global level. Knowledge about the content of major plant available nutrients, i.e. calcium, magnesium, potassium and phosphorus, plays an important role in the sustainable soil management. Mobility of nutrients depends directly on the environmental conditions, two of the most important factors are the pH and organic matter content. Therefore it is essential to have correct information about the content and behaviour of the above named elements in soil, both from the environmental and agronomical viewpoint. During the last decades several extracting solutions which are suitable for the evaluation of nutrient status of soils have been developed for this purpose. One of them is called Mehlich 3 which is widely used in USA, Canada and some European countries (e.g. Estonia, Czech Republic) because of its suitability to extract several major plant nutrients from the soil simultaneously. There are several different instrumental methods used for the analysis of nutrient elements in the soil extract. Potassium, magnesium and calcium are widely analysed by the AAS (atomic absorption spectroscopic) method or by the ICP (inductively coupled plasma) spectroscopic methods. Molecular spectroscopy and ICP spectroscopy were used for the phosphorus determination. In 2011 a new multielemental instrumental method MP-AES (microwave plasma atomic emission spectroscopy) was added to them. Due to its lower detection limits and multielemental character, compared with AAS, and lower exploitation costs, compared with ICP, the MP-AES has a good potential to achieve a leading position in soil nutrient analysis in the future. The objective of this study was to investigate: (i) the impact of soil pH and humus content and (ii) applicability of MP-AES instrumental method for the determination of soil nutrients extracted

  15. Influence of pH on the toxic effects of zinc, cadmium, and pentachlorophenol on pure cultures of soil microorganisms

    SciTech Connect

    Beelen, P. van; Fleuren-Kemilae, A.K.

    1997-02-01

    In this study the effect of acidification of soil pore water on the uptake and toxicity of cationic and anionic pollutants was measured in an experimental model system. The influence of pH on the toxic effects of zinc, cadmium, and pentachlorophenol was studied in buffered suspensions of pure cultures of soil microorganisms. In this system the speciation of the toxicant, the pH, and the biomass are defined, constant, and thus easier to study than in a system with the solid soil matrix and pore water. The mineralization of [{sup 14}C]acetate to {sup 14}CO{sub 2} was used to measure the toxic effects of pollutants on a fungus (Aspergillus niger CBS 121.49), an actinomycete (Streptomyces lividans 66), two Gram-negative Pseudomonas putida strains (MT-2 and DSM 50026), and a gram-positive strain (Rhodococcus erythropolis A177). Large differences in sensitivity were observed between the species. For pentachlorophenol the highest EC50 was 81 mg/L for Pseudomonas putida at pH 8, whereas the lowest was 0.13 mg/L for Aspergillus niger at pH 6. Aspergillus niger was not sensitive to 1,000 mg Zn/L, whereas Pseudomonas putida at pH 7.8 showed the lowest EC50, 0.14 mg Zn/L. When pH was increased, pentachlorophenol became less toxic and showed less sorption to the biomass, whereas zinc and cadmium became more toxic and showed more sorption to the biomass. The results indicate that higher pore-water concentrations due to acidification of zinc- and cadmium-polluted soils may not be accompanied by increased toxic effects on microorganisms because of the relatively low toxicity of these metals in pore water at low pH.

  16. Interrelationships between mycorrhizal symbiosis, soil pH and plant sex modify the performance of Antennaria dioica

    NASA Astrophysics Data System (ADS)

    Varga, Sandra; Kytöviita, Minna-Maarit

    2010-05-01

    AM symbiosis is usually beneficial for plants, but the benefits gained may depend on the soil abiotic factors. In dioecious plants, female and male individuals have different resource demands and allocation patterns. As a consequence of these differences, it is logical to assume that female and male plants differ in their relationship with arbuscular mycorrhizal (AM) fungi, although this has rarely been examined. We used a factorial greenhouse experiment to investigate whether female and male plants in the dioecious model species Antennaria dioica have a different relationship with their AM symbionts under two soil pH levels. In particular, we asked: (1) Do the sexes in A. dioica have sex-specific benefits from AM symbiosis? (2) If so, which sex gains the highest benefit? (3) How does soil pH affect the sex - AM fungal relationship? Our results indicate that the sexes responded similarly to AM symbiosis and pH when mycorrhizal benefit was examined as growth and phosphorus accumulation. However, the sexes differed in response to AM symbiosis in terms of survival, as mortality was increased due to AM symbiosis in female plants whilst the opposite effect was detected in males. The plant-AM fungus relationship was significantly affected by soil pH as lowering the soil pH decreased the benefits gained by the plants from the mycorrhizal fungus. Taken together, our findings indicate that AM symbiosis is beneficial for plants depending on the life history trait considered. In addition, interactions between plants and their AM symbionts are modified by soil factors and the sex of the plant.

  17. Sorption, desorption, and speciation of Cd, Ni, and Fe by four calcareous soils as affected by pH.

    PubMed

    Tahervand, Samaneh; Jalali, Mohsen

    2016-06-01

    The sorption, desorption, and speciation of cadmium (Cd), nickel (Ni), and iron (Fe) in four calcareous soils were investigated at the pH range of 2-9. The results indicated that sorption of Fe by four soils was higher than 80 % at pH 2, while in the case of Cd and Ni was less than 30 %. The most common sequence of metal sorption at pH 2-9 for four soils was in the order of Fe ≫ Ni > Cd. Cadmium and Ni sorption as a function of pH showed the predictable trend of increasing metal sorption with increase in equilibrium pH, while the Fe sorption trend was different and characterized by three phases. With regard to the order of Cd, Ni, and Fe sorption on soils, Cd and Ni showed high affinity for organic matter (OM), whereas Fe had high tendency for calcium carbonate (CaCO3). Results of metal desorption using 0.01 M NaCl demonstrated that metal sorption on soils containing high amounts of CaCO3 was less reversible in comparison to soils containing high OM. In general, Cd and Ni desorption curves were characterized by three phases; (1) the greatest desorption at pH 2, (2) the low desorption at pH 3-7, and (3) the least desorption at pH > 7. The MINTEQ speciation solubility program showed that the percentage of free metals declined markedly with increase of pH, while the percentage of carbonate and hydroxyl species increased. Furthermore, MINTEQ predicted that saturation index (SI) of metals increased with increasing pH. PMID:27147235

  18. Effects of Soil pH on the Biodegradation of Chlorpyrifos and Isolation of a Chlorpyrifos-Degrading Bacterium

    PubMed Central

    Singh, Brajesh K.; Walker, Allan; Morgan, J. Alun W.; Wright, Denis J.

    2003-01-01

    We examined the role of microorganisms in the degradation of the organophosphate insecticide chlorpyrifos in soils from the United Kingdom and Australia. The kinetics of degradation in five United Kingdom soils varying in pH from 4.7 to 8.4 suggested that dissipation of chlorpyrifos was mediated by the cometabolic activities of the soil microorganisms. Repeated application of chlorpyrifos to these soils did not result in the development of a microbial population with an enhanced ability to degrade the pesticide. A robust bacterial population that utilized chlorpyrifos as a source of carbon was detected in an Australian soil. The enhanced ability to degrade chlorpyrifos in the Australian soil was successfully transferred to the five United Kingdom soils. Only soils with a pH of ≥6.7 were able to maintain this degrading ability 90 days after inoculation. Transfer and proliferation of degrading microorganisms from the Australian soil to the United Kingdom soils was monitored by molecular fingerprinting of bacterial 16S rRNA genes by PCR-denaturing gradient gel electrophoresis (DGGE). Two bands were found to be associated with enhanced degradation of chlorpyrifos. Band 1 had sequence similarity to enterics and their relatives, while band 2 had sequence similarity to strains of Pseudomonas. Liquid enrichment culture using the Australian soil as the source of the inoculum led to the isolation of a chlorpyrifos-degrading bacterium. This strain had a 16S rRNA gene with a sequence identical to that of band 1 in the DGGE profile of the Australian soil. DNA probing indicated that genes similar to known organophosphate-degrading (opd) genes were present in the United Kingdom soils. However, no DNA hybridization signal was detected for the Australian soil or the isolated degrader. This indicates that unrelated genes were present in both the Australian soil and the chlorpyrifos-degrading isolate. These results are consistent with our observations that degradation of

  19. Microalgae harvesting by pH adjusted coagulation-flocculation, recycling of the coagulant and the growth media.

    PubMed

    Das, Probir; Thaher, Mahmoud Ibrahim; Abdul Hakim, Mohammed Abdul Quadir Mohd; Al-Jabri, Hareb Mohammed S J; Alghasal, Ghamza Saed H S

    2016-09-01

    Coagulation-flocculation can be considered as one of the least energy intensive microalgae biomass harvesting processes. However, cost of the coagulant and biomass contamination are two critical issues that need to be considered. In this study, ferric chloride (72-96mg/L) was used to effectively harvest Scenedesmus sp. (530mg/L) - grown in BG-11 media and wastewater. Reducing the culture pH below 6.5, greatly improved the harvesting efficiency. Acidic solution (pH 1.0) was very effective to recover (almost 90%) the associated iron from the harvested biomass. Scenedesmus sp. was able to grow in the supernatant and utilize the residual iron in it. Iron extracted solution, with a supplementation of 9.8mg/L ferric chloride, was able to achieve similar harvesting efficiency. The potential recovery of iron from the harvested biomass and its reuse in the harvesting can improve the biomass quality for subsequent downstream processing while reducing the cost. PMID:27318160

  20. Arsenic release from flooded paddy soils is influenced by speciation, Eh, pH, and iron dissolution.

    PubMed

    Yamaguchi, N; Nakamura, T; Dong, D; Takahashi, Y; Amachi, S; Makino, T

    2011-05-01

    Arsenic (As) is highly mobilized when paddy soil is flooded, causing increased uptake of As by rice. We investigated factors controlling soil-to-solution partitioning of As under anaerobic conditions. Changes in As and iron (Fe) speciation due to flooded incubation of two paddy soils (soils A and B) were investigated by HPLC/ICP-MS and XANES. The flooded incubation resulted in a decrease in Eh, a rise in pH, and an increase in the As(III) fraction in the soil solid phase up to 80% of the total As in the soils. The solution-to-soil ratio of As(III) and As(V) (R(L/S)) increased with pH due to the flooded incubation. The R(L/S) for As(III) was higher than that for As(V), indicating that As(III) was more readily released from soil to solution than was As(V). Despite the small differences in As concentrations between the two soils, the amount of As dissolved by anaerobic incubation was lower in soil A. With the development of anaerobic conditions, Fe(II) remained in the soil solid phase as the secondary mineral siderite, and a smaller amount of Fe was dissolved from soil A than from soil B. The dissolution of Fe minerals rather than redox reaction of As(V) to As(III) explained the different dissolution amounts of As in the two paddy soils. Anaerobic incubation for 30 d after the incomplete suppression of microbial activity caused a drop in Eh. However, this decline in Eh did not induce the transformation of As(V) to As(III) in either the soil solid or solution phases, and the dissolution of As was limited. Microbial activity was necessary for the reductive reaction of As(V) to As(III) even when Eh reached the condition necessary for the dominance of As(III). Ratios of released As to Fe from the soils were decreased with incubation time during both anaerobic incubation and abiotic dissolution by sodium ascorbate, suggesting that a larger amount of As was associated with an easily soluble fraction of Fe (hydr) oxide in amorphous phase and/or smaller particles. PMID

  1. Leaching characteristics of toxic constituents from coal fly ash mixed soils under the influence of pH.

    PubMed

    Komonweeraket, Kanokwan; Cetin, Bora; Benson, Craig H; Aydilek, Ahmet H; Edil, Tuncer B

    2015-04-01

    Leaching behaviors of Arsenic (As), Barium (Ba), Calcium (Ca), Cadmium (Cd), Magnesium (Mg), Selenium (Se), and Strontium (Sr) from soil alone, coal fly ash alone, and soil-coal fly ash mixtures, were studied at a pH range of 2-14 via pH-dependent leaching tests. Seven different types of soils and coal fly ashes were tested. Results of this study indicated that Ca, Cd, Mg, and Sr showed cationic leaching pattern while As and Se generally follows an oxyanionic leaching pattern. On the other hand, leaching of Ba presented amphoteric-like leaching pattern but less pH-dependent. In spite of different types and composition of soil and coal fly ash investigated, the study reveals the similarity in leaching behavior as a function of pH for a given element from soil, coal fly ash, and soil-coal fly ash mixtures. The similarity is most likely due to similar controlling mechanisms (e.g., solubility, sorption, and solid-solution formation) and similar controlling factors (e.g., leachate pH and redox conditions). This offers the opportunity to transfer knowledge of coal fly ash that has been extensively characterized and studied to soil stabilized with coal fly ash. It is speculated that unburned carbon in off-specification coal fly ashes may provide sorption sites for Cd resulting in a reduction in concentration of these elements in leachate from soil-coal fly ash mixture. Class C fly ash provides sufficient CaO to initiate the pozzolanic reaction yielding hydrated cement products that oxyanions, including As and Se, can be incorporated into. PMID:25555664

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

    NASA Astrophysics Data System (ADS)

    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

  3. The Molecular Composition of Dissolved Organic Matter in Forest Soils as a Function of pH and Temperature

    PubMed Central

    Roth, Vanessa-Nina; Dittmar, Thorsten; Gaupp, Reinhard; Gleixner, Gerd

    2015-01-01

    We examined the molecular composition of forest soil water during three different seasons at three different sites, using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS). We examined oxic soils and tested the hypothesis that pH and season correlate with the molecular composition of dissolved organic matter (DOM). We used molecular formulae and their relative intensity from ESI-FT-ICR-MS for statistical analysis. Applying unconstrained and constrained ordination methods, we observed that pH, dissolved organic carbon (DOC) concentration and season were the main factors correlating with DOM molecular composition. This result is consistent with a previous study where pH was a main driver of the molecular differences between DOM from oxic rivers and anoxic bog systems in the Yenisei River catchment. At a higher pH, the molecular formulae had a lower degree of unsaturation and oxygenation, lower molecular size and a higher abundance of nitrogen-containing compounds. These characteristics suggest a higher abundance of tannin connected to lower pH that possibly inhibited biological decomposition. Higher biological activity at a higher pH might also be related to the higher abundance of nitrogen-containing compounds. Comparing the seasons, we observed a decrease in unsaturation, molecular diversity and the number of nitrogen-containing compounds in the course of the year from March to November. Temperature possibly inhibited biological degradation during winter, which could cause the accumulation of a more diverse compound spectrum until the temperature increased again. Our findings suggest that the molecular composition of DOM in soil pore waters is dynamic and a function of ecosystem activity, pH and temperature. PMID:25793306

  4. Caribbean mangroves adjust to rising sea level through biotic controls on change in soil elevation

    USGS Publications Warehouse

    McKee, K.L.; Cahoon, D.R.; Feller, Ilka C.

    2007-01-01

    Aim The long-term stability of coastal ecosystems such as mangroves and salt marshes depends upon the maintenance of soil elevations within the intertidal habitat as sea level changes. We examined the rates and processes of peat formation by mangroves of the Caribbean Region to better understand biological controls on habitat stability. Location Mangrove-dominated islands on the Caribbean coasts of Belize, Honduras and Panama were selected as study sites. Methods Biological processes controlling mangrove peat formation were manipulated (in Belize) by the addition of nutrients (nitrogen or phosphorus) to Rhizophora mangle (red mangrove), and the effects on the dynamics of soil elevation were determined over a 3-year period using rod surface elevation tables (RSET) and marker horizons. Peat composition and geological accretion rates were determined at all sites using radiocarbon-dated cores. Results The addition of nutrients to mangroves caused significant changes in rates of mangrove root accumulation, which influenced both the rate and direction of change in elevation. Areas with low root input lost elevation and those with high rates gained elevation. These findings were consistent with peat analyses at multiple Caribbean sites showing that deposits (up to 10 m in depth) were composed primarily of mangrove root matter. Comparison of radiocarbon-dated cores at the study sites with a sea-level curve for the western Atlantic indicated a tight coupling between peat building in Caribbean mangroves and sea-level rise over the Holocene. Main conclusions Mangroves common to the Caribbean region have adjusted to changing sea level mainly through subsurface accumulation of refractory mangrove roots. Without root and other organic inputs, submergence of these tidal forests is inevitable due to peat decomposition, physical compaction and eustatic sea-level rise. These findings have relevance for predicting the effects of sea-level rise and biophysical processes on tropical

  5. The effect of pH and natural microbial phosphatase activity on the speciation of uranium in subsurface soils

    NASA Astrophysics Data System (ADS)

    Beazley, Melanie J.; Martinez, Robert J.; Webb, Samuel M.; Sobecky, Patricia A.; Taillefert, Martial

    2011-10-01

    The biomineralization of U(VI) phosphate as a result of microbial phosphatase activity is a promising new bioremediation approach to immobilize uranium in both aerobic and anaerobic conditions. In contrast to reduced uranium minerals such as uraninite, uranium phosphate precipitates are not susceptible to changes in oxidation conditions and may represent a long-term sink for uranium in contaminated environments. So far, the biomineralization of U(VI) phosphate has been demonstrated with pure cultures only. In this study, two uranium contaminated soils from the Department of Energy Oak Ridge Field Research Center (ORFRC) were amended with glycerol phosphate as model organophosphate source in small flow-through columns under aerobic conditions to determine whether natural phosphatase activity of indigenous soil bacteria was able to promote the precipitation of uranium(VI) at pH 5.5 and 7.0. High concentrations of phosphate (1-3 mM) were detected in the effluent of these columns at both pH compared to control columns amended with U(VI) only, suggesting that phosphatase-liberating microorganisms were readily stimulated by the organophosphate substrate. Net phosphate production rates were higher in the low pH soil (0.73 ± 0.17 mM d -1) compared to the circumneutral pH soil (0.43 ± 0.31 mM d -1), suggesting that non-specific acid phosphatase activity was expressed constitutively in these soils. A sequential solid-phase extraction scheme and X-ray absorption spectroscopy measurements were combined to demonstrate that U(VI) was primarily precipitated as uranyl phosphate minerals at low pH, whereas it was mainly adsorbed to iron oxides and partially precipitated as uranyl phosphate at circumneutral pH. These findings suggest that, in the presence of organophosphates, microbial phosphatase activity can contribute to uranium immobilization in both low and circumneutral pH soils through the formation of stable uranyl phosphate minerals.

  6. Effects of Method and Level of Nitrogen Fertilizer Application on Soil pH, Electrical Conductivity, and Availability of Ammonium and Nitrate in Blueberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blueberries (Vaccinium spp.) require low soil pH and prefer N primarily as ammonium for optimum production. Nitrogen fertilizer methods and rates were evaluated in a new field of ‘Bluecrop’ blueberry (Vaccinium corymbosum L.) to determine their effects on soil pH and availability of ammonium and nit...

  7. Contrasting effects of manure and compost on soil pH, heavy metal availability and growth of Chenopodium album L. in a soil contaminated by pyritic mine waste.

    PubMed

    Walker, David J; Clemente, Rafael; Bernal, M Pilar

    2004-10-01

    Chenopodium album L. was found to be one of the initial plant species colonising a heavy metal-contaminated site, polluted by pyritic (sulphide-rich) waste from the Aznalcóllar mine spill (South-western Spain). This indicates its importance in the re-vegetation of this soil. In a pot experiment, C. album was sown in soil collected from the contaminated site, either non-amended or amended with cow manure or compost produced from olive leaves and olive mill wastewater, in order to study the effect on heavy metal bioavailability and soil pH. In non-amended and compost-amended soils, soil acidification, probably resulting from oxidation and hydrolysis of sulphide, led to increases in the concentrations of soluble sulphate and plant-available Cu, Zn and Mn in the soil (extractable with 0.1 M CaCl(2)). Under these conditions, shoot growth of C. album was negligible and shoot concentrations of Zn (2,420-5,585 microg g(-1)) and Mn (5,513-8,994 microg g(-1)) were phytotoxic. Manure application greatly increased shoot growth and reduced the shoot concentrations of Cu, Zn, and Mn, and their plant-available concentrations in the soil. These effects appeared to be related to an increase of soil pH, due to an inhibition of sulphide oxidation/hydrolysis, relative to the non-amended soil. For metal sulphides-contaminated soil, liable to acidification, manure application appears to be able to enhance the initial stages of re-vegetation, by species such as C. album. PMID:15312738

  8. Influence of soil pH and application rate on the oxidation of calcium sulfite derived from flue gas desulfurization

    SciTech Connect

    Lee, Y.B.; Bigham, J.M.; Dick, W.A.; Jones, E.S.; Ramsier, C.

    2007-01-15

    Calcium sulfite hemihydrate (CaSO{sub 3} {center_dot} 0.5H{sub 2}O), a common byproduct of coal-fired utilities, is fairly insoluble and can decompose to release toxic SO{sub 2} under highly acidic soil conditions; however, it can also oxidize to form gypsum. The objective of this study was to examine the effects of application rate and soil pH on the oxidation of calcium sulfite under laboratory conditions. Oxidation rates measured by release of SO{sub 4}-S to solution decreased with increasing application rate. Leachate SO{sub 4}-S from soils amended with 1.0 to 3.0 g kg{sup -1} CaSO{sub 3} increased over a 21 to 28 d period before reaching a plateau. At 4 g kg{sup -1}, maximum SO{sub 4}-S release was delayed until Week 7. Oxidation and release of SO{sub 4}-S from soil amended with 3.0 g kg{sup -1} calcium sulfite increased markedly with decreasing soil pH. After only 3 d incubation, the concentrations of SO{sub 4}-S in aqueous leachates were 77, 122, 1709 220, and 229 mg L{sup -1} for initial soil pH values of 7.8, 6.5, 5.5, 5.1, and 4.0, respectively. At an initial soil pH value of 4.0, oxidation/dissolution did not increase much after 3 d. At higher pH values, oxidation was maximized after 21 d. These results suggest that autumn surface applications of calcium sulfite in no-till systems should permit ample time for oxidation/dissolution reactions to occur without introducing biocidal effects related to oxygen scavenging. Soil and annual crops can thus benefit from additions of soluble Ca and SO{sub 4} if calcium sulfite is applied in advance of spring planting.

  9. A global meta-analysis of soil exchangeable cations, pH, carbon, and nitrogen with afforestation.

    PubMed

    Berthrong, Sean T; Jobbágy, Esteban G; Jackson, Robert B

    2009-12-01

    Afforestation, the conversion of non-forested lands to forest plantations, can sequester atmospheric carbon dioxide, but the rapid growth and harvesting of biomass may deplete nutrients and degrade soils if managed improperly. The goal of this study is to evaluate how afforestation affects mineral soil quality, including pH, sodium, exchangeable cations, organic carbon, and nitrogen, and to examine the magnitude of these changes regionally where afforestation rates are high. We also examine potential mechanisms to reduce the impacts of afforestation on soils and to maintain long-term productivity. Across diverse plantation types (153 sites) to a depth of 30 cm of mineral soil, we observed significant decreases in nutrient cations (Ca, K, Mg), increases in sodium (Na), or both with afforestation. Across the data set, afforestation reduced soil concentrations of the macronutrient Ca by 29% on average (P < 0.05). Afforestation by Pinus alone decreased soil K by 23% (P < 0.05). Overall, plantations of all genera also led to a mean 71% increase of soil Na (P < 0.05). Mean pH decreased 0.3 units (P < 0.05) with afforestation. Afforestation caused a 6.7% and 15% (P < 0.05) decrease in soil C and N content respectively, though the effect was driven principally by Pinus plantations (15% and 20% decrease, P < 0.05). Carbon to nitrogen ratios in soils under plantations were 5.7-11.6% higher (P < 0.05). In several regions with high rates of afforestation, cumulative losses of N, Ca, and Mg are likely in the range of tens of millions of metric tons. The decreases indicate that trees take up considerable amounts of nutrients from soils; harvesting this biomass repeatedly could impair long-term soil fertility and productivity in some locations. Based on this study and a review of other literature, we suggest that proper site preparation and sustainable harvest practices, such as avoiding the removal or burning of harvest residue, could minimize the impact of afforestation on

  10. The arginine deiminase system facilitates environmental adaptability of Streptococcus equi ssp. zooepidemicus through pH adjustment.

    PubMed

    Xu, Bin; Yang, Xinyi; Zhang, Ping; Ma, Zhe; Lin, Huixing; Fan, Hongjie

    2016-06-01

    The arginine deiminase system (ADS) is a secondary metabolic system found in many different bacterial pathogens and it is often associated with virulence. Here, a systematic study of ADS functions in Streptococcus equi subsp. zooepidemicus (SEZ) was performed. Transcriptional levels of ADS operon genes were observed to be significantly increased when SEZ was grown under acidic conditions. We constructed arcA and arcD deletion mutants (SEZ ΔarcA and SEZ ΔarcD, respectively) and found that SEZ ΔarcA was unable to metabolize arginine and synthesize ammonia; however, arcD deletion resulted in an initial decrease in arginine consumption and ammonia production, followed by recovery to the levels of wild-type SEZ after 24 h of cultivation. Cell extracts of SEZ ΔarcA showed no arginine deiminase (AD) activity, whereas no difference in AD activity between SEZ ΔarcD and wild-type SEZ was observed. SEZ survival tests demonstrated a significant decrease in survival for SEZ ΔarcA, when compared with wild-type SEZ, under acidic conditions and in epithelial cells. These findings indicate that ADS in SEZ contributes to environmental adaptability via ammonia synthesis to reduce pH stress. PMID:27068185

  11. Extraction of oxidized and reduced forms of uranium from contaminated soils: effects of carbonate concentration and pH.

    PubMed

    Zhou, Ping; Gu, Baohua

    2005-06-15

    Uranium may present in soil as precipitated, sorbed, complexed, and reduced forms, which impact its mobility and fate in the subsurface soil environment. In this study, a uranium-contaminated soil was extracted with carbonate/ bicarbonate at varying concentrations (0-1 M), pHs, and redox conditions in an attempt to evaluate their effects on the extraction efficiency and selectivity for various forms of uranium in the soil. Results indicate that at least three differentforms of uranium existed in the contaminated soil: uranium(VI) phosphate minerals, reduced U(IV) phases, and U(VI) complexed with soil organic matter. A small fraction of U(VI) could be sorbed onto soil minerals. The mechanism involved in the leaching of U(VI) by carbonates appears to involve three processes which may act concurrently or independently: the dissolution of uranium(VI) phosphate and other mineral phases, the oxidation-complexation of U(IV) under oxic conditions, and the desorption of U(VI)-organic matter complexes at elevated pH conditions. This study suggests that, depending on site-specific geochemical conditions, the presence of small quantities of carbonate/bicarbonate could result in a rapid and greatly increased leaching and the mobilization of U(VI) from the contaminated soil. Even the reduced U(IV) phases (only sparingly soluble in water) are subjected to rapid oxidation and therefore potential leaching into the environment. PMID:16047778

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

    PubMed

    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

  13. Optimal Soil Eh, pH, and Water Management for Simultaneously Minimizing Arsenic and Cadmium Concentrations in Rice Grains.

    PubMed

    Honma, Toshimitsu; Ohba, Hirotomo; Kaneko-Kadokura, Ayako; Makino, Tomoyuki; Nakamura, Ken; Katou, Hidetaka

    2016-04-19

    Arsenic (As) and cadmium (Cd) concentrations in rice grains are a human health concern. We conducted field experiments to investigate optimal conditions of Eh and pH in soil for simultaneously decreasing As and Cd accumulation in rice. Water managements in the experiments, which included continuous flooding and intermittent irrigation with different intervals after midseason drainage, exerted striking effects on the dissolved As and Cd concentrations in soil through changes in Eh, pH, and dissolved Fe(II) concentrations in the soil. Intermittent irrigation with three-day flooding and five-day drainage was found to be effective for simultaneously decreasing the accumulation of As and Cd in grain. The grain As and Cd concentrations were, respectively, linearly related to the average dissolved As and Cd concentrations during the 3 weeks after heading. We propose a new indicator for expressing the degree to which a decrease in the dissolved As or Cd concentration is compromised by the increase in the other. For minimizing the trade-off relationship between As and Cd in rice grains in the field investigated, water management strategies should target the realization of optimal soil Eh of -73 mV and pH of 6.2 during the 3 weeks after heading. PMID:26999020

  14. Leaching characteristics of toxic constituents from coal fly ash mixed soils under the influence of pH

    SciTech Connect

    Komonweeraket, Kanokwan; Cetin, Bora; Benson, Craig H.; Aydilek, Ahmet H.; Edil, Tuncer B.

    2015-04-15

    Highlights: • The impact of pH on the leaching of elements and metals from fly ash mixed soils. • Generally Ca, Cd, Mg, and Sr follows a cationic leaching pattern. • The leaching of As and Se shows an oxyanionic leaching pattern. • The leaching behavior of elements does not change based on material type. • Different fly ash types show different abilities in immobilizing trace elements. - Abstract: Leaching behaviors of Arsenic (As), Barium (Ba), Calcium (Ca), Cadmium (Cd), Magnesium (Mg), Selenium (Se), and Strontium (Sr) from soil alone, coal fly ash alone, and soil-coal fly ash mixtures, were studied at a pH range of 2–14 via pH-dependent leaching tests. Seven different types of soils and coal fly ashes were tested. Results of this study indicated that Ca, Cd, Mg, and Sr showed cationic leaching pattern while As and Se generally follows an oxyanionic leaching pattern. On the other hand, leaching of Ba presented amphoteric-like leaching pattern but less pH-dependent. In spite of different types and composition of soil and coal fly ash investigated, the study reveals the similarity in leaching behavior as a function of pH for a given element from soil, coal fly ash, and soil-coal fly ash mixtures. The similarity is most likely due to similar controlling mechanisms (e.g., solubility, sorption, and solid-solution formation) and similar controlling factors (e.g., leachate pH and redox conditions). This offers the opportunity to transfer knowledge of coal fly ash that has been extensively characterized and studied to soil stabilized with coal fly ash. It is speculated that unburned carbon in off-specification coal fly ashes may provide sorption sites for Cd resulting in a reduction in concentration of these elements in leachate from soil-coal fly ash mixture. Class C fly ash provides sufficient CaO to initiate the pozzolanic reaction yielding hydrated cement products that oxyanions, including As and Se, can be incorporated into.

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

    PubMed

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Uptake of cadmium, zinc, lead, and copper by earthworms near a zinc-smelting complex: influence of soil pH and organic matter

    SciTech Connect

    Ma, W.; Edelman, T.; van Beersum, I.; Jans, T.

    1983-04-01

    Soil samples were taken from 31 sites near Eindhoven, The Netherlands, mainly along transects of 1 to 15 km from the nearest zinc smelter. Earthworms (Lumbricus rubellus) were taken from the upper 20 cm soil layer and analyzed from accumulation of Cd, Zn, Pb and Cu by atomic absorption spectrophotometry. Cd, Zn, and Pb appeared to be more strongly accumulated by L. rubellus when present in soil with a low pH value. Cu was the only exception in this regard; its uptake by L. rubellus was not significantly influenced by soil pH. The organic matter content of the soil played a significant role only in the worm uptake of Pb. Soil Pb content, soil pH, and soil organic matter content together accounted for almost 70% of the variance in worm Pb content. The results indicate that L. rubellus accumulates Pb more strongly in soil with a low pH and low organic matter content than in soil with higher values of these parameters. The demonstrated influence of pH and organic matter content on element concentration in earthworms emphasizes the importance of soil factors in governing the entrance of toxic metal elements into the food web. (JMT)

  18. Archaeal Abundance across a pH Gradient in an Arable Soil and Its Relationship to Bacterial and Fungal Growth Rates

    PubMed Central

    Sterngren, Anna E.; Rousk, Johannes

    2012-01-01

    Soil pH is one of the most influential factors for the composition of bacterial and fungal communities, but the influence of soil pH on the distribution and composition of soil archaeal communities has yet to be systematically addressed. The primary aim of this study was to determine how total archaeal abundance (quantitative PCR [qPCR]-based estimates of 16S rRNA gene copy numbers) is related to soil pH across a pH gradient (pH 4.0 to 8.3). Secondarily, we wanted to assess how archaeal abundance related to bacterial and fungal growth rates across the same pH gradient. We identified two distinct and opposite effects of pH on the archaeal abundance. In the lowest pH range (pH 4.0 to 4.7), the abundance of archaea did not seem to correspond to pH. Above this pH range, there was a sharp, almost 4-fold decrease in archaeal abundance, reaching a minimum at pH 5.1 to 5.2. The low abundance of archaeal 16S rRNA gene copy numbers at this pH range then sharply increased almost 150-fold with pH, resulting in an increase in the ratio between archaeal and bacterial copy numbers from a minimum of 0.002 to more than 0.07 at pH 8. The nonuniform archaeal response to pH could reflect variation in the archaeal community composition along the gradient, with some archaea adapted to acidic conditions and others to neutral to slightly alkaline conditions. This suggestion is reinforced by observations of contrasting outcomes of the (competitive) interactions between archaea, bacteria, and fungi toward the lower and higher ends of the examined pH gradient. PMID:22706045

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

    PubMed Central

    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

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

    PubMed

    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

  1. Low pH, aluminum and phosphorus coordinately regulate malate exudation through GmALMT1 to improve soybean adaptation to acid soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Low pH, aluminum (Al) toxicity and low phosphorus (P) often coexist in acid soils where crops need to cope with these multiple limiting factors. In this study we found that P addition to acid soils alleviates Al toxicity and enhanced soybean adaptation to acid soils, especially for the P-efficient g...

  2. Sulfamethazine sorption to soil: vegetative management, pH, and dissolved organic matter effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elucidating veterinary antibiotic (VA) interactions with soil is important for assessing and mitigating possible environmental hazards. Objectives of this study were to investigate the effects of vegetative management, soil physical and chemical properties, and manure-derived dissolved organic matte...

  3. Litter quality and pH are strong drivers of carbon turnover and distribution in alpine grassland soils

    NASA Astrophysics Data System (ADS)

    Budge, K.; Leifeld, J.; Hiltbrunner, E.; Fuhrer, J.

    2010-08-01

    Alpine soils are expected to contain large amounts of labile carbon (C) which may become a further source of atmospheric CO2 as a of global warming. However, there is little data available on these soils, and understanding of the influence of environmental factors on soil organic matter (SOM) turnover is limited. We extracted 30 cm deep cores from five grassland sites along a small elevation gradient from 2285 to 2653 m above sea level (a.s.l.) in the central Swiss Alps. Our aim was to determine the quantity, degree of stabilization and mean residence time (MRT) of SOM in relation to site factors such as temperature, soil pH, vegetation, and organic matter (OM) structure. Soil fractions obtained by size and density fractionation revealed a high proportion of labile particulate organic matter C (POM C %) mostly in the uppermost soil layers. POM C in the top 20 cm across the gradient ranged from 39.6-57.6% in comparison to 7.2-29.6% reported in previous studies for lower elevation soils (810-1960 m a.s.l.). At the highest elevation, MRTs measured by means of radiocarbon dating and turnover modelling, increased between fractions of growing stability from 90 years in free POM (fPOM) to 534 years in the mineral-associated fraction (mOM). Depending on elevation and pH, plant community data indicated considerable variation in the quantity and quality of litter input, and these patterns could be reflected in the dynamics of soil C. 13C NMR data confirmed the direct relationship of OM composition to MRT. While temperature is likely to be a major cause for the slow turnover rate observed, other factors such as litter quality and soil pH, as well as the combination of all factors, play an important role in causing small-scale variability of SOM turnover. Ignoring this interplay of controlling factors may impair the performance of models to project SOM responses to environmental change.

  4. Growing up or growing out? How soil pH and light affect seedling growth of a relictual rainforest tree

    PubMed Central

    Offord, Catherine A.; Meagher, Patricia F.; Zimmer, Heidi C.

    2014-01-01

    Seedling growth rates can have important long-term effects on forest dynamics. Environmental variables such as light availability and edaphic factors can exert a strong influence on seedling growth. In the wild, seedlings of Wollemi pine (Wollemia nobilis) grow on very acid soils (pH ∼4.3) in deeply shaded sites (∼3 % full sunlight). To examine the relative influences of these two factors on the growth of young W. nobilis seedlings, we conducted a glasshouse experiment growing seedlings at two soil pH levels (4.5 and 6.5) under three light levels: low (5 % full sun), medium (15 %) and high (50 %). Stem length and stem diameter were measured, stem number and branch number were counted, and chlorophyll and carotenoid content were analysed. In general, increased plant growth was associated with increased light, and with low pH irrespective of light treatment, and pigment content was higher at low pH. Maximum stem growth occurred in plants grown in the low pH/high light treatment combination. However, stem number was highest in low pH/medium light. We hypothesize that these differences in stem development of W. nobilis among light treatments were due to this species' different recruitment strategies in response to light: greater stem growth at high light and greater investment in multiple stem production at low light. The low light levels in the W. nobilis habitat may be a key limitation on stem growth and hence W. nobilis recruitment from seedling to adult. Light and soil pH are two key factors in the growth of this threatened relictual rainforest species. PMID:24790132

  5. Influence of Biochar on Soil pH, Water Holding Capacity, Nitrogen and Carbon Dynamics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent focus of biochar as a soil amendment for improving soil physical-chemical properties and carbon sequestration has revealed knowledge gaps in the research covering different feedstocks in various soil types. Biochars made from four feedstocks (wood pellets [Pseudotsuga menziesii], softw...

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

    NASA Astrophysics Data System (ADS)

    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. Soil pH, total phosphorus, climate and distance are the major factors influencing microbial activity at a regional spatial scale

    PubMed Central

    Cao, Haichuan; Chen, Ruirui; Wang, Libing; Jiang, Lanlan; Yang, Fen; Zheng, Shixue; Wang, Gejiao; Lin, Xiangui

    2016-01-01

    Considering the extensive functional redundancy in microbial communities and great difficulty in elucidating it based on taxonomic structure, studies on the biogeography of soil microbial activity at large spatial scale are as important as microbial community structure. Eighty-four soil samples were collected across a region from south to north China (about 1,000 km) to address the questions if microbial activity displays biogeographic patterns and what are driving forces. These samples represented different soil types, land use and climate. Redundancy analysis and nonmetric multidimensional scaling clearly revealed that soil microbial activities showed distinct differentiation at different sites over a regional spatial scale, which were strongly affected by soil pH, total P, rainfall, temperature, soil type and location. In addition, microbial community structure was greatly influenced by rainfall, location, temperature, soil pH and soil type and was correlated with microbial activity to some extent. Our results suggest that microbial activities display a clear geographic pattern that is greatly altered by geographic distance and reflected by climate, soil pH and total P over large spatial scales. There are common (distance, climate, pH and soil type) but differentiated aspects (TP, SOC and N) in the biogeography of soil microbial community structure and activity. PMID:27170469

  8. Soil pH, total phosphorus, climate and distance are the major factors influencing microbial activity at a regional spatial scale.

    PubMed

    Cao, Haichuan; Chen, Ruirui; Wang, Libing; Jiang, Lanlan; Yang, Fen; Zheng, Shixue; Wang, Gejiao; Lin, Xiangui

    2016-01-01

    Considering the extensive functional redundancy in microbial communities and great difficulty in elucidating it based on taxonomic structure, studies on the biogeography of soil microbial activity at large spatial scale are as important as microbial community structure. Eighty-four soil samples were collected across a region from south to north China (about 1,000 km) to address the questions if microbial activity displays biogeographic patterns and what are driving forces. These samples represented different soil types, land use and climate. Redundancy analysis and nonmetric multidimensional scaling clearly revealed that soil microbial activities showed distinct differentiation at different sites over a regional spatial scale, which were strongly affected by soil pH, total P, rainfall, temperature, soil type and location. In addition, microbial community structure was greatly influenced by rainfall, location, temperature, soil pH and soil type and was correlated with microbial activity to some extent. Our results suggest that microbial activities display a clear geographic pattern that is greatly altered by geographic distance and reflected by climate, soil pH and total P over large spatial scales. There are common (distance, climate, pH and soil type) but differentiated aspects (TP, SOC and N) in the biogeography of soil microbial community structure and activity. PMID:27170469

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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

  11. Sulfate reduction in sulfuric material after re-flooding: Effectiveness of organic carbon addition and pH increase depends on soil properties.

    PubMed

    Yuan, Chaolei; Fitzpatrick, Rob; Mosley, Luke M; Marschner, Petra

    2015-11-15

    Sulfuric material is formed upon oxidation of sulfidic material; it is extremely acidic, and therefore, an environmental hazard. One option for increasing pH of sulfuric material may be stimulation of bacterial sulfate reduction. We investigated the effects of organic carbon addition and pH increase on sulfate reduction after re-flooding in ten sulfuric materials with four treatments: control, pH increase to 5.5 (+pH), organic carbon addition with 2% w/w finely ground wheat straw (+C), and organic carbon addition and pH increase (+C+pH). After 36 weeks, in five of the ten soils, only treatment +C+pH significantly increased the concentration of reduced inorganic sulfur (RIS) compared to the control and increased the soil pore water pH compared to treatment+pH. In four other soils, pH increase or/and organic carbon addition had no significant effect on RIS concentration compared to the control. The RIS concentration in treatment +C+pH as percentage of the control was negatively correlated with soil clay content and initial nitrate concentration. The results suggest that organic carbon addition and pH increase can stimulate sulfate reduction after re-flooding, but the effectiveness of this treatment depends on soil properties. PMID:26024614

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

    PubMed

    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

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

    EPA Science Inventory

    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...

  14. Numerical modeling of the impact of riparian soil water dyanmics on channel width adjustment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Occurrence of streambank failure is closely related to redistribution of soil water that affects soil shear strength and may lead to seepage-induced erosion. Pore-water pressure in a streambank is affected, among others, by infiltrating rainfall, streambank-material texture, riparian vegetation, an...

  15. Spatial distribution of pH and organic matter in urban soils and its implications on site-specific land uses in Xuzhou, China.

    PubMed

    Mao, Yingming; Sang, Shuxun; Liu, Shiqi; Jia, Jinlong

    2014-05-01

    The spatial variation of soil pH and soil organic matter (SOM) in the urban area of Xuzhou, China, was investigated in this study. Conventional statistics, geostatistics, and a geographical information system (GIS) were used to produce spatial distribution maps and to provide information about land use types. A total of 172 soil samples were collected based on grid method in the study area. Soil pH ranged from 6.47 to 8.48, with an average of 7.62. SOM content was very variable, ranging from 3.51 g/kg to 17.12 g/kg, with an average of 8.26 g/kg. Soil pH followed a normal distribution, while SOM followed a log-normal distribution. The results of semi-variograms indicated that soil pH and SOM had strong (21%) and moderate (44%) spatial dependence, respectively. The variogram model was spherical for soil pH and exponential for SOM. The spatial distribution maps were achieved using kriging interpolation. The high pH and high SOM tended to occur in the mixed forest land cover areas such as those in the southwestern part of the urban area, while the low values were found in the eastern and the northern parts, probably due to the effect of industrial and human activities. In the central urban area, the soil pH was low, but the SOM content was high, which is mainly attributed to the disturbance of regional resident activities and urban transportation. Furthermore, anthropogenic organic particles are possible sources of organic matter after entering the soil ecosystem in urban areas. These maps provide useful information for urban planning and environmental management. PMID:24841960

  16. A new method to control electrolytes pH by circulation system in electrokinetic soil remediation.

    PubMed

    Lee, H H; Yang, J W

    2000-10-01

    To simultaneously avoid a decrease of electro-osmotic flow by hydrogen ions and to increase heavy metal precipitation due to hydroxide ions, simulated electrokinetic remediation was conducted in saturated kaolinite specimens loaded with lead(II) using an electrolyte circulation method to control electrolyte pH. At an electrolyte circulation rate of 1.1 ml/min, it was possible to increase the anolyte pH from 2 to 4 and decrease the catholyte pH from 12 to 8. Using electrolyte circulation, it was observed that the rate of decrease of clay pH due to the change of electrolyte pH was reduced. As a result, the operable period was extended and the removal efficiency for lead(II) was also increased. It was observed that most of the effluent lead(II) from the cathode compartment was electroplated onto the cathode and that residual effluent lead(II) did not precipitate onto, or adsorb to, the clay at the anode compartment during circulation. Therefore, there was no need to treat the electrolyte because there was virtually no effluent from the cathode compartment in the circulation system. It was also found that the electrolyte volume required to sustain the electrolytic reaction was sufficient for the whole electrokinetic remediation process. PMID:10946130

  17. The large-scale distribution of ammonia oxidizers in paddy soils is driven by soil pH, geographic distance, and climatic factors

    PubMed Central

    Hu, Hang-Wei; Zhang, Li-Mei; Yuan, Chao-Lei; Zheng, Yong; Wang, Jun-Tao; Chen, Deli; He, Ji-Zheng

    2015-01-01

    Paddy soils distribute widely from temperate to tropical regions, and are characterized by intensive nitrogen fertilization practices in China. Mounting evidence has confirmed the functional importance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in soil nitrification, but little is known about their biogeographic distribution patterns in paddy ecosystems. Here, we used barcoded pyrosequencing to characterize the effects of climatic, geochemical and spatial factors on the distribution of ammonia oxidizers from 11 representative rice-growing regions (75–1945 km apart) of China. Potential nitrification rates varied greatly by more than three orders of magnitude, and were significantly correlated with the abundances of AOA and AOB. The community composition of ammonia oxidizer was affected by multiple factors, but changes in relative abundances of the major lineages could be best predicted by soil pH. The alpha diversity of AOA and AOB displayed contrasting trends over the gradients of latitude and atmospheric temperature, indicating a possible niche separation between AOA and AOB along the latitude. The Bray–Curtis dissimilarities in ammonia-oxidizing community structure significantly increased with increasing geographical distance, indicating that more geographically distant paddy fields tend to harbor more dissimilar ammonia oxidizers. Variation partitioning analysis revealed that spatial, geochemical and climatic factors could jointly explain majority of the data variation, and were important drivers defining the ecological niches of AOA and AOB. Our findings suggest that both AOA and AOB are of functional importance in paddy soil nitrification, and ammonia oxidizers in paddy ecosystems exhibit large-scale biogeographic patterns shaped by soil pH, geographic distance, and climatic factors. PMID:26388866

  18. The large-scale distribution of ammonia oxidizers in paddy soils is driven by soil pH, geographic distance, and climatic factors.

    PubMed

    Hu, Hang-Wei; Zhang, Li-Mei; Yuan, Chao-Lei; Zheng, Yong; Wang, Jun-Tao; Chen, Deli; He, Ji-Zheng

    2015-01-01

    Paddy soils distribute widely from temperate to tropical regions, and are characterized by intensive nitrogen fertilization practices in China. Mounting evidence has confirmed the functional importance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in soil nitrification, but little is known about their biogeographic distribution patterns in paddy ecosystems. Here, we used barcoded pyrosequencing to characterize the effects of climatic, geochemical and spatial factors on the distribution of ammonia oxidizers from 11 representative rice-growing regions (75-1945 km apart) of China. Potential nitrification rates varied greatly by more than three orders of magnitude, and were significantly correlated with the abundances of AOA and AOB. The community composition of ammonia oxidizer was affected by multiple factors, but changes in relative abundances of the major lineages could be best predicted by soil pH. The alpha diversity of AOA and AOB displayed contrasting trends over the gradients of latitude and atmospheric temperature, indicating a possible niche separation between AOA and AOB along the latitude. The Bray-Curtis dissimilarities in ammonia-oxidizing community structure significantly increased with increasing geographical distance, indicating that more geographically distant paddy fields tend to harbor more dissimilar ammonia oxidizers. Variation partitioning analysis revealed that spatial, geochemical and climatic factors could jointly explain majority of the data variation, and were important drivers defining the ecological niches of AOA and AOB. Our findings suggest that both AOA and AOB are of functional importance in paddy soil nitrification, and ammonia oxidizers in paddy ecosystems exhibit large-scale biogeographic patterns shaped by soil pH, geographic distance, and climatic factors. PMID:26388866

  19. Diversity and food web structure of nematode communities under high soil salinity and alkaline pH.

    PubMed

    Salamún, Peter; Kucanová, Eva; Brázová, Tímea; Miklisová, Dana; Renčo, Marek; Hanzelová, Vladimíra

    2014-10-01

    A long-term and intensive magnesium (Mg) ore processing in Slovenské Magnezitové Závody a.s. in Jelšava has resulted in a high Mg content and alkaline pH of the soil environment, noticeable mainly in the close vicinity of the smelter. Nematode communities strongly reacted to the contamination mostly by a decrease in abundance of the sensitive groups. Nematodes from c-p 1 group and bacterivores, tolerant to pollution played a significant role in establishing the dominance at all sites. With increasing distance from the pollution source, the nematode communities were more structured and complex, with an increase in proportion of sensitive c-p 4 and 5 nematodes, composed mainly of carnivores and omnivores. Various ecological indices (e.g. MI2-5, SI, H') indicated similar improvement of farther soil ecosystems. PMID:24996531

  20. Effect of heavy metals on pH buffering capacity and solubility of Ca, Mg, K, and P in non-spiked and heavy metal-spiked soils.

