WorldWideScience

Sample records for soil acidity-related factors

  1. PRINCIPAL COMPONENT ANALYSIS OF FACTORS DETERMINING PHOSPHATE ROCK DISSOLUTION ON ACID SOILS

    Directory of Open Access Journals (Sweden)

    Yusdar Hilman

    2016-10-01

    Full Text Available Many of the agricultural soils in Indonesia are acidic and low in both total and available phosphorus which severely limits their potential for crops production. These problems can be corrected by application of chemical fertilizers. However, these fertilizers are expensive, and cheaper alternatives such as phosphate rock (PR have been considered. Several soil factors may influence the dissolution of PR in soils, including both chemical and physical properties. The study aimed to identify PR dissolution factors and evaluate their relative magnitude. The experiment was conducted in Soil Chemical Laboratory, Universiti Putra Malaysia and Indonesian Center for Agricultural Land Resources Research and Development from January to April 2002. The principal component analysis (PCA was used to characterize acid soils in an incubation system into a number of factors that may affect PR dissolution. Three major factors selected were soil texture, soil acidity, and fertilization. Using the scores of individual factors as independent variables, stepwise regression analysis was performed to derive a PR dissolution function. The factors influencing PR dissolution in order of importance were soil texture, soil acidity, then fertilization. Soil texture factors including clay content and organic C, and soil acidity factor such as P retention capacity interacted positively with P dissolution and promoted PR dissolution effectively. Soil texture factors, such as sand and silt content, soil acidity factors such as pH, and exchangeable Ca decreased PR dissolution.

  2. The influence of organic acids in relation to acid deposition in controlling the acidity of soil and stream waters on a seasonal basis

    International Nuclear Information System (INIS)

    Chapman, Pippa J.; Clark, Joanna M.; Reynolds, Brian; Adamson, John K.

    2008-01-01

    Much uncertainty still exists regarding the relative importance of organic acids in relation to acid deposition in controlling the acidity of soil and surface waters. This paper contributes to this debate by presenting analysis of seasonal variations in atmospheric deposition, soil solution and stream water chemistry for two UK headwater catchments with contrasting soils. Acid neutralising capacity (ANC), dissolved organic carbon (DOC) concentrations and the Na:Cl ratio of soil and stream waters displayed strong seasonal patterns with little seasonal variation observed in soil water pH. These patterns, plus the strong relationships between ANC, Cl and DOC, suggest that cation exchange and seasonal changes in the production of DOC and seasalt deposition are driving a shift in the proportion of acidity attributable to strong acid anions, from atmospheric deposition, during winter to predominantly organic acids in summer. - Seasonal variations in soil solution ANC is controlled by seasonal variations in seasalt deposition and production of dissolved organic acids

  3. Influence of Height Waterlogging on Soil Physical Properties of Potential and Actual Acid Sulphate Soils

    Directory of Open Access Journals (Sweden)

    Arifin Fahmi

    2014-06-01

    Full Text Available Water management is main factor that determines the successful of rice cultivation in acid sulphate soil. Soil waterlogging determines the direction and rate of chemical, geochemical and biological reaction in the soil, indirectly these reactions may influence to the changes of soil psycal properties during soil waterlogging process. The experiment was aimed to study the changes of two type of acid sulphate soils physical properties during rice straw decomposition processes. The research was conducted in the greenhouse consisting of the three treatment factors using the completely randomized design with three replications. The first factor was soil type: potential acid sulphate soil (PASS and actual acid sulphate soil (AASS. The second factor was height of water waterlogging: 0.5-1.0 cm (muddy water–level condition and 4.0 cm from above the soil surface (waterlogged. The third factor was organic matter type: rice straw (RS, purun tikus (Eleocharis dulcis (PT and mixed of RS and PT (MX. Soil physical properties such as aggregate stability, total soil porosity, soil permeability, soil particle density and bulk density were observed at the end of experiment (vegetative maximum stage. The results showed that acid sulphate soil type had large effect on soil physicl properties, soil waterlogging decreased aggregate stability, soil particle density and bulk density both of soil type.

  4. Effect Of Soil Acidity On Some Soybean Varieties

    OpenAIRE

    Hanafiah, Diana Sofia; Lubis, Alida; Asmarlaili

    2015-01-01

    This study aims to determine the mechanism of adaptation and morphophysiology character of soybean genotypes to soil acidity levels. Research using randomized block design with four replications, the first factor consists of soybean varieties: Tanggamus varieties, Detam 2, Anjasmoro and Detam 1, while the second factor is the media's treatment consisted of medium acid soils and limed soil. The results showed that the low level acidity of planting medium will affect the growth and ...

  5. Reduced carbon sequestration potential of biochar in acidic soil.

    Science.gov (United States)

    Sheng, Yaqi; Zhan, Yu; Zhu, Lizhong

    2016-12-01

    Biochar application in soil has been proposed as a promising method for carbon sequestration. While factors affecting its carbon sequestration potential have been widely investigated, the number of studies on the effect of soil pH is limited. To investigate the carbon sequestration potential of biochar across a series of soil pH levels, the total carbon emission, CO 2 release from inorganic carbon, and phospholipid fatty acids (PLFAs) of six soils with various pH levels were compared after the addition of straw biochar produced at different pyrolysis temperatures. The results show that the acidic soils released more CO 2 (1.5-3.5 times higher than the control) after the application of biochar compared with neutral and alkaline soils. The degradation of both native soil organic carbon (SOC) and biochar were accelerated. More inorganic CO 2 release in acidic soil contributed to the increased degradation of biochar. Higher proportion of gram-positive bacteria in acidic soil (25%-36%) was responsible for the enhanced biochar degradation and simultaneously co-metabolism of SOC. In addition, lower substrate limitation for bacteria, indicated by higher C-O stretching after the biochar application in the acidic soil, also caused more CO 2 release. In addition to the soil pH, other factors such as clay contents and experimental duration also affected the phsico-chemical and biotic processes of SOC dynamics. Gram-negative/gram-positive bacteria ratio was found to be negatively related to priming effects, and suggested to serve as an indicator for priming effect. In general, the carbon sequestration potential of rice-straw biochar in soil reduced along with the decrease of soil pH especially in a short-term. Given wide spread of acidic soils in China, carbon sequestration potential of biochar may be overestimated without taking into account the impact of soil pH. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Relations between soil factors and herbage yields of natural ...

    African Journals Online (AJOL)

    Keywords: Cation exchange capacity; Correlation matrix; Nitrogen supplies; Root mass; Root measurements; Soil acidity; Soil variables; Soil water content; Soil water measurements; Yield measurements; nitrogen supply; ph; herbage yield; grassland; soils; productivity; soil depth; dry matter yield; grasses; water content; n; ...

  7. Mechanisms of adaptation of small grains to soil acidity

    OpenAIRE

    Đalović Ivica G.; Maksimović Ivana V.; Kastori Rudolf R.; Jelić Miodrag Ž.

    2010-01-01

    Acid soils limit crop production on 30-40% of the world's arable land and up to 70% of the world's potentially arable land. Over 60% of the total arable lands in Serbia are acid soils. Soil acidity is determined by hydrogen (H+) in soil solution and it is influenced by edaphic, climatic, and biological factors. Major constraints for plant growth on acid mineral soils are toxic concentrations of mineral elements like Al of H+ and/or low mineral nutrient availability due to low solubility (e.g....

  8. Aluminium, extractable from soil samples by the acid ammonium acetate soil-testing method

    Directory of Open Access Journals (Sweden)

    Osmo Mäkitie

    1968-05-01

    Full Text Available The extractant, 0.5 M acetic acid –0.5 M ammonium acetate at pH 4.65, which is used in soil-testing, extracts relatively high amounts of aluminium from acid soils. The mean values of acetate-extractable aluminium at pH 4.65, 1.75 meq Al/100 g of soil, and of exchangeable aluminium (M KCI extraction, 0.41 meq Al were obtained from a material of 30 samples of acid soils (Table 2. Several other acetic acid ammonium acetate extractants, from M acetic acid to M ammonium acetate solution were also used for studying the extractability of soil aluminium. The soil-testing extractant can be used for the estimation of the soluble amounts of aluminium in acid soils, however, further studies are needed for a better interpretation of the ammonium acetate extractable (at pH 4.65 aluminium in our soils.

  9. Mechanisms of adaptation of small grains to soil acidity

    Directory of Open Access Journals (Sweden)

    Đalović Ivica G.

    2010-01-01

    Full Text Available Acid soils limit crop production on 30-40% of the world's arable land and up to 70% of the world's potentially arable land. Over 60% of the total arable lands in Serbia are acid soils. Soil acidity is determined by hydrogen (H+ in soil solution and it is influenced by edaphic, climatic, and biological factors. Major constraints for plant growth on acid mineral soils are toxic concentrations of mineral elements like Al of H+ and/or low mineral nutrient availability due to low solubility (e.g. P and Mo or low reserves and impaired uptake (e.g. Mg2+ at high H+ concentrations. Aluminum (Al toxicity is primary factor limiting crop production on acid soils. This review examines our current understanding of mechanisms of Al-toxicity, as well as the physiological and genetic basis for Al-toxicity and tolerance. Inhibition of root growth by Al leads to more shallow root systems, which may affect the capacity for mineral nutrient acquisition and increase the risk of drought stress. Of the two principal strategies (tolerance and avoidance of plants for adaptation to adverse soil conditions, the strategy of avoidance is more common for adaptation to acid mineral soils. At the same, the short view of the most important genetics tolerance mechanisms, developed and determined in some small grains genotypes, is showed as well.

  10. [Effect of soil phenolic acids on soil microbe of coal-mining depressed land after afforestation restoration by different tree species].

    Science.gov (United States)

    Ji, Li; Yang, Li Xue

    2017-12-01

    Phenolic acids are one of the most important factors that influence microbial community structure. Investigating the dynamic changes of phenolic acids and their relationship with the microbial community structure in plantation soils with different tree species could contribute to better understanding and revealing the mechanisms of microbial community changes under afforestation restoration in coal-mining subsidence areas. In this study, plantations of three conifer and one deciduous species (Pinus koraiensis, Larix gmelinii, Pinus sylvestris var. mongolica, and Populus ussuriensis) were established on abandoned coal-mining subsidence areas in Baoshan District, Shuangyashan City. The contents of soil phenols, 11 types of phenolic acids, and microbial communities in all plots were determined. The results showed that the contents of soil complex phenol in plantations were significantly higher than that of abandoned land overall. Specifically, soils in larch and poplar plantations had higher contents of complex phenol, while soils in larch and Korean pine plantations had greater contents of total phenol. Moreover, soil in the P. koraiensis plantation had a higher content of water-soluble phenol compared with abandoned lands. The determination of 11 phenolic acids indicated that the contents of ferulic acid, abietic acid, β-sitosterol, oleanolic acid, shikimic acid, linoleic acid, and stearic acid were higher in plantation soils. Although soil phenol contents were not related with soil microbial biomass, the individual phenolic acids showed a significant relationship with soil microbes. Ferulic acid, abietic acid, and β-sitosterol showed significant promoting effects on soil microbial biomass, and they showed positive correlations with fungi and fungi/bacteria ratio. These three phenolic acids had higher contents in the poplar plantation, suggesting that poplar affo-restation had a beneficial effect on soil quality in coal-mining subsidence areas.

  11. Regional analysis of groundwater phosphate concentrations under acidic sandy soils: Edaphic factors and water table strongly mediate the soil P-groundwater P relation.

    Science.gov (United States)

    Mabilde, Lisa; De Neve, Stefaan; Sleutel, Steven

    2017-12-01

    Historic long-term P application to sandy soils in NW-Europe has resulted in abundant sorption, saturation and eventually leaching of P from soil to the groundwater. Although many studies recognize the control of site-specific factors like soil texture and phosphate saturation degree (PSD), the regional-scaled relevance of effects exerted by single factors controlling P leaching is unclear. Very large observational datasets of soil and groundwater P content are furthermore required to reveal indirect controls of soil traits through mediating soil variables. We explored co-variation of phreatic groundwater orthophosphate (o-P) concentration and soil factors in sandy soils in Flanders, Belgium. Correlation analyses were complemented with an exploratory model derived using 'path analysis'. Data of oxalate-extractable Al, Fe, P and pH KCl , phosphate sorption capacity (PSC) and PSD in three depth layers (0-30, 30-60, 60-90 cm), topsoil SOC, % clay and groundwater depth (fluctuation) were interpolated to predict soil properties on exact locations of a very extensive net of groundwater monitoring wells. The mean PSD was only poorly correlated to groundwater o-P concentration, indicating the overriding control of other factors in the transport of P to the groundwater. A significant (P soil pH and groundwater table depth than by PSD indicates the likely oversimplification of the latter index to measure the long-term potential risk of P leaching. Accounting for controls on leaching not included in PSD via an alternative index, however, seems problematic as in Flanders for example groundwater o-P turned out to be higher in finer textured soils or soils with higher pedogenic Fe content, probably because of their lower pedogenic Al content and higher soil pH. Path analysis of extensive soil and groundwater datasets seems a viable way to identify prime local determinants of soil P leaching and could be further on used for 'ground-truthing' more complex P-migration simulation

  12. Soil Acidification due to Acid Deposition in Southern China

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Bohan

    1999-12-31

    Anthropogenic emission of SO{sub 2} and NO{sub x} to the atmosphere has made acid deposition one of the most serious environmental problems. In China, acid deposition research started in the late 1970s. The present thesis is part of a joint Chinese-Norwegian research project. The main goal of the thesis was to investigate the mechanism of soil acidification, to estimate soil responses to acid deposition, and to compare relative soil sensitivity to acidification in southern China. Laboratory experiments and modelling simulations were included. Specifically, the thesis (1) studies the characteristics of anion adsorption and cation release of the soils from southern China, (2) examines the effects of increased ionic strength in the precipitation and the effects of anion adsorption on cation release from the soils, (3) compares the relative sensitivity of these soils to acidification and the potentially harmful effects of acid deposition, (4) estimates likely soil responses to different deposition scenarios, including changes in soil waters and soil properties, and (5) investigates long-term changes in soils and soil waters in the Guiyang catchment due to acid deposition. 218 refs., 31 figs., 23 tabs.

  13. Soil Acidification due to Acid Deposition in Southern China

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Bohan

    1998-12-31

    Anthropogenic emission of SO{sub 2} and NO{sub x} to the atmosphere has made acid deposition one of the most serious environmental problems. In China, acid deposition research started in the late 1970s. The present thesis is part of a joint Chinese-Norwegian research project. The main goal of the thesis was to investigate the mechanism of soil acidification, to estimate soil responses to acid deposition, and to compare relative soil sensitivity to acidification in southern China. Laboratory experiments and modelling simulations were included. Specifically, the thesis (1) studies the characteristics of anion adsorption and cation release of the soils from southern China, (2) examines the effects of increased ionic strength in the precipitation and the effects of anion adsorption on cation release from the soils, (3) compares the relative sensitivity of these soils to acidification and the potentially harmful effects of acid deposition, (4) estimates likely soil responses to different deposition scenarios, including changes in soil waters and soil properties, and (5) investigates long-term changes in soils and soil waters in the Guiyang catchment due to acid deposition. 218 refs., 31 figs., 23 tabs.

  14. Amendment of Acid Soils with Crop Residues and Biochars

    Institute of Scientific and Technical Information of China (English)

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

    2011-01-01

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

  15. Deposition and conversion in soil of acids, acid-forming substances and nutrients

    International Nuclear Information System (INIS)

    Mayer, R.

    1990-01-01

    Balancing of material depositions entries is the basis for their evaluation. The acid depositions must be put in relation to the acid neutralization capacity and to the buffer rate of the soil. Every 'excess' in depositons leads to an acid supply into the sub-soil and/or into the groundwater system. On the one hand, the nutrient depositions are interpreted in relation to the nutrient supplies of the soil and their availability to the plants; and on the other hand with a view to the nutrient depletion through the polants. Excesses can also lead to a (non-desirable) pollution of aquatic systems, or else to an enhanced nutrient supply in the soil. Balancing is therefore a necessary aid for the evaluation of material depositions from the atmosphere. (orig./EF) [de

  16. IRON DYNAMICS AND ITS RELATION TO SOIL REDOX POTENTIAL AND PLANT GROWTH IN ACID SULPHATE SOIL OF SOUTH KALIMANTAN, INDONESIA

    Directory of Open Access Journals (Sweden)

    Wahida Annisa

    2017-01-01

    Full Text Available Organic matter has a function to maintain reductive conditions and to chelate toxic elements in acid sulphate soils. The study aimed to assess the dynamics of ferrous iron (Fe2+ in acid sulphate soil and its correlation with soil redox potential (Eh and plant growth. The experiment was arranged in two factorial randomized block design with three replications. The first factor was two types of organic matter: (1 control (without organic matter, (2 rice straw and (3 rush weed (Eleocharis dulcis. The second factor was time of decomposition of organic matter: I1 = 2 weeks, I2 = 4 weeks, I3 = 8 weeks, and I4 = 12 weeks (farmer practice. The results showed that concentration of ferrous iron in the soil ranged from 782 to 1308 mg kg-1 during the rice growing season. The highest constant rate of iron reduction (k F2+ was observed on application of rice straw and rush weed with decomposition time of 8 weeks with the k Fe2+ value of 0.016 and 0.011 per day, respectively, while the ferrous iron formation without organic matter had the k Fe2+ value of 0.077 per day. The ferric iron (Fe3+ reduction served as a function of soil Eh as indicated by the negative correlation of ferrous iron and Eh (r = -0.856*. Organic matter decreased exchangeable iron due to chelating reaction. Iron concentration in roots was negatively correlated with soil soluble iron (r = -0.62*. Application of rice straw decomposed for 8 weeks increased the height of rice plant up to 105.67 cm. The score of Fe2+ toxicity at 8 weeks after planting ranged from 2 to 3, so rice crop did not show iron toxicity symptoms. 

  17. Coastal acid sulphate soils in Poland: a review

    Directory of Open Access Journals (Sweden)

    Hulisz Piotr

    2017-03-01

    Full Text Available This paper presents the state of knowledge on coastal acid sulphate soils in Poland. The properties of these soils are closely related to the influence of brackish water from the Baltic Sea, high accumulation of organic matter and human activity. The obtained results demonstrate that the sulphide accumulation in soils refers to a relatively small areas of the Polish coastal zone with the unique and very valuable habitats. They require an adequate regulation of the water relations to avoid the risk of strong soil acidification and environmental pollution by heavy metals. Currently, there are no relevant criteria for classification of acid sulphate soil materials in the Polish Soil Classification (2011. Therefore, based on the presented data, the authors proposed to identify these features at the lower classification level (for different soil types. The criteria for the Thionic and Sulfidic qualifiers used in the WRB classification (IUSS Working Group WRB 2015 could be accepted for this purpose.

  18. Modeling the influence of organic acids on soil weathering

    Science.gov (United States)

    Lawrence, Corey R.; Harden, Jennifer W.; Maher, Kate

    2014-01-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  19. Soil knowledge for farmers, farmer knowledge for soil scientists : the case of acid sulphate soils in the Mekong delta, Viet Nam

    NARCIS (Netherlands)

    Mensvoort, van M.E.F.

    1996-01-01


    Half the Mekong delta in Vietnam, i.e. around 2 million hectares, suffers soil related problems due to acid sulphate soils. These soils generate sulphuric acid due to the oxidation of pyrite after aeration. Pyrite is most easily formed in tidal swamps. Human interference through land

  20. The soil acidity as restrictive factor of the use of nitrogen fertilizer by spring barley

    International Nuclear Information System (INIS)

    Hejnak, V.; Lippold, H.

    1999-01-01

    In two - year micro - plot trials was studied the effect of soil pH value (pH > 6,5 and pH 15 N in first year and no enriched in second year, rates of 0, 85, 170 and 255 mg N per pot, i.e. 0, 30, 60 and 90 kg N.ha -1 ) on the spring barley productivity and on the use of nitrogen fertilizer by plants in the application year of 15 N and in the following year. The productivity of spring barley is significantly higher in neutral soil than in acid soil. The gradated rates of nitrogen fertilization increased this difference. The total nitrogen uptake by plants was higher in neutral soil. The share of the nitrogen from 'the old soil's supply' in the total uptake by the harvest ranges from 95 to 82 % and is practically identical in studied soils. 'Priming effect' was higher in soil with better fertility (153 - 186 mg N per pot) than in acid soil (to 49 mg N per pot only). The gradated rates of ammonium sulphate increased the uptake nitrogen from fertilizer by harvest of spring barley in the application year of 15 N from 39 mg N to 107 mg N per pot in neutral soil and from 26 mg N to 83 mg N per pot in acid soil and in the following year from 3,05 mg N to 8,15 mg N per pot in neutral soil and from 1,76 mg N to 3,37 mg N per pot in acid soil. The total balance of fertilizer nitrogen ( 15 N) in soil - crop system in two years from application showed that in neutral soil 46 % used by spring barley (42 % in the application year and 4 % in the following year), 16 % rested in soil and loss was 38 % and in acid soil 35 % used by harvest (33 % in first year and 2 % second year), 12 % rested in soil and loss was 53 %. Refs. 5 (author)

  1. [Interrelationships between soil fauna and soil environmental factors in China: research advance].

    Science.gov (United States)

    Wang, Yi; Wei, Wei; Yang, Xing-zhong; Chen, Li-ding; Yang, Lei

    2010-09-01

    Soil fauna has close relations with various environmental factors in soil ecosystem. To explore the interrelationships between soil fauna and soil environmental factors is of vital importance to deep understand the dynamics of soil ecosystem and to assess the functioning of the ecosystem. The environmental factors affecting soil fauna can be classified as soil properties and soil external environment. The former contains soil basic physical and chemical properties, soil moisture, and soil pollution. The latter includes vegetation, land use type, landform, and climate, etc. From these aspects, this paper summarized the published literatures in China on the interrelationships between soil fauna and soil environmental factors. It was considered that several problems were existed in related studies, e.g., fewer researches were made in integrating soil fauna's bio-indicator function, research methods were needed to be improved, and the studies on the multi-environmental factors and their large scale spatial-temporal variability were in deficiency. Corresponding suggestions were proposed, i.e., more work should be done according to the practical needs, advanced experiences from abroad should be referenced, and comprehensive studies on multi-environmental factors and long-term monitoring should be conducted on large scale areas.