    PubMed

    Najafi, Sarvenaz; Jalali, Mohsen

    2016-06-01

    In many parts of the world, soil acidification and heavy metal contamination has become a serious concern due to the adverse effects on chemical properties of soil and crop yield. The aim of this study was to investigate the effect of pH (in the range of 1 to 3 units above and below the native pH of soils) on calcium (Ca), magnesium (Mg), potassium (K), and phosphorus (P) solubility in non-spiked and heavy metal-spiked soil samples. Spiked samples were prepared by cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) as chloride salts and incubating soils for 40 days. The pH buffering capacity (pHBC) of each sample was determined by plotting the amount of H(+) or OH(-) added (mmol kg(-1)) versus the related pH value. The pHBC of soils ranged from 47.1 to 1302.5 mmol kg(-1) for non-spiked samples and from 45.0 to 1187.4 mmol kg(-1) for spiked soil samples. The pHBC values were higher in soil 2 (non-spiked and spiked) which had higher calcium carbonate content. The results indicated the presence of heavy metals in soils generally decreased the solution pH and pHBC values in spiked samples. In general, solubility of Ca, Mg, and K decreased with increasing equilibrium pH of non-spiked and spiked soil samples. In the case of P, increasing the pH to about 7, decreased the solubility in all soils but further increase of pH from 7, enhanced P solubility. The solubility trends and values for Ca, Mg, and K did not differed significantly in non-spiked and spiked samples. But in the case of P, a reduction in solubility was observed in heavy metal-spiked soils. The information obtained in this study can be useful to make better estimation of the effects of soil pollutants on anion and cation solubility from agricultural and environmental viewpoints. PMID:27168329

  1. Evolution of rill networks on soil-mantled experimental landscapes driven by rainfall and baselevel adjustments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted using a soil-mantled flume subjected to simulated rain and downstream baselevel lowering to quantify the growth, development, and evolution of rill networks. Digital elevation models constructed using photogrammetric techniques greatly facilitated data acquisition and ana...

  2. Soil pH, soil type and replant disease affect growth and nutrient absorption in apple rootstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rootstocks are the foundation of a healthy and productive orchard. They are the interface between the scion and the soil, providing anchorage, water, nutrients, and disease protection that ultimately affect the productivity and sustainability of the orchard. Recent advances in the science of genet...

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

    EPA Science Inventory

    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...

  4. Cadmium Accumulation and Pathological Alterations in the Midgut Gland of Terrestrial Snail Helix pomatia L. from a Zinc Smelter Area: Role of Soil pH.

    PubMed

    Włostowski, Tadeusz; Kozłowski, Paweł; Łaszkiewicz-Tiszczenko, Barbara; Oleńska, Ewa

    2016-04-01

    The purpose of this study was to determine whether cadmium (Cd) accumulation and toxicity in the midgut gland of Helix pomatia snails living in a Cd-contaminated area were related to soil pH. Toxic responses in the midgut gland (i.e., increased vacuolization and lipid peroxidation) occurred in H. pomatia snails exhibiting the highest Cd levels in the gland (265-274 µg/g dry wt) and living on acidic soil (pH 5.3-5.5), while no toxicity was observed in snails accumulating less Cd (90 µg/g) and ranging on neutral soil (pH 7.0), despite the fact that total soil Cd was similar in the two cases. The accumulation of Cd in the gland was directly related to the water extractable Cd in soil, which in turn correlated inversely with soil pH, indicating that this factor had a significant effect on tissue Cd. It appeared further that the occurrence of Cd toxicity was associated with low levels of metallothionein in the gland of snails ranging on acidic soil. PMID:26868644

  5. Adjustments of molecular key components of branchial ion and pH regulation in Atlantic cod (Gadus morhua) in response to ocean acidification and warming.

    PubMed

    Michael, Katharina; Kreiss, Cornelia M; Hu, Marian Y; Koschnick, Nils; Bickmeyer, Ulf; Dupont, Sam; Pörtner, Hans-O; Lucassen, Magnus

    2016-03-01

    Marine teleost fish sustain compensation of extracellular pH after exposure to hypercapnia by means of efficient ion and acid-base regulation. Elevated rates of ion and acid-base regulation under hypercapnia may be stimulated further by elevated temperature. Here, we characterized the regulation of transepithelial ion transporters (NKCC1, NBC1, SLC26A6, NHE1 and 2) and ATPases (Na(+)/K(+) ATPase and V-type H(+) ATPase) in gills of Atlantic cod (Gadus morhua) after 4 weeks of exposure to ambient and future PCO2 levels (550 μatm, 1200 μatm, 2200 μatm) at optimum (10 °C) and summer maximum temperature (18 °C), respectively. Gene expression of most branchial ion transporters revealed temperature- and dose-dependent responses to elevated PCO2. Transcriptional regulation resulted in stable protein expression at 10 °C, whereas expression of most transport proteins increased at medium PCO2 and 18 °C. mRNA and protein expression of distinct ion transport proteins were closely co-regulated, substantiating cellular functional relationships. Na(+)/K(+) ATPase capacities were PCO2 independent, but increased with acclimation temperature, whereas H(+) ATPase capacities were thermally compensated but decreased at medium PCO2 and 10 °C. When functional capacities of branchial ATPases were compared with mitochondrial F1Fo ATP-synthase strong correlations of F1Fo ATP-synthase and ATPase capacities generally indicate close coordination of branchial aerobic ATP demand and supply. Our data indicate physiological plasticity in the gills of cod to adjust to a warming, acidifying ocean within limits. In light of the interacting and non-linear, dose-dependent effects of both climate factors the role of these mechanisms in shaping resilience under climate change remains to be explored. PMID:26688541

  6. High-Resolution Denitrification Kinetics in Pasture Soils Link N2O Emissions to pH, and Denitrification to C Mineralization

    PubMed Central

    Samad, Md Sainur; Bakken, Lars R.; Nadeem, Shahid; Clough, Timothy J.; de Klein, Cecile A. M.; Richards, Karl G.; Lanigan, Gary J.; Morales, Sergio E.

    2016-01-01

    Denitrification in pasture soils is mediated by microbial and physicochemical processes leading to nitrogen loss through the emission of N2O and N2. It is known that N2O reduction to N2 is impaired by low soil pH yet controversy remains as inconsistent use of soil pH measurement methods by researchers, and differences in analytical methods between studies, undermine direct comparison of results. In addition, the link between denitrification and N2O emissions in response to carbon (C) mineralization and pH in different pasture soils is still not well described. We hypothesized that potential denitrification rate and aerobic respiration rate would be positively associated with soils. This relationship was predicted to be more robust when a high resolution analysis is performed as opposed to a single time point comparison. We tested this by characterizing 13 different temperate pasture soils from northern and southern hemispheres sites (Ireland and New Zealand) using a fully automated-high-resolution GC detection system that allowed us to detect a wide range of gas emissions simultaneously. We also compared the impact of using different extractants for determining pH on our conclusions. In all pH measurements, soil pH was strongly and negatively associated with both N2O production index (IN2O) and N2O/(N2O+N2) product ratio. Furthermore, emission kinetics across all soils revealed that the denitrification rates under anoxic conditions (NO+N2O+N2 μmol N/h/vial) were significantly associated with C mineralization (CO2 μmol/h/vial) measured both under oxic (r2 = 0.62, p = 0.0015) and anoxic (r2 = 0.89, p<0.0001) conditions. PMID:26990862

  7. High-Resolution Denitrification Kinetics in Pasture Soils Link N2O Emissions to pH, and Denitrification to C Mineralization.

    PubMed

    Samad, Md Sainur; Bakken, Lars R; Nadeem, Shahid; Clough, Timothy J; de Klein, Cecile A M; Richards, Karl G; Lanigan, Gary J; Morales, Sergio E

    2016-01-01

    Denitrification in pasture soils is mediated by microbial and physicochemical processes leading to nitrogen loss through the emission of N2O and N2. It is known that N2O reduction to N2 is impaired by low soil pH yet controversy remains as inconsistent use of soil pH measurement methods by researchers, and differences in analytical methods between studies, undermine direct comparison of results. In addition, the link between denitrification and N2O emissions in response to carbon (C) mineralization and pH in different pasture soils is still not well described. We hypothesized that potential denitrification rate and aerobic respiration rate would be positively associated with soils. This relationship was predicted to be more robust when a high resolution analysis is performed as opposed to a single time point comparison. We tested this by characterizing 13 different temperate pasture soils from northern and southern hemispheres sites (Ireland and New Zealand) using a fully automated-high-resolution GC detection system that allowed us to detect a wide range of gas emissions simultaneously. We also compared the impact of using different extractants for determining pH on our conclusions. In all pH measurements, soil pH was strongly and negatively associated with both N2O production index (IN2O) and N2O/(N2O+N2) product ratio. Furthermore, emission kinetics across all soils revealed that the denitrification rates under anoxic conditions (NO+N2O+N2 μmol N/h/vial) were significantly associated with C mineralization (CO2 μmol/h/vial) measured both under oxic (r2 = 0.62, p = 0.0015) and anoxic (r2 = 0.89, p<0.0001) conditions. PMID:26990862

  8. An evaluation of remote sensing derived soil pH and average spring groundwater table for ecological assessments

    NASA Astrophysics Data System (ADS)

    Roelofsen, Hans D.; van Bodegom, Peter M.; Kooistra, Lammert; van Amerongen, Jorg J.; Witte, Jan-Philip M.

    2015-12-01

    Ecological assessments such as species distribution modelling and benchmarking site quality towards regulations often rely on full spatial coverage information of site factors such as soil acidity, moisture regime or nutrient availability. To determine if remote sensing (RS) is a viable alternative to traditional data sources of site factor estimates, we analysed the accuracy (using ground truth validation measurements) of traditional and RS sources of pH and mean spring groundwater level (MSL, in m) estimates. Traditional sources were a soil map and hydrological model. RS estimates were obtained using vegetation indicator values (IVs) from a Dutch national system as an intermediate between site factors and spectral response. IVs relate to those site factors that dictate vegetation occurrence, whilst also providing a robust link to canopy spectra. For pH, the soil map and the RS estimate were nearly as accurate. For MSL, the RS estimates were much closer to the observed groundwater levels than the hydrological model, but the error margin of the estimates still exceeded the tolerance range of moisture sensitive vegetation. The relatively high accuracy of the RS estimates was made possible by the availability of local calibration points and large environmental gradients in the study site. In addition, the error composition of the RS estimates could be analysed step-by-step, whereas the traditional sources had to be accepted 'as-is'. Also considering that RS offers high spatial and temporal resolution at low costs, RS offered advantages over traditional sources. This will likely hold true for any other situation where prerequisites of accurate RS estimates have been met.

  9. Characterization of Growing Soil Bacterial Communities across a pH gradient Using H218O DNA-Stable Isotope Probing

    NASA Astrophysics Data System (ADS)

    Welty-Bernard, A. T.; Schwartz, E.

    2014-12-01

    Recent studies have established consistent relationships between pH and bacterial diversity and community structure in soils from site-specific to landscape scales. However, these studies rely on DNA or PLFA extraction techniques from bulk soils that encompass metabolically active and inactive, or dormant, communities, and loose DNA. Dormant cells may comprise up to 80% of total live cells. If dormant cells dominate a particular environment, it is possible that previous interpretations of the soil variables assumed to drive communities could be profoundly affected. We used H218O stable isotope probing and bar-coded illumina sequencing of 16S rRNA genes to monitor the response of actively growing communities to changes in soil pH in a soil microcosm over 14 days. This substrate-independent approach has several advantages over 13C or 15N-labelled molecules in that all growing bacteria should be able to make use of water, allowing characterization of whole communities. We hypothesized that Acidobacteria would increasingly dominate the growing community and that Actinobacteria and Bacteroidetes would decline, given previously established responses by these taxa to soil pH. Instead, we observed the reverse. Actinobacteria abundance increased three-fold from 26 to 76% of the overall community as soil pH fell from pH 5.6 to pH 4.6. Shifts in community structure and decreases in diversity with declining soil pH were essentially driven by two families, Streptomyceaca and Microbacteracea, which collectively increased from 2 to 40% of the entire community. In contrast, Acidobacteria as a whole declined although numbers of subdivision 1 remained stable across all soil pH levels. We suggest that the brief incubation period in this SIP study selected for growth of acid-tolerant Actinobacteria over Acidobacteria. Taxa within Actinomycetales have been readily cultured over short time frames, suggesting rapid growth patterns. Conversely, taxa within Acidobacteria have been

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

    PubMed

    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

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

    PubMed

    Chapman, E Emily V; Dave, Göran; Murimboh, John D

    2013-08-01

    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. PMID:23688951

  12. Stability and mobility of cerium oxide nanoparticles in soils: effects of humic substances, pH and ionic strength

    NASA Astrophysics Data System (ADS)

    Chen, Yirui; Mu, Linlin; Li, Chunyan; Bai, Lingyun; Jacobson, Astrid; Darnault, Christophe

    2015-04-01

    Among the large number of types of nanomaterials used in the field of nanotechnology, cerium oxide nanoparticles (CeO2 NPs) are among the top five most commonly utilized by industry, agriculture and nanomedicine for their unique physico-chemical properties. They are used, for example, in the production of catalysts, as fuel additives, and as polishing agents. Therefore, the release and encounter of CeO2 NPs in the environment following their application, waste disposal, life-cycle and accidents is inevitable. It is critical to examine the behavior of CeO2 NPs released in the environment to assess the risk they pose to the environmental and public health. In particular, little is known about the fate and transport of CeO2 NPs in soils and groundwater. To assess the behavior of CeO2 NPs, it is important to investigate the factors that affect their stability and mobility. Humic substances are a major component of soils and have been shown to have the potential to impact the transport and retention of nanoparticles in soils. Consequently, our study characterizes the impacts of humic and fulvic acids on the stability and mobility of cerium oxides in model porous media under various pH and ionic strength conditions. Batch experiments conducted at various concentrations of humic and fulvic acids coupled with a wide range of pHs and ionic strengths were investigated. Selected parameters from these batch studies were then used as experimental conditions representative of environmental systems to perform column transport experiments to assess of the mobility of CeO2 NPs in saturated porous media, which is the first step in simulating their behavior in soil and groundwater systems.

  13. Active microorganisms in forest soils differ from the total community yet are shaped by the same environmental factors: the influence of pH and soil moisture.

    PubMed

    Romanowicz, Karl J; Freedman, Zachary B; Upchurch, Rima A; Argiroff, William A; Zak, Donald R

    2016-10-01

    Predicting the impact of environmental change on soil microbial functions requires an understanding of how environmental factors shape microbial composition. Here, we investigated the influence of environmental factors on bacterial and fungal communities across an expanse of northern hardwood forest in Michigan, USA, which spans a 500-km regional climate gradient. We quantified soil microbial community composition using high-throughput DNA sequencing on coextracted rDNA (i.e. total community) and rRNA (i.e. active community). Within both bacteria and fungi, total and active communities were compositionally distinct from one another across the regional gradient (bacteria P = 0.01; fungi P < 0.01). Taxonomically, the active community was a subset of the total community. Compositional differences between total and active communities reflected changes in the relative abundance of dominant taxa. The composition of both the total and active microbial communities varied by site across the gradient (P < 0.01) and was shaped by differences in soil moisture, pH, SOM carboxyl content, as well as C and N concentration. Our study highlights the importance of distinguishing between metabolically active microorganisms and the total community, and emphasizes that the same environmental factors shape the total and active communities of bacteria and fungi in this ecosystem. PMID:27387909

  14. Chemical Experiments Measuring ph and Gases on "Planetary" Soil by the HUSAR-5 NXT-based Rover Model

    NASA Astrophysics Data System (ADS)

    Lang, Agota; Bérczi, Szaniszló; Erdélyi, Soma; Nickl, Istvan; Kiss, Daniel; Erdősi, Ferenc; Panyi, Tamas; Szalay, Kristof

    2010-05-01

    program. II: For detecting the gases: We use CZGCO type gas-sensor for the detection of the liberated carbon monoxide or methane. This is a semiconductor based sensor which is heated up to working temperature (ca. 400 °C). The gas is measured as a resistance change signal lead into the NXT. The measured values are observed on the NXT as well as on the "terrestrial control" computer. Construction of the rover in the second mission: the skeleton of the rover was a field-rovering car model. We constructed two arms and a pump from LEGO elements. On the first arm we placed a wireless camera, which could rotate 360°, and also could bend down. The role of the second arm was to stretch and place the indicator ribbon to the surface and move it along a distance to contact with the wet soil. The role of the pump was to pour water on the soil surface. The main idea behind our solution is that water dissolves important chemical components from the soil and the indicator ribbon reports the main chemical characteristics of this chemistry, starting with the pH of the soil. Conclusion: Even the basic experiments can be interesting in the high school's chemistry teaching process if everyday materials are studied. It can be easily connected to planetary surface chemistry, where the soil, the rocks and the atmospheric gases form a common platform with their counterparts on the Earth. Both the experiment and the rover building was a big task for high school students, but they enjoyed the work and learned a lot.

  15. Fate of cadmium at the soil-solution interface: a thermodynamic study as influenced by varying pH at South 24 Parganas, West Bengal, India.

    PubMed

    Karak, Tanmoy; Paul, Ranjit Kumar; Das, Sampa; Das, Dilip K; Dutta, Amrit Kumar; Boruah, Romesh K

    2015-11-01

    A study on the sorption kinetics of Cd from soil solution to soils was conducted to assess the persistence of Cd in soil solution as it is related to the leaching, bioavailability, and potential toxicity of Cd. The kinetics of Cd sorption on two non-contaminated alkaline soils from Canning (22° 18' 48.02″ N and 88° 39' 29.0″ E) and Lakshmikantapur (22° 06' 16.61″ N and 88° 19' 08.66″ E) of South 24 Parganas, West Bengal, India, were studied using conventional batch experiment. The variable soil suspension parameters were pH (4.00, 6.00, 8.18, and 9.00), temperatures (308, 318, and 328 K) and Cd concentrations (5-100 mg L(-1)). The average rate coefficient (kavg) and half-life (t1/2) values indicate that the persistence of Cd in soil solution is influenced by both temperature and soil suspension pH. The concentration of Cd in soil solution decreases with increase of temperature; therefore, Cd sorption on the soil-solution interface is an endothermic one. Higher pH decreases the t 1/2 of Cd in soil solution, indicating that higher pH (alkaline) is not a serious concern in Cd toxicity than lower pH (acidic). Based on the energy of activation (Ea) values, Cd sorption in acidic pH (14.76±0.29 to 64.45±4.50 kJ mol(-1)) is a surface control phenomenon and in alkaline pH (9.33±0.09 to 44.60±2.01 kJ mol(-1)) is a diffusion control phenomenon The enthalpy of activation (ΔH∓) values were found to be between 7.28 and 61.73 kJ mol(-1). Additionally, higher positive energy of activation (ΔG∓) values (46.82±2.01 to 94.47±2.36 kJ mol(-1)) suggested that there is an energy barrier for product formation. PMID:26514796

  16. Low pH, Aluminum, and Phosphorus Coordinately Regulate Malate Exudation through GmALMT1 to Improve Soybean Adaptation to Acid Soils1[W][OA

    PubMed Central

    Liang, Cuiyue; Piñeros, Miguel A.; Tian, Jiang; Yao, Zhufang; Sun, Lili; Liu, Jiping; Shaff, Jon; Coluccio, Alison; Kochian, Leon V.; Liao, Hong

    2013-01-01

    Low pH, aluminum (Al) toxicity, and low phosphorus (P) often coexist and are heterogeneously distributed in acid soils. To date, the underlying mechanisms of crop adaptation to these multiple factors on acid soils remain poorly understood. In this study, we found that P addition to acid soils could stimulate Al tolerance, especially for the P-efficient genotype HN89. Subsequent hydroponic studies demonstrated that solution pH, Al, and P levels coordinately altered soybean (Glycine max) root growth and malate exudation. Interestingly, HN89 released more malate under conditions mimicking acid soils (low pH, +P, and +Al), suggesting that root malate exudation might be critical for soybean adaptation to both Al toxicity and P deficiency on acid soils. GmALMT1, a soybean malate transporter gene, was cloned from the Al-treated root tips of HN89. Like root malate exudation, GmALMT1 expression was also pH dependent, being suppressed by low pH but enhanced by Al plus P addition in roots of HN89. Quantitative real-time PCR, transient expression of a GmALMT1-yellow fluorescent protein chimera in Arabidopsis protoplasts, and electrophysiological analysis of Xenopus laevis oocytes expressing GmALMT1 demonstrated that GmALMT1 encodes a root cell plasma membrane transporter that mediates malate efflux in an extracellular pH-dependent and Al-independent manner. Overexpression of GmALMT1 in transgenic Arabidopsis, as well as overexpression and knockdown of GmALMT1 in transgenic soybean hairy roots, indicated that GmALMT1-mediated root malate efflux does underlie soybean Al tolerance. Taken together, our results suggest that malate exudation is an important component of soybean adaptation to acid soils and is coordinately regulated by three factors, pH, Al, and P, through the regulation of GmALMT1 expression and GmALMT1 function. PMID:23341359

  17. Cold, pH and salt tolerant Penicillium spp. inhabit the high altitude soils in Himalaya, India.

    PubMed

    Dhakar, Kusum; Sharma, Avinash; Pandey, Anita

    2014-04-01

    Twenty five fungal cultures (Penicillium spp.), isolated from soil samples from the high altitudes in the Indian Himalayan region, have been characterized following polyphasic approach. Colony morphology performed on five different media gave varying results; potato dextrose agar being the best for the vegetative growth and sporulation as well. Microscopic observations revealed 18 isolates to be biverticillate and 7 monoverticillate. Based on the phenotypic characters (colony morphology and microscopy), all the isolates were designated to the genus Penicillium. Exposure to low temperature resulted in enhanced sporulation in 23 isolates, while it ceased in case of two. The fungal isolates produced watery exudates in varying amount that in many cases increased at low temperature. All the isolates could grow between 4 and 37 °C, (optimum 24 °C), hence considered psychrotolerant. While all the isolates could tolerate pH from 2 to 14 (optimum 5-9), 7 isolates tolerated pH 1.5 as well. While all the fungal isolates tolerated salt concentration above 10 %; 10 isolates showed tolerance above 20 %. Based on ITS region (ITS1-5.8S-ITS2) analysis the fungal isolates belonged to 25 different species of Penicillium (showing similarity between 95 and 100 %). Characters like tolerance for low temperature, wide range of pH, and high salt concentration, and enhancement in sporulation and production of secondary metabolites such as watery exudates at low temperature can be attributed to the ecological resilience possessed by these fungi for survival under low temperature environment of mountain ecosystem. PMID:24233773

  18. Effectiveness of the bran media and bacteria inoculum treatments in increasing pH and reducing sulfur-total of acid sulfate soils

    NASA Astrophysics Data System (ADS)

    Taufieq, Nur Anny Suryaningsih; Rahim, Sahibin Abdul; Jamil, Habibah

    2013-11-01

    This study was carried out to determine the effectiveness ofsulfate reducing bacteria (SRB) in using bran as a source of food and energy, and to see the effectiveness of the bran media and bacteria inoculums treatments for pH and sulfur-total of acid sulfate reduction insoils. This study used two factors in group random designs with four treatments for bacteria inoculum of B1 (1%), B2 (5%), B3 (10%), B4 (15%) and two treatments for organic media (bran) of D1 (1:1) and D2 (1:19). Based on three replications, the combination resulted in a total of 24 treatments. Soil pH was measured using the Duddridge and Wainright method and determination of sulfate content in soil was conducted by the spectrophotometry method. The data obtained was analyzed for significance by Analysis of Variance and the Least Significant Difference Test. The pH of the initial acid sulfate soils ranged from 3 to 4 and the soil sulfur-total ranged from 1.4% to 10%. After mixing sulfate reducing bacteria with the bran mediaand incubated for four days, the pH of the acid sulfate soils increased from 3.67 to 4.20, while the soil sulfur-total contents had been reduced by 2.85% to 0.35%. This experiment has proven that an acid sulfate soil with low pH is a good growth medium for the sulfate reducing bacteria. The bestincubation period to achieve an effective bioremediation resultthrough sulfate percentage reduction by sulfate reducing bacteria was 10 days, while the optimum bran media dose was 1:19, and the bacteria inoculums dose was 10%.

  19. The influence of continuous rice cultivation and different waterlogging periods on morphology, clay mineralogy, Eh, pH and K in paddy soils.

    PubMed

    Bahmanyar, M A

    2007-09-01

    The effect of different rice cultivation periods on the properties of selected soils in alluvial plain were studied in Mazandaran province (north of Iran) in 2004. Soils were sampled form 0, 6, 16, 26 and over 40 years rice cultivation fields. In each treatment three soil profiles and six nearby auger holes were studied. The present study results indicated that continuous rice cultivation have changed soil moisture regime from xeric to aquic, soil color from brown to grayish, surface horizons from mollic to ochric epipedon and soil structure changed from granular or blocky to massive. Therefore, the soil order has changed from Mollisols to Inceptisols. No illuviation and eluviation of clay minerals occurred as a consequence of rice cultivation. X-ray diffraction analysis showed that clay minerals in non-rice cultivated field were illite, vermiculite, montmorillonite, kaolinite and chlorite, but in rice field were illite, montmorillonite, kaolinite and chlorite, respectively. In contrast of montmorillonite, the amount of illite and vermiculite have been decreased by increasing periods of rice cultivation. The pH values of the saturated soil surface in six weeks past plantation have shifted toward neutrality. While Eh value of non-paddy soils were about +90 mv, surface horizons of paddy soils at field conditions had Eh value about +40, -12, -84, -122 mv, respectively. The amounts of organic matter and available Fe, Mn, Zn and Cu were increased whereas available K was decreased in paddy soils. PMID:19090186

  20. [Effects of soil pH value on the bioavailability and fractionation of rare earth elements in wheat seedling (Triticum aestivum L.)].

    PubMed

    Cao, Xinde; Ding, Zhuhong; Hu, Xin; Wang, Xiaorong

    2002-01-30

    The effect of soil pH value on the bioavailability and fractionation of rare earth elements (REEs) in wheat seedling (Triticum aestivum L.) were investigated. The results showed that the concentration of REEs in wheat decreased with increasing pH value, and their inter-relationship was best expressed as quadratic equation, with correlation coefficients from 0.6003 to 0.9572. The response of individual elements to pH value change tended to be Ce > La > Nd > Sm > Gd > Yb > Eu, with Ce most sensitive to changing pH conditions and Eu lest. Chemical fractionation indicated that the order of REEs concentration in three fractions could be as follows: B2(NH2OH.HCl extraction) > B3(H2O2-NH4Ac extract) > B1(HAc extract). The increase of pH value resulted in transformation from B1 to B2 and B3. Multiple regression analysis was utilized to obtain the regression equations for prediction plant uptake of REEs. B1 fraction was most available to wheat. Meanwhile, it was found that the fractionation factors of REEs in wheat were negatively correlated with the soil pH value. PMID:11987417

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

    PubMed Central

    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 collected soil samples for the measurement of potential denitrification activity and quantification of the size of the denitrifying community by quantitative PCR of the narG, napA, nirS, nirK, and nosZ denitrification genes. Overall, our results indicate that soil pH is of importance in determining the nature of denitrification end products. Thus, we found that the N2O/(N2O + N2) ratio increased with decreasing pH due to changes in the total denitrification activity, while no changes in N2O production were observed. Denitrification activity and N2O emissions measured under laboratory conditions were correlated with N fluxes in situ and therefore reflected treatment differences in the field. The size of the denitrifying community was uncoupled from in situ N fluxes, but potential denitrification was correlated with the count of NirS denitrifiers. Significant relationships were observed between nirS, napA, and narG gene copy numbers and the N2O/(N2O + N2) ratio, which are difficult to explain. However, this highlights the need for further studies combining analysis of denitrifier ecology and quantification of denitrification end products for a comprehensive understanding of the regulation of N fluxes by denitrification. PMID:20118356

  2. Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

    PubMed

    Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

    2016-02-01

    Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising. PMID:26629644

  3. Solid-solution partitioning of organic matter in soils as influenced by an increase in pH or Ca concentration.

    PubMed

    Oste, L A; Temminghoff, E J M; van Riemsdijk, W H

    2002-01-15

    Organic matter is an important component of soil with regard to the binding of contaminants. Hence, the partitioning of organic matter influences the partitioning of soil contaminants. The partitioning of organic matter is, among other factors, influenced by the ionic composition and ionic strength of the soil solution. This study focuses on the behavior of organic matter after a change in the ionic composition of the soil solution, particularly in Ca concentration and pH. Different amounts of Ca(NO3)2 and NaOH were added to soil suspensions. The dissolved organic carbon (DOC) concentration increased with increasing pH (addition of NaOH), whereas an increase in Ca (addition of Ca(NO3)2) had the opposite effect. A stronger increase in DOC was observed if a single dose of NaOH was added, compared to a gradual addition of the same amount of NaOH. Cation binding by organic matter in the supernatant was calculated using the NICA-Donnan model. The log DOC concentration appeared to be correlated to the Donnan potential, calculated under the assumption that all DOC equals humic acid. This correlation was found for all eight neutral to acidic soils used in this study, although the slopes and elevations of the regression lines varied. The slope varied by a factor of 2 and the elevation appeared to be strongly influenced by the DOC concentration in the untreated soils, which is related to the total organic matter in the soil. Finally, we predicted the Donnan potential on the basis of an extraction of untreated soil with 0.03 M NaNO3, and the total additions of Ca(NO3)2 and NaOH. Comparison of these predictions with speciation calculations in solution showed a good correlation, indicating that a combination of one batch experiment and the presented calculation procedure can provide good estimations of DOC concentrations after addition of chemicals. PMID:11831217

  4. Aluminium Uptake and Translocation in Al Hyperaccumulator Rumex obtusifolius Is Affected by Low-Molecular-Weight Organic Acids Content and Soil pH

    PubMed Central

    Vondráčková, Stanislava; Száková, Jiřina; Drábek, Ondřej; Tejnecký, Václav; Hejcman, Michal; Müllerová, Vladimíra; Tlustoš, Pavel

    2015-01-01

    Background and Aims 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. Methods 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. Results 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. Conclusions 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. PMID:25880431

  5. In situ production of bacterial branched tetraether lipids in the lower Yangtze River: Implications for soil-derived pH and temperature proxies

    NASA Astrophysics Data System (ADS)

    He, L.; Li, C.; Yang, S.; Zhang, C.

    2013-12-01

    Large rivers play a major role in transporting terrestrial material to the ocean and deposits on continental margins can serve as archives for paleo continental climate studies. Branched glycerol diakly glycerol tetraethers (bGDGTs) are predominantly found in soil, which can serve as proxies for paleo continental air temperature and paleo soil pH. Recently, however, in situ production of bGDGTs in aquatic systems has been observed. The goal of this study was to evaluate whether bGDGTs are produced in situ in the lower Yangtze River and how this in situ production might affect the temperature and pH proxies derived from the soil bGDGTs. Suspended particulate matter (SPM) was collected at three depth locations (left, central, right) of the river (<0.5 m depth) on a biweekly basis between December 2010 and July 2011 at the Datong hydrological station, which is about 600 km upstream of the Yangtze River mouth. Branched GDGTs from the SPM were extracted as core lipids (C-bGDGTs representing fossil lipids from soil)- and polar lipids (P-bGDGTs representing in situ production of lipids in the river water) using liquid chromatography-mass spectrometry. Our results showed that P-bGDGTs account for 4.2-10.6% of total bGDGTs. The flux of P-bGDGTs remained relatively constant in winter (December-January) and summer (June and July) (2.47-5.29 g/day) with higher values (12.39-14.67 g/day) occurred in April and May; whereas the flux of C-bGDGTs increased steady from January (19.21 g/day) to May (175 g/day) followed by an decrease to 122.15 g/day in July. The C- and P-bGDGT derived proxies showed large differences in mean annual air temperature (MAAT) and pH. Comparison with soil samples collected at the Datong station indicates that the C-bGDGTs in the river water reflected the MAAT and soil pH of the region whereas the P-bGDGT-derived values did not. These results suggest that there may be a constant portion of in situ production of bGDGTs in the lower Yangtze River. That

  6. Enriched Seawater Delivery System to Support In Situ Ocean Acidification Experiments using Carbon Dioxide for pH Adjustment of Seawater

    NASA Astrophysics Data System (ADS)

    Kirkwood, W. J.; Peltzer, E. T.; Walz, P. M.; Shane, F.; Kecy, C.; Headley, K. L.; Herlien, B.; Maughan, T.; Scholfield, J.; Salamy, K. A.; O'Reilly, T.; Brewer, P. G.

    2011-12-01

    A series of Free Ocean CO2 Enrichment (FOCE) experiments are underway or are in planning to perform in situ ocean acidification research at a number of locations around the world. One of the most challenging locations is in Monterey Bay at the site of the Monterey Accelerated Research System, the United States test facility for cabled observatories. This site is located at 890 m deep and 4 0C within the local oxygen minimum zone and approximately 50 kilometers from shore. At this depth and temperature the behavior of liquid CO2 presents various challenges that had to be addressed in order to provide the low pH seawater needed for the FOCE apparatus to perform as desired. To solve this challenge a team of engineers and scientists at the Monterey Bay Aquarium Research Institute (MBARI) have developed a standalone device referred to as the Enriched Seawater Delivery System. Simple injections of seawater saturated at one atmosphere with CO2 demonstrated that the FOCE unit itself performs as designed. However, providing a consistent source of CO2 enriched pH altered seawater within the design criteria proved to be an imposing problem which when solved could have a broader impact in the oceanographic community. The decision was made to build a stand-alone device separate from the FOCE flume to perform in situ CO2 experiments in conditions where CO2 hydrate can form. Challenges to be over-come by this work included: (1) liquid CO2 is buoyant at the prescribed depth; (2) minimizing the formation of hydrates while manufacturing the CO2 enriched seawater. Because CO2 hydrate is denser than seawater, management of the phases and stability of liquid CO2 was necessary to prevent clogging within the delivery system. Our earliest field experiments demonstrated that containing and controlling the CO2 and the CO2-enriched seawater is difficult and makes the metering of the enriched fluid with on demand milliliter per second precision an extremely challenging problem. The Enriched

  7. Influence of In Vitro Assay pH and Extractant Composition on As Bioaccessibility in Contaminated Soils

    EPA Science Inventory

    In vitro bioaccessibility assays are often utilised to determine the potential human exposure to soil contaminants through soil ingestion. Comparative studies have identified inconsistencies in the results obtained with different in vitro assays. In this study we investigated the...

  8. The gamma dose assessment and pH correlation for various soil types at Batu Pahat and Kluang districts, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Johar, Saffuwan Mohamed; Embong, Zaidi; Tajudin, Saiful Azhar Ahmad

    2016-01-01

    An assessment of absorbed dose and radiation hazard index as well as its relationship with soil pH was performed in this study. The area was chosen due to its variety of soil types from the Alluvial and the Sedentary group. The radioactivity concentration levels and the soil acidity were measured using the Canberra GC3518 high pure germanium with a relative efficiency of 35% at 1.3 MeV and the Takemura Soil pH and Moisture Tester (DM15), respectively. Overall results show the Holyrood-Lunas soil of Alluvial group recorded the highest external terrestrial gamma radiation dose rate (TGRD) of 286.4±37.9 nGy h-1 and radioactivity concentrations of 78.1±8.9 Bq kg-1 (226Ra), 410.5±55.4 Bq kg-1 (232Th) and 56.4±8.8 Bq kg-1 (40K), respectively, while the Peat soil of Alluvial group recorded the lowest TGRD of 4.4±2.7 nGy h-1 and radioactivity concentrations of 4.8±1.7 Bq kg-1 (226Ra), 3.1±1.1 Bq kg-1 (232Th) and 6.1±2.0 Bq kg-1 (40K), respectively. The estimated mean outdoor annual effective dose, the mean radium equivalent activity (Req) and the mean external (Hext) and internal hazard index (Hint) associated with the alluvial and sedentary soil group were evaluated at 0.15 and 0.20 mSv, 280 and 364 Bq kg-1, Hext = 0.78 and 1.01, and Hint = 0.93 and 1.26, respectively. Correlation analysis between 238U, 232Th and 40K with soil pH level for alluvial group was r = +0.68, +0.48 and 0, respectively, while for sedentary soil, the Pearson's, r = -0.30, -0.90 and +0.14, respectively.

  9. 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

    NASA Astrophysics Data System (ADS)

    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.

  10. Carbon Loss and Germinability, Viability, and Virulence of Chlamydospores of Fusarium solani f. sp. phaseoli After Exposure to Soil at Different pH Levels, Temperatures, and Matric Potentials.

    PubMed

    Mondal, S N; Hyakumachi, M

    1998-02-01

    ABSTRACT (14)C-labeled chlamydospores of Fusarium solani f. sp. phaseoli were exposed to soil at 5, 15, 25, or 30 degrees C at pH 5 or 8 and water potential of -1 kPa or to soil at 0, -1, or -10 kPa at 25 degrees C at pH 6.9. Total carbon loss was greatest at 25 or 30 degrees C at pH 8 and -1 kPa. (14)CO(2) from respiration of chlamydospores and from soil microbes utilizing chlamydospore exudates accounted for the largest share of total carbon loss under all conditions. (14)(CO)(2) from soil microbial metabolism of (14)CO(2) exudates of chlamydospores was greatest in soil at 15, 25, and 30 degrees C, pH 8, and at either -1 or -10 kPa. Chlamydospore germinability in the absence of a C source (nutrient independence), viability in potato-dextrose broth, and virulence to kidney bean declined rapidly after exposure to soil at high temperatures (25 and 30 degrees C), pH 8, and the higher matric potentials (0 to-1 kPa). By contrast, germinability remained high (>50%), as did virulence, in soil at 5 degrees C and -10 kPa even after 70 days of incubation. Carbon loss was inversely correlated with germinability, viability, and virulence after exposure to soil at different pH levels, temperatures, and matric potentials. PMID:18944984

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

    PubMed

    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

  12. The Community Structures of Prokaryotes and Fungi in Mountain Pasture Soils are Highly Correlated and Primarily Influenced by pH.

    PubMed

    Lanzén, Anders; Epelde, Lur; Garbisu, Carlos; Anza, Mikel; Martín-Sánchez, Iker; Blanco, Fernando; Mijangos, Iker

    2015-01-01

    Traditionally, conservation and management of mountain pastures has been managed solely on the basis of visible biota. However, microorganisms play a vital role for the functioning of the soil ecosystem and, hence, pasture sustainability. Here, we studied the links between soil microbial (belowground) community structure (using amplicon sequencing of prokaryotes and fungi), other soil physicochemical and biological properties and, finally, a variety of pasture management practices. To this aim, during two consecutive years, we studied 104 environmental sites characterized by contrasting elevation, habitats, bedrock, and pasture management; located in or near Gorbeia Natural Park (Basque Country/Spain). Soil pH was found to be one of the most important factors in structuring soil microbial diversity. Interestingly, we observed a striking correlation between prokaryotic, fungal and macrofauna diversity, likely caused by interactions between these life forms. Further studies are needed to better understand such interactions and target the influence of different management practices on the soil microbial community, in face of the significant heterogeneity present. However, clearing of bushes altered microbial community structure, and in sites with calcareous bedrock also the use of herbicide vs. mechanical clearing of ferns. PMID:26640462

  13. The Community Structures of Prokaryotes and Fungi in Mountain Pasture Soils are Highly Correlated and Primarily Influenced by pH

    PubMed Central

    Lanzén, Anders; Epelde, Lur; Garbisu, Carlos; Anza, Mikel; Martín-Sánchez, Iker; Blanco, Fernando; Mijangos, Iker

    2015-01-01

    Traditionally, conservation and management of mountain pastures has been managed solely on the basis of visible biota. However, microorganisms play a vital role for the functioning of the soil ecosystem and, hence, pasture sustainability. Here, we studied the links between soil microbial (belowground) community structure (using amplicon sequencing of prokaryotes and fungi), other soil physicochemical and biological properties and, finally, a variety of pasture management practices. To this aim, during two consecutive years, we studied 104 environmental sites characterized by contrasting elevation, habitats, bedrock, and pasture management; located in or near Gorbeia Natural Park (Basque Country/Spain). Soil pH was found to be one of the most important factors in structuring soil microbial diversity. Interestingly, we observed a striking correlation between prokaryotic, fungal and macrofauna diversity, likely caused by interactions between these life forms. Further studies are needed to better understand such interactions and target the influence of different management practices on the soil microbial community, in face of the significant heterogeneity present. However, clearing of bushes altered microbial community structure, and in sites with calcareous bedrock also the use of herbicide vs. mechanical clearing of ferns. PMID:26640462

  14. Extraction of heavy metals from a contaminated soil using citrate-enhancing extraction by pH control and ultrasound application.

    PubMed

    Furukawa, Makoto; Tokunaga, Shuzo

    2004-01-01

    A novel extraction method has been developed for remediation of a heavy-metal contaminated soil. Citrate was used as environmentally-friendly extractant to remove Pb, Zn, Cd, and Cu. Heavy metals were extracted effectively at two different pH regions around 2 and 4-5. Kinetic study showed that heavy metal extraction by washing at pH around 2 reached equilibrium within 4h, while extraction by washing at pH 4-5 increased gradually by the end of 24 h washing. Washing extraction at pH 2 for 6 h which was followed by washing at pH 5 for 16 h increased the percentage extraction of Pb and Cu from 67.6 to 85.9% and from 77.5 to 83.4%, respectively. Ultrasound application has been also investigated to enhance extraction of heavy metals by using citrate. Only 30 min ultrasound application at 19.5 KHz attained higher extraction of heavy metals than those by washing for 24h, showing the enhancement of heavy-metal removal. Thus, the performance of citrate for removing heavy metals was improved. PMID:15055930

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

    NASA Astrophysics Data System (ADS)

    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 < 5 kDa and lower aromaticity. Thus, the DOC was mostly composed

  16. Char-amended farm soils – effects on soil chemistry and wheat growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    On-farm gasification of agricultural residues, the non-food byproducts from crop harvests, could provide a means to generate value-added income from the production of fuel or electrical generation. Char produced during the process also has potential value as a soil amendment to adjust acid soil pH (...

  17. Trace elements, pH and organic matter evolution in contaminated soils under assisted natural remediation: a 4-year field study.

    PubMed

    Madejón, E; Madejón, P; Burgos, P; Pérez de Mora, A; Cabrera, F

    2009-03-15

    A 4-year study was undertaken on the effect of three amendments (biosolid compost (BC), sugar beet lime (SL), and combination of leonardite plus sugar beet lime (LESL)) on reclamation of a moderately trace element-contaminated soil under field conditions. Results showed that organic C increased in BC and LESL treatments. BC and SL treatments increased soil pH and reduced CaCl(2)-extractable metal concentrations more efficiently. At the end of the experiment, CaCl(2)-extractable metal concentrations decreased and were similar in all treatments pointing out the importance of the natural remediation processes in contaminated soils. Addition of amendments showed no clear reduction in EDTA-extractable trace element concentrations, even, BC and LESL subplots showed some little increase of these elements with time. Amendments did not cause any change in total trace element concentration in soil. Addition of amendments could be a successful and reliable long term technique for stabilization of trace elements in contaminated soils at a field scale with minimum maintenance. PMID:18602216

  18. Effect of pH on transport of Pb2+, Mn2+, Zn2+ and Ni2+ through lateritic soil: column experiments and transport modeling.

    PubMed

    Chotpantarat, Srilert; Ong, Say Kee; Sutthirat, Chakkaphan; Osathaphan, Khemarath

    2011-01-01

    This study investigated the effects of pH on the transport of Pb2+, Mn2+, Zn2+ and Ni2+ through lateritic soil columns. Model results by fitting the symmetric breakthrough curves (BTCs) of bromide (Br-) with CXTFIT model suggested that physical non-equilibrium processes were absent in the columns. The heavy metal BTCs were, however, asymmetrical and exhibited a tailing phenomenon, indicating the presence of chemical non-equilibrium processes in the columns. The retardation factors of Pb2+ were the largest of the four metal ions at both pH 4.0 (33.3) and pH 5.0 (35.4). The use of Langmuir isotherm parameters from batch studies with HYDRUS-1D did not predict the BTCs well. Rather the two-site model (TSM) described the heavy metal BTCs better than the equilibrium linear/nonlinear Langmuir model. The fraction of instantaneous sorption sites (f) of all four metal ions on the lateritic soil was consistently about 30%-44% of the total sorption sites. PMID:21793407

  19. Destabilization dynamics of clay and acid-free polymers of ferric and magnesium salts in AMD without pH adjustment.

    PubMed

    Ntwampe, I O; Waanders, F B; Bunt, J R

    2016-01-01

    The physicochemical treatment was employed to treat acid mine drainage (AMD) in the removal of turbid materials using clay only (exp A) and a combination of clay, FeCl3 and Mg(OH)2 (exp B) to form a polymer. A 5 g sample of clay (bentonite) was added to 1.2 L of AMD and treated in a jar test at 250 rpm for 2 min and reduced to 100 rpm for 10 min. A 200 mL sub-sample from the 1.2 L mother liquor was poured into five 500 mL glass beakers, and 20 mL dosages of a polymer of 0.1 M Fe(3+) in (FeCl3) and 0.1 M Mg(2+) in (Mg(OH)2) was added to the beakers. The samples were allowed to settle for 1 h, after which the supernatant was analyzed for pH, total suspended solids (TSS), dissolved oxygen (DO) and oxidation-reduction potential (ORP) (exp A). A similar set of experiments was conducted where 200 mL of the AMD sample was poured into 500 mL glass beakers and (20-60 mL) dosages of a combination of 5 g clay, 0.1 M Fe(3+) (FeCl3) and Mg(2+) (Mg(OH)2) polymer was added and similar mixing, settling time and measurements were conducted (exp B). The polymers used in exp A exhibited TSS removal efficiency (E%) which was slightly lower compared with the polymer used in exp B, above 90%. Clay has a high TSS removal efficiency in the treatment of the AMD, indicating that adsorption was a predominant process in exps A and B. The scanning electron microscope (SEM) micrographs of the AMD sludge of both exps A and B, with a rigid and compacted structure consisting of dense flocs surrounded by the smaller flocs bound together, corroborate the fact that adsorption is a predominant process. PMID:27533861

  20. Predicting Soluble Nickel in Soils Using Soil Properties and Total Nickel

    PubMed Central

    Zhang, Xiaoqing; Li, Jumei; Wei, Dongpu; Li, Bo; Ma, Yibing

    2015-01-01

    Soil soluble nickel (Ni) concentration is very important for determining soil Ni toxicity. In the present study, the relationships between soil properties, total and soluble Ni concentrations in soils were developed in a wide range of soils with different properties and climate characteristics. The multiple regressions showed that soil pH and total soil Ni concentrations were the most significant parameters in predicting soluble Ni concentrations with the adjusted determination coefficients (Radj2) values of 0.75 and 0.68 for soils spiked with soluble Ni salt and the spiked soils leached with artificial rainwater to mimic field conditions, respectively. However, when the soils were divided into three categories (pH < 7, 7–8 and > 8), they obtained better predictions with Radj2 values of 0.78–0.90 and 0.79–0.94 for leached and unleached soils, respectively. Meanwhile, the other soil properties, such as amorphous Fe and Al oxides and clay, were also found to be important for determining soluble Ni concentrations, indicating that they were also presented as active adsorbent surfaces. Additionally, the whole soil speciation including bulk soil properties and total soils Ni concentrations were analyzed by mechanistic speciation models WHAM VI and Visual MINTEQ3.0. It was found that WHAM VI provided the best predictions for the soils with pH < 7, was relatively reasonable for pH 7 to 8, and gave an overestimation for pH > 8. The Visual MINTEQ3.0 could provide better estimation for pH < 8 and meanwhile quite reasonable results for pH > 8. These results indicated the possibility and applicability of these models to predict soil soluble Ni concentration by soil properties. PMID:26217951

  1. Influence of CO2 exposure on pH value, electrochemical properties, and the formation of calcium-phosphate on Ti-6Al-4V under adjusted in vitro conditions in DMEM

    NASA Astrophysics Data System (ADS)

    Höhn, Sarah; Virtanen, Sannakaisa

    2015-06-01

    Immersion tests for studying biomaterials surface reactions should be carried out at a pH value of 7.4 and an adjusted blood physiological electrolyte to simulate as far as possible in vivo conditions. The present work deals with surface reactivity of the biocompatible Ti-6Al-4V alloy in Dulbecco's Modified Eagle Medium (DMEM) and the influence of different immersion conditions on the pH value of solution and thus on the surface charge and calcium-phosphate formation on the oxide covered alloy surface. More specifically, the influence of the temperature (room temperature vs. 37 °C) and atmospheric exposure (solution open-to-air vs. solution exposed to 5% CO2 in air) was investigated. Electrochemical measurements, XPS and ATR-IR studies were carried out for interface characterization. Precipitations of calcium-phosphate (Ca-P) on Ti-6Al-4V in DMEM are formed depending on the atmospheric conditions (presence or absence of CO2). In the absence of CO2 strong coverage of the surface by a Ca-P layer takes place; in solution exposed to 5% CO2, however, only minor amounts of Ca-P are found on the surface. This drastically different behavior can be explained by different surface terminations of OH and TiO2, induced by atmosphere-dependent pH change in solution. In consequence, different surface charges on Ti-6Al-4V can be formed at the interface depending on the type of hydroxides after contact with the electrolyte. Hence, the surface charge influences the interaction with adsorption of charged species and further modifies the oxide properties. The adsorption of the charged cations (Ca2 +) and anions (PO43 -, HPO42 -, H2PO4 -) leads to the formation of additional calcium phosphate layers. The pH of the solution is also important. At higher pH the titanium surface is more negatively charged leading to an increased electrostatic interaction with Ca2 + and reduced solubility of the calcium phosphates. Additional experiments indicate that the CO2 content in the atmosphere is

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

    PubMed Central

    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

  3. The influence of redox chemistry and pH on chemically active forms of arsenic in sewage sludge-amended soil

    SciTech Connect

    Carbonell-Barrachina, A.; Jugsujinda, A.; DeLaune, R.D.; Patrick, W.H. Jr.; Burlo, F.; Sirisukhodom, S.; Anurakpongsatorn, P.