  2. Case studies related to the management of soil acidity and infertility in the West-African Moist Savannah

    International Nuclear Information System (INIS)

    Vanlauwe, B.; Sanginga, N.; Diels, J.; Merckx, R.

    2006-01-01

    Although the soil pH and base status of the soils in the West African Moist Savannah Zone (MSZ) are usually favourable, their buffer capacity is usually low, indicating that while soil acidity may not be a problem initially, inappropriate management of these soils may induce soil-acidity-related problems in the medium to long term. The current paper addresses 3 topics that are closely related to the management of soil pH (acidity) in the West African MSZ. A first experiment addressed the release of P from low reactivity phosphate rock (PR) by mixing it with various N fertilizers. Mixing ammonium-sulphate, urea, and calcium-ammonium nitrate with PR substantially enhanced the soil Olsen-P content, but not for soils with an initial pH above 5.5, while potassium nitrate did not change the Olsen-P content. Changes in soil pH could be predicted based on the production of nitrate from ammonium (nitrification) and the soil buffer capacity. A second experiment examined the changes in topsoil pH as affected by long term management based on the application of organic inputs derived from hedgerow trees (Leucaena leucocephala and Senna siamea), fertilizer, or both. Maize crop yields declined steadily over the 16 years studied, but the least so in the Senna + fertilizer treatment where in 2002 still 2.2 t ha -1 of maize were obtained. The fertilizer only treatment led to a yield of 0.4 t ha -1 in 2002, while the absolute control without any inputs yielded a mere 40 kg ha -1 in the same year. Nitrogen fertilizer use efficiency was usually higher in the Senna treatment compared to the control or the Leucaena treatment. Interactions between fertilizer and organic matter additions were negative for the Leucaena treatments in the first three years, and positive for the Senna treatment in the last 6 years. Trees had a positive effect on the maintenance of exchangeable cations in the topsoil. Exchangeable Ca, Mg and K - and hence ECEC - were only slightly reduced after 16 years of

  3. Soil-plant transfer factors in forest ecosystems

    International Nuclear Information System (INIS)

    Strebl, F.; Gerzabek, M.H.

    1995-04-01

    Within scope of an extended study about 137 Cs behaviour in forest ecosystems several parameters were found to influence soil-plant transfer factors. TF-values of different plant species cover a range of two magnitudes. This is partly due to variations in rooting depth of plants and specific physiological adaptations of nutrient supply. Perrenial plants like trees (Picea abies) and dwarf shrubs (Vaccinium myrtillus) showed a distinct age - dependency of 137 Cs - transfer factors. In young plant parts caesium concentration is higher than in old, more signified twigs. A correlation analysis of physico-chemical soil parameters and TF-values to forest vegetation showed, that soil organic matter, especially the degree of humification and the ratio between extractable fulvic to humic acids are important influencing factors of 137 Cs transfer from forest soils to plants. (author)

  4. Decreased Soil Nitrification Rate with Addition of Biochar to Acid Soils

    Institute of Scientific and Technical Information of China (English)

    Shiyu LI; Xiangshu DONG; Dandan LIU; Li LIU; Feifei HE

    2017-01-01

    This study was conducted to investigate the effects of mixed biochar on the nitrification rate in acidic soils. A 15N tracer experiment with (15NH4)2SO4 was conducted to determine the nitrification rates of 4 acidic agricultural soils with pH 4.03-6.02in Yunnan Province, Southern China. The accumulation of 15N-NO3 - and nitrification rates decreased with the addition of biochar at the end of incubation, suggesting that biochar could be a nitrification inhibitor in acidic fertilized soil. Nitrification rates in soil with pH 4.03 were evidently lower than those in soil with pH 4.81 -6.02 with or without biochar. Decreased nitrification rates were detected in the acidic soils with biochar. Soil pH controlled nitrification more than biochar in certain strongly acidic soils.

  5. The production and degradation of trichloroacetic acid in soil: Results from in situ soil column experiments

    Czech Academy of Sciences Publication Activity Database

    Heal, M. R.; Dickey, C. A.; Heal, K.V.; Stidson, R.T.; Matucha, Miroslav; Cape, J. N.

    2010-01-01

    Roč. 79, č. 4 (2010), s. 401-407 ISSN 0045-6535 Institutional research plan: CEZ:AV0Z50380511 Keywords : Trichloroacetic acid * TCA * Soil lysimeter Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides Impact factor: 3.155, year: 2010

  6. Acidity controls on dissolved organic carbon mobility in organic soils

    Czech Academy of Sciences Publication Activity Database

    Evans, Ch. D.; Jones, T.; Burden, A.; Ostle, N.; Zielinski, P.; Cooper, M.; Peacock, M.; Clark, J.; Oulehle, Filip; Cooper, D.; Freeman, Ch.

    2012-01-01

    Roč. 18, č. 11 (2012), s. 3317-3331 ISSN 1354-1013 Institutional support: RVO:67179843 Keywords : acidity * dissolved organic carbon * organic soil * peat * podzol * soil carbon * sulphur Subject RIV: EH - Ecology, Behaviour Impact factor: 6.910, year: 2012

  7. Predictive mapping of the acidifying potential for acid sulfate soils

    DEFF Research Database (Denmark)

    Boman, A; Beucher, Amélie; Mattbäck, S

    Developing methods for the predictive mapping of the potential environmental impact from acid sulfate soils is important because recent studies (e.g. Mattbäck et al., under revision) have shown that the environmental hazards (e.g. leaching of acidity) related to acid sulfate soils vary depending...... on their texture (clay, silt, sand etc.). Moreover, acidity correlates, not only with the sulfur content, but also with the electrical conductivity (EC) measured after incubation. Electromagnetic induction (EMI) data collected from an EM38 proximal sensor also enabled the detailed mapping of acid sulfate soils...... over a field (Huang et al., 2014).This study aims at assessing the use of EMI data for the predictive mapping of the acidifying potential in an acid sulfate soil area in western Finland. Different supervised classification modelling techniques, such as Artificial Neural Networks (Beucher et al., 2015...

  8. Replenishing Humic Acids in Agricultural Soils

    Directory of Open Access Journals (Sweden)

    Michael Susic

    2016-09-01

    Full Text Available For many decades, it was commonly believed that humic acids were formed in soils by the microbial conversion of plant lignins. However, an experiment to test whether these humic acids were formed prior to plant matter reaching the soil was never reported until the late 1980s (and then only as a side issue, even though humic acids were first isolated and reported in 1786. This was a serious omission, and led to a poor understanding of how the humic acid content of soils could be maintained or increased for optimum fertility. In this study, commercial sugar cane mulch and kelp extracts were extracted with alkali and analyzed for humic acid content. Humic acids in the extracts were positively identified by fluorescence spectrophotometry, and this demonstrated that humic acids are formed in senescent plant and algal matter before they reach the soil, where they are then strongly bound to the soil and are also resistant to microbial metabolism. Humic acids are removed from soils by wind and water erosion, and by water leaching, which means that they must be regularly replenished. This study shows that soils can be replenished or fortified with humic acids simply by recycling plant and algal matter, or by adding outside sources of decomposed plant or algal matter such as composts, mulch, peat, and lignite coals.

  9. Exploring plant factors for increasing phosphorus utilization from rock phosphates and native soil phosphates in acidic soils

    International Nuclear Information System (INIS)

    Feng Guanglin; Xiong Liming

    2002-01-01

    Six plant species with contrasting capacity in utilizing rock phosphates were compared with regard to their responses to phosphorus starvation in hydroponic cultures. Radish, buckwheat and oil rapeseed are known to have strong ability to use rock phosphates while ryegrass, wheat and sesbania are less efficient. Whereas other plants acidified their culture solution under P starvation (-P), radish plants make alkaline the solution. When neutralizing the pH of the solutions cultured with plants under either -P or + P conditions, solutions with P starved buckwheat, rapeseed, and radish had a higher ability to solubilize Al and Fe phosphates than did those cultured with sesbania, ryegrass and wheat. Characterization of organic ligands in the solutions identified that citrate and malate were the major organic anions exuded by rapeseed and radish. Besides citrate and malate, buckwheat exuded a large amount of tartrate under P starvation. In contrast, ryegrass, wheat and sesbania secreted only a limited amount of oxalic acid, regardless of P status. Changes in activities of phosphoenolpyruvate carboxylase, acid phosphatase, and nitrate reductase in these plants were also compared under P- sufficient or -deficient conditions. The results indicated that plant ability to use rock phosphates or soil phosphates is closely related to their responses toward P starvation. The diversity of P starvation responses was discussed in the context of co-evolution between plants and their environment. Approaches to use plant factors to enhance the effectiveness of rock phosphates were also discussed. (author)

  10. Releasing Pattern of Applied Phosphorus and Distribution Change of Phosphorus Fractions in the Acid Upland Soils with Successive Resin Extraction

    Directory of Open Access Journals (Sweden)

    Arief Hartono

    2008-05-01

    Full Text Available The releasing pattern of applied P in the acid upland soils and the soil properties influencing the pattern were studied. Surface horizons of six acid upland soils from Sumatra, Java and Kalimantan were used in this study. The releasing pattern of applied P (300 mg P kg-1 of these soils were studied by successive resin extraction. P fractionation was conducted to evaluate which fractions released P to the soil solution after successive resin extraction. The cumulative of resin-Pinorganic (Pi release of soils was fitted to the first order kinetic. Regression analyses using factor scores obtained from the previous principal components analyses was applied to determine soil properties influencing P releasing pattern. The results suggested that the maximum P release was significantly (P < 0.05 increased by acidity plus 1.4 nm mineral-related factor (PC2 i.e. exchangeable Al and 1.4 nm minerals (smectite and vermiculite and decreased by oxide related factor (PC1 i.e. aluminum (Al plus 1/2 iron (Fe (by ammonium oxalate, crystalline Al and Fe oxides, cation exchange capacity, and clay content. P fractionation analysis after successive resin extraction showed that both labile and less labile in the form of NaHCO3-Pi and NaOH-Pi fractions, respectively, can be transformed into resin-Pi when in the most labile resin-Pi is depleted. Most of P released in high oxides soils were from NaOH-Pi fraction while in low oxides soils were from NaHCO3-Pi. P release from the former fraction resulted in the maximum P release lower than that of the latter one. When NaHCO3-Pi was high, NaOH-Pi was relatively more stable than NaHCO3-Pi despite resin-Pi removal. NaHCO3-Pi and NaOH-Pi are very important P fractions in replenishing resin-Pi in these acid upland soils.