    1999-07-01

    Chemical fractionation procedures were used to quantify the effect of the sediment redox and pH conditions on the adsorption and solubility of arsenic (As) in municipal sewage sludge and sewage sludge-amended soil. Sludge and sludge-amended soil were incubated in microcosms in which Eh-pH conditions were controlled. Samples were sequentially extracted to determine As in various chemical forms (water soluble, exchangeable, bound to carbonates, bound to iron (Fe) and manganese (Mn) oxides, bound to insoluble organics and sulfides) and the chemically inactive fraction (mineral residues). In both sewage sludge and sludge-amended soil, As chemistry was governed by large molecular humic matter and sulfides and Fe and Mn-oxides. Solubility of As remained low and constant under both aerobic and anaerobic conditions in sludge-amended soil. After dissolution of Fe and Mn-oxides, As{sup 5+} was released into sludge solution, reduced to As{sup 3+} and likely precipitated as sulfide. Therefore, an organic amendment rich in sulfur compounds, such as sewage sludge, would drastically reduce the potential risks derived from As pollution under highly anoxic conditions by precipitation of this toxic metalloid as insoluble and immobile sulfides.

  4. Carbon allocation, osmotic adjustment, antioxidant capacity and growth in cotton under long-term soil drought during flowering and boll-forming period.

    PubMed

    Wang, Rui; Gao, Min; Ji, Shu; Wang, Shanshan; Meng, Yali; Zhou, Zhiguo

    2016-10-01

    Responses of plant to drought largely depend on the intensity, duration and developmental stage at which water stress occurs. The purpose of this study was to analyze the dynamic of cotton physiology response to different levels sustained soil water deficit during reproductive growth stage at leaf basis. Three levels of steady-state water regimes [soil relative water content (SRWC) maintained at (75 ± 5)%, (60 ± 5)% and (45 ± 5)%] were imposed when the white flowers had opened on the first fruiting position of the 6-7th fruiting branches (FB6-7), which was the first day post anthesis (i.e. 1 DPA) and lasted to 50 DPA. Results showed decreasing SRWC slowed cotton growth on the base of biomass and leaf area. However, carbon metabolites levels were globally increased under drought despite of notably inhibited photosynthesis throughout the treatment period. Clear diurnal pattern of sucrose and starch concentrations was obtained and sucrose levels were evaluated while starch concentration was reduced with decreasing soil water content during a 24-h cycle. Osmotic adjustment (OA) was observed at most of the sampling dates throughout the drought period. K(+) was the main contributor to osmotic adjustment (OA) at 10 and 24 DPA then turned out to be amino acid at 38 and 50 DPA. The stressed cotton gradually failed to scavenge reactive oxygen species (ROS) with increasing days post anthesis, primarily due to the permanent decrease in SOD activity. Elevated carbohydrates levels suggest cotton growth was more inhibited by other factors than carbon assimilation. OA and antioxidant could be important protective mechanisms against soil water deficit in this species, and transition of these mechanisms was observed with drought intensity and duration increased. PMID:27288990

  5. Evaluation of a commercial multi-sensor system for soil electrical conductivity, organic matter, and pH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Efficient and accurate spatial quantification of soil properties is recognized as an important aspect of precision agriculture. With the current standard practice of in-field sample collection and subsequent laboratory analysis it is often prohibitively expensive to obtain data at the spatial densit...

  6. Urea hydrolysis rates in soil toposequences as influenced by pH, carbon, nitrogen, and soluble metals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A simultaneous increase in the use of urea fertilizer and the incidence of harmful algal blooms worldwide has generated research on potential loss pathways of unhydrolyzed urea from agricultural areas. The objective of this research was to study the dynamics of urea hydrolysis in soil profile topos...

  7. Predicting where enhanced atrazine degradation will occur based on soil pH and herbicide use history

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil bacteria on all continents except Antartica have developed the ability to rapidly degrade the herbicide atrazine, a phenomenon referred to as enhanced degradation. The agronomic significance of enhanced degradation is the potential for reduced residual weed control with atrazine in Corn, Sorgh...

  8. Bacterial diversity in cucumber (Cucumis sativus) rhizosphere in response to salinity, soil pH and boron

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil salinity is a major factor relating microbial communities to environmental stress in the microbial selection process as stress can reduce bacterial diversity. In the San Joaquin Valley (SJV) of California, the problem of increasing salinity and consequently, decreasing crop productivity, due to...

  9. Effects of Temperature and pH on the Activities of Catechol 2,3-dioxygenase Obtained from Crude Oil Contaminated Soil in Ilaje, Ondo State, Nigeria.

    PubMed

    Olukunle, O F; Babajide, O; Boboye, B

    2015-01-01

    Enrichment technique was employed for the isolation of the crude oil degrading bacteria. The isolated bacteria were screened for their degradative ability and the best degrading bacteria were selected based on their growth. Specific activities of Catechol-2,3-dioxygenase and effects of temperature and pH and their stabilities on the enzyme relative activities were observed. Bacteria isolated from the soil sample include; Bacillus cereus, B. amyloliquficiens, B. firmus, Acinetobacter calcoaceticus, Pseudomonas sp. P. fluorescens, P.putida, P.aeruginosa, Achromobacter xylosoxidans and Achromobacter sp. Screening of the degradative ability of the bacteria revealed P. aeruginosa, Bacillus cereus, Acinetobacter calcoaceticus and Achromobacter sp. to be the best degraders. The pH and temperature range with time for the enzyme activity were 6.0-8.0 and 30(o)C-50(o)C respectively. The enzyme exhibited activity that was slightly more tolerant to alkaline pH. Therefore, engineering of Catechol 2,3-dioxygenase may be employed for application on bioremediation of polluted sites. PMID:26464607

  10. Effects of Temperature and pH on the Activities of Catechol 2,3-dioxygenase Obtained from Crude Oil Contaminated Soil in Ilaje, Ondo State, Nigeria

    PubMed Central

    Olukunle, O.F.; Babajide, O.; Boboye, B.

    2015-01-01

    Enrichment technique was employed for the isolation of the crude oil degrading bacteria. The isolated bacteria were screened for their degradative ability and the best degrading bacteria were selected based on their growth. Specific activities of Catechol-2,3-dioxygenase and effects of temperature and pH and their stabilities on the enzyme relative activities were observed. Bacteria isolated from the soil sample include; Bacillus cereus, B. amyloliquficiens, B. firmus, Acinetobacter calcoaceticus, Pseudomonas sp. P. fluorescens, P.putida, P.aeruginosa, Achromobacter xylosoxidans and Achromobacter sp. Screening of the degradative ability of the bacteria revealed P. aeruginosa, Bacillus cereus, Acinetobacter calcoaceticus and Achromobacter sp. to be the best degraders. The pH and temperature range with time for the enzyme activity were 6.0-8.0 and 30oC-50oC respectively. The enzyme exhibited activity that was slightly more tolerant to alkaline pH. Therefore, engineering of Catechol 2,3-dioxygenase may be employed for application on bioremediation of polluted sites. PMID:26464607

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Solubility of lead and copper in biochar-amended small arms range soils: influence of soil organic carbon and pH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In situ application of heavy metal stabilizing agents has in some cases increased the mobility of target metal contaminants. Mechanistic understandings are necessary to better predict (1) the dynamic short- and long-term response to soil amendments, and (2) the utility of biochars in nonremoval and...

  13. [Effects of simulated acid rain on decomposition of soil organic carbon and crop straw].

    PubMed

    Zhu, Xue-Zhu; Huang, Yao; Yang, Xin-Zhong

    2009-02-01

    To evaluate the effects of acid rain on the organic carbon decomposition in different acidity soils, a 40-day incubation test was conducted with the paddy soils of pH 5.48, 6.70 and 8.18. The soils were amended with 0 and 15 g x kg(-1) of rice straw, adjusted to the moisture content of 400 g x kg(-1) air-dried soil by using simulated rain of pH 6.0, 4.5, and 3.0, and incubated at 20 degrees C. The results showed that straw, acid rain, and soil co-affected the CO2 emission from soil system. The amendment of straw increased the soil CO2 emission rate significantly. Acid rain had no significant effects on soil organic carbon decomposition, but significantly affected the straw decomposition in soil. When treated with pH 3.0 acid rain, the amount of decomposed straw over 40-day incubation in acid (pH 5.48) and alkaline (pH 8.18) soils was 8% higher, while that in neutral soil (pH 6.70) was 15% lower, compared to the treatment of pH 6.0 rain. In the treatment of pH 3.0 acid rain, the decomposition rate of soil organic C in acid (pH 5.48) soil was 43% and 50% (P < 0.05) higher than that in neutral (pH 6.70) and alkaline (pH 8.18) soils, while the decomposition rate of straw in neutral soil was 17% and 16% (P < 0.05) lower than that in acid and alkaline soils, respectively. PMID:19459394

  14. Vertical structure and pH as factors for chitinolytic and pectinolytic microbial community of soils and terrestrial ecosystems of different climatic zones

    NASA Astrophysics Data System (ADS)

    Lukacheva, Evgeniya; Natalia, Manucharova

    2016-04-01

    Chitin is a naturally occurring fibre-forming polymer that plays a protective role in many lower animals similar to that of cellulose in plants. Also it's a compound of cell walls of fungi. Chemically it is a long-chain unbranched polysaccharide made of N-acetylglucosamine residues; it is the second most abundant organic compound in nature, after cellulose. Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. Roots of the plants and root crops contain pectin. Chitin and pectin are widely distributed throughout the natural world. Structural and functional features of the complex microbial degradation of biopolymers one of the most important direction in microbial ecology. But there is no a lot of data concerns degradation in vertical structure of terrestrial ecosystems and detailed studies concerning certain abiotic features as pH. Microbial complexes of natural areas were analyzed only as humus horizons (A1) of the soil profile. Only small part of microbial community could be studied with this approach. It is known that ecosystems have their own structure. It is possible to allocate some vertical tiers: phylloplane, litter (soil covering), soil. We investigated chitinolytic and pectinolytic microbial communities dedicated to different layers of the ecosystems. Also it was described depending on pH dominated in certain ecosystem with certain conditions. Quantity of eukaryote and procaryote organisms increased in the test samples with chitin and pectin. Increasing of eukaryote in samples with pectin was more then in samples with chitin. Also should be noted the significant increasing of actinomycet's quantity in the samples with chitin in comparison with samples with pectin. The variety and abundance of bacteria in the litter samples increased an order of magnitude as compared to other probes. Further prokaryote community was investigated by method FISH (fluorescence in situ hybridization). FISH is a cytogenetic

  15. Stability and Mobility of CdSe/ZnS Quantum Dots in Soils: Effects of Organic Ligands, pH and Ionic Strength

    NASA Astrophysics Data System (ADS)

    Li, C.; Darnault, C. J. G.; Snee, P. T.

    2015-12-01

    Quantum dots (QDs) are the key enablers in the domain of nanoscience and have found many applications due to their physico-chemical and optical properties. For example, they are used in solar cells, lighting technologies, and biomedical imaging. Their presence in the environment following their application and life-cycle is inevitable. Therefore, it is critical to understand their behavior in the soil water system to assess the risks they may pose to natural systems and to public health. Assessing the factors that impact the stability and mobility of QDs in the soil water system is important. Natural organic ligands occur in subsurface environments and alter chemical processes in soils through complex reactions with metal ions in solution and ligand exchange reactions on soil surfaces. Consequently, the presence of ligands may alter the surface properties of QDs and impact their stability and mobility in saturated porous media. In this study, characteristics and stability of CdSe/ZnS QDs in water solutions are tested in batch experiments. The impacts of organic ligands (acetate, oxalate, and citrate) on the stability of QDs under various pH (5, 7 and 9) and ionic strength (0.05 and 0.1 M) conditions were investigated. The stability and aggregation kinetics of QDs were examined using UV-vis and DLS methods. Selected parameters from batch experiments were then used as study conditions to perform column transport experiments to generate breakthrough curves and retention profiles to assess the fate and transport of QDs in saturated porous media, which is the first phase in simulating their behavior in the subsurface.

  16. A fine fraction of soil used as an aerosol analogue during the DUNE experiment: sequential solubility in water, decreasing pH step-by-step

    NASA Astrophysics Data System (ADS)

    Aghnatios, C.; Losno, R.; Dulac, F.

    2014-09-01

    A soil sample collected in a desert aerosol source area near Douz (southern Tunisia) was dry-sieved at 20 μm in order to extract the fraction similar to a wind-generated aerosol, and was used to seed mesocosms during the DUNE experiment (a DUst experiment in a low Nutrient, low chlorophyll Ecosystem). In this work, said "aerosol-like" fine dust was sequentially leached by short contacts with water at initial pHs, decreasing from seven to one, representing various wet environmental conditions. For each step, the solubility of a given element is calculated as the amount of its dissolved fraction, relative to its total amount. The evolution of this fractional solubility from the highest to lowest pHs provides information on the chemical strength needed to solubilise a given element and its lability. The behaviour of the elemental solubility was sorted into two groups: (1) Ca, Sr, Ba, Mn, and P, with a solubility between 23% and 70%, and a maximum sequential solubility at pH 3; (2) Al and Fe, with a solubility of less than 2% and the highest release at pH 1. Similar solubility patterns in group 1 for Ca, P, and Mn suggest a possible association of the elements in the same minerals, most probably carbonates.

  17. A~fine fraction of soil used as an aerosol analogue during the DUNE experiment: sequential solubility in water with step-by-step decreasing pH

    NASA Astrophysics Data System (ADS)

    Aghnatios, C.; Losno, R.; Dulac, F.

    2014-02-01

    A soil sample collected in a desert aerosol source area near Douz (South Tunisia) was sieved at 20 μm in order to extract the fraction similar to an aerosol generated by wind and used to seed mesocosms during the DUNE experiment. In the present work, this "aerosol-like" fine dust was sequentially leached by short contacts with water at pHs decreasing from 7 to 1. These pHs are representative of various environmental wet conditions, the lowest of which could be reached during cloud conditions. The evolution of the solubility from the highest to the lowest pHs provides information on the necessary strength for the solubilisation of a given element and its lability. The behaviour of the elemental fractional solubility is sorted into two groups: (i) Ca, Sr, Ba, Mn, P constitute group 1, with a solubility between 23% and 70% and with a maximum solubility at pH 3; (ii) whereas in group 2 (Al, Fe), the solubility is less than 2% with the highest release at pH 1. Similar solubility patterns in group 1 for Ca, P and Mn suggest a~possible association of the elements in the same minerals, most probably carbonates, which gives phosphorus an unexpected high lability.

  18. Terrestrial soil pH and MAAT records based on the MBT/CBT in the southern South China Sea: implications for the atmospheric CO2 evolution in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Dong, L.; Li, L.; Li, Q.; Zhang, C.

    2013-12-01

    Liang Dong1, Li Li1, Qianyu Li1,2, Chuanlun L. Zhang1,3 1State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China 2School of Earth and Environment Sciences, University of Adelaide, SA 5005, Australia 3Department of Marine Sciences, University of Georgia, Athens, GA 30602, USA The methylation index of branched tetraethers (MBT) and/or the cyclization ratio of branched tetraethers (CBT) are derived from the branched glycerol dialkyl Glycerol tetraethers (GDGTs) of bacterial origin and are widely used to reconstruct the terrestrial soil pH and mean annual air temperature (MAAT); however, these proxies are less frequently used in the oceanic settings. Here we provide the first high resolution records of soil pH and MAAT since the last glacial maximum based on the sedimentary core of MD05-2896 in the southern South China Sea. The MAAT record exhibited typical glacial and interglacial cycles and was consistent with the winter insolation variation. The pH values were lower (6.4-7) in the glacial time and higher (7-8.4) in the interglacial time. Changes in soil pH allowed the evaluation of changes in soil CO2 based on the atmosphere-soil CO2 balance. The results imply that the lower winter MAAT variation with a lower winter atmospheric CO2 concentration might have resulted in a higher pH in the interglacial period. Our records provide a new insight into the evolution of atmospheric CO2 between glacial and interglacial cycles in East Asia. Key words: South China Sea, MBT/CBT, b-GDGTs, MAAT, pH

  19. Lysine and novel hydroxylysine lipids in soil bacteria: amino acid membrane lipid response to temperature and pH in Pseudopedobacter saltans

    PubMed Central

    Moore, Eli K.; Hopmans, Ellen C.; Rijpstra, W. Irene C.; Sánchez-Andrea, Irene; Villanueva, Laura; Wienk, Hans; Schoutsen, Frans; Stams, Alfons J. M.; Sinninghe Damsté, Jaap S.

    2015-01-01

    Microbial decomposition of organic matter is an essential process in the global carbon cycle. The soil bacteria Pseudopedobacter saltans and Flavobacterium johnsoniae are both able to degrade complex organic molecules, but it is not fully known how their membrane structures are adapted to their environmental niche. The membrane lipids of these species were extracted and analyzed using high performance liquid chromatography-electrospray ionization/ion trap/mass spectrometry (HPLC-ESI/IT/MS) and high resolution accurate mass/mass spectrometry (HRAM/MS). Abundant unknown intact polar lipids (IPLs) from P. saltans were isolated and further characterized using amino acid analysis and two dimensional nuclear magnetic resonance (NMR) spectroscopy. Ornithine IPLs (OLs) with variable (hydroxy) fatty acid composition were observed in both bacterial species. Lysine-containing IPLs (LLs) were also detected in both species and were characterized here for the first time using HPLC-MS. Novel LLs containing hydroxy fatty acids and novel hydroxylysine lipids with variable (hydroxy) fatty acid composition were identified in P. saltans. The confirmation of OL and LL formation in F. johnsoniae and P. saltans and the presence of OlsF putative homologs in P. saltans suggest the OlsF gene coding protein is possibly involved in OL and LL biosynthesis in both species, however, potential pathways of OL and LL hydroxylation in P. saltans are still undetermined. Triplicate cultures of P. saltans were grown at three temperature/pH combinations: 30°C/pH 7, 15°C/pH 7, and 15°C/pH 9. The fractional abundance of total amino acid containing IPLs containing hydroxylated fatty acids was significantly higher at higher temperature, and the fractional abundance of lysine-containing IPLs was significantly higher at lower temperature and higher pH. These results suggest that these amino acid-containing IPLs, including the novel hydroxylysine lipids, could be involved in temperature and pH stress

  20. Surface Crack Growth Behavior of Pipeline Steel Under Disbonded Coating at Free Corrosion Potential in Near-Neutral pH Soil Environments

    NASA Astrophysics Data System (ADS)

    Egbewande, Afolabi; Chen, Weixing; Eadie, Reg; Kania, Richard; Van Boven, Greg; Worthingham, Robert; Been, Jenny

    2014-10-01

    Crack growth behavior of X65 pipeline steel at free corrosion potential in near-neutral pH soil environment under a CO2 concentration gradient inside a disbonded coating was studied. Growth rates were found to be highest at the open mouth of the simulated disbondment where CO2 concentrations, hence local hydrogen concentration in the local environment, was highest. Careful analysis of growth rate data using a corrosion-fatigue model of the form Δ K α / K {max/ β }/ f γ , where (1/ f γ ) models environmental contribution to growth, revealed that environmental contribution could vary by up to a factor of three. Such intense environmental contribution at the open mouth kept the crack tip atomically sharp despite the simultaneous occurrence of low-temperature creep and crack tip dissolution, which are the factors that blunt the crack tip. At other locations where environmental enhancement was lower, significant crack tip blunting attributed to both low-temperature creep and crack tip dissolution was observed. These factors both led to lower crack growth rates away from the open mouth.

  1. pH tolerance in freshwater bacterioplankton: trait variation of the community as measured by leucine incorporation.

    PubMed

    Bååth, Erland; Kritzberg, Emma

    2015-11-01

    pH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, covering in situ pH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) instantaneously after pH adjustment. The resulting unimodal response curves, reflecting community tolerance to pH, were well modeled with a double logistic equation (mean R(2) = 0.97). The optimal pH for growth (pHopt) among the bacterial communities was closely correlated with in situ pH, with a slope (0.89 ± 0.099) close to unity. The pH interval, in which growth was ≥90% of that at pHopt, was 1.1 to 3 pH units wide (mean 2.0 pH units). Tolerance response curves of communities originating from circum-neutral pH were symmetrical, whereas in high-pH (8.9) and especially in low-pH (<5.5) waters, asymmetric tolerance curves were found. In low-pH waters, decreasing pH was more detrimental for bacterial growth than increasing pH, with a tendency for the opposite for high-pH waters. A pH tolerance index, using the ratio of growth at only two pH values (pH 4 and 8), was closely related to pHopt (R(2) = 0.83), allowing for easy determination of pH tolerance during rapid changes in pH. PMID:26276108

  2. pH Tolerance in Freshwater Bacterioplankton: Trait Variation of the Community as Measured by Leucine Incorporation

    PubMed Central

    Kritzberg, Emma

    2015-01-01

    pH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, covering in situ pH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) instantaneously after pH adjustment. The resulting unimodal response curves, reflecting community tolerance to pH, were well modeled with a double logistic equation (mean R2 = 0.97). The optimal pH for growth (pHopt) among the bacterial communities was closely correlated with in situ pH, with a slope (0.89 ± 0.099) close to unity. The pH interval, in which growth was ≥90% of that at pHopt, was 1.1 to 3 pH units wide (mean 2.0 pH units). Tolerance response curves of communities originating from circum-neutral pH were symmetrical, whereas in high-pH (8.9) and especially in low-pH (<5.5) waters, asymmetric tolerance curves were found. In low-pH waters, decreasing pH was more detrimental for bacterial growth than increasing pH, with a tendency for the opposite for high-pH waters. A pH tolerance index, using the ratio of growth at only two pH values (pH 4 and 8), was closely related to pHopt (R2 = 0.83), allowing for easy determination of pH tolerance during rapid changes in pH. PMID:26276108

  3. The pH Game.

    ERIC Educational Resources Information Center

    Chemecology, 1996

    1996-01-01

    Describes a game that can be used to teach students about the acidity of liquids and substances around their school and enable them to understand what pH levels tell us about the environment. Students collect samples and measure the pH of water, soil, plants, and other natural material. (DDR)

  4. Adjustment disorder

    MedlinePlus

    American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 5th ed. Arlington, Va: American Psychiatric Publishing. 2013. Powell AD. Grief, bereavement, and adjustment disorders. In: Stern TA, Rosenbaum ...

  5. Adjustment of corn nitrogen in-season fertilization based on soil texture and weather conditions: a Meta-analysis of North American trials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil properties and weather conditions are known to affect soil nitrogen (N) availability and plant N uptake. However, studies examining N response as affected by soil and weather sometimes give conflicting results. Meta-analysis is a statistical method for estimating treatment effects in a series o...

  6. Adjustable microforceps.

    PubMed

    Bao, J Y

    1991-04-01

    The commonly used microforceps have a much greater opening distance and spring resistance than needed. A piece of plastic ring or rubber band can be used to adjust the opening distance and reduce most of the spring resistance, making the user feel more comfortable and less fatigued. PMID:2051437

  7. Last-Century Increases in Intrinsic Water-Use Efficiency of Grassland Communities Have Occurred over a Wide Range of Vegetation Composition, Nutrient Inputs, and Soil pH.

    PubMed

    Köhler, Iris H; Macdonald, Andy J; Schnyder, Hans

    2016-02-01

    Last-century climate change has led to variable increases of the intrinsic water-use efficiency (Wi; the ratio of net CO2 assimilation to stomatal conductance for water vapor) of trees and C3 grassland ecosystems, but the causes of the variability are not well understood. Here, we address putative drivers underlying variable Wi responses in a wide range of grassland communities. Wi was estimated from carbon isotope discrimination in archived herbage samples from 16 contrasting fertilizer treatments in the Park Grass Experiment, Rothamsted, England, for the 1915 to 1929 and 1995 to 2009 periods. Changes in Wi were analyzed in relation to nitrogen input, soil pH, species richness, and functional group composition. Treatments included liming as well as phosphorus and potassium additions with or without ammonium or nitrate fertilizer applications at three levels. Wi increased between 11% and 25% (P < 0.001) in the different treatments between the two periods. None of the fertilizers had a direct effect on the change of Wi (ΔWi). However, soil pH (P < 0.05), species richness (P < 0.01), and percentage grass content (P < 0.01) were significantly related to ΔWi. Grass-dominated, species-poor plots on acidic soils showed the largest ΔWi (+14.7 μmol mol(-1)). The ΔWi response of these acidic plots was probably related to drought effects resulting from aluminum toxicity on root growth. Our results from the Park Grass Experiment show that Wi in grassland communities consistently increased over a wide range of nutrient inputs, soil pH, and plant community compositions during the last century. PMID:26620525

  8. Last-Century Increases in Intrinsic Water-Use Efficiency of Grassland Communities Have Occurred over a Wide Range of Vegetation Composition, Nutrient Inputs, and Soil pH1[OPEN

    PubMed Central

    Köhler, Iris H.; Macdonald, Andy J.; Schnyder, Hans

    2016-01-01

    Last-century climate change has led to variable increases of the intrinsic water-use efficiency (Wi; the ratio of net CO2 assimilation to stomatal conductance for water vapor) of trees and C3 grassland ecosystems, but the causes of the variability are not well understood. Here, we address putative drivers underlying variable Wi responses in a wide range of grassland communities. Wi was estimated from carbon isotope discrimination in archived herbage samples from 16 contrasting fertilizer treatments in the Park Grass Experiment, Rothamsted, England, for the 1915 to 1929 and 1995 to 2009 periods. Changes in Wi were analyzed in relation to nitrogen input, soil pH, species richness, and functional group composition. Treatments included liming as well as phosphorus and potassium additions with or without ammonium or nitrate fertilizer applications at three levels. Wi increased between 11% and 25% (P < 0.001) in the different treatments between the two periods. None of the fertilizers had a direct effect on the change of Wi (ΔWi). However, soil pH (P < 0.05), species richness (P < 0.01), and percentage grass content (P < 0.01) were significantly related to ΔWi. Grass-dominated, species-poor plots on acidic soils showed the largest ΔWi (+14.7 μmol mol−1). The ΔWi response of these acidic plots was probably related to drought effects resulting from aluminum toxicity on root growth. Our results from the Park Grass Experiment show that Wi in grassland communities consistently increased over a wide range of nutrient inputs, soil pH, and plant community compositions during the last century. PMID:26620525

  9. Copper, nickel and zinc speciation in a biosolid-amended soil: pH adsorption edge, μ-XRF and μ-XANES investigations.

    PubMed

    Mamindy-Pajany, Yannick; Sayen, Stéphanie; Mosselmans, J Frederick W; Guillon, Emmanuel

    2014-07-01

    Metal solid phase speciation plays an important role in the control of the long-term stability of metals in biosolid-amended soils. The present work used pH-adsorption edge experiments and synchrotron-based spectroscopy techniques to understand the solid phase speciation of copper, nickel and zinc in a biosolid-amended soil. Comparison of metal adsorption edges on the biosolid-amended soil and the soil sample showed that Cu, Ni, and Zn can be retained by both soil and biosolid components such as amorphous iron phases, organic matter and clay minerals. These data are combined with microscopic results to obtain structural information about the surface complexes formed. Linear combination fitting of K-edge XANES spectra of metal hot-spots indicated consistent differences in metal speciation between metals. While organic matter plays a dominant role in Ni binding in the biosolid-amended soil, it was of lesser importance for Cu and Zn. This study suggests that even if the metals can be associated with soil components (clay minerals and organic matter), biosolid application will increase metals retention in the biosolid-amended soil by providing reactive organic matter and iron oxide fractions. Among the studied metals, the long-term mobility of Ni could be affected by organic matter degradation while Cu and Zn are strongly associated with iron oxides. PMID:24899255

  10. Shaft adjuster

    DOEpatents

    Harry, Herbert H.

    1989-01-01

    Apparatus and method for the adjustment and alignment of shafts in high power devices. A plurality of adjacent rotatable angled cylinders are positioned between a base and the shaft to be aligned which when rotated introduce an axial offset. The apparatus is electrically conductive and constructed of a structurally rigid material. The angled cylinders allow the shaft such as the center conductor in a pulse line machine to be offset in any desired alignment position within the range of the apparatus.

  11. Copper removal from contaminated soils by soil washing process using camellian-derived saponin

    NASA Astrophysics Data System (ADS)

    Reyes, Arturo; Fernanda Campos, Maria; Videla, Álvaro; Letelier, María Victoria; Fuentes, Bárbara

    2015-04-01

    Antofagasta Region in North of Chile has been the main copper producer district in the world. As a consequence of a lack of mining closure regulation, a large number of abandon small-to-medium size metal-contaminated sites have been identified in the last survey performed by the Chilean Government. Therefore, more research development on sustainable reclamation technologies must be made in this extreme arid-dry zone. The objective of this study is to test the effectiveness of soil remediation by washing contaminated soil using camellian-derived saponin for the mobilization of copper. Soil samples were taken from an abandoned copper mine site located at 30 km North Antofagasta city. They were dried and sieved at 75 µm for physico-chemical characterization. A commercial saponin extracted from camellias seed was used as biosurfactant. The soil used contains 67.4 % sand, 26.3 % silt and 6.3 % clay. The soil is highly saline (electric conductivity, 61 mScm-1), with low organic matter content (0.41%), with pH 7.30, and a high copper concentration (2200 mg Kg-1 soil). According to the sequential extraction procedure of the whole soil, copper species are mainly as exchangeable fraction (608.2 mg Kg-1 soil) and reducible fraction (787.3 mg Kg-1 soil), whereas the oxidizable and residual fractions are around 205.7 and 598.8 mg Kg-1 soil, respectively. Soil particles under 75 µm contain higher copper concentrations (1242 mg Kg-1 soil) than the particle fraction over 75 µm (912 mg Kg-1 soil). All washing assays were conducted in triplicate using a standard batch technique with and without pH adjustment. The testing protocols includes evaluation of four solid to liquid ratio (0.5:50; 1.0:50; 2.0:50, and 5.0:50) and three saponin concentrations (0, 1, and 4 mg L-1). After shaking (24 h, 20±1 °C) and subsequently filtration (0.45 µm), the supernatants were analyzed for copper and pH. The removal efficiencies of copper by saponin solutions were calculated in according to the

  12. Function of peatland located on secondary transformed peat-moorsh soils on the purification processes of groundwater and the impact of pH on the rates of the elution of organic matter

    NASA Astrophysics Data System (ADS)

    Wojciech Szajdak, Lech; Szczepański, Marek

    2010-05-01

    The investigation of peatland is used to show the water quality functioning with respect to different forms of nitrogen and carbon. The purification of ground water by the transect of 4.5 km long consisting organic soils (peat-moorsh soils) was estimated. This transect is located in the Agroecological Landscape Park in Turew, 40 km South-West of Poznan, West Polish Lowland. There is this transect along Wyskoć ditch. pH, the contents of total and dissolved organic carbon, total nitrogen, N-NO3-, N-NH4+ was measured. Additionally C/N factors of peats were estimated. The investigation has shown the impact of the peatland located on the secondary transformed peat - moorsh soils on the lowering of total nitrogen, ammonium, and nitrates as well as total and dissolved organic carbon in ground water. Peat-moorsh soils were described and classified according to Polish hydrogenic soil classification and World Reference Base Soil Notation. There are four investigated points along to Wyskoc ditch. Two times a month during entire vegetation season the following material was taken from this four chosen sites: samples of peat, from the depth of 0-20 cm, samples of water from the ditch, samples of ground water from wells established for this investigation. Samples of peat-moorsh soils were collected at the depth 0-20 cm. Soils were sampled two times a month from 10 sites of each site. Samples were air dried and crushed to pass a 1 mm-mesh sieve. These 10 sub-samples were mixed for the reason of preparing a 'mean sample', which used for the determination of pH (in 1M KCl), dissolved organic carbon (DOC), total organic carbon (TOC), total nitrogen (Ntotal), and N-NO3- as well as N-NH4+. In water from Wyskoć ditch pH, Ntotal, N-NO3-, N-NH4+, DTC (dissolved total carbon) and DOC (dissolved organic carbon) was measured. Ground water samples were collected from four wells established for this investigation. The water was filtered by the middle velocity separation and pH, N-total, N

  13. EFFECTS OF PH AND PHOSPHATE ON METAL DISTRIBUTION WITH EMPHASIS ON AS SPECIATION AND MOBILIZATION IN SOILS FROM A LEAD SMELTING SITE

    EPA Science Inventory

    Arsenic in soils from the Asarco Lead Smelter in East Helena, Montana was characterized by X-ray absorption spectroscopy (XAS). As oxidation state and geochemical speciation were analyzed as a function of depth (two sampling sites) and surface distribution. These results were c...

  14. AS SPECIATION AND EFFECTS OF PH AND PHOSPHATE ON THE MOBILIZATION OF AS IN SOILS FROM A LEAD SMELTING SITE. PUBLISHED IN ADVANCED PHOTON SOURCE ACTIVITY REPORT 2003.

    EPA Science Inventory

    Arsenic in soils from the Asarco lead smelter in East Helena, Montana was characterized by X-ray absorption spectroscopy (XAS). Arsenic oxidation state and mineralogy were analyzed as a function of depth and surface distribution using bulk and microprobe XAS. These results were c...

  15. pH. Agricultural Lesson Plans.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale. Dept. of Agricultural Education and Mechanization.

    This lesson plan is intended for use in conducting classes on the effect of pH on plant growth. Presented first are an attention step/problem statement and a series of questions and answers designed to convey general information about soil pH and its effect on plants. The following topics are among those discussed: acidity and alkalinity; the…

  16. Phytomass, LAI, and NDVI in northern Alaska: Relationships to summer warmth, soil pH, plant functional types, and extrapolation to the circumpolar Arctic

    NASA Astrophysics Data System (ADS)

    Walker, D. A.; Epstein, H. E.; Jia, G. J.; Balser, A.; Copass, C.; Edwards, E. J.; Gould, W. A.; Hollingsworth, J.; Knudson, J.; Maier, H. A.; Moody, A.; Raynolds, M. K.

    2003-01-01

    We examined the effects of summer warmth on leaf area index (LAI), total aboveground phytomass (TAP), and normalized difference vegetation index (NDVI) across the Arctic bioclimate zone in Alaska and extrapolated our results to the circumpolar Arctic. Phytomass, LAI, and within homogeneous areas of vegetation on acidic and nonacidic soils were regressed against the total summer warmth index (SWI) at 12 climate stations in northern Alaska (SWI = sum of mean monthly temperatures greater than 0°C). SWI varies from 9°C at Barrow to 37°C at Happy Valley. A 5°C increase in the SWI is correlated with about a 120 g m-2 increase in the aboveground phytomass for zonal vegetation on acidic sites and about 60 g m-2 on nonacidic sites. Shrubs account for most of the increase on acidic substrates, whereas mosses account for most of the increase on nonacidic soils. LAI is positively correlated with SWI on acidic sites but not on nonacidic sites. The NDVI is positively correlated with SWI on both acidic and nonacidic soils, but the NDVI on nonacidic parent material is consistently lower than the NDVI on acidic substrates. Extrapolation to the whole Arctic using a five-subzone zonation approach to stratify the circumpolar NDVI and phytomass data showed that 60% of the aboveground phytomass is concentrated in the low-shrub tundra (subzone 5), whereas the high Arctic (subzones 1-3) has only 9% of the total. Estimated phytomass densities in subzones 1-5 are 47, 256, 102, 454, and 791 g m-2, respectively. Climate warming will likely result in increased phytomass, LAI, and NDVI on zonal sites. These changes will be most noticeable in acidic areas with abundant shrub phytomass.

  17. Effect of precyclic loading on stress-corrosion-cracking initiation in an X-65 pipeline steel exposed to near-neutral pH soil environment

    NASA Astrophysics Data System (ADS)

    Chen, W.; Wang, S.-H.; Chu, R.; King, F.; Jack, T. R.; Fessler, R. R.

    2003-11-01

    A study was carried out to understand the effect of precyclic loading on stress-corrosion-crack initiation in an X-65 pipeline steel exposed to a near-neutral-pH soil environment. The test specimens were precyclically loaded before corrosion exposure to represent a service history of up to about 20 years, depending on the severity of pressure fluctuation. Microcracks had initiated on the polished surface of the X-65 pipeline steel after long-time exposure at open-circuit potential (OCP) in a near-neutral-pH synthetic soil solution. These microcracks were mostly initiated from pits at metallurgical discontinuities such as grain boundaries, pearlitic colonies, and banded phases in the steel. Strong preferential dissolution was observed along planes of the banded structures in the steel. The selective corrosion attack at these metallurgical discontinuities is attributed to the galvanic nature of those areas to their neighbors. Cyclic loading prior to corrosion exposure had significant effects on microcrack initiation and propagation during subsequent corrosion exposure. Cyclic loading prior to corrosion exposure either reduced or increased the probability of crack initiation and the rate of crack propagation, depending upon the magnitude of the stress cycles. The largest reduction was seen at a peak cyclic stress of about 0.8 of the yield strength. This cyclic-loading-dependent cracking behavior might be related to the alteration of the substructures and the residual stress in the steel as a result of precyclic loading.

  18. Modeling abiotic processes of aniline in water-saturated soils

    SciTech Connect

    Fabrega-Duque, J.R.; Jafvert, C.T.; Li, H.; Lee, L.S.

    2000-05-01

    The long-term interactions of aromatic amines with soils are important in defining the fate and transport of these compounds in the environment. Abiotic loss of aniline from the aqueous phase to the soil phase occurs with an initial rapid loss due to reversible mass transfer processes, followed by a slow loss due to irreversible reactions. A kinetic model describing these processes in water-saturated soils was developed and evaluated. The model assumes that instantaneous equilibrium occurs for the following reversible processes: (1) acid dissociation of the protonated organic base (BH+) in the aqueous phase; (2) ion exchange between inorganic divalent cations (D{sup 2+} = Ca{sup 2+} + Mg{sup 2+}) on the soil and the protonated organic base; and (3) partitioning of the nonionic species of aniline (B{sub aq}) to soil organic carbon. The model assumes that irreversible loss of aniline occurs through reaction of B{sub aq} with irreversible sites (C{sub ir}) on the soil. A kinetic rate constant, k{sub ir}, and the total concentration of irreversible sites, C{sub T}, were employed as adjustable model parameters. The model was evaluated as adjustable model parameters. The model was evaluated with measured mass distributions of aniline between water and five soils ranging in pH (4.4--7.3), at contact times ranging from 2 to 1,600 h. Some experiments were performed at different soil mass to water volume ratios. A good fit was obtained with a single value of k{sub ir} for all soils, pH values, and soil-water ratios. To accurately predict soil-water distributions at contact times <24 h, mass transfer of the neutral species to the soil was modeled as a kinetic process, again, assuming that ion exchange processes are instantaneous.

  19. Soil acidification as a confounding factor on metal phytotoxicity in soils spiked with copper-rich mine wastes.

    PubMed

    Ginocchio, Rosanna; De la Fuente, Luz María; Sánchez, Pablo; Bustamante, Elena; Silva, Yasna; Urrestarazu, Paola; Rodríguez, Patricio H

    2009-10-01

    Pollution of soil with mine wastes results in both Cu enrichment and soil acidification. This confounding effect may be very important in terms of phytotoxicity, because pH is a key parameter influencing Cu solubility in soil solution. Laboratory toxicity tests were used to assess the effect of acidification by acidic mine wastes on Cu solubility and on root elongation of barley (Hordeum vulgare L.). Three contrasting substrates (two soils and a commercial sand) and two acidic, Cu-rich mine wastes (oxidized tailings [OxT] and smelter dust [SmD]) were selected as experimental materials. Substrates were spiked with a fixed amount of either SmD or OxT, and the pH of experimental mixtures was then modified in the range of 4.0 to 6.0 and 7.0 using PIPES (piperazine-1,4-bis(2-ethanesulfonic acid)), MES (2-(N-morpholino)ethanesulfonic acid), and MOPS (3-(N-Morpholino)-propanesulfonic acid) buffers. Chemical (pore-water Cu and pH) and toxicological (root length of barley plants) parameters were determined for experimental mixtures. Addition of SmD and OxT to substrates resulted in acidification (0.11-1.16 pH units) and high levels of soluble Cu and Zn. Neutralization of experimental mixtures with MES (pH 6.0) and MOPS (pH 7.0) buffers resulted in a marked decrease in soluble Cu and Zn, but the intensity of the effect was substrate-dependent. Adjustment of soil pH above the range normally considered to be toxic to plants (pH in water extract, > 5.5) significantly reduced metal toxicity in barley, but phytotoxicity was not completely eliminated. The present results stress the importance of considering confounding effects on derivation of toxicity thresholds to plants when using laboratory phytotoxicity tests. PMID:19480535

  20. Development of a quantitative method for the detection of enteroviruses in soil.

    PubMed Central

    Hurst, C J; Gerba, C P

    1979-01-01

    A method is described for efficiently concentrating enteroviruses from soil. Viruses were eluted from soil by mechanical agitation in high pH glycine buffer containing ethylenediaminetetraacetic acid. The eluted viruses were concentrated on a floc that formed de novo upon adjustment of the soil eluate to 0.06 M aluminum chloride and pH 3.5. Viruses not pelleted with the floc were concentrated by adsorption to and elution from membrane filters. This method yielded an average efficiency of 66% recovery from loamy sand soil for four enteroviruses. Virus recovery from soil was consistently high, with samples ranging in size from 25 to 500 g. The method was used successfully to isolate naturally occurring viruses from soil beneath a wastewater land treatment site. Recovery of enteroviruses by this method form different types of soil was dependent on percentage of clay, surface area, and cation exchange capacity. Recovery was not dependent on soil saturation pH or on percentage of organic matter. This method should prove useful for studying enterovirus migration and survival during the land application of domestic sewage. PMID:36845

  1. ADJUSTABLE DOUBLE PULSE GENERATOR

    DOEpatents

    Gratian, J.W.; Gratian, A.C.

    1961-08-01

    >A modulator pulse source having adjustable pulse width and adjustable pulse spacing is described. The generator consists of a cross coupled multivibrator having adjustable time constant circuitry in each leg, an adjustable differentiating circuit in the output of each leg, a mixing and rectifying circuit for combining the differentiated pulses and generating in its output a resultant sequence of negative pulses, and a final amplifying circuit for inverting and square-topping the pulses. (AEC)

  2. Adjustable sutures in children.

    PubMed

    Engel, J Mark; Guyton, David L; Hunter, David G

    2014-06-01

    Although adjustable sutures are considered a standard technique in adult strabismus surgery, most surgeons are hesitant to attempt the technique in children, who are believed to be unlikely to cooperate for postoperative assessment and adjustment. Interest in using adjustable sutures in pediatric patients has increased with the development of surgical techniques specific to infants and children. This workshop briefly reviews the literature supporting the use of adjustable sutures in children and presents the approaches currently used by three experienced strabismus surgeons. PMID:24924284

  3. Soil biotransformation of thiodiglycol, the hydrolysis product of mustard gas: understanding the factors governing remediation of mustard gas contaminated soil.

    PubMed

    Li, Hong; Muir, Robert; McFarlane, Neil R; Soilleux, Richard J; Yu, Xiaohong; Thompson, Ian P; Jackman, Simon A

    2013-02-01

    Thiodiglycol (TDG) is both the precursor for chemical synthesis of mustard gas and the product of mustard gas hydrolysis. TDG can also react with intermediates of mustard gas degradation to form more toxic and/or persistent aggregates, or reverse the pathway of mustard gas degradation. The persistence of TDG have been observed in soils and in the groundwater at sites contaminated by mustard gas 60 years ago. The biotransformation of TDG has been demonstrated in three soils not previously exposed to the chemical. TDG biotransformation occurred via the oxidative pathway with an optimum rate at pH 8.25. In contrast with bacteria isolated from historically contaminated soil, which could degrade TDG individually, a consortium of three bacterial strains isolated from the soil never contaminated by mustard gas was able to grow on TDG in minimal medium and in hydrolysate derived from an historical mustard gas bomb. Exposure to TDG had little impacts on the soil microbial physiology or on community structure. Therefore, the persistency of TDG in soils historically contaminated by mustard gas might be attributed to the toxicity of mustard gas to microorganisms and the impact to soil chemistry during the hydrolysis. TDG biodegradation may form part of a remediation strategy for mustard gas contaminated sites, and may be enhanced by pH adjustment and aeration. PMID:22752796

  4. Biodegradation and Bioremediation of Petroleum Pollutants in Soil

    SciTech Connect

    Huesemann, Michael H.

    2004-08-02

    During bioremediation, petroleum hydrocarbons are converted by naturally occurring or indigenous soil microorganisms to carbon dioxide, water, bacterial cells (biomass), and humic materials. Numerous factors are known to affect both the rate and the extent of hydrocarbon biodegradation in contaminated soils. These include soil properties such as moisture content, aeration, nutrient status, pH, and temperature as well as waste characteristics such as the concentration and molecular structure of hydrocarbon compounds or classes, the presence of inhibitors and cometabolic substrates, and the degree of contaminant sequestration which often leads to serious bioavailability limitations, particularly in aged soils. It is the objective of this chapter to outline a strategy for optimizing the hydrocarbon bioremediation process by adjusting the various operational parameters so that none of them become a limiting factor during treatment.

  5. Chemistry Experiment Measuring (pH) of the ``Planetary'' Soil by the Husar-5 NTX-based Rover Model of the Széchenyi István High School, Sopron, Hungary

    NASA Astrophysics Data System (ADS)

    Lang, A.; Szalay, K.; Erdélyi, S.; Nickl, I.; Panyi, T.; Kiss, D.; Bérczi, Sz.

    2009-03-01

    We report by a detailed description of the experiment built by students on Husar-5 rover model: how the chemical characteristics of the "planetary" soil can be measured by the indicator ribbon method, if we artificially made wet the soil.

  6. Soil and Water: Some Teaching Suggestions.

    ERIC Educational Resources Information Center

    Fischer, Richard B.

    1987-01-01

    Outlines six soil and water investigations that students can pursue outdoors, in nature centers, or in classrooms: soil characteristics; relationship between soil ph and plant life; what aggregates tell us; differences in soil structure; differences in rate of water absorption by soil; and soil exploration with a Berlesi funnel. (NEC)

  7. Adjusting the Chain Gear

    NASA Astrophysics Data System (ADS)

    Koloc, Z.; Korf, J.; Kavan, P.

    The adjustment (modification) deals with gear chains intermediating (transmitting) motion transfer between the sprocket wheels on parallel shafts. The purpose of the adjustments of chain gear is to remove the unwanted effects by using the chain guide on the links (sliding guide rail) ensuring a smooth fit of the chain rollers into the wheel tooth gap.

  8. Adjustment to Recruit Training.

    ERIC Educational Resources Information Center

    Anderson, Betty S.

    The thesis examines problems of adjustment encountered by new recruits entering the military services. Factors affecting adjustment are discussed: the recruit training staff and environment, recruit background characteristics, the military's image, the changing values and motivations of today's youth, and the recruiting process. Sources of…

  9. [Leaching behavior of Pb, Cd and Zn from soil stabilized by lime stabilized sludge].

    PubMed

    Li, Xiang; Song, Yun; Liu, Yong-Bing

    2014-05-01

    Stabilization of Pb, Cd and Zn spiked soil by using lime-stabilized sewage sludge( LSS) as amendment was investigated in this study, and the effectiveness was evaluated by using leaching tests ( TCLP, SPLP and de-ionized water) and modified BCR sequential extraction procedure. The results of TCLP indicated that the concentrations of heavy metals in TCLP leachate reduced significantly with the increase of the mass percentage of the LSS and the leaching reduction rates were as high as 99. 54% for Zn, 99. 60% for Pb, 99. 85% for Cd at 40% of LSS addition. When evaluated by SPLP and de-ionized water leaching method, the concentrations of Zn and Pb in leachate decreased obviously at 10% and 20% of LSS additions, but subsequently increased at 30% and 40% because of redissolution of Zn and Pb at strong base condition. After pH value of LLS-stabilized soil was adjusted by ferrous sulfate and phosphoric acid for recovering soil plantation function, the pH value of the soil decreased effectively, in the meantime promoting the stabilization effectiveness of Pb and Zn. The BCR test revealed that compared with the spiked soil exchangeable proportion of Zn, Pb, Cd in the soil and the soils adjusted by ferrous sulfate obviously declined, which implied the migration for Pb, Cd and Zn of contaminated soil could be confined. This study results show that municipal LSS can be reused in the stabilization of heavy metal contaminated soils and physical and chemical properties of LLS-stabilized soil are improved for plantation. PMID:25055691

  10. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign. PMID:26476769

  11. SLIT ADJUSTMENT CLAMP

    DOEpatents

    McKenzie, K.R.

    1959-07-01

    An electrode support which permits accurate alignment and adjustment of the electrode in a plurality of planes and about a plurality of axes in a calutron is described. The support will align the slits in the electrode with the slits of an ionizing chamber so as to provide for the egress of ions. The support comprises an insulator, a leveling plate carried by the insulator and having diametrically opposed attaching screws screwed to the plate and the insulator and diametrically opposed adjusting screws for bearing against the insulator, and an electrode associated with the plate for adjustment therewith.

  12. CMS Frailty Adjustment Model

    PubMed Central

    Kautter, John; Pope, Gregory C.

    2004-01-01

    The authors document the development of the CMS frailty adjustment model, a Medicare payment approach that adjusts payments to a Medicare managed care organization (MCO) according to the functional impairment of its community-residing enrollees. Beginning in 2004, this approach is being applied to certain organizations, such as Program of All-Inclusive Care for the Elderly (PACE), that specialize in providing care to the community-residing frail elderly. In the future, frailty adjustment could be extended to more Medicare managed care organizations. PMID:25372243

  13. Role of Osmotic Adjustment in Plant Productivity

    SciTech Connect

    Gebre, G.M.

    2001-01-11

    Successful implementation of short rotation woody crops requires that the selected species and clones be productive, drought tolerant, and pest resistant. Since water is one of the major limiting factors in poplar (Populus sp.) growth, there is little debate for the need of drought tolerant clones, except on the wettest of sites (e.g., lower Columbia River delta). Whether drought tolerance is compatible with productivity remains a debatable issue. Among the many mechanisms of drought tolerance, dehydration postponement involves the maintenance of high leaf water potential due to, for example, an adequate root system. This trait is compatible with productivity, but requires available soil moisture. When the plant leaf water potential and soil water content decline, the plant must be able to survive drought through dehydration tolerance mechanisms, such as low osmotic potential or osmotic adjustment. Osmotic adjustment and low osmotic potential are considered compatible with growth and yield because they aid in the maintenance of leaf turgor. However, it has been shown that turgor alone does not regulate cell expansion or stomatal conductance and, therefore, the role of osmotic adjustment is debated. Despite this finding, osmotic adjustment has been correlated with grain yield in agronomic crop species, and gene markers responsible for osmotic adjustment are being investigated to improve drought tolerance in productive progenies. Although osmotic adjustment and low osmotic potentials have been investigated in several forest tree species, few studies have investigated the relationship between osmotic adjustment and growth. Most of these studies have been limited to greenhouse or container-grown plants. Osmotic adjustment and rapid growth have been specifically associated in Populus and black spruce (Picea mariuna (Mill.) B.S.P.) progenies. We tested whether these relationships held under field conditions using several poplar clones. In a study of two hybrid poplar

  14. Effect of biochar produced at different pyrolysis temperature on the soil respiration of abandoned mine soil

    NASA Astrophysics Data System (ADS)

    Kim, Yong Seong; Kim, Juhee; Hwang, Wonjae; Hyun, Seunghun

    2015-04-01

    Contaminated soils near an abandoned mine site included the high acidic mine tailing have received great interest due to potential risk to human health, because leachable elements in low pH continuously release from mine site soil with ground water and precipitation event. Biochar, which is the obtained pyrolysis process of biomass, is used as a soil amendments and carbon storage. Especially, many researchers report that the biochar application to soil show increasing soil pH, CEC, adsorption capacity of various elements, as well as, enhanced microbial activity. Therefore, biochar application to contaminated soil near abandoned mine site is expected to have a positive effects on management of these site and soils through the decreased leachability of contaminants. However, effects of biochar application to these site on the soil respiration, as a common measure of soil health, are poorly understood. The objective of this study is to evaluate the effects of biochar application to abandoned mine site soil on the microbial activity with soil respiration test. Biochar was obtained from giant Miscanthus in a slow pyrolysis process (heating rate of 10° C min-1 and N2 gas flow rate of 1.2 L min-1) at the temperature of 400° C (BC4) and 700° C (BC7), respectively. All biochar samples were prepared with grinding and sieving for particle size control (150~500μm). Soil sample was collected from abandoned mine site at Korea (36° 58'N, 128° 10'E). Main contaminants of this soil were As (12.5 g kg-1), Pb (7.3 g kg-1), and Zn (1.1 g kg-1). Biochars were applied (5% by dry weight) to the soil (final mixture weight were 800g), and then moisture contents were adjusted to 100% field capacity (-0.33 bar) in the respirometer with vacuum pump. CO2 efflux of each samples was continuously assessed using continuous aeration system (air flow rate 25 cc min-1) using air cylinder during 130hr (at 20° C and darkness condition). The CO2 emitted from the samples were carried to the

  15. Effect of biochar and liming on soil nitrous oxide emissions from a temperate maize cropping system

    NASA Astrophysics Data System (ADS)

    Hüppi, R.; Felber, R.; Neftel, A.; Six, J.; Leifeld, J.

    2015-12-01

    Biochar, a carbon-rich, porous pyrolysis product of organic residues may positively affect plant yield and can, owing to its inherent stability, promote soil carbon sequestration when amended to agricultural soils. Another possible effect of biochar is the reduction in emissions of nitrous oxide (N2O). A number of laboratory incubations have shown significantly reduced N2O emissions from soil when mixed with biochar. Emission measurements under field conditions however are more scarce and show weaker or no reductions, or even increases in N2O emissions. One of the hypothesised mechanisms for reduced N2O emissions from soil is owing to the increase in soil pH following the application of alkaline biochar. To test the effect of biochar on N2O emissions in a temperate maize cropping system, we set up a field trial with a 20t ha-1 biochar treatment, a limestone treatment adjusted to the same pH as the biochar treatment (pH 6.5), and a control treatment without any addition (pH 6.1). An automated static chamber system measured N2O emissions for each replicate plot (n = 3) every 3.6 h over the course of 8 months. The field was conventionally fertilised at a rate of 160 kg N ha-1 in three applications of 40, 80 and 40 kg N ha-1 as ammonium nitrate. Cumulative N2O emissions were 52 % smaller in the biochar compared to the control treatment. However, the effect of the treatments overall was not statistically significant (p = 0.27) because of the large variability in the data set. Limed soils emitted similar mean cumulative amounts of N2O as the control. There is no evidence that reduced N2O emissions with biochar relative to the control is solely caused by a higher soil pH.

  16. Remotely Adjustable Hydraulic Pump

    NASA Technical Reports Server (NTRS)

    Kouns, H. H.; Gardner, L. D.

    1987-01-01

    Outlet pressure adjusted to match varying loads. Electrohydraulic servo has positioned sleeve in leftmost position, adjusting outlet pressure to maximum value. Sleeve in equilibrium position, with control land covering control port. For lowest pressure setting, sleeve shifted toward right by increased pressure on sleeve shoulder from servovalve. Pump used in aircraft and robots, where hydraulic actuators repeatedly turned on and off, changing pump load frequently and over wide range.

  17. Weighted triangulation adjustment

    USGS Publications Warehouse

    Anderson, Walter L.

    1969-01-01

    The variation of coordinates method is employed to perform a weighted least squares adjustment of horizontal survey networks. Geodetic coordinates are required for each fixed and adjustable station. A preliminary inverse geodetic position computation is made for each observed line. Weights associated with each observed equation for direction, azimuth, and distance are applied in the formation of the normal equations in-the least squares adjustment. The number of normal equations that may be solved is twice the number of new stations and less than 150. When the normal equations are solved, shifts are produced at adjustable stations. Previously computed correction factors are applied to the shifts and a most probable geodetic position is found for each adjustable station. Pinal azimuths and distances are computed. These may be written onto magnetic tape for subsequent computation of state plane or grid coordinates. Input consists of punch cards containing project identification, program options, and position and observation information. Results listed include preliminary and final positions, residuals, observation equations, solution of the normal equations showing magnitudes of shifts, and a plot of each adjusted and fixed station. During processing, data sets containing irrecoverable errors are rejected and the type of error is listed. The computer resumes processing of additional data sets.. Other conditions cause warning-errors to be issued, and processing continues with the current data set.

  18. Genesis of Cr(VI) in Sri Lankan soils and its adsorptive removal by calcined gibbsite

    NASA Astrophysics Data System (ADS)

    Rajapaksha, A. U.; Wijesundara, D. M.; Vithanage, M. S.; Ok, Y. S.

    2012-12-01

    Hexavalent chromium is highly toxic to biota and considered as a priority pollutant. Industrial sources of Cr(VI) include leather tanning, plating, electroplating, anodizing baths, rinse waters, etc. In addition, weathering of ultramafic rocks rich in chromium, such as serpentine, is known to Cr(VI) sources into natural water. The Cr(III) is the most stable in the environment, however, conversion of Cr(III) into Cr(VI) occurs in soil due to presence of naturally occurring minerals such as manganese dioxides. We investigated the amount of Cr(VI) recorded from the soils from anthropogenically and naturally contaminated soils (serpentine soils) in Sri Lanka and the removal efficacy of Cr(VI) by calcined gibbsite (Al oxides). The effect of pH on Cr(VI) adsorption was determined by adjusting the pH in the range of 4-10. In the experiments, the adsorbent concentration was kept at 1 g/l of solution containing 10 mg/l Cr(VI) at 25 0C. Total chromium recorded were around 11,000 mg kg-1 and 6,000 mg kg-1 for serpentine soil and tannery waste-contaminated soil, respectively. Although total Cr was high in the contaminated soils, Cr(VI) concentration was only about 28 mg kg-1 and 210 mg kg-1 in the serpentine and tannery soils, respectively. The calcined gibbsite has maximum adsorption of 85 % around pH 4 and adsorption generally decreased with increase of pH.

  19. Relation between Soil Order and Sorptive Capacity for Dissolved Organic Carbon

    SciTech Connect

    Heal, Katherine R; Brandt, Craig C; Mayes, Melanie; Phillips, Jana Randolph; Jardine, Philip M

    2012-01-01

    Soils have historically been considered a temporary sink for organic C, but deeper soils may serve as longer term C sinks due to the sorption of dissolved organic C (DOC) onto Fe- and clay-rich mineral soil particles. This project provides an improved understanding and predictive capability of the physical and chemical properties of deep soils that control their sorptive capacities for DOC. Two hundred thirteen subsurface soil samples (72 series from five orders) were selected from the eastern and central United States. A characterized natural DOC source was added to the soils, and the Langmuir sorption equation was fitted to the observed data by adjusting the maximum DOC sorption capacity (Q{sub max}) and the binding coefficient (k). Different isotherm shapes were observed for Ultisols, Alfisols, and Mollisols due to statistically significant differences in the magnitude of k, while Q{sub max} was statistically invariant among these three orders. Linear regressions were performed on the entire database and as a function of soil order to correlate Langmuir fitted parameters with measured soil properties, e.g., pH, clay content, total organic C (TOC), and total Fe oxide content. Together, textural clay and Fe oxide content accounted for 35% of the variation in Q{sub max} in the database, and clay was most important for Alfisols and Ultisols. The TOC content, however, accounted for 27% of the variation in Q{sub max} in Mollisols. Soil pH accounted for 45% of the variation in k for the entire database, 41% for Mollisols, and 22% for Alfisols. Our findings demonstrate that correlations between Langmuir parameters and soil properties are different for different soil orders and that k is a more sensitive parameter for DOC sorption than is Q{sub max} for temperate soils from the central and eastern United States.

  20. Removal of arsenic from Janghang smelter site and energy crops-grown soil with soil washing using magnetic iron oxide

    NASA Astrophysics Data System (ADS)

    Han, Jaemaro; Zhao, Xin; Lee, Jong Keun; Kim, Jae Young

    2014-05-01

    Arsenic compounds are considered carcinogen and easily enter drinking water supplies with their natural abundance. US Environmental Protection Agency is finalizing a regulation to reduce the public health risks from arsenic in drinking water by revising the current drinking water standard for arsenic from 50 ppb to 10 ppb in 2001 (USEPA, 2001). Therefore, soil remediation is also growing field to prevent contamination of groundwater as well as crop cultivation. Soil washing is adjusted as ex-situ soil remediation technique which reduces volume of the contaminated soil. The technique is composed of physical separation and chemical extraction to extract target metal contamination in the soil. Chemical extraction methods have been developed solubilizing contaminants containing reagents such as acids or chelating agents. And acid extraction is proven as the most commonly used technology to treat heavy metals in soil, sediment, and sludge (FRTR, 2007). Due to the unique physical and chemical properties, magnetic iron oxide have been used in diverse areas including information technology and biomedicine. Magnetic iron oxides also can be used as adsorbent to heavy metal enhancing removal efficiency of arsenic concentration. In this study, magnetite is used as the washing agent with acid extraction condition so that the injected oxide can be separated by magnetic field. Soil samples were collected from three separate areas in the Janghang smelter site and energy crops-grown soil to have synergy effect with phytoremediation. Each sample was air-dried and sieved (2mm). Soil washing condition was adjusted on pH in the range of 0-12 with hydrogen chloride and sodium hydroxide. After performing soil washing procedure, arsenic-extracted samples were analyzed for arsenic concentration by inductively coupled plasma optical emission spectrometer (ICP-OES). All the soils have exceeded worrisome level of soil contamination for region 1 (25mg/kg) so the soil remediation techniques are

  1. Plant Habitat (PH)

    NASA Technical Reports Server (NTRS)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  2. Partial covariate adjusted regression

    PubMed Central

    Şentürk, Damla; Nguyen, Danh V.

    2008-01-01

    Covariate adjusted regression (CAR) is a recently proposed adjustment method for regression analysis where both the response and predictors are not directly observed (Şentürk and Müller, 2005). The available data has been distorted by unknown functions of an observable confounding covariate. CAR provides consistent estimators for the coefficients of the regression between the variables of interest, adjusted for the confounder. We develop a broader class of partial covariate adjusted regression (PCAR) models to accommodate both distorted and undistorted (adjusted/unadjusted) predictors. The PCAR model allows for unadjusted predictors, such as age, gender and demographic variables, which are common in the analysis of biomedical and epidemiological data. The available estimation and inference procedures for CAR are shown to be invalid for the proposed PCAR model. We propose new estimators and develop new inference tools for the more general PCAR setting. In particular, we establish the asymptotic normality of the proposed estimators and propose consistent estimators of their asymptotic variances. Finite sample properties of the proposed estimators are investigated using simulation studies and the method is also illustrated with a Pima Indians diabetes data set. PMID:20126296

  3. Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid

    PubMed Central

    Donaldson, Melissa A.; Bish, David L.; Raff, Jonathan D.

    2014-01-01

    Nitrous acid (HONO) is an important hydroxyl (OH) radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Recent studies report the release of HONO from nonacidic soils, although it is unclear how soil that is more basic than the pKa of HONO (∼3) is capable of protonating soil nitrite to serve as an atmospheric HONO source. Here, we used a coated-wall flow tube and chemical ionization mass spectrometry (CIMS) to study the pH dependence of HONO uptake onto agricultural soil and model substrates under atmospherically relevant conditions (1 atm and 30% relative humidity). Experiments measuring the evolution of HONO from pH-adjusted surfaces treated with nitrite and potentiometric titrations of the substrates show, to our knowledge for the first time, that surface acidity rather than bulk aqueous pH determines HONO uptake and desorption efficiency on soil, in a process controlled by amphoteric aluminum and iron (hydr)oxides present. The results have important implications for predicting when soil nitrite, whether microbially derived or atmospherically deposited, will act as a net source or sink of atmospheric HONO. This process represents an unrecognized mechanism of HONO release from soil that will contribute to HONO emissions throughout the day. PMID:25512517

  4. Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid.

    PubMed

    Donaldson, Melissa A; Bish, David L; Raff, Jonathan D

    2014-12-30

    Nitrous acid (HONO) is an important hydroxyl (OH) radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Recent studies report the release of HONO from nonacidic soils, although it is unclear how soil that is more basic than the pKa of HONO (∼ 3) is capable of protonating soil nitrite to serve as an atmospheric HONO source. Here, we used a coated-wall flow tube and chemical ionization mass spectrometry (CIMS) to study the pH dependence of HONO uptake onto agricultural soil and model substrates under atmospherically relevant conditions (1 atm and 30% relative humidity). Experiments measuring the evolution of HONO from pH-adjusted surfaces treated with nitrite and potentiometric titrations of the substrates show, to our knowledge for the first time, that surface acidity rather than bulk aqueous pH determines HONO uptake and desorption efficiency on soil, in a process controlled by amphoteric aluminum and iron (hydr)oxides present. The results have important implications for predicting when soil nitrite, whether microbially derived or atmospherically deposited, will act as a net source or sink of atmospheric HONO. This process represents an unrecognized mechanism of HONO release from soil that will contribute to HONO emissions throughout the day. PMID:25512517

  5. pH optrode

    DOEpatents

    Northrup, M. Allen; Langry, Kevin C.

    1993-01-01

    A process is provided for forming a long-lasting, stable, pH-sensitive dye-acrylamide copolymer useful as a pH-sensitive material for use in an optrode or other device sensitive to pH. An optrode may be made by mechanically attaching the copolymer to a sensing device such as an optical fiber.

  6. pH Basics

    ERIC Educational Resources Information Center

    Lunelli, Bruno; Scagnolari, Francesco

    2009-01-01

    The exposition of the pervasive concept of pH, of its foundations and implementation as a meaningful quantitative measurement, in nonspecialist university texts is often not easy to follow because too many of its theoretical and operative underpinnings are neglected. To help the inquiring student we provide a concise introduction to the depth just…

  7. Ph.D. shortage

    NASA Astrophysics Data System (ADS)

    The late 1990s will see a shortage of Ph.D. graduates, according to the Association of American Universities, Washington, D.C. AAU's new comprehensive study, “The Ph.D. Shortage: The Federal Role,” reports that competition for new Ph.D.s is already intense and can only intensify because demand is greater than supply in both academic and nonacademic markets.Doctoral education plays an increasingly important role in U.S. research and development programs. Students have a pivotal part in doing research and enriching it with new ideas. The AAU report says that graduate students are “major determinants of the creativity and productivity of U.S. academic research, the source of more than 50% of the nation's basic research.’ The market for doctoral education extends beyond the university. In 1985, about 43% of all Ph.D.s employed in this country were working outside higher education; the demand for doctorate recipients in nonacademic sectors continues to grow.

  8. Efficient remediation of pentachlorophenol contaminated soil with tetrapolyphosphate washing and subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Wang, Li; Ai, Zhihui; Zhang, Lizhi

    2015-07-15

    In this study, we demonstrate that pentachlorophenol contaminated soil can be efficiently remediated with tetrapolyphosphate washing and subsequent zerovalent iron (ZVI)/Air treatment. 2 mmol L(-1) of tetrapolyphosphate could wash away 52.8% of pentachlorophenol (PCP) at pH 7.0 and 84.2% of pentachlorophenol at pH 11.0 from contaminated soil owing to the promotion effect of tetrapolyphosphate on the soil matrix dispersion and the subsequent solubilization of pentachlorophenol. More importantly, tetrapolyphosphate ions remained in the washing effluent could greatly enhance the molecular oxygen activation by ZVI to oxidize the desorbed PCP without any pH adjustment, and also avoid the competitive consumption of reactive oxygen species, as caused by the common organic surfactants in the washing effluent. Therefore, 85.1% of pentachlorophenol could be aerobically removed from the washing effluent by merely using 5 g L(-1) of ZVI. We also interestingly found that the dissolved iron ions released from the soil could enhance the oxidation of pentachlorophenol in the washing effluent, but the dissolved organic matter had the opposite effect. This study suggests the coupling tetrapolyphosphate washing and subsequent ZVI/Air treatment is an optional approach to remediate pentachlorophenol contaminated soil in view of its low cost and environmental benign. PMID:25781373

  9. Rural to Urban Adjustment

    ERIC Educational Resources Information Center

    Abramson, Jane A.

    Personal interviews with 100 former farm operators living in Saskatoon, Saskatchewan, were conducted in an attempt to understand the nature of the adjustment process caused by migration from rural to urban surroundings. Requirements for inclusion in the study were that respondents had owned or operated a farm for at least 3 years, had left their…

  10. Self adjusting inclinometer

    DOEpatents

    Hunter, Steven L.

    2002-01-01

    An inclinometer utilizing synchronous demodulation for high resolution and electronic offset adjustment provides a wide dynamic range without any moving components. A device encompassing a tiltmeter and accompanying electronic circuitry provides quasi-leveled tilt sensors that detect highly resolved tilt change without signal saturation.

  11. Self Adjusting Sunglasses

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Corning Glass Works' Serengeti Driver sunglasses are unique in that their lenses self-adjust and filter light while suppressing glare. They eliminate more than 99% of the ultraviolet rays in sunlight. The frames are based on the NASA Anthropometric Source Book.

  12. Activation of Hydrogen Peroxide by Iron-Containing Minerals and Catalysts in Circumneutral pH Solutions: Implications for ex situ and in situ Treatment of Contaminated Water and Soil

    NASA Astrophysics Data System (ADS)

    Pham, Anh Le Tuan

    The decomposition of hydrogen peroxide (H2O2) on iron minerals can generate hydroxyl radical (•OH), a strong oxidant capable of transforming a wide range of contaminants. This reaction is critical to ex situ advanced oxidation processes employed in waste treatment systems, as well as in situ chemical oxidation processes used for soil and groundwater remediation. Unfortunately, the process in the ex situ treatment systems is relatively inefficient at circumneutral pH values. In this research, the development of iron-containing catalysts with improved efficiency was investigated. In addition, little is known about the factors that control the performance of in situ treatment systems. Another aim of this dissertation was to elucidate those factors to provide a basis for improving the efficiency of the remediation method. Two types of silica- and alumina-containing iron (hydr)oxide catalysts were synthesized by sol-gel processing techniques (Chapter 2). Relative to iron oxides, such as hematite and goethite, these catalysts were 10 to 80 times more effective in catalyzing the production of •OH from H2O2 under circumneutral conditions. The higher efficiency makes these catalysts promising candidates for ex situ advanced oxidation processes. Moreover, because alumina and silica alter the reactivity of the iron oxides with H2O2, understanding the activity of iron associated with natural aluminosilicates and silica-containing minerals in the subsurface is crucial to explaining the variability of •OH production observed in in situ treatment systems. In addition to the sol-gel technique used in Chapter 2, silica-containing iron (hydr)oxide catalysts were synthesized by immobilizing iron oxide onto mesoporous silica supports, such as SBA-15 (Chapter 5). The iron-containing SBA-15 was 10 times more effective than iron oxides in catalyzing the production of •OH from H2O2. Moreover, this catalyst could be employed for selective oxidation of small organic contaminants

  13. Phylogenetic diversity of acidophilic sporoactinobacteria isolated from various soils.

    PubMed

    Cho, Sung-Heun; Han, Ji-Hye; Seong, Chi Nam; Kim, Seung Bum

    2006-12-01

    Spore forming actinobacteria (sporoactinobacteria) isolated from soils with an acidic pH in Pinus thunbergii forests and coal mine waste were subjected to taxonomic characterization. For the isolation of acidophilic actinobacteria, acidified starch casein agar (pH adjusted to 4-5) was used. The numbers of actinobacteria growing in acidic media were between 3.2 x 10(4) and 8.0 x 10(6) CFU/g soil. Forty three acidophilic actinobacterial strains were isolated and their 16S rDNA sequences were determined. The isolates were divided into eight distinctive phylogenetic clusters within the variation encompassed by the family Streptomycetaceae. Four clusters among them were assigned to the genus Streptacidiphilus, whereas the remaining four were assigned to Streptomyces. The clusters belonging to either Streptomyces or Streptacidiphilus did not form monophyletic clade. The growth pH profiles indicated that the representative isolates grew best between pH 5 and 6. It is evident from this study that acidity has played a critical role in the differentiation of the family Streptomycetaceae, and also that different mechanisms might have resulted in the evolution of two groups, Streptacidiphilus (strict acidophiles) and neutrotolerant acidophilic Streptomyces. The effect of geographic separation was clearly seen among the Streptacidiphilus isolates, which may be a key factor in speciation of the genus. PMID:17205037

  14. 17-4 PH and 15-5 PH

    NASA Technical Reports Server (NTRS)

    Johnson, Howard T.

    1995-01-01

    17-4 PH and 15-5 PH are extremely useful and versatile precipitation-hardening stainless steels. Armco 17-4 PH is well suited for the magnetic particle inspection requirements of Aerospace Material Specification. Armco 15-5 PH and 17-4 PH are produced in billet, plate, bar, and wire. Also, 15-5 PH is able to meet the stringent mechanical properties required in the aerospace and nuclear industries. Both products are easy to heat treat and machine, making them very useful in many applications.

  15. Rhizosphere pH responses to simulated acid rain as measured with glass microelectrodes

    SciTech Connect

    Conkling, B.L.

    1988-01-01

    The objectives of this study were to develop a useful experimental system for studying the rhizosphere of growing roots, and to investigate the effects of bulk soil pH and foliar acid rain application on the rhizosphere pH of alfalfa, corn and soybeans. First, a study was done to compare soil pH measurements made with a standard glass pH electrode with those made using an antimony (Sb) microelectrode. Because of uncertainty with the Sb microelectrodes' response, glass pH-sensitive microelectrodes were made and tested for rhizosphere pH measurements. The influence of soil water pressure gradients in the range of {minus}10 to {minus}1500 kPa in the proximity of the pH and reference electrodes on pH measurements made with microelectrodes was studied. The effect of foliar acid rain application on the rhizosphere pH of alfalfa, corn, and soybean as a function of soil pH were studied. Alfalfa, corn, and soybean were grown into minirhizotrons containing reformed samples of both Seymour A and Bt soil horizons, and the rhizosphere pH measured. The measured in situ bulk soil pH ranged from 4.9 to 6.2 in the A horizon and from 4.0 to 5.7 in the Bt horizon. Plants received acid or non-acid foliar rain applications. Rhizosphere pH was measured using a glass pH-sensitive microelectrode. Acid rain applications caused foliar damage, but had little effect on the rhizosphere pH. The general trend was for the lateral root pH values to be slightly higher than the main root values.

  16. Precision adjustable stage

    DOEpatents

    Cutburth, Ronald W.; Silva, Leonard L.

    1988-01-01

    An improved mounting stage of the type used for the detection of laser beams is disclosed. A stage center block is mounted on each of two opposite sides by a pair of spaced ball bearing tracks which provide stability as well as simplicity. The use of the spaced ball bearing pairs in conjunction with an adjustment screw which also provides support eliminates extraneous stabilization components and permits maximization of the area of the center block laser transmission hole.

  17. Adjustable Autonomy Testbed

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Schrenkenghost, Debra K.

    2001-01-01

    The Adjustable Autonomy Testbed (AAT) is a simulation-based testbed located in the Intelligent Systems Laboratory in the Automation, Robotics and Simulation Division at NASA Johnson Space Center. The purpose of the testbed is to support evaluation and validation of prototypes of adjustable autonomous agent software for control and fault management for complex systems. The AA T project has developed prototype adjustable autonomous agent software and human interfaces for cooperative fault management. This software builds on current autonomous agent technology by altering the architecture, components and interfaces for effective teamwork between autonomous systems and human experts. Autonomous agents include a planner, flexible executive, low level control and deductive model-based fault isolation. Adjustable autonomy is intended to increase the flexibility and effectiveness of fault management with an autonomous system. The test domain for this work is control of advanced life support systems for habitats for planetary exploration. The CONFIG hybrid discrete event simulation environment provides flexible and dynamically reconfigurable models of the behavior of components and fluids in the life support systems. Both discrete event and continuous (discrete time) simulation are supported, and flows and pressures are computed globally. This provides fast dynamic simulations of interacting hardware systems in closed loops that can be reconfigured during operations scenarios, producing complex cascading effects of operations and failures. Current object-oriented model libraries support modeling of fluid systems, and models have been developed of physico-chemical and biological subsystems for processing advanced life support gases. In FY01, water recovery system models will be developed.

  18. Mobilization of phenol and dichlorophenol in unsaturated soils by non-uniform electrokinetics.

    PubMed

    Luo, Qishi; Zhang, Xihui; Wang, Hui; Qian, Yi

    2005-06-01

    The poor mobility of organic pollutants in contaminated sites frequently results in slow remediation processes. Organics, especially hydrophobic compounds, are generally retained strongly in soil matrix as a result of sorption, sequestration, or even formation into non-aqueous-phase liquids and their mobility is thus greatly reduced. The objective of this study was to evaluate the feasibility of using non-uniform electrokinetic transport processes to enhance the mobility of organic pollutants in unsaturated soils with no injection reagents. Phenol and 2,4-dichlorophenol (2,4-DCP), and kaolin and a natural sandy loam soil were selected as model organics and soils, respectively. The results showed that non-uniform electrokinetics can accelerate the desorption and movement of phenol and 2,4-DCP in unsaturated soils. Electromigration and electroosmotic flow were the main driving forces, and their role in the mobilization of phenol and 2,4-DCP varied with soil pH. The movement of 2,4-DCP in the sandy loam towards the anode (about 1.0 cmd(-1)V(-1)) was 1.0-1.5 cmd(-1)V(-1) slower than that in the kaolin soil, but about 0.5 cmd(-1)V(-1) greater than that of phenol in the sandy loam. When the sandy loam was adjusted to pH 9.3, the movement of phenol and 2,4-DCP towards the anode was about twice and five times faster than that at pH 7.7, respectively. The results also demonstrated that the movement of phenol and 2,4-DCP in soils can be easily controlled by regulating the operational mode of electric field. It is believed that non-uniform electrokinetics has the potential for practical application to in situ remediation of organics-contaminated sites. PMID:15857640

  19. Chemical modeling of arsenic(III, V) and selenium(IV, VI) adsorption by soils surrounding ash disposal facilities

    SciTech Connect

    Goldberg, S.; Hyun, S.; Lee, L.S.

    2008-11-15

    Leachate derived from coal ash disposal facilities is a potential anthropogenic source of As and Se to the environment. To establish a practical framework for predicting attenuation and transport of As and Se in ash leachates, the adsorption of As(III), As(V), Se(IV), and Se(VI) had been characterized in prior studies for 18 soils obtained downgradient from ash landfill sites and representing a wide range of soil properties. The constant capacitance model was applied for the first time to describe As(III), As(V), Se(IV), and Se(VI) adsorption on soils as a function of equilibrium solution As(III), As(V), Se(IV), and Se(VI) concentrations. Prior applications of the model had been restricted to describing Se(IV) and As(V) adsorption by soils as a function of solution pH. The constant capacitance model was applied for the first time to describe As(III) and Se(VI) adsorption by soils. The model was able to describe adsorption of these ions on all soils as a function of solution ion concentration by optimizing only one adjustable parameter, the anion surface complexation constant. This chemical model represents an advancement over adsorption isotherm equation approaches that contain two empirical adjustable parameters. Incorporation of these anion surface complexation constants obtained with the constant capacitance model into chemical speciation transport models will allow simulation of soil solution anion concentrations under diverse environmental and agricultural conditions.

  20. 76 FR 26759 - Rate Adjustments for Indian Irrigation Projects

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-09

    ... Federal Register on November 1, 2010 (75 FR 67095) to propose adjustments to the irrigation assessment... Street, Billings, Montana 59101, Telephone: (406) 247-7943 Project Name Agency/Project Contacts Blackfeet..., PH: (406) 653-1752 602 6th Avenue North Wolf Point, MT 59201 Wind River Ed Lone Fight,...

  1. Urine pH test

    MedlinePlus

    A urine pH test measures the level of acid in urine. ... pH - urine ... meat products, or cheese can decrease your urine pH. ... to check for changes in your urine acid levels. It may be done to ... more effective when urine is acidic or non-acidic (alkaline).

  2. Continuously adjustable Pulfrich spectacles

    NASA Astrophysics Data System (ADS)

    Jacobs, Ken; Karpf, Ron

    2011-03-01

    A number of Pulfrich 3-D movies and TV shows have been produced, but the standard implementation has inherent drawbacks. The movie and TV industries have correctly concluded that the standard Pulfrich 3-D implementation is not a useful 3-D technique. Continuously Adjustable Pulfrich Spectacles (CAPS) is a new implementation of the Pulfrich effect that allows any scene containing movement in a standard 2-D movie, which are most scenes, to be optionally viewed in 3-D using inexpensive viewing specs. Recent scientific results in the fields of human perception, optoelectronics, video compression and video format conversion are translated into a new implementation of Pulfrich 3- D. CAPS uses these results to continuously adjust to the movie so that the viewing spectacles always conform to the optical density that optimizes the Pulfrich stereoscopic illusion. CAPS instantly provides 3-D immersion to any moving scene in any 2-D movie. Without the glasses, the movie will appear as a normal 2-D image. CAPS work on any viewing device, and with any distribution medium. CAPS is appropriate for viewing Internet streamed movies in 3-D.

  3. Subsea adjustable choke valves

    SciTech Connect

    Cyvas, M.K. )

    1989-08-01

    With emphasis on deepwater wells and marginal offshore fields growing, the search for reliable subsea production systems has become a high priority. A reliable subsea adjustable choke is essential to the realization of such a system, and recent advances are producing the degree of reliability required. Technological developments have been primarily in (1) trim material (including polycrystalline diamond), (2) trim configuration, (3) computer programs for trim sizing, (4) component materials, and (5) diver/remote-operated-vehicle (ROV) interfaces. These five facets are overviewed and progress to date is reported. A 15- to 20-year service life for adjustable subsea chokes is now a reality. Another factor vital to efficient use of these technological developments is to involve the choke manufacturer and ROV/diver personnel in initial system conceptualization. In this manner, maximum benefit can be derived from the latest technology. Major areas of development still required and under way are listed, and the paper closes with a tabulation of successful subsea choke installations in recent years.

  4. Survival of Rhizobium in Acid Soils

    PubMed Central

    Lowendorf, Henry S.; Baya, Ana Maria; Alexander, Martin

    1981-01-01

    A Rhizobium strain nodulating cowpeas did not decline in abundance after it was added to sterile soils at pH 6.9 and 4.4, and the numbers fell slowly in nonsterile soils at pH 5.5 and 4.1. A strain of R. phaseoli grew when added to sterile soils at pH 6.7 and 6.9; it maintained large, stable populations in soils of pH 4.4, 5.5, and 6.0, but the numbers fell markedly and then reached a stable population size in sterile soils at pH 4.3 and 4.4. The abundance of R. phaseoli added to nonsterile soils with pH values of 4.3 to 6.7 decreased similarly with time regardless of soil acidity, and the final numbers were less than in the comparable sterile soils. The minimum pH values for the growth of strains of R. meliloti in liquid media ranged from 5.3 to 5.9. Two R. meliloti strains, which differed in acid tolerance for growth in culture, did not differ in numbers or decline when added to sterile soils at pH 4.8, 5.2, and 6.3. The population size of these two strains was reduced after they were introduced into nonsterile soils at pH 4.8, 5.4, and 6.4, and the number of survivors was related to the soil pH. The R. meliloti strain that was more acid sensitive in culture declined more readily in sterile soil at pH 4.6 than did the less sensitive strain, and only the former strain was eliminated from nonsterile soil at pH 4.8; however, the less sensitive strain also survived better in limed soil. The cell density of the two R. meliloti strains was increased in pH 6.4 soil in the presence of growing alfalfa. The decline and elimination of the tolerant, but not the sensitive, strain was delayed in soil at pH 4.6 by roots of growing alfalfa. PMID:16345909

  5. 77 FR 40387 - Price Adjustment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-09

    ... Price Adjustment AGENCY: Postal Regulatory Commission. ACTION: Notice. SUMMARY: The Commission is noticing a recently filed Postal Service request to adjust prices for several market dominant products... announcing its intent to adjust prices for several market dominant products within First-Class Mail...

  6. Selected Fe and Mn (nano)oxides as perspective amendments for the stabilization of As in contaminated soils.

    PubMed

    Michálková, Zuzana; Komárek, Michael; Veselská, Veronika; Číhalová, Sylva

    2016-06-01

    An amorphous Mn oxide (AMO), nanomaghemite, and nanomagnetite were used as potential amendments reducing the mobility of As in three contrasting contaminated soils differing in origin of As contamination. Adsorption experiments and XPS analyses combined with incubation batch experiments and pH-static leaching tests were used. The AMO showed excellent adsorption capacity for As(V) reaching a maximum of 1.79 mmol g(-1) at pH 7 and 8. Interestingly, the adsorption capacity in this case decreases with decreasing pH, probably as a result of AMO dissolution at lower pH values. Chemical sorption of As(V) onto AMO was further confirmed with XPS. Both Fe nano-oxides proved the highest adsorption capacity at pH 4 reaching 11 mg g(-1) of adsorbed As(V). The AMO was also the most efficient amendment for decreasing As concentrations in soil solutions during 8 weeks of incubation. Additionally, pH-static leaching tests were performed at pH 4, 5, 6, 7, and natural pH (not adjusted) and AMO again proved the highest ability to decrease As content in leachate. On the other hand, strong dissolution of this amendment at lower pH values (especially pH 4) was observed. For that reason, AMO appears as a promising stabilizing agent for As, especially in neutral, alkaline, or slightly acidic soils, where As(V) species are expected to be more mobile. PMID:26895725

  7. Interactions of Soil Order and Land Use Management on Soil Properties in the Kukart Watershed, Kyrgyzstan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surveys of soil properties related to soil functioning for many regions of Kyrgyzstan are limited. This study established ranges of selected chemical [soil organic matter (SOM), pH and total N (TN)], physical (soil texture), and biochemical (six enzyme activities of C, N, P and S cycling) character...

  8. CLASSIFICATION OF COAL SURFACE MINE SOIL MATERIAL FOR VEGETATION MANAGEMENT AND SOIL WATER QUALITY

    EPA Science Inventory

    An Alabama minesoil classification system was developed based on soil texture, soil color value and soil pH. Only five different soil classes were found in this study. However, the classification scheme allows for the inclusion of any minesoil that occurs on the basis of its text...

  9. [Optimization of electrode configuration in soil electrokinetic remediation].

    PubMed

    Liu, Fang; Fu, Rong-Bing; Xu, Zhen

    2015-02-01

    Electric field distributions of several different electrode configurations in non-uniform electric field were simulated using MATLAB software, and the electrokinetic remediation device was constructed according to the best electrode configuration. The changes of soil pH and heavy metal residues in different parts of the device during the electrokinetic remediation were also studied. The results showed that, in terms of the effectiveness of the electric field strength, the square (1-D-1) and hexagonal (2-D-3) were the optimal electrode configurations for one-dimensional and two-dimensional respectively and the changes of soil pH, the removal of heavy metals and the distribution of electric field were closely related to one another. An acidic migration band, which could prevent premature precipitation of heavy metals to a certain extent and promote electrokinetic removal of heavy metals, was formed gradually along with the remediation in the whole hexagon device when the cathodic pH was controlled during the remediation of the four cationic metallic ions, Cd2+, Ni2+, Pb2+ and Cu2+. After 480-hour remediation, the total removals of Cd, Ni, Pb and Cu were 86.6%, 86.2%, 67.7% and 73.0%, respectively. Remediation duration and replacement frequency of the electrodes could be adjusted according to the repair target. PMID:26031098

  10. The Transitional Stages in the PhD Degree in Mathematics in Terms of Students' Motivation

    ERIC Educational Resources Information Center

    Geraniou, Eirini

    2010-01-01

    This paper presents results of a longitudinal study in the transition to independent graduate studies in mathematics. The analysis of the data collected from 24 students doing a PhD in mathematics revealed the existence of three transitional stages within the PhD degree, namely "Adjustment", "Expertise" and "Articulation". The focus is on the…

  11. Excessive use of nitrogen in Chinese agriculture results in high N2O/(N2O+N2) product ratio of denitrification, primarily due to acidification of the soils

    PubMed Central

    Qu, Zhi; Wang, Jingguo; Almøy, Trygve; Bakken, Lars R

    2014-01-01

    China is the world's largest producer and consumer of fertilizer N, and decades of overuse has caused nitrate leaching and possibly soil acidification. We hypothesized that this would enhance the soils' propensity to emit N2O from denitrification by reducing the expression of the enzyme N2O reductase. We investigated this by standardized oxic/anoxic incubations of soils from five long-term fertilization experiments in different regions of China. After adjusting the nitrate concentration to 2 mM, we measured oxic respiration (R), potential denitrification (D), substrate-induced denitrification, and the denitrification product stoichiometry (NO, N2O, N2). Soils with a history of high fertilizer N levels had high N2O/(N2O+N2) ratios, but only in those field experiments where soil pH had been lowered by N fertilization. By comparing all soils, we found a strong negative correlation between pH and the N2O/(N2O+N2) product ratio (r2 = 0.759, P < 0.001). In contrast, the potential denitrification (D) was found to be a linear function of oxic respiration (R), and the ratio D/R was largely unaffected by soil pH. The immediate effect of liming acidified soils was lowered N2O/(N2O+N2) ratios. The results provide evidence that soil pH has a marginal direct effect on potential denitrification, but that it is the master variable controlling the percentage of denitrified N emitted as N2O. It has been known for long that low pH may result in high N2O/(N2O+N2) product ratios of denitrification, but our documentation of a pervasive pH-control of this ratio across soil types and management practices is new. The results are in good agreement with new understanding of how pH may interfere with the expression of N2O reductase. We argue that the management of soil pH should be high on the agenda for mitigating N2O emissions in the future, particularly for countries where ongoing intensification of plant production is likely to acidify the soils. PMID:24249526

  12. Surfactant adsorption to soil components and soils.

    PubMed

    Ishiguro, Munehide; Koopal, Luuk K

    2016-05-01

    Soils are complex and widely varying mixtures of organic matter and inorganic materials; adsorption of surfactants to soils is therefore related to the soil composition. We first discuss the properties of surfactants, including the critical micelle concentration (CMC) and surfactant adsorption on water/air interfaces, the latter gives an impression of surfactant adsorption to a hydrophobic surface and illustrates the importance of the CMC for the adsorption process. Then attention is paid to the most important types of soil particles: humic and fulvic acids, silica, metal oxides and layered aluminosilicates. Information is provided on their structure, surface properties and primary (proton) charge characteristics, which are all important for surfactant binding. Subsequently, the adsorption of different types of surfactants on these individual soil components is discussed in detail, based on mainly experimental results and considering the specific (chemical) and electrostatic interactions, with hydrophobic attraction as an important component of the specific interactions. Adsorption models that can describe the features semi-quantitatively are briefly discussed. In the last part of the paper some trends of surfactant adsorption on soils are briefly discussed together with some complications that may occur and finally the consequences of surfactant adsorption for soil colloidal stability and permeability are considered. When we seek to understand the fate of surfactants in soil and aqueous environments, the hydrophobicity and charge density of the soil or soil particles, must be considered together with the structure, hydrophobicity and charge of the surfactants, because these factors affect the adsorption. The pH and ionic strength are important parameters with respect to the charge density of the particles. As surfactant adsorption influences soil structure and permeability, insight in surfactant adsorption to soil particles is useful for good soil management. PMID

  13. Influence of Soil Solution Salinity on Molybdenum Adsorption by Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molybdenum (Mo) adsorption on five arid-zone soils from California was investigated as a function of equilibrium solution Mo concentration (0-30 mg L-1), solution pH (4-8), and electrical conductivity (EC = 0.3 or 8 dS m-1). Molybdenum adsorption decreased with increasing pH. An adsorption maximum...

  14. Effect of different soil washing solutions on bioavailability of residual arsenic in soils and soil properties.

    PubMed

    Im, Jinwoo; Yang, Kyung; Jho, Eun Hea; Nam, Kyoungphile

    2015-11-01

    The effect of soil washing used for arsenic (As)-contaminated soil remediation on soil properties and bioavailability of residual As in soil is receiving increasing attention due to increasing interest in conserving soil qualities after remediation. This study investigates the effect of different washing solutions on bioavailability of residual As in soils and soil properties after soil washing. Regardless of washing solutions, the sequential extraction revealed that the residual As concentrations and the amount of readily labile As in soils were reduced after soil washing. However, the bioassay tests showed that the washed soils exhibited ecotoxicological effects - lower seed germination, shoot growth, and enzyme activities - and this could largely be attributed to the acidic pH and/or excessive nutrient contents of the washed soils depending on washing solutions. Overall, this study showed that treated soils having lower levels of contaminants could still exhibit toxic effects due to changes in soil properties, which highly depended on washing solutions. This study also emphasizes that data on the As concentrations, the soil properties, and the ecotoxicological effects are necessary to properly manage the washed soils for reuses. The results of this study can, thus, be utilized to select proper post-treatment techniques for the washed soils. PMID:26086811

  15. Delay Adjusted Incidence Infographic

    Cancer.gov

    This Infographic shows the National Cancer Institute SEER Incidence Trends. The graphs show the Average Annual Percent Change (AAPC) 2002-2011. For Men, Thyroid: 5.3*,Liver & IBD: 3.6*, Melanoma: 2.3*, Kidney: 2.0*, Myeloma: 1.9*, Pancreas: 1.2*, Leukemia: 0.9*, Oral Cavity: 0.5, Non-Hodgkin Lymphoma: 0.3*, Esophagus: -0.1, Brain & ONS: -0.2*, Bladder: -0.6*, All Sites: -1.1*, Stomach: -1.7*, Larynx: -1.9*, Prostate: -2.1*, Lung & Bronchus: -2.4*, and Colon & Rectum: -3/0*. For Women, Thyroid: 5.8*, Liver & IBD: 2.9*, Myeloma: 1.8*, Kidney: 1.6*, Melanoma: 1.5, Corpus & Uterus: 1.3*, Pancreas: 1.1*, Leukemia: 0.6*, Brain & ONS: 0, Non-Hodgkin Lymphoma: -0.1, All Sites: -0.1, Breast: -0.3, Stomach: -0.7*, Oral Cavity: -0.7*, Bladder: -0.9*, Ovary: -0.9*, Lung & Bronchus: -1.0*, Cervix: -2.4*, and Colon & Rectum: -2.7*. * AAPC is significantly different from zero (p<.05). Rates were adjusted for reporting delay in the registry. www.cancer.gov Source: Special section of the Annual Report to the Nation on the Status of Cancer, 1975-2011.

  16. Application of ridge regression to quantify marginal effects of collinear soil properties on phytoaccumulation of arsenic, cadmium, lead, and zinc.