  11. Why plants grow poorly on very acid soils: are ecologists missing the obvious?

    Science.gov (United States)

    Kidd, P S; Proctor, J

    2001-04-01

    Factors associated with soil acidity are considered to be limiting for plants in many parts of the world. This work was undertaken to investigate the role of the toxicity of hydrogen (H(+)) which seems to have been underconsidered by ecologists as an explanation of the reduced plant growth observed in very acid soils. Racial differences are reported in plant growth response to increasing acidity in the grass Holcus lanatus L. (Yorkshire-fog) and the tree Betula pendula Roth (Silver Birch). Soils and seeds were collected from four Scottish sites which covered a range of soils from acid (organic and mineral) to more base-rich. The sites and their pH (1:2.5 fresh soil:0.01 M CaCl(2)) were: Flanders Moss (FM), pH 3.2+/-0.03; Kippenrait Glen (KP), pH 4.8+/- 0.05; Kinloch Rannoch (KR), pH 6.1+/-0.16; and Sheriffmuir (SMM), pH 4.3+/-0.11. The growth rates of two races of H. lanatus, FM and KP, and three races of B. pendula (SMM, KP and KR) were measured in nutrient solution cultures at pH 2.0 (H. lanatus only), 3.0, 4.0, 5.0, and 5.6. Results showed races from acid organic soils (FM) were H(+)-tolerant while those from acid mineral soils (SMM) were Al(3+)-tolerant but not necessarily H(+)-tolerant. These results confirmed that populations were separately adapted to H(+) or Al(3+) toxicity and this was dependent upon the soil characteristics at their site of collection. The fact of plant adaptation to H(+) toxicity supports the view that this is an important factor in very acid soils.

  12. Trichloroacetic acid in Norway spruce/soil-system I. Biodegradation in soil

    Czech Academy of Sciences Publication Activity Database

    Matucha, Miroslav; Forczek, Sándor; Gryndler, Milan; Uhlířová, H.; Fuksová, K.; Schröder, P.

    2003-01-01

    Roč. 50, č. 3 (2003), s. 303-309 ISSN 0045-6535 R&D Projects: GA ČR GA522/99/1465 Institutional research plan: CEZ:AV0Z5020903; CEZ:AV0Z5038910 Keywords : Microbial degradation * Trichloroacetic acid * Forest soil Subject RIV: CE - Biochemistry Impact factor: 1.904, year: 2003

  13. Acid sulfate soils and human health--a Millennium Ecosystem Assessment.

    Science.gov (United States)

    Ljung, Karin; Maley, Fiona; Cook, Angus; Weinstein, Philip

    2009-11-01

    Acid sulfate soils have been described as the "nastiest soils on earth" because of their strong acidity, increased mobility of potentially toxic elements and limited bioavailability of nutrients. They only cover a small area of the world's total problem soils, but often have significant adverse effects on agriculture, aquaculture and the environment on a local scale. Their location often coincides with high population density areas along the coasts of many developing countries. As a result, their negative impacts on ecosystems can have serious implications to those least equipped for coping with the low crop yields and reduced water quality that can result from acid sulfate soil disturbance. The Millennium Ecosystem Assessment called on by the United Nations in 2000 emphasised the importance of ecosystems for human health and well-being. These include the service they provide as sources of food and water, through the control of pollution and disease, as well as for the cultural services ecosystems provide. While the problems related to agriculture, aquaculture and the environment have been the focus of many acid sulfate soil management efforts, the connection to human health has largely been ignored. This paper presents the potential health issues of acid sulfate soils, in relation to the ecosystem services identified in the Millennium Ecosystem Assessment. It is recognised that significant implications on food security and livelihood can result, as well as on community cohesiveness and the spread of vector-borne disease. However, the connection between these outcomes and acid sulfate soils is often not obvious and it is therefore argued that the impact of such soils on human well-being needs to be recognised in order to raise awareness among the public and decision makers, to in turn facilitate proper management and avoid potential human ill-health.

  14. Effect of acid rain on soil microbial processes

    International Nuclear Information System (INIS)

    Myrold, D.D.; Nason, G.E.

    1992-01-01

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

  15. Variability of soil-to-crop transfer factor

    International Nuclear Information System (INIS)

    Uchida, Shigeo; Kamada, Hiroshi; Yokosuka, Setsuko; Ohmomo, Yoichiro

    1987-01-01

    Many European countries have nuclear facilities in inland areas, where extremely low level radioactive waste liquid is discharged to rivers. In those nations, therefore, many studies have been made oncerning the transfer of radioisotopes into plants. In Japan, greater attention has been attracted to such radioisotope transfer into plants and then into human bodies. Thus the present report reviews various studies on this issue. The key parameter for this process is the transfer factor (also called concentration factor, coefficient or ratio). The factor largely depends on various other factors including the characteristics of different nuclides, properties of soil (pH, oxidation-reduction potential, grain size distribution, contents of clay minerals, contents of organic matters, water content, etc.), characteristics of crops and cultivation conditions. It has been reported that I is absorbed by plants more rapidly than IO 3 . Of the various soil parameters, the pH of soil has the greatest effect on the transfer factor. Soil is mostly alkaline in Europe and America while acid soil account for a great part in Japan, suggesting that the transfer factor would be greater in Japan. The total potassium content in soil has the second largest effect on the factor. Radioactive iodine has shown to be transferred into soy beans and spinach 30 times more rapidly than into fruit vegetables. The oxidation-reduction potential also has a significant influence on the transfer factor. (Nogami, K.)

  16. Aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil: a review.

    Science.gov (United States)

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-11-10

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research.

  17. Aliphatic, Cyclic, and Aromatic Organic Acids, Vitamins, and Carbohydrates in Soil: A Review

    Directory of Open Access Journals (Sweden)

    Valerie Vranova

    2013-01-01

    Full Text Available Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research.

  18. Aliphatic, Cyclic, and Aromatic Organic Acids, Vitamins, and Carbohydrates in Soil: A Review

    Science.gov (United States)

    Vranova, Valerie; Rejsek, Klement; Formanek, Pavel

    2013-01-01

    Organic acids, vitamins, and carbohydrates represent important organic compounds in soil. Aliphatic, cyclic, and aromatic organic acids play important roles in rhizosphere ecology, pedogenesis, food-web interactions, and decontamination of sites polluted by heavy metals and organic pollutants. Carbohydrates in soils can be used to estimate changes of soil organic matter due to management practices, whereas vitamins may play an important role in soil biological and biochemical processes. The aim of this work is to review current knowledge on aliphatic, cyclic, and aromatic organic acids, vitamins, and carbohydrates in soil and to identify directions for future research. Assessments of organic acids (aliphatic, cyclic, and aromatic) and carbohydrates, including their behaviour, have been reported in many works. However, knowledge on the occurrence and behaviour of D-enantiomers of organic acids, which may be abundant in soil, is currently lacking. Also, identification of the impact and mechanisms of environmental factors, such as soil water content, on carbohydrate status within soil organic matter remains to be determined. Finally, the occurrence of vitamins in soil and their role in biological and biochemical soil processes represent an important direction for future research. PMID:24319374

  19. Soil bacterial and fungal communities along a soil chronosequence assessed by fatty acid profiling

    Czech Academy of Sciences Publication Activity Database

    Welc, M.; Bünemann, E. K.; Flieβbach, A.; Frossard, E.; Jansa, Jan

    2012-01-01

    Roč. 49, JUN 2012 (2012), s. 184-192 ISSN 0038-0717 Institutional support: RVO:61388971 Keywords : Fatty acid methyl esters * Glacier forefield * Soil chronosequence Subject RIV: EE - Microbiology, Virology Impact factor: 3.654, year: 2012

  20. Soil Forming Factors

    Science.gov (United States)

    It! What is Soil? Chip Off the Old Block Soil Forming Factors Matters of Life and Death Underneath It All Wise Choices A World of Soils Soil Forming Factors 2 A Top to Bottom Guide 3 Making a Soil Monolith 4 Soil Orders 5 State Soil Monoliths 6 Where in the Soil World Are You? >> A Top to

  1. Soil properties influence kinetics of soil acid phosphatase in response to arsenic toxicity.

    Science.gov (United States)

    Wang, Ziquan; Tan, Xiangping; Lu, Guannan; Liu, Yanju; Naidu, Ravi; He, Wenxiang

    2018-01-01

    Soil phosphatase, which plays an important role in phosphorus cycling, is strongly inhibited by Arsenic (As). However, the inhibition mechanism in kinetics is not adequately investigated. In this study, we investigated the kinetic characteristics of soil acid phosphatase (ACP) in 14 soils with varied properties, and also explored how kinetic properties of soil ACP changed with different spiked As concentrations. The results showed that the Michaelis constant (K m ) and maximum reaction velocity (V max ) values of soil ACP ranged from 1.18 to 3.77mM and 0.025-0.133mMh -1 in uncontaminated soils. The kinetic parameters of soil ACP in different soils changed differently with As contamination. The K m remained unchanged and V max decreased with increase of As concentration in most acid and neutral soils, indicating a noncompetitive inhibition mechanism. However, in alkaline soils, the K m increased linearly and V max decreased with increase of As concentration, indicating a mixed inhibition mechanism that include competitive and noncompetitive. The competitive inhibition constant (K ic ) and noncompetitive inhibition constant (K iu ) varied among soils and ranged from 0.38 to 3.65mM and 0.84-7.43mM respectively. The inhibitory effect of As on soil ACP was mostly affected by soil organic matter and cation exchange capacity. Those factors influenced the combination of As with enzyme, which resulted in a difference of As toxicity to soil ACP. Catalytic efficiency (V max /K m ) of soil ACP was a sensitive kinetic parameter to assess the ecological risks of soil As contamination. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Selenium speciation in acidic environmental samples: application to acid rain-soil interaction at Mount Etna volcano.

    Science.gov (United States)

    Floor, Geerke H; Iglesías, Mònica; Román-Ross, Gabriela; Corvini, Philippe F X; Lenz, Markus

    2011-09-01

    Speciation plays a crucial role in elemental mobility. However, trace level selenium (Se) speciation analyses in aqueous samples from acidic environments are hampered due to adsorption of the analytes (i.e. selenate, selenite) on precipitates. Such solid phases can form during pH adaptation up till now necessary for chromatographic separation. Thermodynamic calculations in this study predicted that a pHpH eluent that matches the natural sample pH of acid rain-soil interaction samples from Etna volcano was developed. With a mobile phase containing 20mM ammonium citrate at pH 3, selenate and selenite could be separated in different acidic media (spiked water, rain, soil leachates) in rain-soil interaction using synthetic rain based on H(2)SO(4) and soil samples collected at the flanks of Etna volcano demonstrated the dominance of selenate over selenite in leachates from samples collected close to the volcanic craters. This suggests that competitive behavior with sulfate present in acid rain might be a key factor in Se mobilization. The developed speciation method can significantly contribute to understand Se cycling in acidic, Al/Fe rich environments. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Effects of simulated acid rain on soil fauna community composition and their ecological niches.

    Science.gov (United States)

    Wei, Hui; Liu, Wen; Zhang, Jiaen; Qin, Zhong

    2017-01-01

    Acid rain is one of the severest environmental issues globally. Relative to other global changes (e.g., warming, elevated atmospheric [CO 2 ], and nitrogen deposition), however, acid rain has received less attention than its due. Soil fauna play important roles in multiple ecological processes, but how soil fauna community responds to acid rain remains less studied. This microcosm experiment was conducted using latosol with simulated acid rain (SAR) manipulations to observe potential changes in soil fauna community under acid rain stress. Four pH levels, i.e., pH 2.5, 3.5, 4.5, and 5.5, and a neutral control of pH 7.0 were set according to the current pH condition and acidification trend of precipitation in southern China. As expected, we observed that the SAR treatments induced changes in soil fauna community composition and their ecological niches in the tested soil; the treatment effects tended to increase as acidity increased. This could be attributable to the environmental stresses (such as acidity, porosity and oxygen supply) induced by the SAR treatments. In addition to direct acidity effect, we propose that potential changes in permeability and movability of water and oxygen in soils induced by acid rain could also give rise to the observed shifts in soil fauna community composition. These are most likely indirect pathways of acid rain to affect belowground community. Moreover, we found that nematodes, the dominating soil fauna group in this study, moved downwards to mitigate the stress of acid rain. This is probably detrimental to soil fauna in the long term, due to the relatively severer soil conditions in the deep than surface soil layer. Our results suggest that acid rain could change soil fauna community and the vertical distribution of soil fauna groups, consequently changing the underground ecosystem functions such as organic matter decomposition and greenhouse gas emissions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Pyrolysis temperature influences ameliorating effects of biochars on acidic soil.