    PubMed

    Anderson, Richard H; Basta, Nicholas T

    2009-03-01

    Soil properties that mitigate hazardous effects of environmental contaminants through soil chemical sequestration should be considered when evaluating ecological risk from terrestrial contamination. The objective of this research was to identify predominant soil chemical/physical properties that modify phytoaccumulation of As, Cd, Pb, and Zn to the non-hyperaccumulating higher plants: Alfalfa (Medicago sativa L.), perennial ryegrass (Lolium perenne L.), and Japanese millet (Echinochloa crusgalli L.). Transmission coefficients were estimated from a dose-response experiment with the use of aboveground tissue contaminant concentrations and correlated with selected soil property measurements to develop statistical prediction models for soil-specific adjustments to ecological risk assessments. Significant correlations between soil properties and transmission coefficients were observed for all four contaminants. Intercorrelation was also observed among soil properties, including cation exchange capacity (CEC) and soil pH (p = 0.035), CEC and total clay (p = 0.030), organic carbon (OC) and total clay content (p = 0.085), reactive iron oxides (FeOX) and OC (p = 0.078), and reactive Mn oxide (MnOX) and total clay content (p < 0.001). Ridge regression, a technique that suppresses the effects of multicollinearity and enables prediction, was used to assess the marginal contributions of soil properties found to mitigate phytoaccumulation. Prediction models were developed for all four contaminants. Significant variables were FeOX for As or pH, OC, CEC, clay content, or a combination of factors for cationic metal models. Ridge regression provides a powerful alternative to conventional multiple regression techniques for ecotoxicological studies when intercorrelated predictors are experimentally unavoidable, as with soil properties. PMID:18980389

  17. Active synthetic soil

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Henninger, Donald L. (Inventor); Allen, Earl R. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium and micronutrients dispersed in a calcium phosphate matrix, a zeolite cation exchange medium saturated with a charge of potassium and nitrogen cations, and an optional pH buffer. Moisture dissolves the apatite and mobilizes the nutrient elements from the apatite matrix and the zeolite charge sites.

  18. Active synthetic soil

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Henninger, Donald L. (Inventor); Allen, Earl R. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium, and micronutrients dispersed in a calcium phosphate matrix, a zeolite cation exchange medium saturated with a charge of potassium and nitrogen cations, and an optional pH buffer. Moisture dissolves the apatite and mobilizes the nutrient elements from the apatite matrix and the zeolite charge sites.

  19. Influence of ionic strength, pH, and cation valence on aggregation kinetics of titanium dioxide nanoparticles.

    PubMed

    French, Rebecca A; Jacobson, Astrid R; Kim, Bojeong; Isley, Sara L; Penn, R Lee; Baveye, Philippe C

    2009-03-01

    The extensive use of titanium dioxide nanoparticles (nano-TiO2) in many consumer products has raised concerns about possible risks to the environment The magnitude of the threat may depend on whether nano-TiO2 remains dispersed in the environment, or forms much larger-sized aggregates or clusters. Currently, limited information is available on the issue. In this context, the purpose of the present article is to report initial measurements of the morphology and rate of formation of nano-TiO2 aggregates in aqueous suspensions as a function of ionic strength and of the nature of the electrolyte in a moderately acid to circumneutral pH range typical of soil and surface water conditions. Dynamic light scattering results show that 4-5 nm titanium dioxide particles readily form stable aggregates with an average diameter of 50-60 nm at pH approximately 4.5 in a NaCl suspension adjusted to an ionic strength of 0.0045 M. Holding the pH constant but increasing the ionic strength to 0.0165 M, leads to the formation of micron-sized aggregates within 15 min. At all other pH values tested (5.8-8.2), micron-sized aggregates form in less than 5 min (minimum detection time), even at low ionic strength (0.0084-0.0099 M with NaCl). In contrast, micron-sized aggregates form within 5 min in an aqueous suspension of CaCl2 at an ionic strength of 0.0128 M and pH of 4.8, which is significantly faster than observed for NaCI suspensions with similar ionic strength and pH. This result indicates that divalent cations may enhance aggregation of nano-TiO2 in soils and surface waters. Optical micrographs show branching aggregates of sizes ranging from the 1 microm optical limit of the microscope to tens of micrometers in diameter. PMID:19350903

  20. In vitro alkaline pH resistance of Enterococcus faecalis.

    PubMed

    Weckwerth, Paulo Henrique; Zapata, Ronald Ordinola; Vivan, Rodrigo Ricci; Tanomaru Filho, Mário; Maliza, Amanda Garcia Alves; Duarte, Marco Antonio Hungaro

    2013-01-01

    Enterococcus faecalis is a bacterial species often found in root canals with failed endodontic treatment. Alkaline pastes are widely used in Endodontics because of their biocompatibility and antimicrobial activity, but this microorganism can resist alkalinity. The purpose of this study was to evaluate in vitro the alkaline pH resistance of E. faecalis for different periods up to 14 days. Samples were obtained from the oral cavity of 150 patients from the Endodontic clinic. The pH of the experimental tubes (n=84) was first adjusted with 6M NaOH to pH values of 9.5, 10.5, 11.5 and 12.5 (21 tubes per pH). Twenty clinical isolates and the ATCC 29212 strain were tested. The 5 positive controls and experimental tubes of each pH were inoculated with 10 µL of bacterial suspension and incubated at 36 °C for 24, 48 and 72 h, 7 and 14 days. For each period, the turbidity of the medium was visually compared with a 0.5 McFarland standard. The presence of the microorganism was confirmed by seeding on M-Enterococcus agar. Four tubes containing BHI broth adjusted to the tested pHs were incubated for 14 days to verify if pH changes occurred. The pH of inoculated BHI broth was also measured on day 14 to determine if the microorganism acidified the medium. The growth of all E. faecalis strains occurred at pH 9.5 to 11.5 in all periods. Although turbidity was not observed at pH 12.5, there was growth of 13 and 2 strains at 24 and 48 h, respectively, on M-Enterococcus agar. No tube showed growth at pH 12.5 after 72 h. It was concluded that E. faecalis can survive in highly alkaline pH, and some clinical isolates require 72 h at pH 12.5 to be killed. PMID:24474287

  1. Improved granular activated carbon for the stabilization of wastewater PH

    SciTech Connect

    Farmer, R.W.; Dussert, B.W.; Kovacic, S.L.

    1996-12-31

    Laboratory studies have identified the cause of the pH rise, which occurs during water treatment with activated carbon, as an interaction between the naturally occurring anions and protons in the water and the carbon surface. The interaction can be described as an ion exchange type of phenomenon, in which the carbon surface sorbs the anions and corresponding hydronium ions from the water. These studies have shown that the anion sorption and resulting pH increase is independent of the raw material used for the activated carbon production, e.g. bituminous or subbituminous coal, peat, wood or coconut. Also, the pH excursions occur with virgin, reactivated, and acid washed granular carbons. Current pH control technologies focus on adjustment of the wastewater pH prior to discharge or recycle of the initial effluent water until the pH increase abates. However, improved water pH control options have been realized by altering the carbon surface through controlled oxidation rather than the water chemistry or extended preprocessing at the treatment site.

  2. Influence of soil solution salinity on boron adsorption by soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Boron adsorption on two arid-zone soils from the San Joaquin Valley of California was investigated as a function of equilibrium solution B concentration (0-250 mg L-1), solution pH (3-12), and electrical conductivity (EC = 0.3 or 7.8 dS m-1). Boron adsorption on both soils increased with increasing...

  3. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - I

    EPA Science Inventory

    The bioavailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  4. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - II

    EPA Science Inventory

    The bioabailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  5. Transfer of cadmium from a sandy acidic soil to man: A population study

    SciTech Connect

    Staessen, J.A.; Celis, H.G.; Fagard, R.H.; Lijnen, P.J.; Thijs, L.B.; Amery, A.K. ); Vyncke, G. ); Lauwerys, R.R.; Roels, H.A. ); Claeys, F. ); Dondeyne, F. ); Ide, G. ); Rondia, D.; Sartor, F. )

    1992-06-01

    This population study included 230 subjects (age range 20-83 years) who consumed vegetables grown in kitchen gardens on a sandy acidic soil (mean pH {approximately}6.3). The study investigated the association between the Cd (cadmium) levels in blood and urine and the Cd concentration in the soil (range 0.2-44 ppm). Seventy-six subjects were current smokers and 122 participants lived in a district with known Cd pollution. Urinary Cd in the 230 subjects averaged 8.7 nmole/24 hr, (range 1.3 to 47 nmole/24 hr) after age adjustment positively correlated with the Cd level in the soil; a twofold increase of the Cd concentration in the soil was accompanied by a 7% rise in urinary Cd in men and by a 4% rise in women. Blood Cd averaged 11.5 nmole/liter (range 1.8-41 nmole/liter) and was negatively associated with the Cd level in the soil. After adjustment for significant covariates (smoking and serum {gamma}-glutamyl transpeptidase in both sexes, and age and serum ferritin in women), a twofold increase in the Cd concentration in the soil was accompanied by a 6% decrease in blood Cd in men and by a 10% decrease in women. In conclusion, in a rural population, consuming vegetables grown on a sandy acidic soil, 2 to 4% of the variance of urinary Cd was directly related to the Cd level in the soil. The negative correlation with blood Cd, a measure of more recent exposure, was biased by the implementation of preventive measures in the polluted district.

  6. Enhancing electrokinetic remediation of cadmium- contaminated soils with stepwise moving anode method.

    PubMed

    Chen, Xue J; Shen, Zhe M; Yuan, Tao; Zheng, Shen S; Ju, Bing X; Wang, Wen H

    2006-01-01

    This paper proposed an innovative approach by stepwise moving anode towards cathode to enhance the cadmium (Cd) removal from soil during the process of electrokinetic (EK) remediation. Fixed anode tests and moving anode tests were carried out for 60 hours to compare their performances. The anode-cathode spacing was 21 cm. Constant voltage grade of 1.0 V cm(-1) was applied in this study. The parameters included pH, electrical conductivity, current, Cd concentration and speciation distributions, energy consumptions, etc. It was found that the pH values in the moving anode tests were relatively lower than those of the fixed tests. In the moving anode test, the removal efficiency of Cd in the soils at the fraction of S4 was enhanced by 54.9% compared with that of the fixed anode tests. After 60 hours of treatment, approximately 80% of the spiked soils (100.63 mg x kg(-1) of Cd) in the system were successfully remedied in the moving anode tests; and the mean removal efficiency was 73% for actual field-contaminated soil (54.26 mg x kg(-1) of Cd). It is effective to remedy actual contaminated soils. In addition, the cumulative energy consumptions were 59.29 kWhm(-3) and 31.52 kWhm(-3) for the fixed and moving tests, respectively. The results revealed that the Cd removal efficiency was improved by the moving anode method. Moreover, less energy was consumed in the moving test. The proposed approach does not need to introduce extra chemicals nor adjust the pH in the system to enhance the Cd removal by EK remediation. The basic idea proposed in this paper provides a novel and environmental friendly method to enhance the EK remediation of heavy metals contaminated soils. PMID:17000543

  7. 78 FR 62712 - Rate Adjustment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-22

    ... Rate Adjustment AGENCY: Postal Regulatory Commission. ACTION: Notice. SUMMARY: The Commission is noticing a recent Postal Service filing seeking postal rate adjustments based on exigent circumstances... On September 26, 2013, the Postal Service filed an exigent rate request with the Commission...

  8. Adjustable holder for transducer mounting

    NASA Technical Reports Server (NTRS)

    Deotsch, R. C.

    1980-01-01

    Positioning of acoustic sensor, strain gage, or similar transducer is facilitated by adjustable holder. Developed for installation on Space Shuttle, it includes springs for maintaining uniform load on transducer with adjustable threaded cap for precisely controlling position of sensor with respect to surrounding structure.

  9. Spousal Adjustment to Myocardial Infarction.

    ERIC Educational Resources Information Center

    Ziglar, Elisa J.

    This paper reviews the literature on the stresses and coping strategies of spouses of patients with myocardial infarction (MI). It attempts to identify specific problem areas of adjustment for the spouse and to explore the effects of spousal adjustment on patient recovery. Chapter one provides an overview of the importance in examining the…

  10. Mood Adjustment via Mass Communication.

    ERIC Educational Resources Information Center

    Knobloch, Silvia

    2003-01-01

    Proposes and experimentally tests mood adjustment approach, complementing mood management theory. Discusses how results regarding self-exposure across time show that patterns of popular music listening among a group of undergraduate students differ with initial mood and anticipation, lending support to mood adjustment hypotheses. Describes how…

  11. Designer, acidic biochar influences calcareous soil characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An acidic (pH 5.8) biochar was created using a low pyrolysis temperature (350 degrees celsius) and steam activation to potentially improve the soil physicochemical status of an eroded calcareous soil. Biochar was added at 0, 1, 2, and 10 percent (by weight) to an eroded Portneuf soil (coarse-silty,...

  12. Exploring Soil Ecosystems.

    ERIC Educational Resources Information Center

    Finley, Deborah R.

    1991-01-01

    Describes a soil lab that can be performed with a minimum of equipment and time, utilizing a lawn, field, or woodlot. Students dig a 1-meter-deep pit and observe the litter and humus layers where most microbial and fungal decomposition occurs. Describes comparing different locations by pH level and concentration of potassium, phosphorous, and…

  13. pH dependent salinity-boron interactions impact yield, biomass, evapotranspiration and boron uptake in broccoli (Brassica oleracea L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil pH is known to influence many important biochemical processes in plants and soils, however its role in salinity - boron interactions affecting plant growth and ion relations has not been examined. The purpose of this research was to evaluate the interactive effects of salinity, boron and soil ...

  14. The potentiometric titration of fluoride using pH electrodes

    SciTech Connect

    Selig, W.S.

    1987-07-01

    Sodium fluoride solutions with an initial pH of 4.46 yielded poorly defined endpoint breaks with a pH electrode system and Ce(III) or La(III) as titrants. At this initial pH, however, the fluoride ISE yielded acceptable S-shaped titration curves. At an initial pH of 6.30, both electrode systems and titrant combinations yielded acceptable endpoint breaks and titration curves. While a partially nonaqueous medium (50% methanol) enhanced the steepness of the endpoint breaks, the standard deviation also increased. This was possibly caused by evaporation of some of the solvent. We therefore do not see the necessity for, nor recommend a partially nonaqueous medium. There is no advantage in using Ce(III) rather than La(III) as titrant. Increasing the initial pH from 4.46 to 6.3 decreased the mean normality of the titrant (or increased the titration volume) for both electrode systems and titrants. We therefore recommend that the sodium fluoride standard solutions be adjusted to the same pH as the samples to be determined. For the most accurate results, the standardization should be done with a good approximation of the salt content of the unknown solution.

  15. Influence of soil solution cation composition on boron adsorption by soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Boron (B) adsorption on five arid-zone soil samples from California was investigated as a function of solution pH (4-10) and cation composition (Na, Ca, or Mg). Boron adsorption increased with increasing solution pH, reached an adsorption maximum near pH 9, and decreased with further increases with...

  16. Esophageal pH monitoring

    MedlinePlus

    pH monitoring - esophageal; Esophageal acidity test ... esophagitis You may need to have the following tests if your doctor suspects esophagitis : Barium swallow Esophagogastroduodenoscopy (also called upper GI endoscopy)

  17. Carbon Mineralizability Determines Interactive Effects on Mineralization of Pyrogenic Organic Matter and Soil Organic Carbon

    SciTech Connect

    Whitman, Thea L.; Zhu, Zihua; Lehmann, Johannes C.

    2014-10-31

    Soil organic carbon (SOC) is a critical and active pool in the global C cycle, and the addition of pyrogenic organic matter (PyOM) has been shown to change SOC cycling, increasing or decreasing mineralization rates (often referred to as priming). We adjusted the amount of easily mineralizable C in the soil, through 1-day and 6-month pre-incubations, and in PyOM made from maple wood at 350°C, through extraction. We investigated the impact of these adjustments on C mineralization interactions, excluding pH and nutrient effects and minimizing physical effects. We found short-term increases (+20-30%) in SOC mineralization with PyOM additions in the soil pre-incubated for 6 months. Over the longer term, both the 6-month and 1-day pre-incubated soils experienced net ~10% decreases in SOC mineralization with PyOM additions. This was possibly due to stabilization of SOC on PyOM surfaces, suggested by nanoscale secondary ion mass spectrometry. Additionally, the duration of pre-incubation affected priming interactions, indicating that there may be no optimal pre-incubation time for SOC mineralization studies. We show conclusively that relative mineralizability of SOC in relation to PyOM-24 C is an important determinant of the effect of PyOM additions on SOC mineralization.

  18. PhEDEx Data Service

    NASA Astrophysics Data System (ADS)

    Egeland, Ricky; Wildish, Tony; Huang, Chih-Hao

    2010-04-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the "SiteDB" service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  19. Insights into tetrabromobisphenol A adsorption onto soils: Effects of soil components and environmental factors.

    PubMed

    Tong, Fei; Gu, Xueyuan; Gu, Cheng; Ji, Rong; Tan, Yinyue; Xie, Jinyu

    2015-12-01

    Concerns regarding tetrabromobisphenol A (TBBPA), the most widely utilized brominated flame retardant in the world, are growing because of the wide application and endocrine-disrupting potential of this compound. To properly assess its environmental impacts, it is important to understand the mobility and fate of TBBPA in soil environments. In this study, the effects of soil components, dissolved organic carbon (DOC) and heavy metal cations on TBBPA adsorption onto two Chinese soils (red soil and black soil) were investigated using batch sorption experiments. The desorption behavior of TBBPA when the two soils are irrigated with eutrophicated river water was also investigated. The results showed that pH greatly affects the adsorptive behavior of TBBPA in soils. Iron oxide minerals and phyllosilicate minerals are both active surfaces for TBBPA sorption, in addition to soil organic matter (SOM). DOC (50 mg OC L(-1)) exhibited a limited effect on TBBPA sorption only under neutral conditions. TBBPA sorption was only minimally affected by the heavy metals (Cu2+, Pb2+ and Cd2+) in the studied pH range. Eutrophicated river water significantly enhanced the desorption of TBBPA from red soil due to the change in soil solution pH. These findings indicate that mobility of TBBPA in soils is mainly associated with soil pH, organic matter and clay fractions: it will be retained by soils or sediments with high organic matter and clay fractions under acidic conditions but becomes mobile under alkaline conditions. PMID:26247687

  20. SOIL Geo-Wiki: A tool for improving soil information

    NASA Astrophysics Data System (ADS)

    Skalský, Rastislav; Balkovic, Juraj; Fritz, Steffen; See, Linda; van der Velde, Marijn; Obersteiner, Michael

    2014-05-01

    soil classification system) and allow experts to upload and share scientifically rigorous soil data; and an application oriented towards the general public, which will be more focused on describing well observed, individual soil properties using simplified classification keys. The latter application will avoid the use of soil science related terminology and focus on the most useful soil parameters such as soil surface features, stone content, soil texture, soil plasticity, calcium carbonate presence, soil color, soil pH, soil repellency, and soil depth. Collection of soil and landscape pictures will also be supported in Soil Geo-Wiki to allow for comprehensive data collection while simultaneously allowing for quality checking by experts.

  1. Voltammetric pH Nanosensor.

    PubMed

    Michalak, Magdalena; Kurel, Malgorzata; Jedraszko, Justyna; Toczydlowska, Diana; Wittstock, Gunther; Opallo, Marcin; Nogala, Wojciech

    2015-12-01

    Nanoscale pH evaluation is a prerequisite for understanding the processes and phenomena occurring at solid-liquid, liquid-liquid, and liquid-gas interfaces, e.g., heterogeneous catalysis, extraction, partitioning, and corrosion. Research on the homogeneous processes within small volumes such as intracellular fluids, microdroplets, and microfluidic chips also requires nanometer scale pH assessment. Due to the opacity of numerous systems, optical methods are useless and, if applicable, require addition of a pH-sensitive dye. Potentiometric probes suffer from many drawbacks such as potential drift and lack of selectivity. Here, we present a voltammetric nanosensor for reliable pH assessment between pH 2 and 12 with high spatial resolution. It consists of a pyrolytic carbon nanoelectrode obtained by chemical vapor deposition (CVD) inside a quartz nanopipette. The carbon is modified by adsorption of syringaldazine from its ethanolic solution. It exhibits a stable quasi-reversible cyclic voltammogram with nearly Nernstian dependency of midpeak potentials (-54 mV/pH). This sensor was applied as a probe for scanning electrochemical microscopy (SECM) in order to map pH over a platinum ultramicroelectrode (UME), generating hydroxide ions (OH(-)) by the oxygen reduction reaction (ORR) at a diffusion-controlled rate in aerated phosphate buffered saline (PBS). The results reveal the alkalization of the electrolyte close to the oxygen reducing electrode, showing the insufficient buffer capacity of PBS to maintain a stable pH at the given conditions. PMID:26516786

  2. Cadmium chemical speciation and absorption in plant in a polluted soil

    NASA Astrophysics Data System (ADS)

    Gigliotti, Giovanni; Massaccesi, Luisa

    2013-04-01

    Cadmium is a very toxic heavy metal presents in nature in small amounts, with an average content of 0.2 mg kg-1 in the geosphere. Nonetheless, anthropogenic activities such as industrial processes, large use of phosphate fertilizers and sewage sludge disposals may determine a massive accumulation of Cd in soil. Cd is considered a particularly interesting heavy metal as it can be accumulated by plants to levels that can be toxic to humans and animals, when consumed even in minor amounts. The aim of the present work was to study in a soil polluted with Cd for a long time i) the distribution of Cd in different chemical fractions by means of a sequential extraction procedure; ii) the adsorption of Cd by plants grown in this polluted soil; iii) the change in the distribution of Cd in the soil fractions possibly due to root exudates after plant growing. The chemical fractionation procedure used involved the following forms: a) exchangeable, b) bound to carbonates, c) bound to Fe-Mn oxides and hydroxides, d) bound to organic matter, e) residual part. The following reagents and extraction times were applied: a) 1 M CH3COONa (1:10, w/v; pH 8.2) for 16 h at room temperature; b) 0,1 M CH3COOH for 16 h at room temperature; c) 0,1 M NH2OH•HCl (1:10, w/v; adjusted to pH 2.0 with HNO3) for 16 h at room temperature; d) 30% H2O2 (adjusted to pH 2.0 with HNO3) at 85 °C, followed by extraction with 1 M CH3COONH4 (1:10, w/v; adjusted to pH 2.0 with HNO3) for 16 h at room temperature; e) acid digestion with concentrated HNO3 and 30% H2O2 for residue fraction. Festuca seeds were germinated in the contaminated soil in plastic flats and non-contaminated soil. After two days the seedling were submitted to day/night conditions. The seedlings were collected 6 weeks after seeding and divided in roots and shoots and analysed for Cd concentration. The polluted soil has average Cd content of 200 mg kg-1, instead, the Cd content in the same unpolluted soil was about 0.44 mg kg-1. The

  3. Adjustable Induction-Heating Coil

    NASA Technical Reports Server (NTRS)

    Ellis, Rod; Bartolotta, Paul

    1990-01-01

    Improved design for induction-heating work coil facilitates optimization of heating in different metal specimens. Three segments adjusted independently to obtain desired distribution of temperature. Reduces time needed to achieve required temperature profiles.

  4. Soil cultivation in vineyards alters interactions between soil biota and soil physical and hydrological properties

    NASA Astrophysics Data System (ADS)

    Zaller, Johann G.; Buchholz, Jacob; Querner, Pascal; Winter, Silvia; Kratschmer, Sophie; Pachinger, Bärbel; Strauss, Peter; Bauer, Thomas; Stiper, Katrin; Potthoff, Martin; Guernion, Muriel; Scimia, Jennifer; Cluzeau, Daniel

    2016-04-01

    Several ecosystem services provided by viticultural landscapes result from interactions between soil organisms and soil parameters. However, to what extent different soil cultivation intensities in vineyards compromise soil organisms and their interactions between soil physical and hydrological properties is not well understood. In this study we examined (i) to what extent different soil management intensities affect the activity and diversity of soil biota (earthworms, Collembola, litter decomposition), and (ii) how soil physical and hydrological properties influence these interactions, or vice versa. Investigating 16 vineyards in Austria, earthworms were assessed by hand sorting, Collembola via pitfall trapping and soil coring, litter decomposition by using the tea bag method. Additionally, soil physical (water infiltration, aggregate stability, porosity, bulk density, soil texture) and chemical (pH, soil carbon content, cation exchange capacity, potassium, phosphorus) parameters were assessed. Results showed complex ecological interactions between soil biota and various soil characteristics altered by management intensity. These investigations are part of the transdisciplinary BiodivERsA project VineDivers and will ultimately lead into management recommendations for various stakeholders.

  5. Relative bioaccessibility of Pb-based paint in soil.

    PubMed

    Hunt, Andrew

    2016-08-01

    The threat posed by lead (Pb) in soil for pediatric populations continues to be a public health issue. In long-established residential areas, a principal source of Pb in soil is likely to be old Pb-based paint originating from building surfaces. The health hazard posed by Pb from paint in soil will likely depend on quantity of paint incorporated, its Pb-mineral composition, whether the Pb is locked in some other material and the paint residence time in the soil (degree of aging). Here the relative bioavailability (RBA) of Pb in different types of Pb-bearing paint has been assessed. Tests were performed with individual paints, with paints mixed with a low-Pb soil, and with paints mixed with soil and the biogenic phosphate apatite II. Thirteen Pb-bearing paint samples were ground and passed through 250- and 100-µm screens. Samples nominally <100 µm from all the paints were analyzed, and six of the paints for which there was sufficient material in the 100- to 250-µm-size range were also tested. RBA extraction of Pb employed a simulated gastric fluid (SGF) of HCl and glycine adjusted to a pH of 1.5 in which samples were agitated (in an end-over-end rotator) for 2 h. Original paints were examined by SEM/EDX, and by XRD, residues collected after RBA extraction were examined by SEM/EDX. The concentration of Pb in the extraction fluid was measured by AAS. The quantity of Pb mobilized in each test batch was approximately an order of magnitude less in the paint-soil mix compared to the corresponding paint-only sample. The difference in the amount of Pb extracted from the paint-soil mix compared to the paint-soil-phosphate mix was minimal. However, in the post-RBA residues of the paint-soil mix, a PbCl precipitate was observed, and in the extraction residues of the paint-soil-apatite II mixes PbClP phases were recorded. Precipitation of these secondary phases obviously modified the amount of Pb in the extraction fluid, and this may need to be considered, i.e., under

  6. Yogurt made from milk heated at different pH values.

    PubMed

    Ozcan, Tulay; Horne, David S; Lucey, John A

    2015-10-01

    Milk for yogurt manufacture is subjected to high heat treatment to denature whey proteins. Low milk pH values (≤ 6.5) at heating result in most denatured whey proteins becoming associated with casein micelles, whereas high milk pH values (≥ 7.0) at heating result in the formation of mostly soluble (nonmicellar) denatured whey protein complexes. There are conflicting reports on the relative importance of soluble and casein-bound whey protein aggregates on the properties of acid gels. Prior studies investigating the effect of pH of milk at heating used model gels in which milk was acidified by glucono-δ-lactone; in this study, we prepared yogurt gels using commercial starter cultures. Model acid gels can have very different texture and physical properties from those made by fermentation with starter cultures. In this study, we investigated the effects of different pH values of milk at heating on the rheological, light backscatter, and microstructural properties of yogurt gels. Reconstituted skim milk was adjusted to pH values 6.2, 6.7, and 7.2 and heated at 85°C for 30 min. A portion of the heated milk samples was readjusted back to pH 6.7 after heating. Milks were inoculated with 3% (wt/wt) yogurt starter culture and incubated at 40°C until pH 4.6. Gel formation was monitored using dynamic oscillatory rheology, and parameters measured included the storage modulus (G') and loss tangent (LT) values. Light-backscattering properties, such as the backscatter ratio (R) and the first derivative of light backscatter ratio (R'), were also monitored during fermentation. Fluorescence microscopy was used to observe gel microstructure. The G' values at pH 4.6 were highest in gels made from milk heated at pH 6.7 and lowest in milk heated at pH 6.2, with or without pH adjustment after heating. The G' values at pH 4.6 were lower in samples after adjustment back to pH 6.7 after heating. No maximum in the LT parameter was observed during gelation for yogurts made from milk

  7. Amount of organic matter required to induce sulfate reduction in sulfuric material after re-flooding is affected by soil nitrate concentration.

    PubMed

    Yuan, Chaolei; Mosley, Luke M; Fitzpatrick, Rob; Marschner, Petra

    2015-03-15

    Acid sulfate soils (ASS) with sulfuric material can be remediated through microbial sulfate reduction stimulated by adding organic matter (OM) and increasing the soil pH to >4.5, but the effectiveness of this treatment is influenced by soil properties. Two experiments were conducted using ASS with sulfuric material. In the first experiment with four ASS, OM (finely ground mature wheat straw) was added at 2-6% (w/w) and the pH adjusted to 5.5. After 36 weeks under flooded conditions, the concentration of reduced inorganic sulfur (RIS) and pore water pH were greater in all treatments with added OM than in the control without OM addition. The RIS concentration increased with OM addition rate. The increase in RIS concentration between 4% and 6% OM was significant but smaller than that between 2% and 4%, suggesting other factors limited sulfate reduction. In the second experiment, the effect of nitrate addition on sulfate reduction at different OM addition rates was investigated in one ASS. Organic matter was added at 2 and 4% and nitrate at 0, 100, and 200 mg nitrate-N kg(-1). After 2 weeks under flooded conditions, soil pH and the concentration of FeS measured as acid volatile sulfur (AVS) were lower with nitrate added at both OM addition rates. At a given nitrate addition rate, pH and AVS concentration were higher at 4% OM than at 2%. It can be concluded that sulfate reduction in ASS at pH 5.5 can be limited by low OM availability and high nitrate concentrations. Further, the inhibitory effect of nitrate can be overcome by high OM addition rates. PMID:25600239

  8. Empirical algorithms to estimate water column pH in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Williams, N. L.; Juranek, L. W.; Johnson, K. S.; Feely, R. A.; Riser, S. C.; Talley, L. D.; Russell, J. L.; Sarmiento, J. L.; Wanninkhof, R.

    2016-04-01

    Empirical algorithms are developed using high-quality GO-SHIP hydrographic measurements of commonly measured parameters (temperature, salinity, pressure, nitrate, and oxygen) that estimate pH in the Pacific sector of the Southern Ocean. The coefficients of determination, R2, are 0.98 for pH from nitrate (pHN) and 0.97 for pH from oxygen (pHOx) with RMS errors of 0.010 and 0.008, respectively. These algorithms are applied to Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemical profiling floats, which include novel sensors (pH, nitrate, oxygen, fluorescence, and backscatter). These algorithms are used to estimate pH on floats with no pH sensors and to validate and adjust pH sensor data from floats with pH sensors. The adjusted float data provide, for the first time, seasonal cycles in surface pH on weekly resolution that range from 0.05 to 0.08 on weekly resolution for the Pacific sector of the Southern Ocean.

  9. Soil and Surface Runoff Phosphorus Relationships for Five Typical USA Midwest Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessively high soil P can increase P loss with surface runoff. This study used indoor rainfall simulations to characterize soil and runoff P relationships for five Midwest soils (Argiudoll, Calciaquaoll, Hapludalf, and two Hapludolls). Topsoil (15-cm depth, 241–289 g clay kg–1 and pH 6.0–8.0) was ...

  10. Soil acidification stimulates the emission of ethylene from temperate forest soils

    NASA Astrophysics Data System (ADS)

    Xu, Xingkai; Kazuyuki, Inubushi

    2009-11-01

    Soil acidification via acid precipitation is recognized to have detrimental impacts on forest ecosystems, which is in part associated with the function of ethylene released from the soil. However, the impacts of acidification on the cycling of ethylene in forest soils have not been fully taken into consideration in global change studies. Forest topsoils (0-5 cm) under four temperate forest stands were sampled to study the effects of a pH change on the emissions of ethylene and carbon dioxide from the soils and concentrations of dissolved organic carbon (DOC) released into the soils. Increasing acidification or alkalinization of forest soils could increase concentrations of DOC released into the soils under anoxic and oxic conditions. The ethylene emission from these forest topsoils could significantly increase with a decreasing pH, when the soils were acidified experimentally to a pH<4.0, and it increased with an increasing concentration of DOC released into the soils, which was different from the carbon dioxide emission from the soils. Hence, the short-term stimulating responses of ethylene emission to a decreasing pH in such forest soils resulted from the increase in the DOC concentration due to acidification rather than carbon mineralization. The results would promote one to study the effects of soil acidification on the cycling of ethylene under different forest stands, particularly under degraded forest stands with heavy acid depositions.

  11. 7 CFR 251.7 - Formula adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Formula adjustments. 251.7 Section 251.7 Agriculture... GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION THE EMERGENCY FOOD ASSISTANCE PROGRAM § 251.7 Formula adjustments. Formula adjustments. (a) Commodity adjustments. The Department will make annual adjustments...

  12. 12 CFR 1209.80 - Inflation adjustments.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 10 2014-01-01 2014-01-01 false Inflation adjustments. 1209.80 Section 1209.80... PROCEDURE Civil Money Penalty Inflation Adjustments § 1209.80 Inflation adjustments. The maximum amount of... thereafter adjusted in accordance with the Inflation Adjustment Act, on a recurring four-year cycle, is...

  13. 12 CFR 1209.80 - Inflation adjustments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 9 2012-01-01 2012-01-01 false Inflation adjustments. 1209.80 Section 1209.80... PROCEDURE Civil Money Penalty Inflation Adjustments § 1209.80 Inflation adjustments. The maximum amount of... thereafter adjusted in accordance with the Inflation Adjustment Act, on a recurring four-year cycle, is...

  14. 12 CFR 1209.80 - Inflation adjustments.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 9 2013-01-01 2013-01-01 false Inflation adjustments. 1209.80 Section 1209.80... PROCEDURE Civil Money Penalty Inflation Adjustments § 1209.80 Inflation adjustments. The maximum amount of... thereafter adjusted in accordance with the Inflation Adjustment Act, on a recurring four-year cycle, is...

  15. Bacterial community structure and soil properties of a subarctic tundra soil in Council, Alaska

    PubMed Central

    Kim, Hye Min; Jung, Ji Young; Yergeau, Etienne; Hwang, Chung Yeon; Hinzman, Larry; Nam, Sungjin; Hong, Soon Gyu; Kim, Ok-Sun; Chun, Jongsik; Lee, Yoo Kyung

    2014-01-01

    The subarctic region is highly responsive and vulnerable to climate change. Understanding the structure of subarctic soil microbial communities is essential for predicting the response of the subarctic soil environment to climate change. To determine the composition of the bacterial community and its relationship with soil properties, we investigated the bacterial community structure and properties of surface soil from the moist acidic tussock tundra in Council, Alaska. We collected 70 soil samples with 25-m intervals between sampling points from 0–10 cm to 10–20 cm depths. The bacterial community was analyzed by pyrosequencing of 16S rRNA genes, and the following soil properties were analyzed: soil moisture content (MC), pH, total carbon (TC), total nitrogen (TN), and inorganic nitrogen ( and ). The community compositions of the two different depths showed that Alphaproteobacteria decreased with soil depth. Among the soil properties measured, soil pH was the most significant factor correlating with bacterial community in both upper and lower-layer soils. Bacterial community similarity based on jackknifed unweighted unifrac distance showed greater similarity across horizontal layers than through the vertical depth. This study showed that soil depth and pH were the most important soil properties determining bacterial community structure of the subarctic tundra soil in Council, Alaska. PMID:24893754

  16. The potentiation of zinc toxicity by soil moisture in a boreal forest ecosystem.

    PubMed

    Owojori, Olugbenga J; Siciliano, Steven D

    2015-03-01

    Northern boreal forests often experience forest dieback as a result of metal ore mining and smelting. The common solution is to lime the soil, which increases pH, reducing metal toxicity and encouraging recovery. In certain situations, however, such as in Flin Flon, Manitoba, Canada, liming has yielded only moderate benefits, with some locations responding well to liming and other locations not at all. In an effort to increase the effectiveness of the ecorestoration strategy, the authors investigated if these differences in liming responsiveness were linked to differences in toxicity. Toxicity of metal-impacted Flin Flon soils on the oribatid mite Oppia nitens and the collembolan Folsomia candida was assessed, with a view toward identifying the metal of concern in the area. The effects of moisture content on metal sorption, uptake, and toxicity to the invertebrates were also investigated. Toxicity tests with the invertebrates were conducted using either Flin Flon soils or artificial soils with moisture content adjusted to 30%, 45%, 60%, or 75% of the maximum water-holding capacity of the soil samples. The Relative to Cd Toxicity Model identified Zn as the metal of concern in the area, and this was confirmed using validation tests with field contaminated soils. Furthermore, increasing the moisture content in soils increased the amount of mobile Zn available for uptake with the ion exchange resin. Survival and reproduction of both invertebrates were reduced under Zn exposure as moisture level increased. Thus, moisture-collecting landforms, which are often also associated with high Zn concentrations at Flin Flon, have, as a result, higher Zn toxicity to the soil ecosystem because of increases in soil moisture. PMID:25502519

  17. pH Optrode Instrumentation

    NASA Technical Reports Server (NTRS)

    Tabacco, Mary Beth; Zhou, Quan

    1995-01-01

    pH-sensitive chromophoric reagents immobilized in porous optical fibers. Optoelectronic instrumentation system measures acidity or alkalinity of aqueous nutrient solution. Includes one or more optrodes, which are optical-fiber chemical sensors, in sense, analogous to electrodes but not subject to some of spurious effects distorting readings taken by pH electrodes. Concept of optrodes also described in "Ethylene-Vapor Optrodes" (KSC-11579). pH optrode sensor head, with lead-in and lead-out optical fibers, convenient for monitoring solutions located away from supporting electronic equipment.

  18. Soils as records of past and present environments

    NASA Astrophysics Data System (ADS)

    Sauer, Daniela

    2015-04-01

    This contribution reflects selected pedological concepts that are helpful for interpreting soil properties related to past and present environments. These concepts are illustrated by examples from various landscapes, and their combination finally leads to some further conclusions. The concept of Targulian and Gerasimova (2009) distinguishes soil system and soil body. Soil system is defined as "open multiphase system functioning in any solid-phase substrate at its interface with the atmosphere, hydrosphere and biota", and soil body as "solid-phase part of a soil system produced by its long-term functioning and composed of a vertical sequence of genetic horizons". Soil system functioning corresponds to the recent environmental factors and includes heat and moisture dynamics, biomass production, biogeochemical cycles, and other processes. In contrast, a soil body is a record of the long-term functioning of a soil system. It thus provides a record not only of the functioning of the soil system under the present environmental conditions but also under past, possibly different, conditions. Hence, Targulian and Goryachkin (2004) called it the "memory" of the landscape. Richter and Yaalon (2012) argued that most soils comprise both, features that developed under the present environmental conditions and features that reflect different conditions that the soils experienced in the past; they concluded that most soils are polygenetic. Although the current functioning of the soil system in the concept of Targulian and Gerasimova (2009) is mainly controlled by the present-day combination of environmental factors, it should be added that past processes also influence the soil system, because past processes changed the soil properties in a way that also the present-day functioning of the soil system is affected by these changes. Earlier, Yaalon (1971) had categorised soil properties according to the time-span required for their adjustment to the actual environment, distinguishing

  19. Final RQ adjustments rule issued

    SciTech Connect

    Bergeson, L.L.

    1995-08-01

    On June 12, 1995, the US Environmental Protection Agency (EPA) issued its long awaited final rule adjusting certain reportable quantities (RQs) for hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). The rule: revises the table of hazardous substances to add 47 individual Clean Air Act (CAA) hazardous air pollutants (HAPs); adjustments their statutory one-pound RQs; adds five other CAA HAPs that are categories of substances and assigns no RQ to the categories; and adjusts RQs for 11 Resource Conservation and Recovery Act (RCRA) listed hazardous wastes. EPA made conforming changes to the Clean Water Act table of hazardous substances and the Emergency Planning and Community Right-to-Know Act (EPCRA) table of extremely hazardous substances. The rule became effective July 12, 1995.

  20. MCCB warm adjustment testing concept

    NASA Astrophysics Data System (ADS)

    Erdei, Z.; Horgos, M.; Grib, A.; Preradović, D. M.; Rodic, V.

    2016-08-01

    This paper presents an experimental investigation in to operating of thermal protection device behavior from an MCCB (Molded Case Circuit Breaker). One of the main functions of the circuit breaker is to assure protection for the circuits where mounted in for possible overloads of the circuit. The tripping mechanism for the overload protection is based on a bimetal movement during a specific time frame. This movement needs to be controlled and as a solution to control this movement we choose the warm adjustment concept. This concept is meant to improve process capability control and final output. The warm adjustment device design will create a unique adjustment of the bimetal position for each individual breaker, determined when the testing current will flow thru a phase which needs to trip in a certain amount of time. This time is predetermined due to scientific calculation for all standard types of amperages and complies with the IEC 60497 standard requirements.

  1. Glycine crystallization during spray drying: the pH effect on salt and polymorphic forms.

    PubMed

    Yu, Lian; Ng, Kingman

    2002-11-01

    Spray drying of aqueous solutions of glycine revealed a strong pH effect on the salt and polymorphic forms of the resulting powders. Adjusting pH by aqueous HCl or NaOH between 1.7 and 10.0 caused the glycine solutions to crystallize as two polymorphs (alpha and gamma) of the neutral glycine ((+)H(3)NCH(2)CO(2) (-)) and as three salts (diglycine HCl, (+)H(3)NCH(2)CO(2) (-). (+)H(3)NCH(2)CO(2)H. C1(-); glycine HCl, (+)H(3)NCH(2)CO(2)H. C1(-); and sodium glycinate, H(2)NCH(2)CO(2) (-). Na(+)). Although alpha-glycine crystallized from solutions without pH adjustment (pH 6.2), changing the pH to 4.0 and 8.0 caused gamma-glycine to crystallize as the preferred polymorph. This phenomenon is attributed to the pH effect on the dimeric growth unit of alpha-glycine. The formation of alpha-glycine by spray drying solutions of neutral glycine contrasts the outcome of freeze drying, which yields beta-glycine. Because gamma-glycine is thermodynamically more stable than alpha-glycine, the crystallization of gamma-glycine by pH adjustment provides a way to improve the physical stability of glycine-containing formulations. Spray drying at low pH yielded various mixtures of neutral glycine and its HCl salts: pH 3.0, gamma-glycine and diglycine HCl; pH 2.0, diglycine HCl; and pH 1.7 (the natural pH of glycine HCl), diglycine HCl (major component) and glycine HCl (minor component). Spray drying glycine HCl solutions (pH 1.7) yielded the same diglycine HCl/glycine HCl mixture as did spray drying neutral glycine solutions acidified to pH 1.7. Obtaining diglycine HCl by spray drying glycine HCl solutions indicates a 50% loss of HCl during processing. The extent of HCl loss could be altered by changing the inlet temperature of the spray drier. Spray drying glycine solutions at pH 9.0 and 10.0 gave predominantly gamma-glycine and an additional crystalline product, possibly sodium glycinate. The glycine powders spray dried at different pH had different particle morphologies and sizes, which

  2. Urine pH test

    MedlinePlus

    ... J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team. Related MedlinePlus Health Topics Kidney Stones Urinalysis Browse the Encyclopedia A. ...

  3. Making pH Tangible.

    ERIC Educational Resources Information Center

    McIntosh, Elizabeth; Moss, Robert

    1995-01-01

    Presents a laboratory exercise in which students test the pH of different substances, study the effect of a buffer on acidic solutions by comparing the behavior of buffered and unbuffered solutions upon the addition of acid, and compare common over-the-counter antacid remedies. (MKR)

  4. Adjustable spacer with rotational lock

    SciTech Connect

    Bowyer, M.L.

    1984-02-28

    A spacing apparatus for tubing conduit in a subterranean well, normally for use with an electric component with a longitudinally extending external electrical cable, permits irrotational adjustment of the length of the tubing conduit. The spacing apparatus comprises telescoping members which are keyed to prevent rotation therebetween. A threaded member, longitudinally fixed relative to one longitudinal member, normally engages threads extending substantially along the entire length of the other telescoping member. Movement of a retaining sleeve permits disengagement of the threaded segments which ratchet along the threads during telescoping movement. The length of the conduit can thus be irrotationally adjusted to remove slack from the electrical cable.

  5. Convective adjustment in baroclinic atmospheres

    NASA Technical Reports Server (NTRS)

    Emanuel, Kerry A.

    1986-01-01

    Local convection in planetary atmospheres is generally considered to result from the action of gravity on small regions of anomalous density. That in rotating baroclinic fluids the total potential energy for small scale convection contains a centrifugal as well as a gravitational contribution is shown. Convective adjustment in such an atmosphere results in the establishment of near adiabatic lapse rates of temperature along suitably defined surfaces of constant angular momentum, rather than in the vertical. This leads in general to sub-adiabatic vertical lapse rates. That such an adjustment actually occurs in the earth's atmosphere is shown by example and the magnitude of the effect for several other planetary atmospheres is estimated.

  6. Statistical modeling of global soil NOx emissions

    NASA Astrophysics Data System (ADS)

    Yan, Xiaoyuan; Ohara, Toshimasa; Akimoto, Hajime

    2005-09-01

    On the basis of field measurements of NOx emissions from soils, we developed a statistical model to describe the influences of soil organic carbon (SOC) content, soil pH, land-cover type, climate, and nitrogen input on NOx emission. While also considering the effects of soil temperature, soil moisture change-induced pulse emission, and vegetation fire, we simulated NOx emissions from global soils at resolutions of 0.5° and 6 hours. Canopy reduction was included in both data processing and flux simulation. NOx emissions were positively correlated with SOC content and negatively correlated with soil pH. Soils in dry or temperate regions had higher NOx emission potentials than soils in cold or tropical regions. Needleleaf forest and agricultural soils had high NOx emissions. The annual NOx emission from global soils was calculated to be 7.43 Tg N, decreasing to 4.97 Tg N after canopy reduction. Global averages of nitrogen fertilizer-induced emission ratios were 1.16% above soil and 0.70% above canopy. Soil moisture change-induced pulse emission contributed about 4% to global annual NOx emission, and the effect of vegetation fire on soil NOx emission was negligible.

  7. Carbon and nitrogen dynamics across a bedrock-regulated subarctic pH gradient

    NASA Astrophysics Data System (ADS)

    Tomczyk, N.; Heim, E. W.; Sadowsky, J.; Remiszewski, K.; Varner, R. K.; Bryce, J. G.; Frey, S. D.

    2014-12-01

    Bedrock geochemistry has been shown to influence landscape evolution due to nutrient limitation on primary production. There may also be less direct interactions between bedrock-derived chemicals and ecosystem function. Effects of calcium (Ca) and pH on soil carbon (C) and nitrogen (N) cycling have been shown in acid impacted forests o f North America. Understanding intrinsic factors that affect C and nutrient dynamics in subarctic ecosystems has implications for how these ecosystems will respond to a changing climate. How the soil microbial community allocates enzymes to acquire resources from the environment can indicate whether a system is nutrient or energy limited. This study examined whether bedrock geochemistry exerts pressure on nutrient cycles in the overlying soils. In thin, weakly developed soils, bedrock is the primary mineral material and is a source of vital nutrients. Nitrogen (N) and C are not derived from bedrock, but their cycling is still affected by reactions with geologically-derived chemicals. Our study sites near Abisko, Sweden (~68°N) were selected adjacent to five distinct bedrock outcrops (quartzite, slate, carbonate, and two different metasedimenty units). All sites were at a similar elevation (~700 m a.s.l.) and had similar vegetation (subarctic heath). Nutrient concentrations in bedrock and soils were measured in addition to soil microbial biomass and extracellular enzyme activity. We found a statistically significant correlation between soil Ca concentrations and soil pH (r = 0.88, p < 0.01). There were also significant relationships between soil pH and the ratio of C-acquiring to N-acquiring enzyme activity (r = -0.89, p < 0.01), soil pH and soil C-to-N ratio (r = -0.76, p < 0.01), and the ratio of C-acquiring to N-acquiring enzyme activity and soil C-to-N ratio (r = 0.78, p < 0.01). These results suggest that soil Ca concentrations influence C and N cycling dynamics in these soils through their effect on soil pH.

  8. 75 FR 33379 - Railroad Cost Recovery Procedures-Productivity Adjustment; Quarterly Rail Cost Adjustment Factor

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... Surface Transportation Board Railroad Cost Recovery Procedures--Productivity Adjustment; Quarterly Rail... Railroads that the Board restate the previously published productivity adjustment for the 2003-2007 averaging period (2007 productivity adjustment) so that it tracks the 2007 productivity adjustment...

  9. Effect of soil coarseness on soil base cations and available micronutrients in a semi-arid sandy grassland

    NASA Astrophysics Data System (ADS)

    Lü, Linyou; Wang, Ruzhen; Liu, Heyong; Yin, Jinfei; Xiao, Jiangtao; Wang, Zhengwen; Zhao, Yan; Yu, Guoqing; Han, Xingguo; Jiang, Yong

    2016-04-01

    Soil coarseness is the main process decreasing soil organic matter and threatening the productivity of sandy grasslands. Previous studies demonstrated negative effect of soil coarseness on soil carbon storage, but less is known about how soil base cations (exchangeable Ca, Mg, K, and Na) and available micronutrients (available Fe, Mn, Cu, and Zn) response to soil coarseness. In a semi-arid grassland of Northern China, a field experiment was initiated in 2011 to mimic the effect of soil coarseness on soil base cations and available micronutrients by mixing soil with different mass proportions of sand: 0 % coarse elements (C0), 10 % (C10), 30 % (C30), 50 % (C50), and 70 % (C70). Soil coarseness significantly increased soil pH in three soil depths of 0-10, 10-20 and 20-40 cm with the highest pH values detected in C50 and C70 treatments. Soil fine particles (smaller than 0.25 mm) significantly decreased with the degree of soil coarseness. Exchangeable Ca and Mg concentrations significantly decreased with soil coarseness degree by up to 29.8 % (in C70) and 47.5 % (in C70), respectively, across three soil depths. Soil available Fe, Mn, and Cu significantly decreased with soil coarseness degree by 62.5, 45.4, and 44.4 %, respectively. As affected by soil coarseness, the increase of soil pH, decrease of soil fine particles (including clay), and decline in soil organic matter were the main driving factors for the decrease of exchangeable base cations (except K) and available micronutrients (except Zn) through soil profile. Developed under soil coarseness, the loss and redistribution of base cations and available micronutrients along soil depths might pose a threat to ecosystem productivity of this sandy grassland.

  10. Plant selenium from soil and the atmosphere

    SciTech Connect

    Haygarth, P.M.; Jones, K.C.; Harrison, A.F.

    1995-07-01

    Transfer of selenium (Se) to pasture is important for prevention of Se deficiency in livestock, yet little is known about the relative importance of inputs to pasture from soil and the atmosphere. An isotope dilution method was used to assess quantitatively the importance of these inputs to ryegrass. Soil was labelled with {sup 75}Se and subjected to two field treatments that were untreated (pH 6.0) and limed (pH 7.0). After an initial period of equilibration, the specific activity of Se associated with unwashed leaves became lower than that of soil. This indicated that atmospheric Se had been deposited onto and possibly incorporated into the ryegrass. The percent contribution of {sup 75}Se in pasture leaves derived from the soil was 47% (pH 6.0) and 70% (pH 7.0), with, by inference, the remainder coming from the atmosphere. 23 refs., 1 fig., 4 tabs.

  11. A global pattern of soil acidification caused by nitrogen deposition

    NASA Astrophysics Data System (ADS)

    Niu, S.; Tian, D., Sr.

    2014-12-01

    Nitrogen (N) deposition-induced soil acidification has become a global problem. However, the response patterns of soil acidification to N addition and the underlying mechanisms remain far from unclear. Here, we conducted a meta-analysis of 106 studies to reveal global patterns of soil acidification in responses to N addition. We found that N addition significantly reduced soil pH by 0.23 on average globally. However, the response ratio of soil pH varied with ecosystem types, N addition rate, N fertilization forms, and experimental durations. Soil pH decreased most in grassland, whereas boreal forest was insensitive to N addition in soil acidification. Soil pH decreased linearly with N addition rates. Addition of urea and NH4NO3 contributed more to soil acidification than NH4-form fertilizer. When experimental duration was longer than 20 years, N addition effects on soil acidification diminished. Environmental factors such as initial soil pH, soil carbon and nitrogen content, precipitation, and temperature all influenced the response ratio of soil pH. Base cations of Ca2+, Mg2+ and K+ were critical important in buffering against N-induced soil acidification at the early stage. However, N addition has shifted global soils into the Al3+ buffering phase. Overall, this study indicates that acidification in global soils is very sensitive to N deposition, which is greatly modified by biotic and abiotic factors. Global soils are now at a buffering transition from base cations (Ca2+, Mg2+ and K+) to non-base cations (Mn2+ and Al3+). This calls our attention to care about the limitation of base cations and the toxic impact of non-base cations for terrestrial ecosystems with N deposition.

  12. [Key microbial processes in nitrous oxide emissions of agricultural soil and mitigation strategies].

    PubMed

    Zhu, Yong-Guan; Wang, Xiao-Hui; Yang, Xiao-Ru; Xu, Hui-Juan; Jia, Yan

    2014-02-01

    Nitrous oxide (N2O) is a powerful atmospheric greenhouse gas, which does not only have a strong influence on the global climate change but also depletes the ozone layer and induces the enhancement of ultraviolet radiation to ground surface, so numerous researches have been focused on global climate change and ecological environmental change. Soil is the foremost source of N2O emissions to the atmosphere, and approximately two-thirds of these emissions are generally attributed to microbiological processes including bacterial and fungal denitrification and nitrification processes, largely as a result of the application of nitrogenous fertilizers. Here the available knowledge concerning the research progress in N2O production in agricultural soils was reviewed, including denitrification, nitrification, nitrifier denitrification and dissimilatory nitrate reduction to ammonium, and the abiotic (including soil pH, organic and inorganic nitrogen, organic matter, soil humidity and temperature) and biotic factors that have direct and indirect effects on N2O fluxes from agricultural soils were also summarized. In addition, the strategies for mitigating N2O emissions and the future research direction were proposed. Therefore, these studies are expected to provide valuable and scientific evidence for the study on mitigation strategies for the emission of greenhouse gases, adjustment of nitrogen transformation processes and enhancement of nitrogen use efficiency. PMID:24812980

  13. Goal Directed Resuscitation in the Prehospital Setting: A Propensity Adjusted Analysis

    PubMed Central

    Brown, Joshua B.; Cohen, Mitchell J.; Minei, Joseph P.; Maier, Ronald V.; West, Michael A.; Billiar, Timothy R.; Peitzman, Andrew B.; Moore, Ernest E.; Cuschieri, Joseph; Sperry, Jason L.

    2013-01-01

    Background The scope of prehospital (PH) interventions has expanded recently; not always with clear benefit. PH crystalloid resuscitation has been challenged, particularly in penetrating trauma. Optimal PH crystalloid resuscitation strategies remain unclear in blunt trauma as does the influence of PH hypotension. The objective was to characterize outcomes for PH crystalloid volume in patients with and without PH hypotension. Methods Data were obtained from a multicenter prospective study of blunt injured adults transported from the scene with ISS > 15. Subjects were divided into HIGH (>500cc) and LOW (≤500cc) PH crystalloid groups. Propensity adjusted regression determined the association of PH crystalloid group with mortality and acute coagulopathy (admission INR>1.5) in subjects with and without PH hypotension (SBP<90mmHg) after controlling for confounders. Results Of 1,216 subjects, 822 (68%) received HIGH PH crystalloid and 616 (51%) had PH hypotension. Initial base deficit and ISS were similar between HIGH and LOW crystalloid groups in subjects with and without PH hypotension. In subjects without PH hypotension, HIGH crystalloid was associated with an increase in the risk of mortality (HR 2.5; 95%CI 1.3 – 4.9, p<0.01) and acute coagulopathy (OR 2.2; 95%CI 1.01–4.9, p=0.04) but not in subjects with PH hypotension. HIGH crystalloid was associated with correction of PH hypotension on ED arrival (OR 2.02; 1.06–3.88, p=0.03). The mean corrected SBP in the ED was 104mmHg. Each 1mmHg increase in ED systolic blood pressure was associated with a 2% increase in survival in subjects with PH hypotension (OR 1.02; 1.01–1.03, p<0.01). Conclusions In severely injured blunt trauma patients, PH crystalloid >500cc was associated with worse outcome in patients without PH hypotension but not with PH hypotension. HIGH crystalloid was associated with corrected PH hypotension. This suggests PH resuscitation should be goal directed based on the presence or absence of PH

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

    EPA Science Inventory

    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 ...

  15. Visual adjustments to temporal blur

    NASA Astrophysics Data System (ADS)

    Bilson, Aaron C.; Mizokami, Yoko; Webster, Michael A.

    2005-10-01

    After observers have adapted to an edge that is spatially blurred or sharpened, a focused edge appears too sharp or blurred, respectively. These adjustments to blur may play an important role in calibrating spatial sensitivity. We examined whether similar adjustments influence the perception of temporal edges, by measuring the appearance of a step change in the luminance of a uniform field after adapting to blurred or sharpened transitions. Stimuli were square-wave alternations (at 1 to 8 Hz) filtered by changing the slope of the amplitude spectrum. A two-alternative-forced-choice task was used to adjust the slope until it appeared as a step change, or until it matched the perceived transitions in a reference stimulus. Observers could accurately set the waveform to a square wave, but only at the slower alternation rates. However, these settings were strongly biased by prior adaptation to filtered stimuli, or when the stimuli were viewed within temporally filtered surrounds. Control experiments suggest that the latter induction effects result directly from the temporal blur and are not simply a consequence of brightness induction in the fields. These results suggest that adaptation and induction adjust visual coding so that images are focused not only in space but also in time.

  16. Self-Adjusting Fluency Therapy.

    ERIC Educational Resources Information Center

    Schneider, Phillip

    1998-01-01

    Presents a rationale and methodology for a self-adjusting "fluency sensitive" approach to working with children who exhibit overt speech-fluency interruptions and a minimal amount of avoidance behavior. The approach emphasizes repeated experiences of volitional increases and decreases in loudness and pauses. Case examples demonstrate how several…

  17. Adjustable Walker for the Handicapped

    NASA Technical Reports Server (NTRS)

    Kitts, R. G.

    1984-01-01

    Front legs adjust at touch of lever for use on stairs or ramps. Spring loaded legs extend when lever is depressed by user. Legs lock in position when lever is released. Lever mounted on either side of walker or on both sides, so legs operated independently.

  18. Adjustable Optical-Fiber Attenuator

    NASA Technical Reports Server (NTRS)

    Buzzetti, Mike F.

    1994-01-01

    Adjustable fiber-optic attenuator utilizes bending loss to reduce strength of light transmitted along it. Attenuator functions without introducing measurable back-reflection or insertion loss. Relatively insensitive to vibration and changes in temperature. Potential applications include cable television, telephone networks, other signal-distribution networks, and laboratory instrumentation.

  19. Adjustable-Angle Drill Block

    NASA Technical Reports Server (NTRS)

    Gallimore, F. H.

    1986-01-01

    Adjustable angular drill block accurately transfers hole patterns from mating surfaces not normal to each other. Block applicable to transfer of nonperpendicular holes in mating contoured assemblies in aircraft industry. Also useful in general manufacturing to transfer mating installation holes to irregular and angular surfaces.

  20. Economic Pressures and Family Adjustment.

    ERIC Educational Resources Information Center

    Haccoun, Dorothy Markiewicz; Ledingham, Jane E.

    The relationships between economic stress on the family and child and parental adjustment were examined for a sample of 199 girls and boys in grades one, four, and seven. These associations were examined separately for families in which both parents were present and in which mothers only were at home. Economic stress was associated with boys'…

  1. Modifications to the new soil extractant H3A-1: A multinutrient extractant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new soil extractant (H3A-1) with the ability to extract NH4-N, NO3-N, and P from soil was originally developed and tested against 32 soils, which varied greatly in clay content, organic C, and soil pH (Haney et al. 2006). The use of H3A eliminates the need for multiple soil extractants when analyz...

  2. Long-term tobacco plantation induces soil acidification and soil base cation loss.

    PubMed

    Zhang, Yuting; He, Xinhua; Liang, Hong; Zhao, Jian; Zhang, Yueqiang; Xu, Chen; Shi, Xiaojun

    2016-03-01

    Changes in soil exchangeable cations relative to soil acidification are less studied particularly under long-term cash crop plantation. This study investigated soil acidification in an Ali-Periudic Argosols after 10-year (2002-2012) long-term continuous tobacco plantation. Soils were respectively sampled at 1933 and 2143 sites in 2002 and 2012 (also 647 tobacco plants), from seven tobacco plantation counties in the Chongqing Municipal City, southwest China. After 10-year continuous tobacco plantation, a substantial acidification was evidenced by an average decrease of 0.20 soil pH unit with a substantial increase of soil sites toward the acidic status, especially those pH ranging from 4.5 to 5.5, whereas 1.93 kmol H(+) production ha(-1) year(-1) was mostly derived from nitrogen (N) fertilizer input and plant N uptake output. After 1 decade, an average decrease of 27.6 % total exchangeable base cations or of 0.20 pH unit occurred in all seven tobacco plantation counties. Meanwhile, for one unit pH decrease, 40.3 and 28.3 mmol base cations kg(-1) soil were consumed in 2002 and 2012, respectively. Furthermore, the aboveground tobacco biomass harvest removed 339.23 kg base cations ha(-1) year(-1) from soil, which was 7.57 times higher than the anions removal, leading to a 12.52 kmol H(+) production ha(-1) year(-1) as the main reason inducing soil acidification. Overall, our results showed that long-term tobacco plantation not only stimulated soil acidification but also decreased soil acid-buffering capacity, resulting in negative effects on sustainable soil uses. On the other hand, our results addressed the importance of a continuous monitoring of soil pH changes in tobacco plantation sites, which would enhance our understanding of soil fertility of health in this region. PMID:26566613

  3. Remediation and Reuse of Soils

    NASA Astrophysics Data System (ADS)

    Zihms, Stephanie; Switzer, Christine; Tarantino, Alessandro

    2013-04-01

    Links between contaminant remediation and impacts on soil properties have not been explored in a systematic way. Most remediation studies focus on the effectiveness of the remediation process. Contamination and remediation can have significant effects on soil properties and function. Considering that in most remediation cases the soil will be re-used in some way, it is important to understand the effects of the remediation process on soil properties and the post-remediation soil behaviour. This understanding can help to determine the best re-use of the soil and therefore improve post-remediation site development. Laboratory experiments on coal tar contaminated soil treated with smouldering remediation show that thermal treatments affect a variety of soil properties ranging from mineralogical composition, particle size distribution, and pH. Dynamic responses like permeability and shear strength are impacted as well and these responses are linked to the changes in soil properties. Soil permeability, capillary rise, and contact angle change dramatically after this remediation process, indicating some degree of hydrophobicity and significant implications for water movement through the post-remediation soil. The observed changes in permeability are linked to physical changes to the soil grain surface combined with small amounts (<1ppm) of coal tar and combustion product residue. Decoupling these effects is essential to understanding the extent of impact remediation processes have on long-term soil function. While chemical residue within the pores can be removed through "polishing" remediation steps, physical changes are likely to be permanent. Physical changes and chemical residue also have important implications with respect to the response of the soil under shear. These observed changes indicate that the remediated soil and its behaviour should be considered by remediation research. Monitoring of soil properties and behaviour during aggressive remediation can improve

  4. Uptakes of Cs and Sr on San Joaquin soil measured following ASTM method C1733.

    SciTech Connect

    Ebert, W.L.; Petri, E.T.

    2012-04-04

    x 10{sup -5} m, 1 x 10{sup -4} m, and 5 x 10{sup -4} m to measure the effects of the Cs and Sr concentrations on their uptake by the soil. The pH values of all solutions were adjusted to about pH 8.5 so that the effects of pH and concentration could be measured separately. The 1 x 10{sup -4} m solutions were used to measure the repeatability of the test and the effects of duration, scale, and imposed pH on the test response.

  5. The Methods Behind PH WINS

    PubMed Central

    Leider, Jonathon P.; Bharthapudi, Kiran; Pineau, Vicki; Liu, Lin; Harper, Elizabeth

    2015-01-01

    The Public Health Workforce Interests and Needs Survey (PH WINS) has yielded the first-ever nationally representative sample of state health agency central office employees. The survey represents a step forward in rigorous, systematic data collection to inform the public health workforce development agenda in the United States. PH WINS is a Web-based survey and was developed with guidance from a panel of public health workforce experts including practitioners and researchers. It draws heavily from existing and validated items and focuses on 4 main areas: workforce perceptions about training needs, workplace environment and job satisfaction, perceptions about national trends, and demographics. This article outlines the conceptualization, development, and implementation of PH WINS, as well as considerations and limitations. It also describes the creation of 2 new data sets that will be available in public use for public health officials and researchers—a nationally representative data set for permanently employed state health agency central office employees comprising over 10 000 responses, and a pilot data set with approximately 12 000 local and regional health department staff responses. PMID:26422490

  6. The Methods Behind PH WINS.

    PubMed

    Leider, Jonathon P; Bharthapudi, Kiran; Pineau, Vicki; Liu, Lin; Harper, Elizabeth

    2015-01-01

    The Public Health Workforce Interests and Needs Survey (PH WINS) has yielded the first-ever nationally representative sample of state health agency central office employees. The survey represents a step forward in rigorous, systematic data collection to inform the public health workforce development agenda in the United States. PH WINS is a Web-based survey and was developed with guidance from a panel of public health workforce experts including practitioners and researchers. It draws heavily from existing and validated items and focuses on 4 main areas: workforce perceptions about training needs, workplace environment and job satisfaction, perceptions about national trends, and demographics. This article outlines the conceptualization, development, and implementation of PH WINS, as well as considerations and limitations. It also describes the creation of 2 new data sets that will be available in public use for public health officials and researchers--a nationally representative data set for permanently employed state health agency central office employees comprising over 10,000 responses, and a pilot data set with approximately 12,000 local and regional health department staff responses. PMID:26422490

  7. Phosphorus Solubility in Response to Acidification of Dairy Manure Amended Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phosphorus (P) additions from animal manure beyond plant needs results in accumulated soil calcium phosphate (Ca-P). Although stable near neutral pH levels, there is concern about the solubility of accumulated soil Ca-P when soil pH conditions become acidic, potentially releasing water soluble P (WS...

  8. 12 CFR 19.240 - Inflation adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b)...

  9. 12 CFR 19.240 - Inflation adjustments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b)...

  10. 12 CFR 19.240 - Inflation adjustments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Inflation adjustments. 19.240 Section 19.240... PROCEDURE Civil Money Penalty Inflation Adjustments § 19.240 Inflation adjustments. (a) The maximum amount... Civil Penalties Inflation Adjustment Act of 1990 (28 U.S.C. 2461 note) as follows: ER10NO08.001 (b)...

  11. Cultural Adjustment and the Puerto Rican.

    ERIC Educational Resources Information Center

    Prewitt-Diaz, Joseph O.

    This review of the literature on cultural adjustment is divided into four sections: the nature of cultural adjustment; acculturation as a model of cultural adjustment; psychological responses to acculturation; and a model of cultural adjustment developed by the author as a result of his immigration from Puerto Rico to the United States mainland.…

  12. Adjusting to University: The Hong Kong Experience

    ERIC Educational Resources Information Center

    Yau, Hon Keung; Sun, Hongyi; Cheng, Alison Lai Fong

    2012-01-01

    Students' adjustment to the university environment is an important factor in predicting university outcomes and is crucial to their future achievements. University support to students' transition to university life can be divided into three dimensions: academic adjustment, social adjustment and psychological adjustment. However, these…

  13. Bromide Adsorption by Reference Minerals and Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bromide, Br-, adsorption behavior was investigated on amorphous Al and Fe oxide, montmorillonite, kaolinite, and temperate and tropical soils. Bromide adsorption decreased with increasing solution pH with minimal adsorption occurring above pH 7. Bromide adsorption was higher for amorphous oxides t...

  14. Influence of indian mustard (Brassica juncea) on rhizosphere soil solution chemistry in long-term contaminated soils: a rhizobox study.

    PubMed

    Kim, Kwon-Rae; Owens, Gary; Kwon, Soon-lk

    2010-01-01

    This study investigated the influence of Indian mustard (Brassica juncea) root exudation on soil solution properties (pH, dissolved organic carbon (DOC), metal solubility) in the rhizosphere using a rhizobox. Measurement was conducted following the cultivation of Indian mustard in the rhizobox filled four different types of heavy metal contaminated soils (two alkaline soils and two acidic soils). The growth of Indian mustard resulted in a significant increase (by 0.6 pH units) in rhizosphere soil solution pH of acidic soils and only a slight increase (< 0.1 pH units) in alkaline soils. Furthermore, the DOC concentration increased by 17-156 mg/L in the rhizosphere regardless of soil type and the extent of contamination, demonstrating the exudation of DOC from root. Ion chromatographic determination showed a marked increase in the total dissolved organic acids (OAs) in rhizosphere. While root exudates were observed in all soils, the amount of DOC and OAs in soil solution varied considerably amongst different soils, resulting in significant changes to soil solution metals in the rhizosphere. For example, the soil solution Cd, Cu, Pb, and Zn concentrations increased in the rhizosphere of alkaline soils compared to bulk soil following plant cultivation. In contrast, the soluble concentrations of Cd, Pb, and Zn in acidic soils decreased in rhizosphere soil when compared to bulk soils. Besides the influence of pH and DOC on metal solubility, the increase of heavy metal concentration having high stability constant such as Cu and Pb resulted in a release of Cd and Zn from solid phase to liquid phase. PMID:20397393

  15. Recovery of ammonia from swine manure using gas-permeable membranes: effect of waste strength and pH.

    PubMed

    Garcia-González, M C; Vanotti, M B

    2015-04-01

    Nitrogen recovery from swine manure was investigated using gas-permeable membranes. The process involved a continuous recirculation of an acidic solution through a gas-permeable membrane submerged in manure. Ammonia from manure was concentrated in the acidic solution increasing its pH, while pH decreased in manure. In the first set of experiments, nitrogen recovery efficiency was evaluated with no pH adjustment of manure; whereas in the second, manure with three different ammonia (NH3) concentrations (from 1070 to 2290 mg/L) was used adjusting their pH to 9 whenever pH decreased below 7.7. With no pH adjustment, NH3 recovery from manure was 55%, while NH3 recovery averaged 81% when pH of manure was adjusted. This work showed that as waste strength and available NH3 content increased in manure, more N was captured by the membrane. These results suggested that the gas-permeable membranes are a useful technology for NH3 recovery from manure, reducing environmental pollution whilst converting NH3 into a valuable ammonium (NH4(+)) salt fertilizer. PMID:25687948

  16. Mining machine with adjustable jib

    SciTech Connect

    Hart, D.

    1987-05-26

    A mining machine is described having a pair of crawler tracks, a means for individually driving each of the crawler tracks, a frame mounted on the crawler tracks, an elongated jib carrying a sprocket at each end, an endless cutting chain supported on the sprockets, cutters and loading flights mounted on the endless cutting chain, and means on the frame supporting the elongated jib. The means support the elongated jib consisting of a bridge on the frame, at least one scissors linkage pivotally mounted on the bridge, and arm having a first end attached to the scissors linkage, a front plate mounted on the second end of the arm and means adjustably mounting the elongated jib on the front plate. The means adjustably mount the elongated jib on the front plate including a first means for rotating the elongated jib between a vertical position and a horizontal position.

  17. Coverage-adjusted entropy estimation.

    PubMed

    Vu, Vincent Q; Yu, Bin; Kass, Robert E

    2007-09-20

    Data on 'neural coding' have frequently been analyzed using information-theoretic measures. These formulations involve the fundamental and generally difficult statistical problem of estimating entropy. We review briefly several methods that have been advanced to estimate entropy and highlight a method, the coverage-adjusted entropy estimator (CAE), due to Chao and Shen that appeared recently in the environmental statistics literature. This method begins with the elementary Horvitz-Thompson estimator, developed for sampling from a finite population, and adjusts for the potential new species that have not yet been observed in the sample-these become the new patterns or 'words' in a spike train that have not yet been observed. The adjustment is due to I. J. Good, and is called the Good-Turing coverage estimate. We provide a new empirical regularization derivation of the coverage-adjusted probability estimator, which shrinks the maximum likelihood estimate. We prove that the CAE is consistent and first-order optimal, with rate O(P)(1/log n), in the class of distributions with finite entropy variance and that, within the class of distributions with finite qth moment of the log-likelihood, the Good-Turing coverage estimate and the total probability of unobserved words converge at rate O(P)(1/(log n)(q)). We then provide a simulation study of the estimator with standard distributions and examples from neuronal data, where observations are dependent. The results show that, with a minor modification, the CAE performs much better than the MLE and is better than the best upper bound estimator, due to Paninski, when the number of possible words m is unknown or infinite. PMID:17567838

  18. BEHAVIOR OF DDT, KEPONE, AND PERMETHRIN IN SEDIMENT-WATER SYSTEMS UNDER DIFFERENT OXIDATION-REDUCTION AND PH CONDITIONS

    EPA Science Inventory

    A study was conducted to determine the effects of pH and oxidation-reduction (redox) conditions of soil and sediment-water systems on the persistence of three insecticide compounds. Three pH levels, ranging from moderately acid to mildy alkaline, were studied for each compound. F...

  19. A surface complexation and ion exchange model of Pb and Cd competitive sorption on natural soils

    NASA Astrophysics Data System (ADS)

    Serrano, Susana; O'Day, Peggy A.; Vlassopoulos, Dimitri; García-González, Maria Teresa; Garrido, Fernando

    2009-02-01

    The bioavailability and fate of heavy metals in the environment are often controlled by sorption reactions on the reactive surfaces of soil minerals. We have developed a non-electrostatic equilibrium model (NEM) with both surface complexation and ion exchange reactions to describe the sorption of Pb and Cd in single- and binary-metal systems over a range of pH and metal concentration. Mineralogical and exchange properties of three different acidic soils were used to constrain surface reactions in the model and to estimate surface densities for sorption sites, rather than treating them as adjustable parameters. Soil heterogeneity was modeled with >FeOH and >SOH functional groups, representing Fe- and Al-oxyhydroxide minerals and phyllosilicate clay mineral edge sites, and two ion exchange sites (X - and Y -), representing clay mineral exchange. An optimization process was carried out using the entire experimental sorption data set to determine the binding constants for Pb and Cd surface complexation and ion exchange reactions. Modeling results showed that the adsorption of Pb and Cd was distributed between ion exchange sites at low pH values and specific adsorption sites at higher pH values, mainly associated with >FeOH sites. Modeling results confirmed the greater tendency of Cd to be retained on exchange sites compared to Pb, which had a higher affinity than Cd for specific adsorption on >FeOH sites. Lead retention on >FeOH occurred at lower pH than for Cd, suggesting that Pb sorbs to surface hydroxyl groups at pH values at which Cd interacts only with exchange sites. The results from the binary system (both Pb and Cd present) showed that Cd retained in >FeOH sites decreased significantly in the presence of Pb, while the occupancy of Pb in these sites did not change in the presence of Cd. As a consequence of this competition, Cd was shifted to ion exchange sites, where it competes with Pb and possibly Ca (from the background electrolyte). Sorption on >SOH

  20. Soil Evaporation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil evaporation can significantly influence energy flux partitioning of partially vegetated surfaces, ultimately affecting plant transpiration. While important, quantification of soil evaporation, separately from canopy transpiration, is challenging. Techniques for measuring soil evaporation exis...

  1. An invisible soil acidification: Critical role of soil carbonate and its impact on heavy metal bioavailability

    NASA Astrophysics Data System (ADS)

    Wang, Cheng; Li, Wei; Yang, Zhongfang; Chen, Yang; Shao, Wenjing; Ji, Junfeng

    2015-07-01

    It is well known that carbonates inhibit heavy metals transferring from soil to plants, yet the mechanism is poorly understood. Based on the Yangtze River delta area, we investigated bioaccumulation of Ni and Cd in winter wheat as affected by the presence of carbonates in soil. This study aimed to determine the mechanism through which soil carbonates restrict transport and plant uptake of heavy metals in the wheat cropping system. The results indicate that soil carbonates critically influenced heavy metal transfer from soil to plants and presented a tipping point. Wheat grains harvested from carbonates-depleted (due to severe leaching) soils showed Ni and Cd concentrations 2-3 times higher than those of the wheat grains from carbonates-containing soils. Correspondingly, the incidence of Ni or Cd contamination in the wheat grain samples increased by about three times. With the carbonate concentration >1% in soil, uptake and bioaccumulation of Ni and Cd by winter wheat was independent with the soil pH and carbonate content. The findings suggest that soil carbonates play a critical role in heavy metal transfer from soil to plants, implying that monitoring soil carbonate may be necessary in addition to soil pH for the evaluating soil quality and food safety.

  2. An invisible soil acidification: Critical role of soil carbonate and its impact on heavy metal bioavailability

    PubMed Central

    Wang, Cheng; Li, Wei; Yang, Zhongfang; Chen, Yang; Shao, Wenjing; Ji, Junfeng

    2015-01-01

    It is well known that carbonates inhibit heavy metals transferring from soil to plants, yet the mechanism is poorly understood. Based on the Yangtze River delta area, we investigated bioaccumulation of Ni and Cd in winter wheat as affected by the presence of carbonates in soil. This study aimed to determine the mechanism through which soil carbonates restrict transport and plant uptake of heavy metals in the wheat cropping system. The results indicate that soil carbonates critically influenced heavy metal transfer from soil to plants and presented a tipping point. Wheat grains harvested from carbonates-depleted (due to severe leaching) soils showed Ni and Cd concentrations 2–3 times higher than those of the wheat grains from carbonates-containing soils. Correspondingly, the incidence of Ni or Cd contamination in the wheat grain samples increased by about three times. With the carbonate concentration >1% in soil, uptake and bioaccumulation of Ni and Cd by winter wheat was independent with the soil pH and carbonate content. The findings suggest that soil carbonates play a critical role in heavy metal transfer from soil to plants, implying that monitoring soil carbonate may be necessary in addition to soil pH for the evaluating soil quality and food safety. PMID:26227091

  3. An invisible soil acidification: Critical role of soil carbonate and its impact on heavy metal bioavailability.

    PubMed

    Wang, Cheng; Li, Wei; Yang, Zhongfang; Chen, Yang; Shao, Wenjing; Ji, Junfeng

    2015-01-01

    It is well known that carbonates inhibit heavy metals transferring from soil to plants, yet the mechanism is poorly understood. Based on the Yangtze River delta area, we investigated bioaccumulation of Ni and Cd in winter wheat as affected by the presence of carbonates in soil. This study aimed to determine the mechanism through which soil carbonates restrict transport and plant uptake of heavy metals in the wheat cropping system. The results indicate that soil carbonates critically influenced heavy metal transfer from soil to plants and presented a tipping point. Wheat grains harvested from carbonates-depleted (due to severe leaching) soils showed Ni and Cd concentrations 2-3 times higher than those of the wheat grains from carbonates-containing soils. Correspondingly, the incidence of Ni or Cd contamination in the wheat grain samples increased by about three times. With the carbonate concentration >1% in soil, uptake and bioaccumulation of Ni and Cd by winter wheat was independent with the soil pH and carbonate content. The findings suggest that soil carbonates play a critical role in heavy metal transfer from soil to plants, implying that monitoring soil carbonate may be necessary in addition to soil pH for the evaluating soil quality and food safety. PMID:26227091

  4. How mangrove forests adjust to rising sea level

    USGS Publications Warehouse

    Krauss, Ken W.; McKee, Karen L.; Lovelock, Catherine E.; Cahoon, Donald R.; Saintilan, Neil; Reef, Ruth; Chen, Luzhen

    2014-01-01

    Mangroves are among the most well described and widely studied wetland communities in the world. The greatest threats to mangrove persistence are deforestation and other anthropogenic disturbances that can compromise habitat stability and resilience to sea-level rise. To persist, mangrove ecosystems must adjust to rising sea level by building vertically or become submerged. Mangroves may directly or indirectly influence soil accretion processes through the production and accumulation of organic matter, as well as the trapping and retention of mineral sediment. In this review, we provide a general overview of research on mangrove elevation dynamics, emphasizing the role of the vegetation in maintaining soil surface elevations (i.e. position of the soil surface in the vertical plane). We summarize the primary ways in which mangroves may influence sediment accretion and vertical land development, for example, through root contributions to soil volume and upward expansion of the soil surface. We also examine how hydrological, geomorphological and climatic processes may interact with plant processes to influence mangrove capacity to keep pace with rising sea level. We draw on a variety of studies to describe the important, and often under-appreciated, role that plants play in shaping the trajectory of an ecosystem undergoing change.

  5. Evaluating Metal Probe Meters for Soil Testing.

    ERIC Educational Resources Information Center

    Hershey, David R.

    1992-01-01

    Inexpensive metal probe meters that are sold by garden stores can be evaluated by students for their accuracy in measuring soil pH, moisture, fertility, and salinity. The author concludes that the meters are inaccurate and cannot be calibrated in standard units. However, the student evaluations are useful in learning the methods of soil analysis…

  6. Effect of Dead Algae on Soil Permeability

    SciTech Connect

    Harvey, R.S.

    2003-02-21

    Since existing basins support heavy growths of unicellular green algae which may be killed by temperature variation or by inadvertent pH changes in waste and then deposited on the basin floor, information on the effects of dead algae on soil permeability was needed. This study was designed to show the effects of successive algal kills on the permeability of laboratory soil columns.

  7. Soil carbon stock and soil characteristics at Tasik Chini Forest Reserve, Pahang, Malaysia

    NASA Astrophysics Data System (ADS)

    Nur Aqlili Riana, R.; Sahibin A., R.

    2015-09-01

    This study was carried out to determine soil carbon stock and soil characteristic at Tasik Chini Forest Reserve (TCFR), Pahang. A total of 10 (20 m x 25 m) permanent sampling plot was selected randomly within the area of TCFR. Soil samples were taken from all subplots using dutch auger based on soil depth of 0-20cm, 20-40cm, 40-60cm. Soil parameters determined were size distribution, soil water content, bulk density, organic matter, organic carbon content, pH and electrical conductivity. All parameters were determined following their respective standard methods. Results obtained showed that the soil in TCFR was dominated by clay texture (40%), followed by sandy clay loam (30%), loam (20%). Silty clay, clay loam and sandy loam constitutes about 10% of the soil texture. Range of mean percentage of organic matter and bulk density are from 2.42±0.06% to 11.64±0.39% and 1.01 to 1.04 (gcm-ł), respectively. Soil pH are relatively very acidic and mean of electrical conductivity is low. Soil carbon content ranged from 0.83±0.03 to 1.87±0.41%. All soil parameter showed a decreasing trend with depth except electrical conductivity. ANOVA test of mean percentage of organic matter, soil water content, soil pH and electrical conductivity showed a significant difference between plot (p<0.05). However there are no significant difference of mean bulk density between plots (p>0.05). There are no significant difference in mean percentage of soil water content, organic matter and bulk density between three different depth (p>0.05). There were a significant difference on percentage of soil carbon organic between plots and depth. The mean of soil organic carbon stock in soil to a depth of 60 cm calculated was 35.50 t/ha.

  8. Key soil functional properties affected by soil organic matter - evidence from published literature

    NASA Astrophysics Data System (ADS)

    Murphy, Brian

    2015-07-01

    The effect of varying the amount of soil organic matter on a range of individual soil properties was investigated using a literature search of published information largely from Australia, but also included relevant information from overseas. Based on published pedotransfer functions, soil organic matter was shown to increase plant available water by 2 to 3 mm per 10 cm for each 1% increase in soil organic carbon, with the largest increases being associated with sandy soils. Aggregate stability increased with increasing soil organic carbon, with aggregate stability decreasing rapidly when soil organic carbon fell below 1.2 to 1.5 5%. Soil compactibility, friability and soil erodibility were favourably improved by increasing the levels of soil organic carbon. Nutrient cycling was a major function of soil organic matter. Substantial amounts of N, P and S become available to plants when the soil organic matter is mineralised. Soil organic matter also provides a food source for the microorganisms involved in the nutrient cycling of N, P, S and K. In soils with lower clay contents, and less active clays such as kaolinites, soil organic matter can supply a significant amount of the cation exchange capacity and buffering capacity against acidification. Soil organic matter can have a cation exchange capacity of 172 to 297 cmol(+)/kg. As the cation exchange capacity of soil organic matter varies with pH, the effectiveness of soil organic matter to contribute to cation exchange capacity below pH 5.5 is often minimal. Overall soil organic matter has the potential to affect a range of functional soil properties.

  9. Adsorption and desorption of ammonium by maple wood biochar as a function of oxidation and pH.

    PubMed

    Wang, Bing; Lehmann, Johannes; Hanley, Kelly; Hestrin, Rachel; Enders, Akio

    2015-11-01

    The objective of this work was to investigate the retention mechanisms of ammonium in aqueous solution by using progressively oxidized maple wood biochar at different pH values. Hydrogen peroxide was used to oxidize the biochar to pH values ranging from 8.1 to 3.7, with one set being adjusted to a pH of 7 afterwards. Oxidizing the biochars at their lowered pH did not increase their ability to adsorb ammonium. However, neutralizing the oxygen-containing surface functional groups on oxidized biochar to pH 7 increased ammonia adsorption two to three-fold for biochars originally at pH 3.7-6, but did not change adsorption of biochars oxidized to pH 7 and above. The adsorption characteristics of ammonium are well described by the Freundlich equation. Adsorption was not fully reversible in water, and less than 27% ammonium was desorbed in water in two consecutive steps than previously adsorbed, for biochars with a pH below 7, irrespective of oxidation. Recovery using an extraction with 2M KCl increased from 34% to 99% of ammonium undesorbed by both preceding water extractions with increasing oxidation, largely irrespective of pH adjustment. Unrecovered ammonium in all extractions and residual biochar was negligible at high oxidation, but increased to 39% of initially adsorbed amounts at high pH, likely due to low amounts adsorbed and possible ammonia volatilization losses. PMID:26057391

  10. Adjustable link for kinematic mounting systems

    DOEpatents

    Hale, L.C.

    1997-07-01

    An adjustable link for kinematic mounting systems is disclosed. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two. 3 figs.

  11. Adjustable link for kinematic mounting systems

    DOEpatents

    Hale, Layton C.

    1997-01-01

    An adjustable link for kinematic mounting systems. The adjustable link is a low-cost, passive device that provides backlash-free adjustment along its single constraint direction and flexural freedom in all other directions. The adjustable link comprises two spheres, two sockets in which the spheres are adjustable retain, and a connection link threadly connected at each end to the spheres, to provide a single direction of restraint and to adjust the length or distance between the sockets. Six such adjustable links provide for six degrees of freedom for mounting an instrument on a support. The adjustable link has applications in any machine or instrument requiring precision adjustment in six degrees of freedom, isolation from deformations of the supporting platform, and/or additional structural damping. The damping is accomplished by using a hollow connection link that contains an inner rod and a viscoelastic separation layer between the two.

  12. Evaluation the anaerobic hydrolysis acidification stage of kitchen waste by pH regulation.

    PubMed

    Wang, Yaya; Zang, Bing; Li, Guoxue; Liu, Yu

    2016-07-01

    This study analyzed the composition and characteristic of kitchen waste (KW) from closed cleaning station of Chaoyang District, Beijing. It was featured by high vegetables and peels contents. This study investigated effect of pH regulation and uncontrolled pH (CK) on the lab-scale anaerobic hydrolysis acidification stage of KW. The optimal adjusting mode by NaOH (including dosage and frequency) was evaluated according to indexes of pH, VFAs, NH4(+)-N, TS, VS, TS/VS, TS and VS removal rate. The treatment 4 as first two days adjusting per 16h and then one time per day at pH 7 was chosen as the optimal mode with high VFAs content(47.31g/L), TS and VS removal rate (42.95% and 54.01%, respectively), low adjusting frequency, fewer dosage and practical operability. Thus, adjusting mode of treatment 4 could be considered using in anaerobic hydrolysis acidification stage on engineering. PMID:27156363

  13. A novel non-invasive optical method for quantitative visualization of pH dynamics in the rhizosphere of plants.

    PubMed

    Blossfeld, Stephan; Gansert, Dirk

    2007-02-01

    A novel optical method for non-invasive, quantitative and high-resolution imaging of spatial and temporal pH dynamics in soils mediated by plant roots is introduced. This method overcomes present limitations of measurement of pH, mainly short-term and punctiform measurements, by recording long-term dynamics of the micro-pattern of pH in the root-soil interface without disturbance of the biological and physico-chemical conditions. Juncus effusus L., rooting in a permanently flooded rhizotron, was selected as the test organism for qualifying the technique. The measurements showed pronounced diurnal variations of pH along the roots, particularly along the elongation zone. Diurnal oscillation of pH caused by the roots reached up to 0.5 units. Long-term records at 4 s intervals over more than 8 weeks revealed considerable spatial and temporal patterns of pH dynamics in the rhizosphere of about 10% of the pH scale (pH 7.0-8.5). The measured data were validated by the use of pH electrodes. Concomitantly measured oxygen concentration showed hypoxic conditions around root tips (10-70 micromol O2 L-1) and almost anoxic conditions (0.9 micromol O2 L-1) in the bulk soil. The present study qualifies this novel pH-sensing technique as a powerful analytical tool for quantitative visualization of undisturbed bioprocess dynamics. PMID:17238909

  14. Characterization of soils containing adipocere.

    PubMed

    Fiedler, S; Schneckenberger, K; Graw, M

    2004-11-01

    The formation of adipocere (commonly known as grave wax), a spontaneous inhibition of postmortem changes, has been extensively analyzed in forensic science. However, soils in which adipocere formation occurs have never been described in detail. Therefore, this study is intended as a first step in the characterization of soils containing adipocere. Two grave soils (Gleyic Anthrosols) that prevent the timely reuse of graves due to the occurrence of adipocere and a control soil (Gleyic Luvisol) were selected from a cemetery in the Central Black Forest (Southwest Germany). Descriptions of soil morphology and a wide assay of physical, chemical, and microbiologic soil characteristics were accomplished. In contrast to the control soil, the grave soils were characterized by lower bulk density and pH. The degradation of the soil structure caused by digging led to a higher water table and the expansion of the reducing conditions in the graves where the prevalent absence of oxygen in range of the coffins inhibited decomposition processes. Although the formation of adipocere led to the conservation of the buried corpses, phosphorus, dissolved organic carbon, and cadavarine leaching from the graves was observed. Microbial biomass and microbial activity were higher in the control soil and hence reflected the inert character of adipocere. The study results clearly show the need for additional approaches in forensic, pedologic, and microbiologic research. PMID:15499507

  15. The effect of pH on the survival of leptospires in water*

    PubMed Central

    Smith, C. E. Gordon; Turner, L. H.

    1961-01-01

    One of the factors on which the incidence of leptospirosis is dependent is the survival time of shed leptospires in surface water or soil water, and this time is in turn affected by the acidity or alkalinity of the water. The authors have therefore studied the survival of four leptospiral serotypes in buffered distilled water at pH's ranging from 5.3 to 8.0. All survived longer in alkaline than in acid water, and significant differences between the serotypes were found in response to pH. Survival at pH's under 7.0 ranged from 10 to 117 days and at pH's over 7.0 from 21 to 152 days. Survival was also studied in aqueous extracts of soil samples from different areas in Malaya; no correlation was found between pH and survival time. It was also noted that in a group of Malayan ricefields a low incidence of leptospirosis in man was accompanied by a high infection rate among rodents, and when it was found that this phenomenon could not be explained by pH or salinity, attention was turned to the soil. Bentonite clay, similar to the montmorrillonite clay of the ricefields, was found to adsorb about half the leptospires in suspension. The authors recommend that field study of this laboratory observation be undertaken. PMID:20604084

  16. Estimating Soil Cation Exchange Capacity from Soil Physical and Chemical Properties

    NASA Astrophysics Data System (ADS)

    Bateni, S. M.; Emamgholizadeh, S.; Shahsavani, D.

    2014-12-01

    The soil Cation Exchange Capacity (CEC) is an important soil characteristic that has many applications in soil science and environmental studies. For example, CEC influences soil fertility by controlling the exchange of ions in the soil. Measurement of CEC is costly and difficult. Consequently, several studies attempted to obtain CEC from readily measurable soil physical and chemical properties such as soil pH, organic matter, soil texture, bulk density, and particle size distribution. These studies have often used multiple regression or artificial neural network models. Regression-based models cannot capture the intricate relationship between CEC and soil physical and chemical attributes and provide inaccurate CEC estimates. Although neural network models perform better than regression methods, they act like a black-box and cannot generate an explicit expression for retrieval of CEC from soil properties. In a departure with regression and neural network models, this study uses Genetic Expression Programming (GEP) and Multivariate Adaptive Regression Splines (MARS) to estimate CEC from easily measurable soil variables such as clay, pH, and OM. CEC estimates from GEP and MARS are compared with measurements at two field sites in Iran. Results show that GEP and MARS can estimate CEC accurately. Also, the MARS model performs slightly better than GEP. Finally, a sensitivity test indicates that organic matter and pH have respectively the least and the most significant impact on CEC.

  17. The pH of antiseptic cleansers

    PubMed Central

    Kulthanan, Kanokvalai; Varothai, Supenya; Nuchkull, Piyavadee

    2014-01-01

    Background Daily bathing with antiseptic cleansers are proposed by some physicians as an adjunctive management of atopic dermatitis (AD). As atopic skin is sensitive, selection of cleansing products becomes a topic of concern. Objective Our purpose is to evaluate the pH of various antiseptic body cleansers to give an overview for recommendation to patients with AD. Methods Commonly bar and liquid cleansers consisted of antiseptic agents were measured for pH using pH meter and pH-indicator strips. For comparison, mild cleansers and general body cleansers were also measured. Results All cleansing bars had pH 9.8-11.3 except syndet bar that had neutral pH. For liquid cleansers, three cleansing agents had pH close to pH of normal skin, one of antiseptic cleansers, one of mild cleansers and another one of general cleansers. The rest of antiseptic cleansers had pH 8.9-9.6 while mild cleansers had pH 6.9-7.5. Syndet liquid had pH 7 and general liquid cleansers had pH 9.6. Conclusion The pH of cleanser depends on composition of that cleanser. Adding antiseptic agents are not the only factor determining variation of pH. Moreover, benefit of antiseptic properties should be considered especially in cases of infected skin lesions in the selection of proper cleansers for patients with AD. PMID:24527408

  18. Soil Phosphorus Stoichiometry Drives Carbon Turnover Along a Soil C Gradient Spanning Mineral and Organic Soils Under Rice Cultivation

    NASA Astrophysics Data System (ADS)

    Hartman, W.; Ye, R.; Horwath, W. R.; Tringe, S. G.

    2014-12-01

    Soil carbon (C) cycling is linked to the availability of nutrients like nitrogen (N) and phosphorus (P). However, the role of soil P in influencing soil C turnover and accumulation is poorly understood, with most models focusing on C:N ratios based on the assumption that terrestrial ecosystems are N limited. To determine the effects of N and P availability on soil C turnover, we compared soil respiration over the course of a growing season in four adjacent rice fields with 5%, 10%, 20% and 25% soil C. In each of these fields, plots were established to test the effect of N additions on plant growth, using control and N addition treatments (80 kg N/ha urea). Although soil P was not manipulated in parallel, prior work has shown soil P concentrations decline markedly with increasing soil C content. Soil CO2 flux was monitored using static chambers at biweekly intervals during the growing season, along with porewater dissolved organic C and ammonium. Soils were collected at the end of the growing season, and tested for total C, N, and P, extractable N and P, pH, base cations and trace metals. Soil DNA was also extracted for 16S rRNA sequencing to profile microbial communities. Soil N additions significantly increased CO2 flux and soil C turnover (seasonal CO2 flux per unit soil C) in 5% and 10% C fields, but not in 20% or 25% C fields. Soil C content was closely related to soil N:P stoichiometry, with N:P ratios of ca. 12, 16, 24, and 56 respectively in the 5, 10, 20 and 25% C fields. Seasonal CO2 fluxes (per m2) were highest in 10% C soils. However, soil C turnover was inversely related to soil C concentrations, with the greatest C turnover at the lowest values of soil C. Soil C turnover showed stronger relationships with soil chemical parameters than seasonal CO2 fluxes alone, and the best predictors of soil C turnover were soil total and extractable N:P ratios, along with extractable P alone. Our results show that soil P availability and stoichiometry influence the

  19. Bias Adjustment of PERSIANN Rainfall for Hydrologic Applications

    NASA Astrophysics Data System (ADS)

    Hsu, K.; Braithwaite, D.; Imam, B.; Gao, X.; Sorooshian, S.