    Science.gov (United States)

    Wan, Qing; Yuan, Jin-Hua; Xu, Ren-Kou; Li, Xing-Hui

    2014-02-01

    The biochars were prepared from straws of canola, corn, soybean, and peanut at different temperatures of 300, 500, and 700 °C by means of oxygen-limited pyrolysis.Amelioration effects of these biochars on an acidic Ultisol were investigated with incubation experiments, and application rate of biochars was 10 g/kg. The incorporation of these biochars induced the increase in soil pH, soil exchangeable base cations, base saturation, and cation exchange capacity and the decrease in soil exchangeable acidity and exchangeable Al. The ameliorating effects of biochars on acidic soil increased with increase in their pyrolysis temperature. The contribution of oxygen-containing functional groups on the biochars to their ameliorating effects on the acidic soil decreased with the rise in pyrolysis temperature, while the contribution from carbonates in the biochars changed oppositely. The incorporation of the biochars led to the decrease in soil reactive Al extracted by 0.5mol/L CuCl2, and the content of reactive Al was decreased with the increase in pyrolysis temperature of incorporated biochars. The biochars generated at 300 °C increased soil organically complexed Al due to ample quantity of oxygen-containing functional groups such as carboxylic and phenolic groups on the biochars, while the biochars generated at 500 and 700 °C accelerated the transformation of soil exchangeable Al to hydroxyl-Al polymers due to hydrolysis of Al at higher pH. Therefore, the crop straw-derived biochars can be used as amendments for acidic soils and the biochars generated at relatively high temperature have great ameliorating effects on the soils.

  5. The influence of use-related, environmental, and managerial factors on soil loss from recreational trails

    Science.gov (United States)

    Olive, Nathaniel D.; Marion, Jeffrey L.

    2009-01-01

    Recreational uses of unsurfaced trails inevitably result in their degradation, with the type and extent of resource impact influenced by factors such as soil texture, topography, climate, trail design and maintenance, and type and amount of use. Of particular concern, the loss of soil through erosion is generally considered a significant and irreversible form of trail impact. This research investigated the influence of several use-related, environmental, and managerial factors on soil loss on recreational trails and roads at Big South Fork National River and Recreation Area, a unit of the U.S. National Park Service. Regression modeling revealed that trail position, trail slope alignment angle, grade, water drainage, and type of use are significant determinants of soil loss. The introduction of individual and groups of variables into a series of regression models provides improved understanding and insights regarding the relative influence of these variables, informing the selection of more effective trail management actions. Study results suggest that trail erosion can be minimized by avoiding “fall-line” alignments, steep grades, and valley-bottom alignments near streams, installing and maintaining adequate densities of tread drainage features, applying gravel to harden treads, and reducing horse and all-terrain vehicle use or restricting them to more resistant routes.This research also sought to develop a more efficient Variable Cross-Sectional Area method for assessing soil loss on trails. This method permitted incorporation of CSA measures in a representative sampling scheme applied to a large (24%) sample of the park's 526 km trail system. The variety of soil loss measures derived from the Variable CSA method, including extrapolated trail-wide soil loss estimates, permit an objective quantification of soil erosion on recreational trails and roads. Such data support relational analyses to increase understanding of trail degradation, and long

  6. The influence of use-related, environmental, and managerial factors on soil loss from recreational trails.

    Science.gov (United States)

    Olive, Nathaniel D; Marion, Jeffrey L

    2009-03-01

    Recreational uses of unsurfaced trails inevitably result in their degradation, with the type and extent of resource impact influenced by factors such as soil texture, topography, climate, trail design and maintenance, and type and amount of use. Of particular concern, the loss of soil through erosion is generally considered a significant and irreversible form of trail impact. This research investigated the influence of several use-related, environmental, and managerial factors on soil loss on recreational trails and roads at Big South Fork National River and Recreation Area, a unit of the U.S. National Park Service. Regression modeling revealed that trail position, trail slope alignment angle, grade, water drainage, and type of use are significant determinants of soil loss. The introduction of individual and groups of variables into a series of regression models provides improved understanding and insights regarding the relative influence of these variables, informing the selection of more effective trail management actions. Study results suggest that trail erosion can be minimized by avoiding "fall-line" alignments, steep grades, and valley-bottom alignments near streams, installing and maintaining adequate densities of tread drainage features, applying gravel to harden treads, and reducing horse and all-terrain vehicle use or restricting them to more resistant routes. This research also sought to develop a more efficient Variable Cross-Sectional Area method for assessing soil loss on trails. This method permitted incorporation of CSA measures in a representative sampling scheme applied to a large (24%) sample of the park's 526 km trail system. The variety of soil loss measures derived from the Variable CSA method, including extrapolated trail-wide soil loss estimates, permit an objective quantification of soil erosion on recreational trails and roads. Such data support relational analyses to increase understanding of trail degradation, and long-term monitoring of

  7. Acid-base status of soils in groundwater discharge zones — relation to surface water acidification

    Science.gov (United States)

    Norrström, Ann Catrine

    1995-08-01

    Critical load calculations have suggested that groundwater at depth of 2 m in Sweden is very sensitive to acid load. As environmental isotope studies have shown that most of the runoff in streams has passed through the soil, there is a risk in the near future of accelerated acidification of surface waters. To assess the importance of the last soil horizon of contact before discharge, the upper 0-0.2m of soils in seven discharge zones were analysed for pools of base cations, acidity and base saturation. The sites were about 3-4 m 2 in size and selected from two catchments exposed to different levels of acid deposition. The soils in the seven sites had high concentrations of exchangeable base cations and consequently high base saturation. The high correlation ( r2 = 0.74) between base saturation in the soils of the discharge zones and mean pH of the runoff waters suggested that the discharge zone is important for surface water acidification. The high pool of exchangeable base cations will buffer initially against the acid load. As the cation exchange capacity (meq dm -3) and base saturation were lower in the sites from the catchment receiving lower deposition, these streams may be more vulnerable to acidification in the near future. The high concentration of base cations in non-exchangeable fractions may also buffer against acidification as it is likely that some of these pools will become exchangeable with time.

  8. 134Cs uptake by four plant species and Cs-K relations in the soil-plant system as affected by Ca(OH)2 application to an acid soil

    International Nuclear Information System (INIS)

    Massas, I.; Skarlou, V.; Haidouti, C.; Giannakopoulou, F.

    2010-01-01

    Three rates of Ca(OH) 2 were applied to an acid soil and the 134 Cs uptake by radish, cucumber, soybean and sunflower plants was studied. The 134 Cs concentration in all plant species was reduced from 1.6-fold in the sunflower seeds to 6-fold in the soybean vegetative parts at the higher Ca(OH) 2 rate. Potassium (K) concentration in plants was also reduced, but less effectively. The significantly decreased 134 Cs-K soil to plant distribution factors (D.F.) clearly suggest a stronger effect of soil liming on 134 Cs than on K plant uptake. This observation was discussed in terms of ionic interactions in the soil matrix and within the plants. The results also indicated that the increased Ca 2+ concentration in the exchange phase and in the soil solution along with the improved root activity, due to the soil liming, enhanced the immobilization of 134 Cs in the soil matrix and consequently lowered the 134 Cs availability for plant uptake.

  9. What are the most crucial soil factors for predicting the distribution of alpine plant species?

    Science.gov (United States)

    Buri, A.; Pinto-Figueroa, E.; Yashiro, E.; Guisan, A.

    2017-12-01

    H remains one of the most important soil factor for predicting plant species distributions, closely followed by water, organic and inorganic carbon related properties. Finally, we were able to extract three main categories of important soil properties for plant species distributions: grain size distribution, acidity and water in the soil.

  10. Management and conservation of tropical acid soils for sustainable crop production. Proceedings of a consultants meeting

    International Nuclear Information System (INIS)

    2000-06-01

    Forests of the tropics are invaluable ecosystems of global, regional and local importance, particularly in terms of protection and conservation of biodiversity and water resources. The indiscriminate conversion of tropical forests into agricultural land as a result of intense human activities - logging and modem shifting cultivation - continues to cause soil erosion and degradation. However, the acid savannahs of the world, such as the cerrado of Brazil, the Llanos in Venezuela and Colombia, the savannahs of Africa, and the largely anthropic savannahs of tropical Asia, encompass vast areas of potentially arable land. The acid soils of the savannahs are mostly considered marginal because of low inherent fertility and susceptibility to rapid degradation. These constraints for agricultural development are exacerbated by the poverty of new settlers who try to cultivate such areas after deforestation. Low- or minimum-input systems are not sustainable on these tropical acid soils but, with sufficient investment and adequate technologies, they can be highly productive. Thus, there is a need to develop management practices for sustainable agricultural production systems on such savannah acid soils. The Soil and Water Management and Crop Nutrition Sub-programme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture strongly supports an integrated approach to soil, water and nutrient management within cropping systems. In this context, nuclear and related techniques can be used to better understand the processes and factors influencing the productivity of agricultural production systems, and improve them through the use of better soil, water and nutrient management practices. A panel of experts actively engaged in field projects on acid soils of savannah agro-ecosystems in the humid and sub-humid tropics convened in March 1999 in Vienna to review and discuss recent research progress, along the following main lines of investigation: (i) utilization of

  11. HONO (nitrous acid) emissions from acidic northern soils

    Science.gov (United States)

    Maljanen, Marja; Yli-Pirilä, Pasi; Joutsensaari, Jorma; Martikainen, Pertti J.

    2015-04-01

    The photolysis of HONO (nitrous acid) is an important source of OH radical, the key oxidizing agent in the atmosphere, contributing also to removal of atmospheric methane (CH4), the second most important greenhouse gas after carbon dioxide (CO2). The emissions of HONO from soils have been recently reported in few studies. Soil HONO emissions are regarded as missing sources of HONO when considering the chemical reactions in the atmosphere. The soil-derived HONO has been connected to soil nitrite (NO2-) and also directly to the activity of ammonia oxidizing bacteria, which has been studied with one pure culture. Our hypothesis was that boreal acidic soils with high nitrification activity could be also sources of HONO and the emissions of HONO are connected with nitrification. We selected a range of dominant northern acidic soils and showed in microcosm experiments that soils which have the highest nitrous oxide (N2O) and nitric oxide (NO) emissions (drained peatlands) also have the highest HONO production rates. The emissions of HONO are thus linked to nitrogen cycle and also NO and N2O emissions. Natural peatlands and boreal coniferous forests on mineral soils had the lowest HONO emissions. It is known that in natural peatlands with high water table and in boreal coniferous forest soils, low nitrification activity (microbial production of nitrite and nitrate) limits their N2O production. Low availability of nitrite in these soils is the likely reason also for their low HONO production rates. We also studied the origin of HONO in one peat soil with acetylene and other nitrification inhibitors and we found that HONO production is not closely connected to ammonium oxidation (nitrification). Acetylene blocked NO emissions but did not affect HONO or N2O emissions, thus there is another source behind HONO emission from these soils than ammonium oxidation. It is still an open question if this process is microbial or chemical origin.

  12. Chloroacetic acids - Degradation intermediates of organic matter in forest soil

    Czech Academy of Sciences Publication Activity Database

    Matucha, Miroslav; Gryndler, Milan; Schröder, P.; Forczek, Sándor; Uhlířová, H.; Fuksová, Květoslava; Rohlenová, Jana

    2007-01-01

    Roč. 39, č. 1 (2007), s. 382-385 ISSN 0038-0717 R&D Projects: GA ČR GA522/02/0874; GA ČR GA526/05/0636 Institutional research plan: CEZ:AV0Z50380511 Keywords : trichloroacetic acid * dichloroacetic acid * chlorination * soil organic matter Subject RIV: EF - Botanics Impact factor: 2.580, year: 2007

  13. On the structural factors of soil humic matter related to soil water repellence in fire-affected soils

    Science.gov (United States)

    Almendros, G.; González-Vila, F. J.; González-Pérez, J. A.; Knicker, H.; De la Rosa, J. M.; Dettweiler, C.; Hernández, Z.

    2012-04-01

    In order to elucidate the impact of forest fires on physical and chemical properties of the soils as well as on the chemical composition of the soil organic matter, samples from two Mediterranean soils with contrasted characteristics and vegetation (O horizon, Lithic Leptosols under Quercus ilex and Pinus pinaster) and one agricultural soil (Ap horizon, Luvisol) were heated at 350 °C in laboratory conditions for three successive steps up to 600 s. The C- and N-depletion in the course of the heating showed small changes up to an oxidation time of 300 s. On the other side, and after 600 s, considerable C-losses (between 21% in the Luvisol and 50% in the Leptosols) were observed. The relatively low N-depletion ca. 4% (Luvisol) and 21% (Leptosol under pine) suggested preferential loss of C and the subsequent relative enrichment of nitrogen. Paralleling the progressive depletion of organic matter, the Leptosols showed a significant increase of both pH and electrical conductivity. The former change paralleled the rapid loss of carboxyl groups, whereas the latter point to the relative enrichment of ash with a bearing on the concentration of inorganic ions, which could be considered a positive effect for the post-fire vegetation. The quantitative and qualitative analyses by solid-state 13C NMR spectra of the humic fractions in the samples subjected to successive heating times indicate significant concentration of aromatic structures newly-formed in the course of the dehydration and cyclization of carbohydrates (accumulation of black carbon-type polycyclic aromatic structures), and probably lipids and peptides. The early decarboxylation, in addition to the depletion of O-alkyl hydrophilic constituents and further accumulation of secondary aromatic structures resulted in the dramatic increase in the soil water drop penetration time. It was confirmed that this enhancement of the soil hydrophobicity is not related to an increased concentration of soil free lipid, but is

  14. Daily changes of radon concentration in soil gas under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity

    International Nuclear Information System (INIS)

    Lara, Evelise G.; Oliveira, Arno Heeren de

    2015-01-01

    This work aims at relating the daily change in the radon concentration in soil gas in a Red Yellow Acrisol (SiBCS) under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity. The 226 Ra, 232 Th, U content and permeability were also performed. The measurements of radon soil gas were carried out by using an AlphaGUARD monitor. The 226 Ra activity concentration was made by Gamma Spectrometry (HPGe); the permeability was carried out using the RADON-JOK permeameter and ICP-MS analysis to 232 Th and U content. The soil permeability is 5.0 x 10 -12 , which is considered average. The 226 Ra (22.2 ± 0.3 Bq.m -3 ); U content (73.4 ± 3.6 Bq.kg -1 ) and 232 Th content (55.3 ± 4.0 Bq.kg -1 ) were considered above of average concentrations, according to mean values for soils typical (~ 35.0 Bq.kg -1 ) by UNSCEAR. The results showed a difference of 26.0% between the highest and the lowest concentration of radon in soil gas: at midnight (15.5 ± 1.0 kBq.m -3 ) and 3:00 pm, the highest mean radon concentration (21.0 ± 1.0 kBq.m -3 ). The room temperature and surface soil temperature showed equivalent behavior and the surface soil temperature slightly below room temperature during the entire monitoring time. Nevertheless, the relative humidity showed the highest cyclical behavior, showing a higher relationship with the radon concentration in soil gas. (author)

  15. Comparative effects of sulfuric and nitric acid rain on litter decomposition and soil microbial community in subtropical plantation of Yangtze River Delta region.

    Science.gov (United States)

    Liu, Xin; Zhang, Bo; Zhao, Wenrui; Wang, Ling; Xie, Dejin; Huo, Wentong; Wu, Yanwen; Zhang, Jinchi

    2017-12-01

    Acid rain is mainly caused by dissolution of sulfur dioxide and nitrogen oxides in the atmosphere, and has a significant negative effect on ecosystems. The relative composition of acid rain is changing gradually from sulfuric acid rain (SAR) to nitric acid rain (NAR) with the rapidly growing amount of nitrogen deposition. In this study, we investigated the impact of simulated SAR and NAR on litter decomposition and the soil microbial community over four seasons since March 2015. Results first showed that the effects of acid rain on litter decomposition and soil microbial were positive in the early period of the experiment, except for SAR on soil microbes. Second, soil pH with NAR decreased more rapidly with the amount of acid rain increased in summer than with SAR treatments. Only strongly acid rain (both SAR and NAR) was capable of depressing litter decomposition and its inhibitory effect was stronger on leaf than on fine root litter. Meanwhile, NAR had a higher inhibitory effect on litter decomposition than SAR. Third, in summer, autumn and winter, PLFAs were negatively impacted by the increased acidity level resulting from both SAR and NAR. However, higher acidity level of NAR (pH=2.5) had the strongest inhibitory impact on soil microbial activity, especially in summer. In addition, Gram-negative bacteria (cy19:0) and fungi (18:1ω9) were more sensitive to both SAR and NAR, and actinomycetes was more sensitive to SAR intensity. Finally, soil total carbon, total nitrogen and pH were the most important soil property factors affecting soil microbial activity, and high microbial indices (fungi/bacteria) with high soil pH. Our results suggest that the ratio of SO 4 2- to NO 3 - in acid rain is an important factor which could affect litter decomposition and soil microbial in subtropical forest of China. Copyright © 2017. Published by Elsevier B.V.

  16. Aluminium tolerance and high phosphorus efficiency helps Stylosanthes better adapt to low-P acid soils.

    Science.gov (United States)

    Du, Yu-Mei; Tian, Jiang; Liao, Hong; Bai, Chang-Jun; Yan, Xiao-Long; Liu, Guo-Dao

    2009-06-01

    Stylosanthes spp. (stylo) is one of the most important pasture legumes used in a wide range of agricultural systems on acid soils, where aluminium (Al) toxicity and phosphorus (P) deficiency are two major limiting factors for plant growth. However, physiological mechanisms of stylo adaptation to acid soils are not understood. Twelve stylo genotypes were surveyed under field conditions, followed by sand and nutrient solution culture experiments to investigate possible physiological mechanisms of stylo adaptation to low-P acid soils. Stylo genotypes varied substantially in growth and P uptake in low P conditions in the field. Three genotypes contrasting in P efficiency were selected for experiments in nutrient solution and sand culture to examine their Al tolerance and ability to utilize different P sources, including Ca-P, K-P, Al-P, Fe-P and phytate-P. Among the three tested genotypes, the P-efficient genotype 'TPRC2001-1' had higher Al tolerance than the P-inefficient genotype 'Fine-stem' as indicated by relative tap root length and haematoxylin staining. The three genotypes differed in their ability to utilize different P sources. The P-efficient genotype, 'TPRC2001-1', had superior ability to utilize phytate-P. The findings suggest that possible physiological mechanisms of stylo adaptation to low-P acid soils might involve superior ability of plant roots to tolerate Al toxicity and to utilize organic P and Al-P.

  17. Acid-base status and changes in Swedish forest soils

    International Nuclear Information System (INIS)

    Karltun, Erik; Stendahl, Johan; Lundin, Lars

    2003-01-01

    In this paper we use data from the Swedish National Survey of Forest Soils and Vegetation (NSFSV) to evaluate the present acid-base status of forest soils to try to answer the following questions. Which role do anthropogenic and biological acidification play for the present acid-base status of the soil profile? What is the present acid-base status of Swedish forest soils and how large areas may be considered as severely acidified? Do the current tendencies in soil acid-base status correspond with the positive development in surface waters?

  18. Accumulation of Heavy Metals in Roadside Soil in Urban Area and the Related Impacting Factors.

    Science.gov (United States)

    Wang, Meie; Zhang, Haizhen

    2018-05-24

    Heavy metal contamination in roadside soil due to traffic emission has been recognized for a long time. However, seldom has been reported regarding identification of critical factors influencing the accumulation of heavy metals in urban roadside soils due to the frequent disturbances such as the repair of damaged roads and green belt maintanance. Heavy metals in the roadside soils of 45 roads in Xihu district, Hangzhou city were investigated. Results suggested the accumulation of Cu, Pb, Cd, Cr, and Zn in roadside soil was affected by human activity. However, only two sites had Pb and Zn excessing the standards for residential areas, respectively, according to Chinese Environmental Quality Standards for soils. The concentrations of Cu, Pb, Cd, and Zn were significantly and positively correlated to soil pH and organic matter. An insignificant correlation between the age of the roads or vegetation cover types and the concentration of heavy metals was found although they were reported closely relating to the accumulation of heavy metals in roadside soils of highways. The highest Pb, Cd, and Cr taking place in sites with heavy traffic and significant differences in the concentrations of Cu, Pb, Cd, and Zn among the different categories of roads suggested the contribution of traffic intensity. However, it was difficult to establish a quantitative relationship between traffic intensity and the concentrations of heavy metals in the roadside soil. It could be concluded that impaction of traffic emission on the accumulation of heavy metals in roadside soils in urban area was slight and soil properties such as pH and organic matters were critical factors influencing the retention of heavy metals in soils.

  19. The response of amino acid cycling to global change across multiple biomes: Feedbacks on soil nitrogen availability

    Science.gov (United States)

    Brzostek, E. R.; Finzi, A. C.

    2010-12-01

    The cycling of organic nitrogen (N) in soil links soil organic matter decomposition to ecosystem productivity. Amino acids are a key pool of organic N in the soil, whose cycling is sensitive to alterations in microbial demand for carbon and N. Further, the amino acids released from the breakdown of protein by proteolytic enzymes are an important source of N that supports terrestrial productivity. The objective of this study was to measure changes in amino acid cycling in response to experimental alterations of precipitation and temperature in twelve global change experiments during the 2009 growing season. The study sites ranged from arctic tundra to xeric grasslands. The treatments experimentally increased temperature, increased or decreased precipitation, or some combination of both factors. The response of amino acid cycling to temperature and precipitation manipulations tended to be site specific, but the responses could be placed into a common framework. Changes in soil moisture drove a large response in amino acid cycling. Precipitation augmentation in xeric and mesic sites increased both amino acid pool sizes and production. However, treatments that decreased precipitation drove decreases in amino acid cycling in xeric sites, but led to increases in amino acid cycling in more mesic sites. Across sites, the response to soil warming was horizon specific. Amino acid cycling in organic rich horizons responded positively to warming, while negative responses were exhibited in lower mineral soil horizons. The variable response likely reflects a higher availability of protein substrate to sustain high rates of proteolytic enzyme activity in organic rich horizons. Overall, these results suggest that soil moisture and the availability of protein substrate may be important factors that mediate the response of amino acid cycling to predicted increases in soil temperatures.