    2008-05-01

    The exchange of water and energy through the land and atmospheric interaction occurs at various space and time scales. Modeling these exchanges, in general, and more specifically, adequate capturing of land surface hydrologic processes such as soil moisture and runoff generation requires reliable modeling and measurement of precipitation at fine time scale. The maturity of Satellite-based rainfall estimates is now sufficient to consider the value of such products in improving land surface models. This study addresses the measurement and bias correction of PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks) rainfall to sub-daily scale of 0.25ox0.25o with emphasis on its potential use in land-surface hydrologic applications. The satellite-based PERSIANN system estimates surface rainfall based on infrared temperature and local image texture from geostationary satellites. Model parameters of PERSIANN are frequently adjusted when passive microwave rainfall estimates from low-orbital satellites (EOS, TRMM, NOAA, and DMSP) are available. PERSIANN estimates rainfall at hourly and 0.25ox0.25o lat-long scales. Its products are accumulated to daily and monthly scales for various applications. In this presentation, PERSIANN bias adjustment using monthly estimates from the Global Precipitation Climatology Project (GPCP) product is explored. Hourly PERSIANN rainfall estimates are first aggregated both spatially and temporally to the monthly 2.5ox2.5o scale and subsequently adjusted using GCPC monthly estimates as reference. Values of bias in PERSIANN are used to adjust PERSIANN rainfall at the 0.25ox0.25o hourly scale. The effectiveness of bias adjustment is evaluated using radar and gauge measurements at sub- daily to monthly scales at a spatial resolution of 0.25ox0.25o lat-long. The potential use of adjusted PERSIANN in hydrologic applications will be presented and discussed.

  20. Correlates of household seismic hazard adjustment adoption.

    PubMed

    Lindell, M K; Whitney, D J

    2000-02-01

    This study examined the relationships of self-reported adoption of 12 seismic hazard adjustments (pre-impact actions to reduce danger to persons and property) with respondents' demographic characteristics, perceived risk, perceived hazard knowledge, perceived protection responsibility, and perceived attributes of the hazard adjustments. Consistent with theoretical predictions, perceived attributes of the hazard adjustments differentiated among the adjustments and had stronger correlations with adoption than any of the other predictors. These results identify the adjustments and attributes that emergency managers should address to have the greatest impact on improving household adjustment to earthquake hazard. PMID:10795335

  1. Adjustable extender for instrument module

    DOEpatents

    Sevec, J.B.; Stein, A.D.

    1975-11-01

    A blank extender module used to mount an instrument module in front of its console for repair or test purposes has been equipped with a rotatable mount and means for locking the mount at various angles of rotation for easy accessibility. The rotatable mount includes a horizontal conduit supported by bearings within the blank module. The conduit is spring-biased in a retracted position within the blank module and in this position a small gear mounted on the conduit periphery is locked by a fixed pawl. The conduit and instrument mount can be pulled into an extended position with the gear clearing the pawl to permit rotation and adjustment of the instrument.

  2. pH control in biological systems using calcium carbonate.

    PubMed

    Salek, S S; van Turnhout, A G; Kleerebezem, R; van Loosdrecht, M C M

    2015-05-01

    Due to its abundance, calcium carbonate (CaCO3) has high potentials as a source of alkalinity for biotechnological applications. The application of CaCO3 in biological systems as neutralizing agent is, however, limited due to potential difficulties in controlling the pH. The objective of the present study was to determine the dominant processes that control the pH in an acid-forming microbial process in the presence of CaCO3. To achieve that, a mathematical model was made with a minimum set of kinetically controlled and equilibrium reactions that was able to reproduce the experimental data of a batch fermentation experiment using finely powdered CaCO3. In the model, thermodynamic equilibrium was assumed for all speciation, complexation and precipitation reactions whereas, rate limited reactions were included for the biological fatty acid production, the mass transfer of CO2 from the liquid phase to the gas phase and the convective transport of CO2 out of the gas phase. The estimated pH-pattern strongly resembled the measured pH, suggesting that the chosen set of kinetically controlled and equilibrium reactions were establishing the experimental pH. A detailed analysis of the reaction system with the aid of the model revealed that the pH establishment was most sensitive to four factors: the mass transfer rate of CO2 to the gas phase, the biological acid production rate, the partial pressure of CO2 and the Ca(+2) concentration in the solution. Individual influences of these factors on the pH were investigated by extrapolating the model to a continuously stirred-tank reactor (CSTR) case. This case study indicates how the pH of a commonly used continuous biotechnological process could be manipulated and adjusted by altering these four factors. Achieving a better insight of the processes controlling the pH of a biological system using CaCO3 as its neutralizing agent can result in broader applications of CaCO3 in biotechnological industries. PMID:25425281

  3. SoilInfo App: global soil information on your palm

    NASA Astrophysics Data System (ADS)

    Hengl, Tomislav; Mendes de Jesus, Jorge

    2015-04-01

    ISRIC ' World Soil Information has released in 2014 and app for mobile de- vices called 'SoilInfo' (http://soilinfo-app.org) and which aims at providing free access to the global soil data. SoilInfo App (available for Android v.4.0 Ice Cream Sandwhich or higher, and Apple v.6.x and v.7.x iOS) currently serves the Soil- Grids1km data ' a stack of soil property and class maps at six standard depths at a resolution of 1 km (30 arc second) predicted using automated geostatistical mapping and global soil data models. The list of served soil data includes: soil organic carbon (), soil pH, sand, silt and clay fractions (%), bulk density (kg/m3), cation exchange capacity of the fine earth fraction (cmol+/kg), coarse fragments (%), World Reference Base soil groups, and USDA Soil Taxonomy suborders (DOI: 10.1371/journal.pone.0105992). New soil properties and classes will be continuously added to the system. SoilGrids1km are available for download under a Creative Commons non-commercial license via http://soilgrids.org. They are also accessible via a Representational State Transfer API (http://rest.soilgrids.org) service. SoilInfo App mimics common weather apps, but is also largely inspired by the crowdsourcing systems such as the OpenStreetMap, Geo-wiki and similar. Two development aspects of the SoilInfo App and SoilGrids are constantly being worked on: Data quality in terms of accuracy of spatial predictions and derived information, and Data usability in terms of ease of access and ease of use (i.e. flexibility of the cyberinfrastructure / functionalities such as the REST SoilGrids API, SoilInfo App etc). The development focus in 2015 is on improving the thematic and spatial accuracy of SoilGrids predictions, primarily by using finer resolution covariates (250 m) and machine learning algorithms (such as random forests) to improve spatial predictions.

  4. Adsorption and Degradation of Mesotrione in Four Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adsorption and degradation of mesotrione in four soils Dale Shaner, Galen Brunk, Scott Nissen and Phil Westra The adsorption and fate of mesotrione was studied in four diverse soil types varying in pH, organic matter (OM), and texture. The adsorption of mesotrione to each soil was determined using ...

  5. Improving the spatial representation of soil properties and hydrology using topographically derived watershed model initialization processes

    NASA Astrophysics Data System (ADS)

    Easton, Z. M.; Fuka, D.; Collick, A.; Kleinman, P. J. A.; Auerbach, D.; Sommerlot, A.; Wagena, M. B.

    2015-12-01

    Topography exerts critical controls on many hydrologic, geomorphologic, and environmental biophysical processes. Unfortunately many watershed modeling systems use topography only to define basin boundaries and stream channels and do not explicitly account for the topographic controls on processes such as soil genesis, soil moisture distributions and hydrological response. We develop and demonstrate a method that uses topography to spatially adjust soil morphological and soil hydrological attributes [soil texture, depth to the C-horizon, saturated conductivity, bulk density, porosity, and the field capacities at 33kpa (~ field capacity) and 1500kpa (~ wilting point) tensions]. In order to test the performance of the method the topographical adjusted soils and standard SSURGO soil (available at 1:20,000 scale) were overlaid on soil pedon pit data in the Grasslands Soil and Water Research Lab in Resiel, TX. The topographically adjusted soils exhibited significant correlations with measurements from the soil pits, while the SSURGO soil data showed almost no correlation to measured data. We also applied the method to the Grasslands Soil and Water Research watershed using the Soil and Water Assessment Tool (SWAT) model to 15 separate fields as a proxy to propagate changes in soil properties into field scale hydrological responses. Results of this test showed that the topographically adjusted soils resulted better model predictions of field runoff in 50% of the field, with the SSURGO soils preforming better in the remainder of the fields. However, the topographically adjusted soils generally predicted baseflow response more accurately, reflecting the influence of these soil properties on non-storm responses. These results indicate that adjusting soil properties based on topography can result in more accurate soil characterization and, in some cases improve model performance.

  6. Acid loading test (pH)

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003615.htm Acid loading test (pH) To use the sharing features on this page, please enable JavaScript. The acid loading test (pH) measures the ability of the ...

  7. Mycelial bacteria of saline soils

    NASA Astrophysics Data System (ADS)

    Zvyagintsev, D. G.; Zenova, G. M.; Oborotov, G. V.

    2008-10-01

    The actinomycetal complexes of saline soils comprise the representatives of the Streptomyces and Micromonospora genera, the number of which are hundreds and thousands of CFU/g soil. Complexes of mycelial bacteria in saline soils are poorer in terms of number (by 1-3 orders of magnitude) and taxonomic composition than the complexes of the zonal soil types. A specific feature of the actinomycetal complexes of saline soils is the predominance of halophilic, alkaliphilic, and haloalkaliphilic streptomycetes that well grow at pH 8-9 and concentrations of NaCl close to 5%. Actinomycetes in saline soils grow actively, and the length of their mycelium reaches 140 m in 1 gram of soil. The haloalkaliphilic streptomycetes grow fast and inhibit the formation of spores at pH 9 and high concentrations of salts (Na2SO4 and MgCl2, 5%) as compared to their behavior on a neutral medium with a salt concentration of 0.02%. They are characterized by the maximal radial growth rate of colonies on an alkaline medium with 5% NaCl.

  8. Formulation of humic-based soil conditioners

    NASA Astrophysics Data System (ADS)

    Amanova, M. A.; Mamytova, G. A.; Mamytova, B. A.; Kydralieva, K. A.; Jorobekova, Sh. J.

    2009-04-01

    The goal of the study is to prepare soil conditioners (SC) able to carry out the following functions: (i) the chemical conditioning of soil mainly comprising the adjustment of pH, (ii) the balancing of inorganic nutrients, (iii) the physical conditioning of soil mainly comprising the improvement of water permeability, air permeability and water retention properties, and (iv) improvement of the ecological system concerning of useful microorganisms activity in the soil. The SC was made of a mixture of inorganic ingredients, a chemical composition and physical and chemical properties of which promoted improvement of physical characteristic of soil and enrichment by its mineral nutritious elements. In addition to aforesaid ingredients, this soil conditioner contains agronomical-valued groups of microorganisms having the function promoting the growth of the crop. As organic component of SC humic acids (HA) was used. HA serve many major functions that result in better soil and plant health. In soil, HA can increase microbial and mycorrhizal activity while enhancing nutrient uptake by plant roots. HA work as a catalyst by stimulating root and plant growth, it may enhance enzymatic activity that in turn accelerates cell division which can lead to increased yields. HA can help to increase crop yields, seed germination, and much more. In short, humic acids helps keep healthy plants health. The first stage goal was to evaluate mineral and organic ingredients for formulation of SC. Soil conditioners assessed included ash and slag. The use of slags has been largelly used in agriculture as a source of lime and phosphoric acid. The silicic acid of slags reduces Al-acitivity thus, promoting a better assimilation of P-fertilizer by plants. Additionally, silicic acid is also known to improve soil moisture capacity, thus enhancing soil water availability to plants. Physico-chemical characteristics of ash and slag were determined, as a total - about 20 samples. Results include

  9. Influences of soil acidity on Streptomyces populations inhabiting forest soils.

    PubMed Central

    Hagedorn, C

    1976-01-01

    The Streptomyces populations inhabiting five acidic forest soils were examined. It was found that lowering the pH of a medium selective for streptomycetes (starch-casein agar) to the pH of the particular soil horizon being plated influenced both the total numbers and types of streptomycetes that were isolated from the soils examined in this study. On the acidified medium both the numbers of streptomycetes and the percentage of total bacteria on the plates represented by streptomycetes increased (as compared with the same medium with a pH of 7.2). These differences were greatest on the isolations from the most acid soils. The largest concentrations of streptomycetes were found in the surface horizon (0 to 15 cm) and the litter layer immediately over the surface mineral horizon. Acidity tolerance tests demonstrated that random samplings of isolates contained acidophilic, neutrophilic, and acidoduric strains, with the largest numbers of acidophiles being found on the acidified media from the most acid soils. There were no differences between overall utilization of selected carbohydrates among the isolates taken from either the neutral or acidic media, although a larger proportion of the acid media isolates produced acid from the carbohydrates. Evidence is presented which indicates that different types of streptomycetes were isolated on the acid media, and possible reasons for the presence of these acid-tolerant populations are discussed. PMID:10835

  10. Biochar soil amendment: Impact of soil types on heavy metal sorption-desorption behaviors and repeated nutrient leaching

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Depending on soil types, properties of chars especially pH and leachable organic/inorganic components can have varying impacts when used as a soil amendment. We have investigated sorption-desorption behaviors of metal contaminant of concern in shooting ranges and urban soils (Cu), nutrient supply (...

  11. Archaeal Communities in a Heterogeneous Hypersaline-Alkaline Soil.

    PubMed

    Navarro-Noya, Yendi E; Valenzuela-Encinas, César; Sandoval-Yuriar, Alonso; Jiménez-Bueno, Norma G; Marsch, Rodolfo; Dendooven, Luc

    2015-01-01

    In this study the archaeal communities in extreme saline-alkaline soils of the former lake Texcoco, Mexico, with electrolytic conductivities (EC) ranging from 0.7 to 157.2 dS/m and pH from 8.5 to 10.5 were explored. Archaeal communities in the 0.7 dS/m pH 8.5 soil had the lowest alpha diversity values and were dominated by a limited number of phylotypes belonging to the mesophilic Candidatus Nitrososphaera. Diversity and species richness were higher in the soils with EC between 9.0 and 157.2 dS/m. The majority of OTUs detected in the hypersaline soil were members of the Halobacteriaceae family. Novel phylogenetic branches in the Halobacteriales class were detected in the soil, and more abundantly in soil with the higher pH (10.5), indicating that unknown and uncharacterized Archaea can be found in this soil. Thirteen different genera of the Halobacteriaceae family were identified and were distributed differently between the soils. Halobiforma, Halostagnicola, Haloterrigena, and Natronomonas were found in all soil samples. Methanogenic archaea were found only in soil with pH between 10.0 and 10.3. Retrieved methanogenic archaea belonged to the Methanosarcinales and Methanomicrobiales orders. The comparison of the archaeal community structures considering phylogenetic information (UniFrac distances) clearly clustered the communities by pH. PMID:26074731

  12. Archaeal Communities in a Heterogeneous Hypersaline-Alkaline Soil

    PubMed Central

    Navarro-Noya, Yendi E.; Valenzuela-Encinas, César; Sandoval-Yuriar, Alonso; Jiménez-Bueno, Norma G.; Marsch, Rodolfo

    2015-01-01

    In this study the archaeal communities in extreme saline-alkaline soils of the former lake Texcoco, Mexico, with electrolytic conductivities (EC) ranging from 0.7 to 157.2 dS/m and pH from 8.5 to 10.5 were explored. Archaeal communities in the 0.7 dS/m pH 8.5 soil had the lowest alpha diversity values and were dominated by a limited number of phylotypes belonging to the mesophilic Candidatus Nitrososphaera. Diversity and species richness were higher in the soils with EC between 9.0 and 157.2 dS/m. The majority of OTUs detected in the hypersaline soil were members of the Halobacteriaceae family. Novel phylogenetic branches in the Halobacteriales class were detected in the soil, and more abundantly in soil with the higher pH (10.5), indicating that unknown and uncharacterized Archaea can be found in this soil. Thirteen different genera of the Halobacteriaceae family were identified and were distributed differently between the soils. Halobiforma, Halostagnicola, Haloterrigena, and Natronomonas were found in all soil samples. Methanogenic archaea were found only in soil with pH between 10.0 and 10.3. Retrieved methanogenic archaea belonged to the Methanosarcinales and Methanomicrobiales orders. The comparison of the archaeal community structures considering phylogenetic information (UniFrac distances) clearly clustered the communities by pH. PMID:26074731

  13. Lowering N2O emissions from soils using eucalypt biochar: the importance of redox reactions

    NASA Astrophysics Data System (ADS)

    Quin, P.; Joseph, S.; Husson, O.; Donne, S.; Mitchell, D.; Munroe, P.; Phelan, D.; Cowie, A.; van Zwieten, L.

    2015-11-01

    Agricultural soils are the primary anthropogenic source of atmospheric nitrous oxide (N2O), contributing to global warming and depletion of stratospheric ozone. Biochar addition has shown potential to lower soil N2O emission, with the mechanisms remaining unclear. We incubated eucalypt biochar (550 °C) - 0, 1 and 5% (w/w) in Ferralsol at 3 water regimes (12, 39 and 54% WFPS) - in a soil column, following gamma irradiation. After N2O was injected at the base of the soil column, in the 0% biochar control 100% of expected injected N2O was released into headspace, declining to 67% in the 5% amendment. In a 100% biochar column at 6% WFPS, only 16% of the expected N2O was observed. X-ray photoelectron spectroscopy identified changes in surface functional groups suggesting interactions between N2O and the biochar surfaces. We have shown increases in -O-C = N /pyridine pyrrole/NH3, suggesting reactions between N2O and the carbon (C) matrix upon exposure to N2O. With increasing rates of biochar application, higher pH adjusted redox potentials were observed at the lower water contents. Evidence suggests that biochar has taken part in redox reactions reducing N2O to dinitrogen (N2), in addition to adsorption of N2O.

  14. Lowering N2O emissions from soils using eucalypt biochar: the importance of redox reactions

    PubMed Central

    Quin, P; Joseph, S; Husson, O; Donne, S; Mitchell, D; Munroe, P; Phelan, D; Cowie, A; Van Zwieten, L

    2015-01-01

    Agricultural soils are the primary anthropogenic source of atmospheric nitrous oxide (N2O), contributing to global warming and depletion of stratospheric ozone. Biochar addition has shown potential to lower soil N2O emission, with the mechanisms remaining unclear. We incubated eucalypt biochar (550 °C) – 0, 1 and 5% (w/w) in Ferralsol at 3 water regimes (12, 39 and 54% WFPS) – in a soil column, following gamma irradiation. After N2O was injected at the base of the soil column, in the 0% biochar control 100% of expected injected N2O was released into headspace, declining to 67% in the 5% amendment. In a 100% biochar column at 6% WFPS, only 16% of the expected N2O was observed. X-ray photoelectron spectroscopy identified changes in surface functional groups suggesting interactions between N2O and the biochar surfaces. We have shown increases in -O-C = N /pyridine pyrrole/NH3, suggesting reactions between N2O and the carbon (C) matrix upon exposure to N2O. With increasing rates of biochar application, higher pH adjusted redox potentials were observed at the lower water contents. Evidence suggests that biochar has taken part in redox reactions reducing N2O to dinitrogen (N2), in addition to adsorption of N2O. PMID:26615820

  15. Lowering N2O emissions from soils using eucalypt biochar: the importance of redox reactions.

    PubMed

    Quin, P; Joseph, S; Husson, O; Donne, S; Mitchell, D; Munroe, P; Phelan, D; Cowie, A; Van Zwieten, L

    2015-01-01

    Agricultural soils are the primary anthropogenic source of atmospheric nitrous oxide (N2O), contributing to global warming and depletion of stratospheric ozone. Biochar addition has shown potential to lower soil N2O emission, with the mechanisms remaining unclear. We incubated eucalypt biochar (550 °C)--0, 1 and 5% (w/w) in Ferralsol at 3 water regimes (12, 39 and 54% WFPS)--in a soil column, following gamma irradiation. After N2O was injected at the base of the soil column, in the 0% biochar control 100% of expected injected N2O was released into headspace, declining to 67% in the 5% amendment. In a 100% biochar column at 6% WFPS, only 16% of the expected N2O was observed. X-ray photoelectron spectroscopy identified changes in surface functional groups suggesting interactions between N2O and the biochar surfaces. We have shown increases in -O-C = N /pyridine pyrrole/NH3, suggesting reactions between N2O and the carbon (C) matrix upon exposure to N2O. With increasing rates of biochar application, higher pH adjusted redox potentials were observed at the lower water contents. Evidence suggests that biochar has taken part in redox reactions reducing N2O to dinitrogen (N2), in addition to adsorption of N2O. PMID:26615820

  16. Conserving Soil.

    ERIC Educational Resources Information Center

    Soil Conservation Service (USDA), Washington, DC.

    Designed as enrichment materials for grades six through nine, this program is an interdisciplinary study of soils. As part of the program students: (1) examine soil organisms; (2) research history of local Native Americans to see how they and others have used the land and its soils; (3) investigate how soils are degraded and how they are conserved…

  17. Adjusting the Contour of Reflector Panels

    NASA Technical Reports Server (NTRS)

    Palmer, W. B.; Giebler, M. M.

    1984-01-01

    Postfabrication adjustment of contour of panels for reflector, such as parabolic reflector for radio antennas, possible with simple mechanism consisting of threaded stud, two nuts, and flexure. Contours adjusted manually.

  18. 48 CFR 1450.103 - Contract adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract adjustments. 1450.103 Section 1450.103 Federal Acquisition Regulations System DEPARTMENT OF THE INTERIOR CONTRACT... Contract adjustments....

  19. Lasagna{trademark} soil remediation

    SciTech Connect

    1996-04-01

    Lasagna{trademark} is an integrated, in situ remediation technology being developed which remediates soils and soil pore water contaminated with soluble organic compounds. Lasagna{trademark} is especially suited to sites with low permeability soils where electroosmosis can move water faster and more uniformly than hydraulic methods, with very low power consumption. The process uses electrokinetics to move contaminants in soil pore water into treatment zones where the contaminants can be captured and decomposed. Initial focus is on trichloroethylene (TCE), a major contaminant at many DOE and industrial sites. Both vertical and horizontal configurations have been conceptualized, but fieldwork to date is more advanced for the vertical configuration. Major features of the technology are electrodes energized by direct current, which causes water and soluble contaminants to move into or through the treatment layers and also heats the soil; treatment zones containing reagents that decompose the soluble organic contaminants or adsorb contaminants for immobilization or subsequent removal and disposal; and a water management system that recycles the water that accumulates at the cathode (high pH) back to the anode (low pH) for acid-base neutralization. Alternatively, electrode polarity can be reversed periodically to reverse electroosmotic flow and neutralize pH.

  20. Relative Bioavailability and Bioaccessability and Speciation of Arsenic in Contaminated Soils

    EPA Science Inventory

    Background: Assessment of soil arsenic (As) bioavailability may profoundly affect the extent of remediation required at contaminated sites by improving human exposure estimates. Because small adjustments in soil As bioavailability estimates can significantly alter risk assessment...

  1. BOREAS TE-2 NSA Soil Lab Data

    NASA Technical Reports Server (NTRS)

    Veldhuis, Hugo; Hall, Forrest G. (Editor); Knapp, David E. (Editor)

    2000-01-01

    This data set contains the major soil properties of soil samples collected in 1994 at the tower flux sites in the Northern Study Area (NSA). The soil samples were collected by Hugo Veldhuis and his staff from the University of Manitoba. The mineral soil samples were largely analyzed by Barry Goetz, under the supervision of Dr. Harold Rostad at the University of Saskatchewan. The organic soil samples were largely analyzed by Peter Haluschak, under the supervision of Hugo Veldhuis at the Centre for Land and Biological Resources Research in Winnipeg, Manitoba. During the course of field investigation and mapping, selected surface and subsurface soil samples were collected for laboratory analysis. These samples were used as benchmark references for specific soil attributes in general soil characterization. Detailed soil sampling, description, and laboratory analysis were performed on selected modal soils to provide examples of common soil physical and chemical characteristics in the study area. The soil properties that were determined include soil horizon; dry soil color; pH; bulk density; total, organic, and inorganic carbon; electric conductivity; cation exchange capacity; exchangeable sodium, potassium, calcium, magnesium, and hydrogen; water content at 0.01, 0.033, and 1.5 MPascals; nitrogen; phosphorus: particle size distribution; texture; pH of the mineral soil and of the organic soil; extractable acid; and sulfur. These data are stored in ASCII text files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  2. 76 FR 4395 - Postal Service Price Adjustment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ... Postal Service Price Adjustment AGENCY: Postal Regulatory Commission. ACTION: Notice. SUMMARY: The Commission is noticing a recently-filed Postal Service request to establish price adjustments for all market... with the Commission announcing price adjustments, effective April 17, 2011, affecting all...

  3. 12 CFR 1780.80 - Inflation adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Inflation adjustments. 1780.80 Section 1780.80... DEVELOPMENT RULES OF PRACTICE AND PROCEDURE RULES OF PRACTICE AND PROCEDURE Civil Money Penalty Inflation Adjustments § 1780.80 Inflation adjustments. The maximum amount of each civil money penalty within...

  4. 34 CFR 36.2 - Penalty adjustment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Penalty adjustment. 36.2 Section 36.2 Education Office of the Secretary, Department of Education ADJUSTMENT OF CIVIL MONETARY PENALTIES FOR INFLATION § 36.2..., Section 36.2—Civil Monetary Penalty Inflation Adjustments Statute Description New maximum (and minimum,...

  5. 19 CFR 201.205 - Salary adjustments.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 3 2011-04-01 2011-04-01 false Salary adjustments. 201.205 Section 201.205 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Debt Collection § 201.205 Salary adjustments. Any negative adjustment to pay arising out of an employee's...

  6. 19 CFR 201.205 - Salary adjustments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Salary adjustments. 201.205 Section 201.205 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION GENERAL RULES OF GENERAL APPLICATION Debt Collection § 201.205 Salary adjustments. Any negative adjustment to pay arising out of an employee's...

  7. 34 CFR 36.2 - Penalty adjustment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 1 2011-07-01 2011-07-01 false Penalty adjustment. 36.2 Section 36.2 Education Office of the Secretary, Department of Education ADJUSTMENT OF CIVIL MONETARY PENALTIES FOR INFLATION § 36.2..., Section 36.2—Civil Monetary Penalty Inflation Adjustments Statute Description New maximum (and minimum,...

  8. 34 CFR 36.2 - Penalty adjustment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 34 Education 1 2013-07-01 2013-07-01 false Penalty adjustment. 36.2 Section 36.2 Education Office of the Secretary, Department of Education ADJUSTMENT OF CIVIL MONETARY PENALTIES FOR INFLATION § 36.2..., Section 36.2—Civil Monetary Penalty Inflation Adjustments Statute Description New maximum (and minimum,...

  9. 34 CFR 36.2 - Penalty adjustment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 34 Education 1 2014-07-01 2014-07-01 false Penalty adjustment. 36.2 Section 36.2 Education Office of the Secretary, Department of Education ADJUSTMENT OF CIVIL MONETARY PENALTIES FOR INFLATION § 36.2..., Section 36.2—Civil Monetary Penalty Inflation Adjustments Statute Description New maximum (and minimum,...

  10. 34 CFR 36.2 - Penalty adjustment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 34 Education 1 2012-07-01 2012-07-01 false Penalty adjustment. 36.2 Section 36.2 Education Office of the Secretary, Department of Education ADJUSTMENT OF CIVIL MONETARY PENALTIES FOR INFLATION § 36.2..., Section 36.2—Civil Monetary Penalty Inflation Adjustments Statute Description New maximum (and minimum,...

  11. 12 CFR 1780.80 - Inflation adjustments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 7 2011-01-01 2011-01-01 false Inflation adjustments. 1780.80 Section 1780.80... DEVELOPMENT RULES OF PRACTICE AND PROCEDURE RULES OF PRACTICE AND PROCEDURE Civil Money Penalty Inflation Adjustments § 1780.80 Inflation adjustments. The maximum amount of each civil money penalty within...

  12. Adjustment to College in Students with ADHD

    ERIC Educational Resources Information Center

    Rabiner, David L.; Anastopoulos, Arthur D.; Costello, Jane; Hoyle, Rick H.; Swartzwelder, H. Scott

    2008-01-01

    Objective: To examine college adjustment in students reporting an ADHD diagnosis and the effect of medication treatment on students' adjustment. Method: 1,648 first-semester freshmen attending a public and a private university completed a Web-based survey to examine their adjustment to college. Results: Compared with 200 randomly selected control…

  13. Dimensions of Adjustment among College Women.

    ERIC Educational Resources Information Center

    Tomlinson-Clarke, Saundra

    1998-01-01

    Examines academic, social, and personal-emotional adjustment, as well as institutional attachment for women (N=198) attending a predominantly white coeducational research university. Significant main effects were found on academic achievement for year in college. Students differed on personal-emotional adjustment by race. Academic adjustment and…

  14. Rain pH estimation based on the particulate matter pollutants and wet deposition study.

    PubMed

    Singh, Shweta; Elumalai, Suresh Pandian; Pal, Asim Kumar

    2016-09-01

    In forecasting of rain pH, the changes caused by particulate matter (PM) are generally neglected. In regions of high PM concentration like Dhanbad, the role of PM in deciding the rain pH becomes important. Present work takes into account theoretical prediction of rain pH by two methods. First method considers only acid causing gases (ACG) like CO2, SO2 and NOx in pH estimation, whereas, second method additionally accounts for effect of PM (ACG-PM). In order to predict the rain pH, site specific deposited dust that represents local PM was studied experimentally for its impact on pH of neutral water. After incorporation of PM correction factor, it was found that, rain pH values estimated were more representative of the observed ones. Fractional bias (FB) for the ACG-PM method reduced to values of the order of 10(-2) from those with order of 10(-1) for the ACG method. The study confirms neutralization of rain acidity by PM. On account of this, rain pH was found in the slightly acidic to near neutral range, despite of the high sulfate flux found in rain water. Although, the safer range of rain pH blurs the severity of acid rain from the picture, yet huge flux of acidic and other ions get transferred to water bodies, soil and ultimately to the ground water system. Simple use of rain pH for rain water quality fails to address the issues of its increased ionic composition due to the interfering pollutants and thus undermines severity of pollutants transferred from air to rain water and then to water bodies and soil. PMID:27139302

  15. Metal Sequestration Is Influenced By Biochar Properties and Changes in pH

    NASA Astrophysics Data System (ADS)

    Clemente, J.; Beauchemin, S.; MacKinnon, T.; Martin, J.; Joern, B.; Johnston, C. T.

    2014-12-01

    Addition of biochars to impounded metal mine waste may improve the physical and chemical properties, and the biological activity and diversity of these contaminated sites. However, understanding how biochar addition influences metal(loid) mobility is necessary. Here, the sequestration of 5 metal(loid)s in suspensions of biochars adjusted to pH 4.5 or 6.0 were characterized. Solutions of the oxyanion As and the cations Ni, Cu, Zn, Cd were added at a single rate of 3 mmol kg-1 biochar. Six biochars were obtained by large-scale pyrolysis of softwood, hardwood, grass, and poultry litter under different conditions. Biochars were characterized using N2-BET (surface area), proximate analysis, elemental analysis, X-ray diffraction and Fourier transform infrared spectroscopy. In this study, metal(loid) sequestration depended on the suspension pH, metal(loid), and biochar characteristics. In most cases, a significantly (α=0.05) greater proportion of cation was sequestered in biochar suspensions adjusted to pH 6.0 compared to pH 4.5. In contrast, pH had no significant effect on the sequestration of As. The magnitude of the increase in sequestration at pH 6.0 compared to pH 4.5 can be attributed to specific biochar characteristics. Enhancement of Ni, Zn, and Cd sequestration at pH 6.0 compared to pH 4.5 was correlated (R2>0.50) to inorganic C content and neutralization potential of biochars. Furthermore, increased Cu sequestration at pH 6.0 compared to pH 4.5 was correlated (R2>0.50) to % Fixed matter and organic C content of biochars. This data suggests that at pH 6.0, sequestration of Ni, Zn, and Cd as carbonates and interactions between organic C and Cu were more favourable compared to pH 4.5. For Ni, Cu, and Cd, differences in sequestration at the two pH were also related (R2>0.50) to the relative distribution of functional groups. This study emphasizes the need for a more holistic understanding of how biochar properties influence metal sequestration.

  16. Soil carbonates and soil water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of soil carbonates occurring as solidified masses or dispersed particles can alter soil water dynamics from what would be expected based on non-carbonate soil properties. Carbonate minerals in the soil can be derived from high carbonate parent material, additions in the form of carbonat...

  17. COOPERATION MAINTAINED BY FITNESS ADJUSTMENT

    PubMed Central

    TAYLOR, CHRISTINE; CHEN, JANET; IWASA, YOH

    2008-01-01

    Questions Whether or not cooperation can be enhanced if players with a performance higher than the mean are forced to pay an additional cost in each generation? Mathematical Methods Analysis of replicator dynamics with mutation. The ESS distribution of cooperation level is obtained. Key Assumptions Players engage in cooperative dilemma game, and at the end of each generation, those with higher performance than the mean are forced to pay additional cost. Conclusions Without mutation, the entire population eventually conforms to a single cooperation level determined by the initial composition of the population. With mutation, there is an equilibrium distribution of cooperation level, which has a peak at an intermediate level of cooperation. Whether it is institutionalized such as tax or just a social custom, fitness adjustment based ultimately on people’s emtion of “envy” is able to maintain cooperation. PMID:19079742

  18. Analysis of green tea compounds and their stability in dentifrices of different pH levels.

    PubMed

    Jang, Jong-Hwa; Park, Yong-Duk; Ahn, Hyo-Kwang; Kim, Seung-Jin; Lee, Joo-Young; Kim, Eun-Cheol; Chang, Yeon-Soo; Song, Yun-Jung; Kwon, Ha-Jeong

    2014-01-01

    In this study, green tea compounds (flavonoids, alkaloids, and phenolic acids) were analyzed in green tea-containing dentifrices, and their stability at different pH levels was evaluated. The compounds were separated under 0.01% phosphoric acid-acetonitrile gradient conditions and detected by photodiode array detector at 210, 280, 300, 335 nm. Column temperature was set at 20°C based on the results of screening various temperatures. Each compound showed good linearity at optimized wavelength as well as showing good precision and accuracy in dentifrices. Using this method, the stability of compounds was investigated in pH 4, 7, 8, and 10 solutions for 96 h, and in pH 7 and pH 10 solutions for 6 months. The green tea compounds were more stable at low pH levels; purine alkaloids were more stable than flavonoids. In particular, gallocatechin (GC), epigallocatechin (EGC), epigallocatechin gallate (EGCG), gallocatechin gallate (GCG), and myricetin almost disappeared in pH 10 solutions after 96 h. In dentifrices, the compounds were gradually decreased until 6 months in both pH types, while gallic acid was increased because of production of galloyl ester of other green tea compounds. Therefore, it is beneficial to adjust to as low a pH as possible when produce green tea-containing dentifrices. PMID:24695342

  19. Effect of wine pH and bottle closure on tannins.

    PubMed

    McRae, Jacqui M; Kassara, Stella; Kennedy, James A; Waters, Elizabeth J; Smith, Paul A

    2013-11-27

    The impact of wine pH and closure type on color, tannin concentration, and composition was investigated. A single vintage of Cabernet Sauvignon wine was divided into three batches, the pH was adjusted to 3.2, 3.5 or 3.8, and the wines were bottled under screw caps with either SaranTin (ST) or Saranex (Sx) liners. After 24 months, the tannin concentration, tannin percent yield (relating to the proportion of acid-labile interflavan bonds), and the mean degree of polymerization (mDp) had decreased significantly, all of which can contribute to the softening of wine astringency with aging. The higher pH wines contained less percent (-)-epicatechin 3-O-gallate subunits, whereas the Sx pH 3.2 wines were significantly lower in percent yield and mDp than the other wines. Overall, the tannin structure and wine color of the lower pH wines (pH 3.2) bottled under Sx screw caps changed more rapidly with aging than those of the higher pH wines (pH 3.8) bottled under ST screw caps. PMID:24195587

  20. Electroplated Fe-Pt thick films prepared in plating baths with various pH values

    NASA Astrophysics Data System (ADS)

    Yanai, T.; Furutani, K.; Masaki, T.; Ohgai, T.; Nakano, M.; Fukunaga, H.

    2016-05-01

    Fe-Pt thick-films were electroplated on a Ta substrate using a direct current, and the effect of the pH value of the plating bath on the magnetic properties of the films was evaluated. For the films prepared from the baths with the same bath composition, the Fe composition and the thickness increased with increasing the pH value. In order to remove the effect of the change in the film composition on the magnetic properties, we controlled the film composition at approximately Fe50Pt50 or Fe60Pt40 by the change in the amount of the iron sulfate. The remanence of the annealed Fe60Pt40 films did not depend on the pH value clearly, and showed almost constant value of 0.75 T. We obtained the large coercivity of approximately 460 kA/m in the pH value from 4 to 7. Since the Fe52Pt48 film prepared at pH ≈ 4 shows much higher (BH)max value of 70 kJ/m3 than that of 57 kJ/m3 for our previously-reported Fe50Pt50 film (pH ≈ 2), we concluded that slight higher pH value than not-adjusted one (pH ≈ 2) is effective to increase the coercivity.

  1. Adsorption and degradation of the weak acid mesotrione in soil and environmental fate implications.

    PubMed

    Dyson, J S; Beulke, S; Brown, C D; Lane, M C G

    2002-01-01

    The ability of soils to adsorb and degrade pesticides strongly influences their environmental fate. This paper examines the adsorption and degradation of a weak acid, a new herbicide mesotrione 12-[4-(methylsulfonyl)-2-nitrobenzoyl]-1,3-cyclohexanedione], in 15 different soils from Europe and the USA. Experiments were conducted to understand the influence of soil properties, covering a wide range of soil textures, soil pH values (4.4 to 7.5), and organic carbon contents (0.6 to 3.35%). Mesotrione adsorption (Kd values ranged from 0.13 to 5.0 L/kg) was primarily related to soil pH, and to a lesser extent by percent organic carbon (%OC). As soil pH rose. mesotrione Kd values got smaller as mesotrione dissociated from the molecular to anionic form. Mesotrione degradation (half-lives ranged from 4.5 to 32 d) was also related to soil pH, getting shorter as soil pH rose. Simple regression of mesotrione adsorption against soil pH and %OC and against degradation provided a close fit to the data. The correlation between mesotrione adsorption and degradation means that Kd and half-life values are only relevant for use in environmental fate assessment if these values are "paired" for the same soil pH and %OC. The implications were as illustrated for leaching, raising important issues about combining pesticide adsorption and degradation behavior in environmental fate assessments. PMID:11931453

  2. Dependence of soil respiration on soil temperature and soil moisture in successional forests in Southern China

    USGS Publications Warehouse

    Tang, X.-L.; Zhou, G.-Y.; Liu, S.-G.; Zhang, D.-Q.; Liu, S.-Z.; Li, J.; Zhou, C.-Y.

    2006-01-01

    The spatial and temporal variations in soil respiration and its relationship with biophysical factors in forests near the Tropic of Cancer remain highly uncertain. To contribute towards an improvement of actual estimates, soil respiration rates, soil temperature, and soil moisture were measured in three successional subtropical forests at the Dinghushan Nature Reserve (DNR) in southern China from March 2003 to February 2005. The overall objective of the present study was to analyze the temporal variations of soil respiration and its biophysical dependence in these forests. The relationships between biophysical factors and soil respiration rates were compared in successional forests to test the hypothesis that these forests responded similarly to biophysical factors. The seasonality of soil respiration coincided with the seasonal climate pattern, with high respiration rates in the hot humid season (April-September) and with low rates in the cool dry season (October-March). Soil respiration measured at these forests showed a clear increasing trend with the progressive succession. Annual mean (?? SD) soil respiration rate in the DNR forests was (9.0 ?? 4.6) Mg CO2-C/hm2per year, ranging from (6.1 ?? 3.2) Mg CO2-C/hm2per year in early successional forests to (10.7 ?? 4.9) Mg CO2-C/hm2 per year in advanced successional forests. Soil respiration was correlated with both soil temperature and moisture. The T/M model, where the two biophysical variables are driving factors, accounted for 74%-82% of soil respiration variation in DNR forests. Temperature sensitivity decreased along progressive succession stages, suggesting that advanced-successional forests have a good ability to adjust to temperature. In contrast, moisture increased with progressive succession processes. This increase is caused, in part, by abundant respirators in advanced-successional forest, where more soil moisture is needed to maintain their activities. ?? 2006 Institute of Botany, Chinese Academy of

  3. SOIL TEMPERATURE AND SEWAGE SLUDGE EFFECTS ON PLANT AND SOIL PROPERTIES

    EPA Science Inventory

    A field experiment was conducted to determine the influence of soil temperature and sewage sludge on growth and composition of corn (Zea mays L.). Changes in soil organic matter, extractable metals, pH, bulb density, aggregation, fecal coliform, and fecal streptococcus were deter...

  4. SOIL PHYSICOCHEMICAL PARAMETERS AFFECTING METAL AVAILABILITY IN SLUDGE-AMENDED SOILS

    EPA Science Inventory

    A series of laboratory studies was conducted to determine the effects of soil pH and redox potential onlevels of trace metals (Cu, Zn, Cd, Pb, Cr, Ni, and As) in selected chemical forms and their availability to plants. This research demonstrates the important effects of soil red...

  5. Improving the global applicability of the RUSLE model - adjustment of the topographical and rainfall erosivity factors

    NASA Astrophysics Data System (ADS)

    Naipal, V.; Reick, C.; Pongratz, J.; Van Oost, K.

    2015-03-01

    Large uncertainties exist in estimated rates and the extent of soil erosion by surface runoff on a global scale, and this limits our understanding of the global impact that soil erosion might have on agriculture and climate. The Revised Universal Soil Loss Equation (RUSLE) model is due to its simple structure and empirical basis a frequently used tool in estimating average annual soil erosion rates at regional to global scales. However, large spatial scale applications often rely on coarse data input, which is not compatible with the local scale at which the model is parameterized. This study aimed at providing the first steps in improving the global applicability of the RUSLE model in order to derive more accurate global soil erosion rates. We adjusted the topographical and rainfall erosivity factors of the RUSLE model and compared the resulting soil erosion rates to extensive empirical databases on soil erosion from the USA and Europe. Adjusting the topographical factor required scaling of slope according to the fractal method, which resulted in improved topographical detail in a coarse resolution global digital elevation model. Applying the linear multiple regression method to adjust rainfall erosivity for various climate zones resulted in values that are in good comparison with high resolution erosivity data for different regions. However, this method needs to be extended to tropical climates, for which erosivity is biased due to the lack of high resolution erosivity data. After applying the adjusted and the unadjusted versions of the RUSLE model on a global scale we find that the adjusted RUSLE model not only shows a global higher mean soil erosion rate but also more variability in the soil erosion rates. Comparison to empirical datasets of the USA and Europe shows that the adjusted RUSLE model is able to decrease the very high erosion rates in hilly regions that are observed in the unadjusted RUSLE model results. Although there are still some regional

  6. Amelioration of acidic soil using various renewable waste resources.

    PubMed

    Moon, Deok Hyun; Chang, Yoon-Young; Ok, Yong Sik; Cheong, Kyung Hoon; Koutsospyros, Agamemnon; Park, Jeong-Hun

    2014-01-01

    In this study, improvement of acidic soil with respect to soil pH and exchangeable cations was attempted for sample with an initial pH of approximately 5. Acidic soil was amended with various waste resources in the range of 1 to 5 wt.% including waste oyster shells (WOS), calcined oyster shells (COS), Class C fly ash (FA), and cement kiln dust (CKD) to improve soil pH and exchangeable cations. Upon treatment, the soil pH was monitored for periods up to 3 months. The exchangeable cations were measured after 1 month of curing. After a curing period of 1 month, a maize growth experiment was conducted with selected-treated samples to evaluate the effectiveness of treatment. The treatment results indicate that in order to increase the soil pH to a value of 7, 1 wt.% of WOS, 3 wt.% of FA, and 1 wt.% of CKD are required. In the case of COS, 1 wt.% was more than enough to increase the soil pH value to 7 because of COS's strong alkalinity. Moreover, the soil pH increases after a curing period of 7 days and remains virtually unchanged thereafter up to 1 month of curing. Upon treatment, the summation of cations (Ca, Mg, K, and Na) significantly increased. The growth of maize is superior in the treated samples rather than the untreated one, indicating that the amelioration of acidic soil is beneficial to plant growth, since soil pH was improved and nutrients were replenished. PMID:24078235

  7. Sensitivity of soil organic matter in anthropogenically disturbed organic soils

    NASA Astrophysics Data System (ADS)

    Säurich, Annelie; Tiemeyer, Bärbel; Bechtold, Michel; Don, Axel; Freibauer, Annette

    2016-04-01

    Drained peatlands are hotspots of carbon dioxide (CO2) emissions from agriculture. However, the variability of CO2 emissions increases with disturbance, and little is known on the soil properties causing differences between seemingly similar sites. Furthermore the driving factors for carbon cycling are well studied for both genuine peat and mineral soil, but there is a lack of information concerning soils at the boundary between organic and mineral soils. Examples for such soils are both soils naturally relatively high in soil organic matter (SOM) such as Humic Gleysols and former peat soils with a relative low SOM content due to intensive mineralization or mixing with underlying or applied mineral soil. The study aims to identify drivers for the sensitivity of soil organic matter and therefore for respiration rates of anthropogenically disturbed organic soils, especially those near the boundary to mineral soils. Furthermore, we would like to answer the question whether there are any critical thresholds of soil organic carbon (SOC) concentrations beyond which the carbon-specific respiration rates change. The German agricultural soil inventory samples all agricultural soils in Germany in an 8x8 km² grid following standardized protocols. From this data and sample base, we selected 120 different soil samples from more than 80 sites. As reference sites, three anthropogenically undisturbed peatlands were sampled as well. We chose samples from the soil inventory a) 72 g kg-1 SOC and b) representing the whole range of basic soil properties: SOC (72 to 568 g kg-1), total nitrogen (2 to 29 g kg-1), C-N-ratio (10 to 80) bulk density (0.06 to 1.41 g/cm³), pH (2.5 to 7.4), sand (0 to 95 %) and clay (2 to 70 %) content (only determined for samples with less than 190 g kg-1 SOC) as well as the botanical origin of the peat (if determinable). Additionally, iron oxides were determined for all samples. All samples were sieved (2 mm) and incubated at standardized water content and

  8. Temperature effects on propylene glycol-contaminated soil cores

    SciTech Connect

    Davis-Hoover, W.J.; Vesper, S.J.

    1995-12-31

    The authors are examining the effect of temperature on the biodegradation of propylene glycol (PPG) in subsurface soil cores. Subsurface soils were contaminated in situ with PPG and allowed to diffuse into the soil for 30 days. The treated soil was reexposed, and intact were incubated for 30 days at temperatures ranging from 9 to 39 C in a temperature gradient incubator. At 30 days, soil moisture, soil pH, microbial activity [fluorescein diacetate (FDA) test], R2A plate counts, and plate counts of PPG degraders were studied. Although the soil moisture and pH remained relatively unchanged, the parameters of microbial activity varied rather consistently with temperature. Multiple populations or subpopulations of bacteria appear to exist between temperatures of 9 and 39 C in these soils.

  9. Soil experiment

    NASA Technical Reports Server (NTRS)

    Hutcheson, Linton; Butler, Todd; Smith, Mike; Cline, Charles; Scruggs, Steve; Zakhia, Nadim

    1987-01-01

    An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment.

  10. [Environmental Education Units.] Soil Sampling. Stream Profiles. Tree Watching. Plant Puzzles.

    ERIC Educational Resources Information Center

    Minneapolis Independent School District 275, Minn.

    Five of these eleven units describe methods elementary school students can use when studying soil characteristics. Soil nitrogen and water holding capacity tests are included with two techniques for measuring soil pH. Survey methods for soil organisms are suggested. The remaining pamphlets describe diverse activities associated with field…

  11. Relationships between soil properties and toxicity of copper and nickel to bok choy and tomato in Chinese soils.

    PubMed

    Li, Bo; Zhang, Hongtao; Ma, Yibing; McLaughlin, Mike J

    2013-10-01

    The toxicity of copper (Cu) and nickel (Ni) to bok choy and tomato shoot growth was investigated in a wide range of Chinese soils with and without leaching with artificial rainwater. The results showed that the variations of Ni toxicity induced by soil properties were wider than those of Cu toxicity to both tomato and bok choy plant growth. Leaching generally decreased the toxicity of Cu and Ni added to soils, which also depended on soils, metals, and test plant species. Soil factors controlling metal phytotoxicity were found to be soil pH and soil organic carbon content for Cu, and soil pH for Ni. It was also found that soil pH had stronger effects on Ni toxicity than on Cu toxicity. Predictive toxicity models based on these soil factors were developed. These toxicity models for Cu and Ni toxicity to tomato plant growth were validated using an independent data set for European soils. These models could be applied to predict the Cu and Ni phytotoxicity in not only Chinese soils but also European soils. PMID:23787779

  12. Influence of ph in the Uptake and Accumulation of Mineral Elements on Vine Leaf (Vitis vinifera L.) from Castilla-La Mancha (SPAIN.)