  20. Daily changes of radon concentration in soil gas under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Lara, Evelise G.; Oliveira, Arno Heeren de, E-mail: evelise.lara@gmail.com, E-mail: heeren@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Rocha, Zildete; Rios, Francisco Javier, E-mail: rochaz@cdtn.br, E-mail: javier@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    This work aims at relating the daily change in the radon concentration in soil gas in a Red Yellow Acrisol (SiBCS) under influence of atmospheric factors: room temperature, soil surface temperature and relative humidity. The {sup 226}Ra, {sup 232}Th, U content and permeability were also performed. The measurements of radon soil gas were carried out by using an AlphaGUARD monitor. The {sup 226}Ra activity concentration was made by Gamma Spectrometry (HPGe); the permeability was carried out using the RADON-JOK permeameter and ICP-MS analysis to {sup 232}Th and U content. The soil permeability is 5.0 x 10{sup -12}, which is considered average. The {sup 226}Ra (22.2 ± 0.3 Bq.m{sup -3}); U content (73.4 ± 3.6 Bq.kg{sup -1}) and {sup 232}Th content (55.3 ± 4.0 Bq.kg{sup -1}) were considered above of average concentrations, according to mean values for soils typical (~ 35.0 Bq.kg{sup -1}) by UNSCEAR. The results showed a difference of 26.0% between the highest and the lowest concentration of radon in soil gas: at midnight (15.5 ± 1.0 kBq.m{sup -3}) and 3:00 pm, the highest mean radon concentration (21.0 ± 1.0 kBq.m{sup -3}). The room temperature and surface soil temperature showed equivalent behavior and the surface soil temperature slightly below room temperature during the entire monitoring time. Nevertheless, the relative humidity showed the highest cyclical behavior, showing a higher relationship with the radon concentration in soil gas. (author)

  1. Organic Acids Regulation of Chemical-Microbial Phosphorus Transformations in Soils.

    Science.gov (United States)

    Menezes-Blackburn, Daniel; Paredes, Cecilia; Zhang, Hao; Giles, Courtney D; Darch, Tegan; Stutter, Marc; George, Timothy S; Shand, Charles; Lumsdon, David; Cooper, Patricia; Wendler, Renate; Brown, Lawrie; Blackwell, Martin; Wearing, Catherine; Haygarth, Philip M

    2016-11-01

    We have used an integrated approach to study the mobility of inorganic phosphorus (P) from soil solid phase as well as the microbial biomass P and respiration at increasing doses of citric and oxalic acid in two different soils with contrasting agronomic P status. Citric or oxalic acids significantly increased soil solution P concentrations for doses over 2 mmol kg -1 . However, low organic acid doses (<2 mmol kg -1 ) were associated with a steep increase in microbial biomass P, which was not seen for higher doses. In both soils, treatment with the tribasic citric acid led to a greater increase in soil solution P than the dibasic oxalic acid, likely due to the rapid degrading of oxalic acids in soils. After equilibration of soils with citric or oxalic acids, the adsorbed-to-solution distribution coefficient (K d ) and desorption rate constants (k -1 ) decreased whereas an increase in the response time of solution P equilibration (T c ) was observed. The extent of this effect was shown to be both soil and organic acid specific. Our results illustrate the critical thresholds of organic acid concentration necessary to mobilize sorbed and precipitated P, bringing new insight on how the exudation of organic acids regulate chemical-microbial soil phosphorus transformations.

  2. Bromine accumulation in acidic black colluvial soils

    Science.gov (United States)

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

    2016-02-01

    Recent investigations showed that bromine is incorporated to soil organic matter (SOM), its content increasing with humification. But few research was done on its long-term accumulation and the role played by pedogenetic processes, as those involved in organic matter stabilization. We investigated bromine content and distribution in four deep, acidic, organic-rich, Holocene soils from an oceanic area of Western Europe. Bromine concentrations (93-778 μg g-1) in the silt + clay (stabilized as aluminium-OM associations, and to a lesser extent on soil acidity (pH) and iron-OM associations. Thus, at scales of thousands of years, bromine accumulation in acidic soils is linked to the pool of metal-clay-stabilized organic matter.

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

    Science.gov (United States)

    Wong, Vanessa; Yau, Chin; Kennedy, David

    2015-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Nurhidayati

    2014-10-01

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

  5. Acidity field of soils as ion-exchange systems and the diagnostics of genetic soil horizons

    Science.gov (United States)

    Kokotov, Yu. A.; Sukhacheva, E. Yu.; Aparin, B. F.

    2014-12-01

    For the comprehensive description of the acidity of a two-phase ion-exchange system, we should analyze two curves of the ionite titration by a strong base in water and salt solutions and find the quantitative relationships between the corresponding pH characteristics. An idea of the three-dimensional field of acidity of ion-exchange systems (the phase space of the soil acidity characteristics) and its three two-dimensional projections is suggested. For soils, three interrelated characteristics—the pH values of the salt and water extracts and the degree of base saturation—can serve as spatial coordinates for the acidity field. Representation of factual data in this field makes it possible to compare and analyze the acidity characteristics of different soils and soil horizons and to determine their specific features. Differentiation of the field into separate volumes allows one to present the data in a discrete form. We have studied the distribution patterns of the groups of soil horizons from Leningrad oblast and other regions of northwestern Russia in the acidity field. The studied samples are grouped in different partially overlapping areas of the projections of the acidity field. The results of this grouping attest to the correctness of the modern classification of Russian soils. A notion of the characteristic soil area in the acidity field is suggested; it can be applied to all the soils with a leaching soil water regime.

  6. The Role of Organic Acids on the Release of Phosphorus and Zinc in a Calcareous Soil

    Directory of Open Access Journals (Sweden)

    Sareh Nezami

    2017-02-01

    that the effect of different concentrations of organic acids at various times on the pH of extractions was significant at 1% level. Low concentrations of organic acids at various times had no effect on the pH of soil extractions compared to control, but organic acids at 10 mM concentration increased the pH of extractions. This high pH amount was related to the organic acid mineralization and consumption of H+ by microorganisms in the soil. The results of variance analysis also showed that the effect of different concentrations of organic acids at various times in the extraction of Ca from the soil was significant at 1% level .Citric acid extracted higher Ca from the soil compared to oxalic acid. The maximum extracted Ca was observed at 10 mM concentration of citric acid at 10 minutes of shaking time. Extracted Ca at 0.1 and 1 mM concentrations of both organic acids was almost the same at all the times. The higher extraction of Ca with citric acid was due to the Ca precipitation as oxalate. The analysis of variance for P showed that the effect of different concentrations of organic acids at various times was significant at the 1% level. Extracted P by oxalic acid was more than citric acid .The highest amount of P was obtained by 10 mM concentration of oxalic acid at 360 minutes. The amounts of extracted P by both organic acids at 0.1 and 1 mM concentrations were similar to control. Citric acid at 10 mM concentration also released lower P compared to other concentrations and control. More P extraction of oxalate than citrate was due to the Ca-oxalate formation and P release from calcium phosphate in calcareous soil. Different concentrations of organic acids at different time periods had no effect on Zn extraction from the soil and the amount of extracted Zn by organic acids was lower than control. Conclusion: Organic acids at 10 mM concentration were effective in Ca and P extraction from the soil but had no significant effect on the Zn extraction. It seems that organic

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

    International Nuclear Information System (INIS)

    Fernandez-Calvino, D.; Soler-Rovira, P.; Polo, A.; Arias-Estevez, M.; Plaza, C.

    2010-01-01

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

  8. Transfer factors of 134Cs for olive and orange trees grown on different soils

    International Nuclear Information System (INIS)

    Skarlou, V.; Nobeli, C.; Anoussis, J.; Haidouti, C.; Papanicolaou, E.

    1999-01-01

    Transfer factors (TF) of 134 Cs to olive and citrus trees grown on two different soils, were determined for a 3-year greenhouse experiment. Two-year-old trees were transplanted with their entire rootball into large pots containing the contaminated soil (110 kg pot -1 ). The soil was transferred to each pot in layers on the top of which 134 Cs as CsCl was dripped (18.5 MBq pot -1 ). For both evergreen trees, soil type significantly influenced radiocaesium transfer. 134 Cs concentration was lower for the calcareous-heavy soil than for the acid-light soil. Transfer factors of orange trees were higher than those of olive trees in the acid-light soil. Although a significant amount of 134 Cs was measured in olives grown on the acid-light soil, no 134 Cs was detected in the unprocessed olive oil when an oil fraction (5% f.w.) was extracted. On the contrary the edible part of the oranges showed the highest 134 Cs concentration of all plant parts. The relationship between 134 Cs uptake and potassium content in the different plant compartments was also studied when selected trees were cut down. The potassium concentration in the plants was not significantly different between the trees growing in the two types of soil in spite of the big differences in the 134 Cs uptake in the two soils. TF values and potassium content in the different plant compartments of each tree were highly correlated. For both crops transfer factors as well as potassium content were the highest in the developing plant parts (new leaves and branches, flowers). The transfer factors of 134 Cs for the studied trees are in the same order of magnitude as the values of annual crops grown under similar conditions. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. Soil properties related to 60Co bioavailability in tropical soils

    International Nuclear Information System (INIS)

    Bartoly, Flavia; Wasserman, Maria Angelica; Rochedo, Elaine Ruas Rodriguez; Viana, Aline Gonzalez; Souza, Rodrigo Camara; Oliveira, Giselle Rodrigues; Reis, Wagner Goncalves Soares; Perez, Daniel Vidal

    2005-01-01

    This work presents the results of field experiments to obtain soil to plants Transfer factor (TF) for 60 Co in reference plants cultivated in Ferralsol, Acrisol and Nitisol. These soils represent the majority of Brazilian agricultural area. Values of TF varied from 0.001 to 0.05 for corn and from 0.001 to 0.81 for cabbage. Results of 60 Co TF were discussed in relation to the physical and chemical properties of the soils and 60 Co geochemical partition. The sequential chemical extraction showed that more than 40% of the 60 Co present in the soils are associated to manganese oxides. These results will provide regional values for parameters used in the environmental radiological modeling aiming to optimize the planning of emergency interventions or the waste management related to tropical soils. (author)

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

    International Nuclear Information System (INIS)

    Wang, H.; Ambe, S.; Takematsu, N.; Ambe, F.