    NASA Astrophysics Data System (ADS)

    Bravo, Sandra; Amorós, José Angel; Pérez-de-los-Reyes, Caridad; García-Navarro, Francisco J.; Higueras, Pablo; Sanchez-Ormeño, Mónica

    2015-04-01

    Each soil-plant system has specific parameters on the uptake of different minerals in the soil, depending on several factors. One of these factors, perhaps the most important, is the pH. 101 Vineyard plots have been selected in Castilla-La Mancha (Spain) and have been analysed (pH among other parameters) by the methods described by FAO. Leaf samples have also been taken in each plot. We analysed the content of 25 mineral elements in both soil and leaf through FRX technique. In addition, we calculated the BAC (bioaccumulation coefficient, calculated as the ratio between the concentration of element in the plant and soil) to stablish if the soil pH influences the accumulation of mineral elements for the plant. As a result we have observed a different behavior of groups of elements for acids or alkaline soils. Thus, the alkaline elements (Na, K, Rb) have a higher BAC value in alkaline soils except cesium (Cs) that has a similar value; while the alkaline-earth elements (Ca, Mg, Sr) present lower BAC in alkaline soils except for barium (Ba) that shows similar value in both cases. Rare Earths (Y, La, Ce, Th and Nd) have very similar values in bioaccumulation for acidic and alkaline soils, while metals (Fe, Al, V, Cr, Co, Cu, Rb and Pb) show a higher bioaccumulation in alkaline soils. Instead Mn, Zn and Ga are preferently bioaccumulated in acid soils. The values obtained for the sulfur (S) are superior in acid soils. We conclude that certain mineral elements accumulate in the leaves of vines depending on the soil pH. The pH will influence the ionic form in which the element is present in the soil and plants preferentially uptake mineral elements in certain ionic forms.

  13. Improved granular activated carbon for the stabilization of wastewater pH

    SciTech Connect

    1996-10-01

    Many times the start up of granular activated carbon adsorption systems for the control of organic contaminants in wastewater cm exhibit unacceptable increases in the adscurber effluent pH. Experience shows that the duration of the pH increase ranges from several hours to several days, during which time several hundred bed volumes of water can be discharged with a pH in excess of 9. Laboratory studies have identified the cause of the pH rise as an interaction between the naturally occurring anions and protons ar the water and the carbon surface. The interaction can be described as an ion exchange type of phenomenon, in which the carbon surface sorbs the anions and corresponding hydronium ions from the water. Capacities of the carbon for the anions range from 2 to 9 mg/g GAC, depending upon the water characteristics, the carbon type, the nature of the anion and its influent concentration. These studies have shown de the anion sorption and resulting pH increase is independent of the raw material used for die activated carbon production, e.g. bituminous or sub-bituminous coal, peat, wood or coconut. Also, the pH excursions occur with virgin, reactivated, and acid washed granular carbons. Current pH control technologies focus on adjustment of wastewater pH prior to discharge or recycle of the initial effluent water until the pH increase abates. However, improved water pH control options have been realized by altering the carbon surface rather than the water chemistry. The change to the carbon surface is accomplished through a controlled oxidation process. This process provides a more acidic carbon surface with a reduced affinity for the anions in the waste water. As a result, the pH excursions above 9 are eliminated and the initial effluent from the adsorption system can be discharged without further treatment.

  14. Determination of baseline human nasal pH and the effect of intranasally administered buffers.

    PubMed

    Washington, N; Steele, R J; Jackson, S J; Bush, D; Mason, J; Gill, D A; Pitt, K; Rawlins, D A

    2000-04-01

    The nose is becoming a common route of drug administration, however, little is known about the pH of the human nasal cavity. Local pH may have a direct effect on the rate and extent of absorption of ionizable compounds and hence this study was performed to investigate normal pH values and whether pH could be manipulated by various buffers. Twelve healthy volunteers participated in a study to measure pH in the anterior and posterior sites of the nasal cavity. Miniature pH electrodes were placed 3 cm apart in the nasal cavity and a baseline was recorded for 30 min once the pH had stabilized. One hundred microlitres of isotonic solution was sprayed into the nostril and the pH was measured for 4 h post-dose. The following five formulations were tested: formulation A--sodium chloride (0.9%) at pH 7.2; formulation B--sodium chloride (0.9%) at pH 5.8; formulation C--Sorensens phosphate buffer (0.06 M) at pH 5. 8; formulation D--Sorensens phosphate buffer (0.13 M) at pH 5.8 and formulation E--formulation as (c) but adjusted to pH 5.0. Each formulation also contained saccharin sodium (0.5%) as a taste marker for nasal clearance. The time at which each subject detected the taste of saccharin was noted. The 30-minute baseline recording prior to administration of the nasal spray formulation demonstrates that there was both considerable intersubject and intrasubject variation in nasal pH. The average pH in the anterior of the nose was 6.40 (+0. 11, -0.15 S.D.) when calculated from H(+) values. The pH in the posterior of the nasal cavity was 6.27 (+0.13, -0.18 S.D.). The overall range in pH was 5.17-8.13 for anterior pH and 5.20-8.00 for posterior pH. Formulation A caused the pH in the anterior part of the nasal cavity to reach a maximum of 7.06 in 11.25 min from the baseline of pH 6.14 (P<0.05). The mean baseline pH was 6.5 for the posterior part of the nose which did not change over the recording period. Formulation B caused the anterior pH to increase from pH 6. 60 to 7

  15. Functional photoacoustic microscopy of pH

    NASA Astrophysics Data System (ADS)

    Chatni, M. Rameez; Yao, Junjie; Danielli, Amos; Favazza, Christopher P.; Maslov, Konstantin I.; Wang, Lihong V.

    2012-02-01

    pH is a tightly regulated indicator of metabolic activity. In mammalian systems, imbalance of pH regulation may result from or result in serious illness. Even though the regulation system of pH is very robust, tissue pH can be altered in many diseases such as cancer, osteoporosis and diabetes mellitus. Traditional high-resolution optical imaging techniques, such as confocal microscopy, routinely image pH in cells and tissues using pH sensitive fluorescent dyes, which change their fluorescence properties with the surrounding pH. Since strong optical scattering in biological tissue blurs images at greater depths, high-resolution pH imaging is limited to penetration depths of 1mm. Here, we report photoacoustic microscopy (PAM) of commercially available pH-sensitive fluorescent dye in tissue phantoms. Using both opticalresolution photoacoustic microscopy (OR-PAM), and acoustic resolution photoacoustic microscopy (AR-PAM), we explored the possibility of recovering the pH values in tissue phantoms. In this paper, we demonstrate that PAM was capable of recovering pH values up to a depth of 2 mm, greater than possible with other forms of optical microscopy.

  16. Inferences about radionuclide mobility in soils based on the solid/liquid partition coefficients and soil properties.

    PubMed

    Sohlenius, Gustav; Saetre, Peter; Nordén, Sara; Grolander, Sara; Sheppard, Steve

    2013-05-01

    To assist transport modeling in assessments of the radiological impact of a geological repository for radioactive wastes, the mobility of various elements was studied in arable and wetland soils in the Forsmark region, Sweden. Pore water and total element contents were determined for five types of unconsolidated deposits (regolith), spanning a wide range of soil properties with respect to pH and organic matter content. Two soil depths were sampled to capture element mobility in regolith layers affected and unaffected by soil-forming processes. The solid/liquid partition coefficients (K d values) for most elements varied significantly among regolith types. For most elements, the observed variations in K d values could be explained by variations in soil properties. For many elements, mobility increased with decreasing soil pH. The results provide a significant addition of data on radionuclide retention in soils, taking account of soil properties and processes. PMID:23619799

  17. BOREAS TE-1 SSA Soil Lab Data

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Knapp, David E. (Editor); Nerbas, Tim; Anderson, Darwin

    2000-01-01

    This data set was collected by TE-1 to provide a set of soil properties for BOREAS investigators in the SSA. The soil samples were collected at sets of soil pits in 1993 and 1994. Each set of soil pits was in the vicinity of one of the five flux towers in the BOREAS SSA. The collected soil samples were sent to a lab, where the major soil properties were determined. These properties include, but are not limited to, soil horizon; dry soil color; pH; bulk density; total, organic, and inorganic carbon; electric conductivity; cation exchange capacity; exchangeable sodium, potassium, calcium, magnesium, and hydrogen; water content at 0.01, 0.033, and 1.5 MPascals; nitrogen; phosphorus; particle size distribution; texture; pH of the mineral soil and of the organic soil; extractable acid; and sulfur. The data are stored in tabular ASCII text files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  18. Evaluation of soil quality indicators in paddy soils under different crop rotation systems

    NASA Astrophysics Data System (ADS)

    Nadimi-Goki, Mandana; Bini, Claudio; Haefele, Stephan; Abooei, Monireh

    2013-04-01

    Evaluation of soil quality indicators in paddy soils under different crop rotation systems Soil quality, by definition, reflects the capacity to sustain plant and animal productivity, maintain or enhance water and air quality, and promote plant and animal health. Soil quality assessment is an essential issue in soil management for agriculture and natural resource protection. This study was conducted to detect the effects of four crop rotation systems (rice-rice-rice, soya-rice-rice, fallow-rice and pea-soya-rice) on soil quality indicators (soil moisture, porosity, bulk density, water-filled pore space, pH, extractable P, CEC, OC, OM, microbial respiration, active carbon) in paddy soils of Verona area, Northern Italy. Four adjacent plots which managed almost similarly, over five years were selected. Surface soil samples were collected from each four rotation systems in four times, during growing season. Each soil sample was a composite of sub-samples taken from 3 points within 350 m2 of agricultural land. A total of 48 samples were air-dried and passed through 2mm sieve, for some chemical, biological, and physical measurements. Statistical analysis was done using SPSS. Statistical results revealed that frequency distribution of most data was normal. The lowest CV% was related to pH. Analysis of variance (ANOVA) and comparison test showed that there are significant differences in soil quality indicators among crop rotation systems and sampling times. Results of multivariable regression analysis revealed that soil respiration had positively correlation coefficient with soil organic matter, soil moisture and cation exchange capacity. Overall results indicated that the rice rotation with legumes such as bean and soybean improved soil quality over a long time in comparison to rice-fallow rotation, and this is reflected in rice yield. Keywords: Soil quality, Crop Rotation System, Paddy Soils, Italy

  19. Chemical Features of Soil: Advanced Crop and Soil Science. A Course of Study.

    ERIC Educational Resources Information Center

    Miller, Larry E.

    The course of study represents the fifth of six modules in advanced crop and soil science and introduces the agriculture student to chemical features of the soil. Upon completing the four day lesson, the student will be able to: (1) list macro- and micro-nutrients, (2) define pH and its effect on plants, (3) outline Cation Exchange of the soil,…

  20. Soil Science and Global Issues

    NASA Astrophysics Data System (ADS)

    Lal, Rattan

    2015-04-01

    Sustainable management of soil is integral to any rational approach to addressing global issues of the 21st century. A high quality soil is essential to: i) advancing food and nutritional security, ii) mitigating and adapting to climate change, iii) improving quality and renewability of water, iv) enriching biodiversity, v) producing biofuel feedstocks for reducing dependence on fossil fuel, and vi) providing cultural, aesthetical and recreational opportunities. Being the essence of all terrestrial life, soil functions and ecosystem services are essential to wellbeing of all species of plants and animals. Yet, soil resources are finite, unequally distributed geographically, and vulnerable to degradation by natural and anthropogenic perturbations. Nonetheless, soil has inherent resilience, and its ecosystem functions and services can be restored over time. However, soil resilience depends on several key soil properties including soil organic carbon (SOC) concentration and pool, plant-available water capacity (PWAC), nutrient reserves, effective rooting depth, texture and clay mineralogy, pH, cation exchange capacity (CEC) etc. There is a close inter-dependence among these properties. For example, SOC concentration strongly affects, PWAC, nutrient reserve, activity and species diversity of soil flora and fauna, CEC etc. Thus, judicious management of SOC concentration to maintain it above the threshold level (~1.5-2%) in the root zone is critical to sustaining essential functions and ecosystem services. Yet, soils of some agroecosystems (e.g., those managed by resources-poor farmers and small landholders in the tropics and sub-tropics) are severely depleted of their SOC reserves. Consequently. Agronomic productivity and wellbeing of people dependent on degraded soils is jeopardized. The ecosystem C pool of the terrestrial biosphere has been mined by extractive practices, the nature demands recarbonization of its biosphere for maintenance of its functions and

  1. Suppression of N2O and NO from denitrification by biochar: the role of pH

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Denitrification reduces NO3- to N2 and returns excess nitrogen to the atmosphere. NO and N2O are gaseous intermediates of denitrification which, once escaped to the atmosphere, have adverse effects on chemistry and radiative forcing in the atmosphere. We studied the effect of biochar on denitrification and its gaseous intermediates in two acidic soils and tried to distinguish between the alkalizing effect of biochars on soil pH, and other, unknown effects of biochar on denitrification. Anoxic soil slurries were incubated with untreated biochars or biochars from which part of the alkalinity had been removed by water- and acid leaching. Soils amended with NaOH and uncharred cacao shell were used as controls. Biochar addition stimulated overall denitrification depending on biochar and soil type. This stimulation was not strictly coupled to pH increase, suggesting that biochar fueled respiration processes by contributing microbially available C. High resolution gas kinetics of NO, N2O and N2 showed that biochar amended soils induced denitrification enzymes earlier and with higher activity, resulting in less NO and N2O accumulation relative to N2 production. The extent to which biochar suppressed NO and N2O was dose-dependent and clearly related to the effective pH increase during incubation. Acid leaching of BC reduced or eliminated its ability to suppress N2O and NO net production. Comparison of BC with NaOH-amended soils showed that the reduction of N2O and NO net production was mainly an effect of increase in soil pH. Even though other factors supporting N2O reductase activity could not be excluded, our results indicate that soil pH increase might be an important driver behind the often-reported suppression of N2O emissions after biochar addition.

  2. Fertilization with liquid digestate in organic farming - effects on humus balance, soil potassium contents and soil physical properties

    NASA Astrophysics Data System (ADS)

    Erhart, Eva; Siegl, Thomas; Bonell, Marion; Unterfrauner, Hans; Peticzka, Robert; Ableidinger, Christoph; Haas, Dieter; Hartl, Wilfried

    2014-05-01

    Biogas production and use of liquid digestate are subject of controversial discussion in organic farming. Using biomass from intercrops as feedstock for biogas production makes it possible to produce renewable energy without compromising food production. With liquid digestate, crops can be fertilized in a more targeted way than by incorporating intercrop biomass into the soil. For long-term sustainability in organic farming, however, this practice must not have adverse effects on soil fertility. In order to assess the effects of fertilization with liquid digestate on soil fertility, two randomised field experiments were conducted for two years on different soil types near Bruck/Leitha (Lower Austria). One experiment was set up on a calcareous chernozem with 4 % humus content, the other on a parachernozem with pH 5.9 and 2.1 % humus. Soil potassium content, both in the water-soluble fraction and in the exchangeable fraction, increased significantly at both sites. As fertilization with liquid digestate exceeded the potassium requirements of the crops by far, the proportion of potassium of the exchangeable cations increased rapidly. Soil physical properties were not influenced by digestate fertilization on the chernozem site. On the parachernozem, aggregate stability was increased by the organic matter applied via digestate. On this acidic site low in humus content, the supply of 4 t/ha organic matter, which featured a lignin content of 37 % and was relatively resistant to decomposition, had a clearly positive impact on soil physical properties. Humus balances were computed both with the 'Humuseinheiten'-method and with the site-adapted method STAND. They were calculated on the basis of equal amounts of intercrop biomass either left on the field as green manure or used for biogas production and the resulting amount of liquid digestate brought back to the field. The humus balances indicated that the humus-efficacy of the liquid digestate was equal to slightly higher

  3. Effect of pH on fecal recovery of energy derived from volatile fatty acids.

    PubMed

    Kien, C L; Liechty, E A

    1987-01-01

    We assessed the effect of pH on volatilization of short-chain fatty acids during lyophilization. Acetic, propionic, valeric, and butyric acids were added to a fecal homogenate in amounts sufficient to raise the energy density by 18-27%. Fecal homogenate samples were either acidified (pH 2.8-3.2), alkalinized (pH 7.9-8.7), or left unchanged (4.0-4.8) prior to lyophilization and subsequent bomb calorimetry. Alkalinizing the fecal samples prevented the 20% loss of energy derived from each of these volatile fatty acids observed in samples either acidified or without pH adjustment. These data suggest that in energy balance studies involving subjects with active colonic fermentation, fecal samples should be alkalinized prior to lyophilization and bomb calorimetry. PMID:3681570

  4. Zinc movement in sewage-sludge-treated soils as influenced by soil properties, irrigation water quality, and soil moisture level

    USGS Publications Warehouse

    Welch, J.E.; Lund, L.J.

    1989-01-01

    A soil column study was conducted to assess the movement of Zn in sewage-sludge-amended soils. Varables investigated were soil properties, irrigation water quality, and soil moisture level. Bulk samples of the surface layer of six soil series were packed into columns, 10.2 cm in diameter and 110 cm in length. An anaerobically digested municipal sewage sludge was incorporated into the top 20 cm of each column at a rate of 300 mg ha-1. The columns were maintained at moisture levels of saturation and unsaturation and were leached with two waters of different quality. At the termination of leaching, the columns were cut open and the soil was sectioned and analyzed. Zinc movement was evaluated by mass balance accounting and correlation and regression analysis. Zinc movement in the unsaturated columns ranged from 3 to 30 cm, with a mean of 10 cm. The difference in irrigation water quality did not have an effect on Zn movement. Most of the Zn applied to the unsaturated columns remained in the sludge-amended soil layer (96.1 to 99.6%, with a mean of 98.1%). The major portion of Zn leached from the sludge-amended soil layer accumulated in the 0- to 3-cm depth (35.7 to 100%, with a mean of 73.6%). The mean final soil pH values decreased in the order: saturated columns = sludge-amended soil layer > untreated soils > unsaturated columns. Total Zn leached from the sludge-amended soil layer was correlated negatively at P = 0.001 with final pH (r = -0.85). Depth of Zn movement was correlated negatively at P = 0.001 with final pH (r = -0.91). Multiple linear regression analysis showed that the final pH accounted for 72% of the variation in the total amounts of Zn leached from the sludge-amended soil layer of the unsaturated columns and accounted for 82% of the variation in the depth of Zn movement among the unsaturated columns. A significant correlation was not found between Zn and organic carbon in soil solutions, but a negative correlation significant at P = 0.001 was found

  5. Wetland treatment at extremes of pH: a review.

    PubMed

    Mayes, W M; Batty, L C; Younger, P L; Jarvis, A P; Kõiv, M; Vohla, C; Mander, U

    2009-06-15

    Constructed wetlands are an established treatment technology for a diverse range of polluted effluents. There is a long history of using wetlands as a unit process in treating acid mine drainage, while recent research has highlighted the potential for wetlands to buffer highly alkaline (pH>12) drainage. This paper reviews recent evidence on this topic, looking at wetlands treating acidic mine drainage, and highly alkaline leachates associated with drainage from lime-rich industrial by-products or where such residues are used as filter media in constructed wetlands for wastewater treatment. The limiting factors to the success of wetlands treating highly acidic waters are discussed with regard to design practice for the emerging application of wetlands to treat highly alkaline industrial discharges. While empirically derived guidelines (with area-adjusted contaminant removal rates typically quoted at 10 g Fe m(2)/day for influent waters pH>5.5; and 3.5-7 g acidity/m(2)/day for pH>4 to <5.5) for informing sizing of mine drainage treatment wetlands have generally been proved robust (probably due to conservatism), such data exhibit large variability within and between sites. Key areas highlighted for future research efforts include: (1) wider collation of mine drainage wetland performance data in regionalised datasets to improve empirically-derived design guidelines and (2) obtaining an improved understanding of nature of the extremophile microbial communities, microbially-mediated pollutant attenuation and rhizospheral processes in wetlands at extremes of pH. An enhanced knowledge of these (through multi-scale laboratory and field studies), will inform engineering design of treatment wetlands and assist in the move from the empirically-derived conservative sizing estimates that currently prevail to process-based optimal design guidance that could reduce costs and enhance the performance and longevity of wetlands for treating acidic and highly alkaline drainage waters

  6. Exploration adjustment by ant colonies

    PubMed Central

    2016-01-01

    How do animals in groups organize their work? Division of labour, i.e. the process by which individuals within a group choose which tasks to perform, has been extensively studied in social insects. Variability among individuals within a colony seems to underpin both the decision over which tasks to perform and the amount of effort to invest in a task. Studies have focused mainly on discrete tasks, i.e. tasks with a recognizable end. Here, we study the distribution of effort in nest seeking, in the absence of new nest sites. Hence, this task is open-ended and individuals have to decide when to stop searching, even though the task has not been completed. We show that collective search effort declines when colonies inhabit better homes, as a consequence of a reduction in the number of bouts (exploratory events). Furthermore, we show an increase in bout exploration time and a decrease in bout instantaneous speed for colonies inhabiting better homes. The effect of treatment on bout effort is very small; however, we suggest that the organization of work performed within nest searching is achieved both by a process of self-selection of the most hard-working ants and individual effort adjustment. PMID:26909180

  7. Exploration adjustment by ant colonies.

    PubMed

    Doran, Carolina; Stumpe, Martin C; Sendova-Franks, Ana; Franks, Nigel R

    2016-01-01

    How do animals in groups organize their work? Division of labour, i.e. the process by which individuals within a group choose which tasks to perform, has been extensively studied in social insects. Variability among individuals within a colony seems to underpin both the decision over which tasks to perform and the amount of effort to invest in a task. Studies have focused mainly on discrete tasks, i.e. tasks with a recognizable end. Here, we study the distribution of effort in nest seeking, in the absence of new nest sites. Hence, this task is open-ended and individuals have to decide when to stop searching, even though the task has not been completed. We show that collective search effort declines when colonies inhabit better homes, as a consequence of a reduction in the number of bouts (exploratory events). Furthermore, we show an increase in bout exploration time and a decrease in bout instantaneous speed for colonies inhabiting better homes. The effect of treatment on bout effort is very small; however, we suggest that the organization of work performed within nest searching is achieved both by a process of self-selection of the most hard-working ants and individual effort adjustment. PMID:26909180

  8. Distribution and interactions of pentachlorophenol in soils: The roles of soil iron oxides and organic matter.

    PubMed

    Diagboya, Paul N; Olu-Owolabi, Bamidele I; Adebowale, Kayode O

    2016-08-01

    Soil iron oxides (IOs) and organic matter (OM) play varying roles in pentachlorophenol (PCP) retention and mobility, but the extent and mechanism are still unknown. Therefore, in order to have a better understanding of the adsorption of PCP on soils, batch sorption studies were carried out on whole soils and soils selectively treated to remove IOs (IOR) and OM (OMR). The effects of pH, time, and temperature were investigated. Results showed that PCP sorption was temperature and pH dependent; sorption decreased as both temperature and pH increased. Sorption was partly surface adsorption and partly partitioning within voids of IOs components as revealed by the kinetics models. The surface adsorption was multi-layer in nature. Equilibria were faster in the IOR soils than the untreated and OMR soils. IOs played greater roles in PCP sorption than OM. Removal of soil components, especially the IOs, as experienced in soils plagued by soil erosion, may lead to increased risks of PCP pollution of environmental media especially the aquifer. PMID:27344260

  9. Distribution and interactions of pentachlorophenol in soils: The roles of soil iron oxides and organic matter

    NASA Astrophysics Data System (ADS)

    Diagboya, Paul N.; Olu-Owolabi, Bamidele I.; Adebowale, Kayode O.

    2016-08-01

    Soil iron oxides (IOs) and organic matter (OM) play varying roles in pentachlorophenol (PCP) retention and mobility, but the extent and mechanism are still unknown. Therefore, in order to have a better understanding of the adsorption of PCP on soils, batch sorption studies were carried out on whole soils and soils selectively treated to remove IOs (IOR) and OM (OMR). The effects of pH, time, and temperature were investigated. Results showed that PCP sorption was temperature and pH dependent; sorption decreased as both temperature and pH increased. Sorption was partly surface adsorption and partly partitioning within voids of IOs components as revealed by the kinetics models. The surface adsorption was multi-layer in nature. Equilibria were faster in the IOR soils than the untreated and OMR soils. IOs played greater roles in PCP sorption than OM. Removal of soil components, especially the IOs, as experienced in soils plagued by soil erosion, may lead to increased risks of PCP pollution of environmental media especially the aquifer.

  10. Streptococcus suis sorption on agricultural soils: role of soil physico-chemical properties.

    PubMed

    Zhao, Wenqiang; Liu, Xing; Huang, Qiaoyun; Cai, Peng

    2015-01-01

    Understanding pathogen sorption on natural soil particles is crucial to protect public health from soilborne and waterborne diseases. Sorption of pathogen Streptococcus suis on 10 agricultural soils was examined, and its correlations with soil physico-chemical properties were also elucidated. S. suis sorption isotherms conformed to the linear equation, with partition coefficients (Ks) ranging from 12.7 mL g(-1) to 100.1 mL g(-1). Bacteria were observed to sorb on the external surfaces of soil aggregates by scanning electron microscopy. Using Pearson correlation and linear regression analysis, solution pH was found to have significant negative correlations with Ks. Stepwise multiple regression and path analysis revealed that pH and cation exchange capacity (CEC) were the main factors influencing sorption behaviors. The obtained overall model (Ks=389.6-45.9×pH-1.3×CEC, R(2)=0.943, P<0.001) can accurately predict Ks values. However, the variability in Ks was less dependent on soil organic matter, specific surface area, soil texture and zeta potential, probably due to the internal-surface shielding phenomenon of soil aggregates. Additionally, the sorption trends cannot be interpreted by interaction energy barriers calculated using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, suggesting the limits of DLVO theory in describing pathogen sorption on natural soils. Our results also indicated soil pH and CEC should be preferentially considered when modeling S. suis sorption process. PMID:24968305

  11. Effects of Ph gene-associated versus induced resistance to tobacco cyst nematode in flue-cured tobacco.

    PubMed

    Parkunan, Venkatesan; Johnson, Charles S; Eisenback, Jon D

    2009-12-01

    Effects of the systemic acquired resistance (SAR)-inducing compound acibenzolar-S-methyl (ASM) and the plant-growth promoting rhizobacterial mixture Bacillus subtilis A13 and B. amyloliquefaciens IN937a (GB99+GB122) were assessed on the reproduction of a tobacco cyst nematode (TCN- Globodera tabacum solanacearum) under greenhouse conditions. Two sets of two independent experiments were conducted, each involving soil or root sampling. Soil sample experiments included flue-cured tobacco cultivars with (Ph(p)+: NC71 and NC102) and without (Ph(p)-: K326 and K346) a gene (Ph(p)) suppressing TCN parasitism. Root sample experiments examined TCN root parasitism of NC71 and K326. Cultivars possessing the Ph(p) gene (Ph(p)+) were compared with Ph(p)- cultivars to assess the effects of resistance mediated via Ph(p) gene vs. induced resistance to TCN. GB99+GB122 consistently reduced nematode reproductive ratio on both Ph(p)+ and Ph(p)- cultivars, but similar effects of ASM across Ph(p)- cultivars were less consistent. In addition, ASM application resulted in leaf yellowing and reduced root weight. GB99+GB122 consistently reduced nematode development in roots of both Ph(p)+ and Ph(p)- cultivars, while similar effects of ASM were frequently less consistent. The results of this study indicate that GB99+GB122 consistently reduced TCN reproduction in all flue-cured tobacco cultivars tested, while the effects of ASM were only consistent in Ph(p)+ cultivars. Under most circumstances, GB99+GB122 suppressed nematode reproduction more consistently than ASM compared to the untreated control. PMID:22736824

  12. Effects of suspension pH and mineral dissolution on carbon dioxide hydrate formation

    NASA Astrophysics Data System (ADS)

    Lee, W.; Lamorena, R. B.

    2008-12-01

    CO2 sequestration as a form of hydrate into geological formations could be significantly affected by soil mineral heterogeneity potentially contributing to the stochastic behavior of hydrate formation. In this study, we controlled the pH of soil mineral suspensions (Na-montmorillonite, kaolinite mixture, and pyrite) by the addition of 2M/10M NaOH and 2M/10M HCl before the dissolution of CO2. The soil mineral suspensions were prepared in deionized water (DIW) and NaCl (3.5 %) solutions. The formation of mass of CO2 hydrates was observed in most of the soil mineral suspensions at 30 bar and 0.3°C. In montmorillonite and kaolinite mixture suspensions with and without NaCl near neutral (pH 6~8) suspension pHs can provide the fastest hydrate formation kinetics followed by basic (~pH 12.0) and acidic (pH 2.0) suspension pHs. Acidic suspension pH gives the fastest kinetics in pyrite suspensions without NaCl followed by neutral and basic pHs, while no hydrate formations were observed in basic and near neutral pyrite suspensions with NaCl. The experimental results suggest that different types of soil mineral structures and chemical species can form under different suspension pHs, significantly affecting the hydrate formation time. Chemical species (e.g. Al+3) that could potentially affect hydrate formation times were identified by a chemical equilibrium modeling software, PHREEQC. The results obtained from this research could provide promising avenues for hydrate formation mechanism studies.

  13. pH Sensitive Microcapsules for Delivery of Corrosion Inhibitors

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Calle, Luz M.

    2006-01-01

    A considerable number of corrosion problems can be solved by coatings. However, even the best protective coatings can fail by allowing the slow diffusion of oxygen and moisture to the metal surface. Corrosion accelerates when a coating delaminates. Often, the problems start when microscopic nicks or pits on the surface develop during manufacturing or through wear and tear. This problem can be solved by the incorporation of a self-healing function into the coating. Several new concepts are currently under development to incorporate this function into a coating. Conductive polymers, nanoparticles, and microcapsules are used to release corrosion-inhibiting ions at a defect site. The objective of this investigation is to develop a smart coating for the early detection and inhibition of corrosion. The dual function of this new smart coating system is performed by pH-triggered release microcapsules. The microcapsules can be used to deliver healing agents to terminate the corrosion process at its early stage or as corrosion indicators by releasing dyes at the localized corrosion sites. The dyes can be color dyes or fluorescent dyes, with or without pH sensitivity. Microcapsules were formed through the interfacial polymerization process. The average size of the microcapsules can be adjusted from 1 to 100 micron by adjusting the emulsion formula and the microcapsule forming conditions. A typical microcapsule size is around 10 microns with a narrow size distribution. The pH sensitivity of the microcapsule can also be controlled by adjusting the emulsion formula and the polymerization reaction time. Both corrosion indicator (pH indicator) and corrosion inhibitor containing microcapsules were formed and incorporated into paint systems. Test panels of selected steels and aluminum alloys were painted using these paints. Testing of compatibility between the microcapsule system and different paint systems are in progress. Initial experiments with the microcapsule containing paint

  14. Effects of pH and magnetic material on immunomagnetic separation of Cryptosporidium oocysts from concentrated water samples.

    PubMed

    Kuhn, Ryan C; Rock, Channah M; Oshima, Kevin H

    2002-04-01

    In this study, we examined the effect that magnetic materials and pH have on the recoveries of Cryptosporidium oocysts by immunomagnetic separation (IMS). We determined that particles that were concentrated on a magnet during bead separation have no influence on oocyst recovery; however, removal of these particles did influence pH values. The optimal pH of the IMS was determined to be 7.0. The numbers of oocysts recovered from deionized water at pH 7.0 were 26.3% higher than those recovered from samples that were not at optimal pH. The results indicate that the buffers in the IMS kit did not adequately maintain an optimum pH in some water samples. By adjusting the pH of concentrated environmental water samples to 7.0, recoveries of oocysts increased by 26.4% compared to recoveries from samples where the pH was not adjusted. PMID:11916735

  15. Effects of pH and Magnetic Material on Immunomagnetic Separation of Cryptosporidium Oocysts from Concentrated Water Samples

    PubMed Central

    Kuhn, Ryan C.; Rock, Channah M.; Oshima, Kevin H.

    2002-01-01

    In this study, we examined the effect that magnetic materials and pH have on the recoveries of Cryptosporidium oocysts by immunomagnetic separation (IMS). We determined that particles that were concentrated on a magnet during bead separation have no influence on oocyst recovery; however, removal of these particles did influence pH values. The optimal pH of the IMS was determined to be 7.0. The numbers of oocysts recovered from deionized water at pH 7.0 were 26.3% higher than those recovered from samples that were not at optimal pH. The results indicate that the buffers in the IMS kit did not adequately maintain an optimum pH in some water samples. By adjusting the pH of concentrated environmental water samples to 7.0, recoveries of oocysts increased by 26.4% compared to recoveries from samples where the pH was not adjusted. PMID:11916735

  16. Microbial communities play important roles in modulating paddy soil fertility

    NASA Astrophysics Data System (ADS)

    Luo, Xuesong; Fu, Xiaoqian; Yang, Yun; Cai, Peng; Peng, Shaobing; Chen, Wenli; Huang, Qiaoyun

    2016-02-01

    We studied microbial communities in two paddy soils, which did not receive nitrogen fertilization and were distinguished by the soil properties. The two microbial communities differed in the relative abundance of gram-negative bacteria and total microbial biomass. Variability in microbial communities between the two fields was related to the levels of phosphorus and soil moisture. Redundancy analysis for individual soils showed that the bacterial community dynamics in the high-yield soil were significantly correlated with total carbon, moisture, available potassium, and pH, and those in the low-yield cores were shaped by pH, and nitrogen factors. Biolog Eco-plate data showed a more active microbial community in the high yield soil. The variations of enzymatic activities in the two soils were significantly explained by total nitrogen, total potassium, and moisture. The enzymatic variability in the low-yield soil was significantly explained by potassium, available nitrogen, pH, and total carbon, and that in the high-yield soil was partially explained by potassium and moisture. We found the relative abundances of Gram-negative bacteria and Actinomycetes partially explained the spatial and temporal variations of soil enzymatic activities, respectively. The high-yield soil microbes are probably more active to modulate soil fertility for rice production.

  17. Microbial communities play important roles in modulating paddy soil fertility

    PubMed Central

    Luo, Xuesong; Fu, Xiaoqian; Yang, Yun; Cai, Peng; Peng, Shaobing; Chen, Wenli; Huang, Qiaoyun

    2016-01-01

    We studied microbial communities in two paddy soils, which did not receive nitrogen fertilization and were distinguished by the soil properties. The two microbial communities differed in the relative abundance of gram-negative bacteria and total microbial biomass. Variability in microbial communities between the two fields was related to the levels of phosphorus and soil moisture. Redundancy analysis for individual soils showed that the bacterial community dynamics in the high-yield soil were significantly correlated with total carbon, moisture, available potassium, and pH, and those in the low-yield cores were shaped by pH, and nitrogen factors. Biolog Eco-plate data showed a more active microbial community in the high yield soil. The variations of enzymatic activities in the two soils were significantly explained by total nitrogen, total potassium, and moisture. The enzymatic variability in the low-yield soil was significantly explained by potassium, available nitrogen, pH, and total carbon, and that in the high-yield soil was partially explained by potassium and moisture. We found the relative abundances of Gram-negative bacteria and Actinomycetes partially explained the spatial and temporal variations of soil enzymatic activities, respectively. The high-yield soil microbes are probably more active to modulate soil fertility for rice production. PMID:26841839

  18. Spatial Variability of the Topsoil Organic Carbon in the Moso Bamboo Forests of Southern China in Association with Soil Properties

    PubMed Central

    Zhang, Houxi; Zhuang, Shunyao; Qian, Haiyan; Wang, Feng; Ji, Haibao

    2015-01-01

    Understanding the spatial variability of soil organic carbon (SOC) must be enhanced to improve sampling design and to develop soil management strategies in terrestrial ecosystems. Moso bamboo (Phyllostachys pubescens Mazel ex Houz.) forests have a high SOC storage potential; however, they also vary significantly spatially. This study investigated the spatial variability of SOC (0-20 cm) in association with other soil properties and with spatial variables in the Moso bamboo forests of Jian’ou City, which is a typical bamboo hometown in China. 209 soil samples were collected from Moso bamboo stands and then analyzed for SOC, bulk density (BD), pH, cation exchange capacity (CEC), and gravel content (GC) based on spatial distribution. The spatial variability of SOC was then examined using geostatistics. A Kriging map was produced through ordinary interpolation and required sample numbers were calculated by classical and Kriging methods. An aggregated boosted tree (ABT) analysis was also conducted. A semivariogram analysis indicated that ln(SOC) was best fitted with an exponential model and that it exhibited moderate spatial dependence, with a nugget/sill ratio of 0.462. SOC was significantly and linearly correlated with BD (r = −0.373**), pH (r = −0.429**), GC (r = −0.163*), CEC (r = 0.263**), and elevation (r = 0.192**). Moreover, the Kriging method requires fewer samples than the classical method given an expected standard error level as per a variance analysis. ABT analysis indicated that the physicochemical variables of soil affected SOC variation more significantly than spatial variables did, thus suggesting that the SOC in Moso bamboo forests can be strongly influenced by management practices. Thus, this study provides valuable information in relation to sampling strategy and insight into the potential of adjustments in agronomic measure, such as in fertilization for Moso bamboo production. PMID:25789615

  19. Spatial variability of the topsoil organic carbon in the Moso bamboo forests of southern China in association with soil properties.

    PubMed

    Zhang, Houxi; Zhuang, Shunyao; Qian, Haiyan; Wang, Feng; Ji, Haibao

    2015-01-01

    Understanding the spatial variability of soil organic carbon (SOC) must be enhanced to improve sampling design and to develop soil management strategies in terrestrial ecosystems. Moso bamboo (Phyllostachys pubescens Mazel ex Houz.) forests have a high SOC storage potential; however, they also vary significantly spatially. This study investigated the spatial variability of SOC (0-20 cm) in association with other soil properties and with spatial variables in the Moso bamboo forests of Jian'ou City, which is a typical bamboo hometown in China. 209 soil samples were collected from Moso bamboo stands and then analyzed for SOC, bulk density (BD), pH, cation exchange capacity (CEC), and gravel content (GC) based on spatial distribution. The spatial variability of SOC was then examined using geostatistics. A Kriging map was produced through ordinary interpolation and required sample numbers were calculated by classical and Kriging methods. An aggregated boosted tree (ABT) analysis was also conducted. A semivariogram analysis indicated that ln(SOC) was best fitted with an exponential model and that it exhibited moderate spatial dependence, with a nugget/sill ratio of 0.462. SOC was significantly and linearly correlated with BD (r = -0.373**), pH (r = -0.429**), GC (r = -0.163*), CEC (r = 0.263**), and elevation (r = 0.192**). Moreover, the Kriging method requires fewer samples than the classical method given an expected standard error level as per a variance analysis. ABT analysis indicated that the physicochemical variables of soil affected SOC variation more significantly than spatial variables did, thus suggesting that the SOC in Moso bamboo forests can be strongly influenced by management practices. Thus, this study provides valuable information in relation to sampling strategy and insight into the potential of adjustments in agronomic measure, such as in fertilization for Moso bamboo production. PMID:25789615

  20. Communicating soil property variability in heterogeneous soil mapping units

    NASA Astrophysics Data System (ADS)

    Farewell, Timothy

    2014-05-01

    Soil properties and classes can change over very short distances. For the purpose of scale, clarity and field sampling density, soil maps in England and Wales commonly use mapping units which are groupings of taxonomic soil series, commonly found in association with each other in the landscape. These mixed units (Soil Associations), typically contain between 3 and 7 soil series with physical or chemical properties, which can vary across the mapping unit, or may be relatively homogeneous. The degree of variation is not constant between soil properties, for instance, pH may be relatively constant, but volumetric shrinkage potential may be highly variable. Over the past ten years, the number of users of GIS soil property maps has dramatically increased, yet the vast majority of these users do not have a soil or geoscience background. They are instead practitioners in specific industries. As a result, new techniques have been developed to communicate the variation in maps of soil properties to a non-expert audience. GIS data structures allow more flexibility in the reporting of uncertainty or variation in soil mapping units than paper-based maps. Some properties are categorical, others continuous. In England and Wales, the national and regional memberships of soil associations are available, with areal percentages of the comprising soil series being estimated for each association by a combination of expert judgment and field observations. Membership at a local scale can vary considerably from the national average. When summarizing across a whole map unit, for continuous variables, rarely is it appropriate to provide a mean value, or even a weighted average based on membership percentage of the association. Such approaches can make a nonsense of wide-ranging data. For instance a soil association comprising soil series with highly different percentages of sand, silt and clay may result in a 'loamy' mean soil texture which is not reflective of any of the comprising soils

  1. pH Meter probe assembly

    DOEpatents

    Hale, Charles J.

    1983-01-01

    An assembly for mounting a pH probe in a flowing solution, such as a sanitary sewer line, which prevents the sensitive glass portion of the probe from becoming coated with grease, oil, and other contaminants, whereby the probe gives reliable pH indication over an extended period of time. The pH probe assembly utilizes a special filter media and a timed back-rinse feature for flushing clear surface contaminants of the filter. The flushing liquid is of a known pH and is utilized to check performance of the probe.

  2. pH Meter probe assembly

    DOEpatents

    Hale, C.J.

    1983-11-15

    An assembly for mounting a pH probe in a flowing solution, such as a sanitary sewer line, which prevents the sensitive glass portion of the probe from becoming coated with grease, oil, and other contaminants, whereby the probe gives reliable pH indication over an extended period of time. The pH probe assembly utilizes a special filter media and a timed back-rinse feature for flushing clear surface contaminants of the filter. The flushing liquid is of a known pH and is utilized to check performance of the probe. 1 fig.

  3. Soil penetrometer

    NASA Technical Reports Server (NTRS)

    Howard, E. A.; Hotz, G. M.; Bryson, R. P. (Inventor)

    1968-01-01

    An auger-type soil penetrometer for burrowing into soil formations is described. The auger, while initially moving along a predetermined path, may deviate from the path when encountering an obstruction in the soil. Alterations and modifications may be made in the structure so that it may be used for other purposes.

  4. Ergonomic evaluation of the Apple Adjustable Keyboard

    SciTech Connect

    Tittiranonda, P.; Burastero, S.; Shih, M.; Rempel, D.

    1994-05-01

    This study presents an evaluation of the Apple Adjustable Keyboard based on subjective preference and observed joint angles during typing. Thirty five keyboard users were asked to use the Apple adjustable keyboard for 7--14 days and rate the various characteristics of the keyboard. Our findings suggest that the most preferred opening angles range from 11--20{degree}. The mean ulnar deviation on the Apple Adjustable keyboard is 11{degree}, compared to 16{degree} on the standard keyboard. The mean extension was decreased from 24{degree} to 16{degree} when using the adjustable keyboard. When asked to subjectively rate the adjustable keyboard in comparison to the standard, the average subject felt that the Apple Adjustable Keyboard was more comfortable and easier to use than the standard flat keyboard.

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

    PubMed Central

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

    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., <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 not merely

  6. [Effect of different soil types on the remediation of copper-pyrene compound contaminated soils by EK-oxidation process].

    PubMed

    Fan, Guang-Ping; Cang, Long; Zhou, Dong-Mei; Zhou, Li-Xiang

    2011-11-01

    The effect of different soil types (red soil,yellow-brown soil and black soil) on the electrokinetic (EK)-oxidation remediation of heavy metals-organic pollutant contaminated soil was studied in laboratory-scale experiments. Copper and pyrene were chosen as model pollutant, and 12% H2O2, 10% hydroxypropyl-beta-cyclodextrin and 0.01 mol x L(-1) NaNO3 solution were added into the anode and cathode cell. The applied voltage was 1 V x cm(-1). After 15 days of EK remediation, the removal rate of pyrene and copper in red soil, yellow-brown soil and black soil were 38.5%, 46.8%, 51.3% for pyrene and 85.0%, 22.6%, 24.1% for Cu, respectively. The high pH of black soil produced high electroosmotic flow and increased the exposure of oxidants and pollutants, meanwhile the low clay content was also conducive to the desorption of pyrene. The low pH and organic matter of red soil affected the chemical species distribution of Cu and increased its removal rate. It is concluded that soil pH, clay content and heavy metal speciation in soil are the dominant factors affecting the migration and removal efficiency of pollutants. PMID:22295647

  7. Autoinducer-2 detection among commensal oral streptococci is dependent on pH and boric acid.

    PubMed

    Cuadra, Giancarlo A; Frantellizzi, Ashley J; Gaesser, Kimberly M; Tammariello, Steven P; Ahmed, Anika

    2016-07-01

    Autoinducer-2, considered a universal signaling molecule, is produced by many species of bacteria; including oral strains. Structurally, autoinducer-2 can exist bound to boron (borated autoinducer-2). Functionally, autoinducer-2 has been linked to important bacterial processes such as virulence and biofilm formation. In order to test production of autoinducer-2 by a given bacterial strain, a bioassay using marine bioluminescent bacteria Vibrio harveyi as a reporter for autoinducer-2 has been designed. We hypothesize that pH adjustment and addition of boron are required for optimal bioluminescence and accurate autoinducer-2 detection. Using this reporter strain we tested autoinducer-2 activity from two oral commensal species, Streptococcus gordonii DL1 and Streptococcus oralis 34. Spent broth was collected and adjusted to pH 7.5 and supplemented with boric acid prior to measuring autoinducer- 2 activity. Results show that low pH inhibits bioluminescence of the reporter strain, but pH 7.5 allows for bioluminescence induction and proper readings of autoinducer-2 activity. Addition of boric acid also has a positive effect on bioluminescence allowing for a more sensitive detection of autoinducer-2 activity. Our data suggests that although autoinducer-2 is present in spent broth, low pH and/or low levels of boric acid become an obstacle for proper autoinducer-2 detection. For proper autoinducer-2 detection, we propose a protocol using this bioassay to include pH adjustment and boric acid addition to spent broth. Studies on autoinducer-2 activity in several bacteria species represent an important area of study as this universal signaling molecule is involved in critical bacterial phenotypes such as virulence and biofilm formation. PMID:27350615

  8. The History of Electromagnetic Induction Techniques in Soil Survey

    NASA Astrophysics Data System (ADS)

    Brevik, Eric C.; Doolittle, Jim

    2014-05-01

    Electromagnetic induction (EMI) has been used to characterize the spatial variability of soil properties since the late 1970s. Initially used to assess soil salinity, the use of EMI in soil studies has expanded to include: mapping soil types; characterizing soil water content and flow patterns; assessing variations in soil texture, compaction, organic matter content, and pH; and determining the depth to subsurface horizons, stratigraphic layers or bedrock, among other uses. In all cases the soil property being investigated must influence soil apparent electrical conductivity (ECa) either directly or indirectly for EMI techniques to be effective. An increasing number and diversity of EMI sensors have been developed in response to users' needs and the availability of allied technologies, which have greatly improved the functionality of these tools. EMI investigations provide several benefits for soil studies. The large amount of georeferenced data that can be rapidly and inexpensively collected with EMI provides more complete characterization of the spatial variations in soil properties than traditional sampling techniques. In addition, compared to traditional soil survey methods, EMI can more effectively characterize diffuse soil boundaries and identify included areas of dissimilar soils within mapped soil units, giving soil scientists greater confidence when collecting spatial soil information. EMI techniques do have limitations; results are site-specific and can vary depending on the complex interactions among multiple and variable soil properties. Despite this, EMI techniques are increasingly being used to investigate the spatial variability of soil properties at field and landscape scales.

  9. Effect of increasing biochar application rate on soil hydraulic properties of an artificial sandy soil

    NASA Astrophysics Data System (ADS)

    Lopez, V.; Ghezzehei, T. A.

    2013-12-01

    Biochar, a product of the pyrolysis of biomass, has become an increasingly studied subject of interest as an agricultural soil amendment to address issues of carbon emission, population density, and food scarcity. Biochar has been reported to increase content and retention of nutrients, pH, cation-exchange capacity, vegetative growth, microbial community, and carbon sequestration. A number of studies addressing the usefulness of biochar as a soil amendment have focused on chemical and biological properties, disregarding the effects on soil physical properties of amended soil.