    1998-01-01

    Acid rain has become one of the most serious environmental problems. Soil loses its buffering capacity by long exposure to acid rain, and the soil pH value decreases significantly. The acidification of the soil disturbs the adsorption equilibrium of many elements in the soil-water system. Soil is a very complex heterogeneous system, primarily consisting of clay minerals, hydrous oxides and polymeric organic substances, which possess their own characteristic element-adsorbing properties. On the other hand, the intrinsic properties of elements are reflected in their adsorption process as a matter of course. Therefore, both the effects of the pH of acid rain and that of the components of the soil on the adsorption of different elements should be studied when the adsorption process in acid soils is to be clarified. Although leaching of major cations in soil, such as Ca 2+ , Mg 2+ and Al 3+ , by acid rain, has been extensively studied, relatively little attention has been focused on trace elements which can also seriously affect the ecological system. We studied the acid rain effects on element adsorption by kaolin, forest soil, black soil, and also these soils with Fe- and Mn-oxides or organic matter selectively removed by using the radioactive multitracer technique. (author)

  11. Sensitivity Analysis of the USLE Soil Erodibility Factor to Its Determining Parameters

    Science.gov (United States)

    Mitova, Milena; Rousseva, Svetla

    2014-05-01

    Soil erosion is recognized as one of the most serious soil threats worldwide. Soil erosion prediction is the first step in soil conservation planning. The Universal Soil Loss Equation (USLE) is one of the most widely used models for soil erosion predictions. One of the five USLE predictors is the soil erodibility factor (K-factor), which evaluates the impact of soil characteristics on soil erosion rates. Soil erodibility nomograph defines K-factor depending on soil characteristics, such as: particle size distribution (fractions finer that 0.002 mm and from 0.1 to 0.002 mm), organic matter content, soil structure and soil profile water permeability. Identifying the soil characteristics, which mostly influence the K-factor would give an opportunity to control the soil loss through erosion by controlling the parameters, which reduce the K-factor value. The aim of the report is to present the results of analysis of the relative weight of these soil characteristics in the K-factor values. The relative impact of the soil characteristics on K-factor was studied through a series of statistical analyses of data from the geographic database for soil erosion risk assessments in Bulgaria. Degree of correlation between K-factor values and the parameters that determine it was studied by correlation analysis. The sensitivity of the K-factor was determined by studying the variance of each parameter within the range between minimum and maximum possible values considering average value of the other factors. Normalizing transformation of data sets was applied because of the different dimensions and the orders of variation of the values of the various parameters. The results show that the content of particles finer than 0.002 mm has the most significant relative impact on the soil erodibility, followed by the content of particles with size from 0.1 mm to 0.002 mm, the class of the water permeability of the soil profile, the content of organic matter and the aggregation class. The

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  13. Effect of Soil Amendments on Microbial Resilience Capacity of Acid Soil Under Copper Stress.

    Science.gov (United States)

    Mounissamy, Vassanda Coumar; Kundu, Samaresh; Selladurai, Rajendiran; Saha, Jayanta Kumar; Biswas, Ashish Kumar; Adhikari, Tapan; Patra, Ashok Kumar

    2017-11-01

    An incubation study was undertaken to study microbial resilience capacity of acid soil amended with farmyard manure (FYM), charcoal and lime under copper (Cu) perturbation. Copper stress significantly reduced enzymatic activities and microbial biomass carbon (MBC) in soil. Percent reduction in microbial activity of soil due to Cu stress was 74.7% in dehydrogenase activity, 59.9% in MBC, 48.2% in alkaline phosphatase activity and 15.1% in acid phosphatase activity. Soil treated with FYM + charcoal showed highest resistance index for enzymatic activities and MBC. Similarly, the highest resilience index for acid phosphatase activity was observed in soil amended with FYM (0.40), whereas FYM + charcoal-treated soil showed the highest resilience indices for alkaline, dehydrogenase activity and MBC: 0.50, 0.22 and 0.25, respectively. This investigation showed that FYM and charcoal application, either alone or in combination, proved to be better than lime with respect to microbial functional resistance and resilience of acid soil under Cu perturbation.

  14. Relating soil biochemistry to sustainable crop production

    Science.gov (United States)

    Amino acids, amino sugars, carbohydrates, phenols, and fatty acids together comprise appreciable proportions of soil organic matter (SOM). Their cycling contribute to soil processes, including nitrogen availability, carbon sequestration and aggregation. For example, soil accumulation of phenols has ...

  15. Relating microbial community structure to functioning in forest soil organic carbon transformation and turnover.

    Science.gov (United States)

    You, Yeming; Wang, Juan; Huang, Xueman; Tang, Zuoxin; Liu, Shirong; Sun, Osbert J

    2014-03-01

    Forest soils store vast amounts of terrestrial carbon, but we are still limited in mechanistic understanding on how soil organic carbon (SOC) stabilization or turnover is controlled by biotic and abiotic factors in forest ecosystems. We used phospholipid fatty acids (PLFAs) as biomarker to study soil microbial community structure and measured activities of five extracellular enzymes involved in the degradation of cellulose (i.e., β-1,4-glucosidase and cellobiohydrolase), chitin (i.e., β-1,4-N-acetylglucosaminidase), and lignin (i.e., phenol oxidase and peroxidase) as indicators of soil microbial functioning in carbon transformation or turnover across varying biotic and abiotic conditions in a typical temperate forest ecosystem in central China. Redundancy analysis (RDA) was performed to determine the interrelationship between individual PFLAs and biotic and abiotic site factors as well as the linkage between soil microbial structure and function. Path analysis was further conducted to examine the controls of site factors on soil microbial community structure and the regulatory pathway of changes in SOC relating to microbial community structure and function. We found that soil microbial community structure is strongly influenced by water, temperature, SOC, fine root mass, clay content, and C/N ratio in soils and that the relative abundance of Gram-negative bacteria, saprophytic fungi, and actinomycetes explained most of the variations in the specific activities of soil enzymes involved in SOC transformation or turnover. The abundance of soil bacterial communities is strongly linked with the extracellular enzymes involved in carbon transformation, whereas the abundance of saprophytic fungi is associated with activities of extracellular enzymes driving carbon oxidation. Findings in this study demonstrate the complex interactions and linkage among plant traits, microenvironment, and soil physiochemical properties in affecting SOC via microbial regulations.

  16. Determination of amino acids in industrial effluents contaminated soil

    International Nuclear Information System (INIS)

    Mahar, M.T.; Khuhawar, M.Y.

    2014-01-01

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

  17. Characteristics of biomass ashes from different materials and their ameliorative effects on acid soils.

    Science.gov (United States)

    Shi, Renyong; Li, Jiuyu; Jiang, Jun; Mehmood, Khalid; Liu, Yuan; Xu, Renkou; Qian, Wei

    2017-05-01

    The chemical characteristics, element contents, mineral compositions, and the ameliorative effects on acid soils of five biomass ashes from different materials were analyzed. The chemical properties of the ashes varied depending on the source biomass material. An increase in the concrete shuttering contents in the biomass materials led to higher alkalinity, and higher Ca and Mg levels in biomass ashes, which made them particularly good at ameliorating effects on soil acidity. However, heavy metal contents, such as Cr, Cu, and Zn in the ashes, were relatively high. The incorporation of all ashes increased soil pH, exchangeable base cations, and available phosphorus, but decreased soil exchangeable acidity. The application of the ashes from biomass materials with a high concrete shuttering content increased the soil available heavy metal contents. Therefore, the biomass ashes from wood and crop residues with low concrete contents were the better acid soil amendments. Copyright © 2016. Published by Elsevier B.V.

  18. {sup 134}Cs uptake by four plant species and Cs-K relations in the soil-plant system as affected by Ca(OH){sub 2} application to an acid soil

    Energy Technology Data Exchange (ETDEWEB)

    Massas, I., E-mail: massas@aua.g [Soil Science Laboratory, Department of Natural Resources Management and Agricultural Engineering, Agricultural University of Athens, Iera Odos 75, 11855 Athens (Greece); Skarlou, V.; Haidouti, C.; Giannakopoulou, F. [Soil Science Laboratory, Department of Natural Resources Management and Agricultural Engineering, Agricultural University of Athens, Iera Odos 75, 11855 Athens (Greece)

    2010-03-15

    Three rates of Ca(OH){sub 2} were applied to an acid soil and the {sup 134}Cs uptake by radish, cucumber, soybean and sunflower plants was studied. The {sup 134}Cs concentration in all plant species was reduced from 1.6-fold in the sunflower seeds to 6-fold in the soybean vegetative parts at the higher Ca(OH){sub 2} rate. Potassium (K) concentration in plants was also reduced, but less effectively. The significantly decreased {sup 134}Cs-K soil to plant distribution factors (D.F.) clearly suggest a stronger effect of soil liming on {sup 134}Cs than on K plant uptake. This observation was discussed in terms of ionic interactions in the soil matrix and within the plants. The results also indicated that the increased Ca{sup 2+} concentration in the exchange phase and in the soil solution along with the improved root activity, due to the soil liming, enhanced the immobilization of {sup 134}Cs in the soil matrix and consequently lowered the {sup 134}Cs availability for plant uptake.

  19. Microbial community analysis in rice paddy soils irrigated by acid mine drainage contaminated water.

    Science.gov (United States)

    Sun, Min; Xiao, Tangfu; Ning, Zengping; Xiao, Enzong; Sun, Weimin

    2015-03-01

    Five rice paddy soils located in southwest China were selected for geochemical and microbial community analysis. These rice fields were irrigated with river water which was contaminated by Fe-S-rich acid mine drainage. Microbial communities were characterized by high-throughput sequencing, which showed 39 different phyla/groups in these samples. Among these phyla/groups, Proteobacteria was the most abundant phylum in all samples. Chloroflexi, Acidobacteria, Nitrospirae, and Bacteroidetes exhibited higher relative abundances than other phyla. A number of rare and candidate phyla were also detected. Moreover, canonical correspondence analysis suggested that pH, sulfate, and nitrate were significant factors that shaped the microbial community structure. In addition, a wide diversity of Fe- and S-related bacteria, such as GOUTA19, Shewanella, Geobacter, Desulfobacca, Thiobacillus, Desulfobacterium, and Anaeromyxobacter, might be responsible for biogeochemical Fe and S cycles in the tested rice paddy soils. Among the dominant genera, GOUTA19 and Shewanella were seldom detected in rice paddy soils.

  20. Soil amino acid composition across a boreal forest successional sequence

    Science.gov (United States)

    Nancy R. Werdin-Pfisterer; Knut Kielland; Richard D. Boone

    2009-01-01

    Soil amino acids are important sources of organic nitrogen for plant nutrition, yet few studies have examined which amino acids are most prevalent in the soil. In this study, we examined the composition, concentration, and seasonal patterns of soil amino acids across a primary successional sequence encompassing a natural gradient of plant productivity and soil...

  1. [Relation between species distribution of plant community and soil factors under grazing in alpine meadow].

    Science.gov (United States)

    Niu, Yu Jie; Yang, Si Wei; Wang, Gui Zhen; Liu, Li; Du, Guo Zhen; Hua, Li Min

    2017-12-01

    The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

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

    International Nuclear Information System (INIS)

    Zhou, Jun; Wang, Zhangwei; Zhang, Xiaoshan; Chen, Jian

    2015-01-01

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

  3. Plant uptake and soil retention of phthalic acid applied to Norfolk sandy loam

    International Nuclear Information System (INIS)

    Dorney, J.R.; Weber, J.B.; Overcash, M.R.; Strek, H.J.

    1985-01-01

    Plant uptake and soil retention of 14 C carboxyl-labeled phthalic acid were studied at application rates of 0.6, 6.0, 60.0, and 600.0 ppm (soil dry weight) to Norfolk sandy loam (Typic Paleudult, fine loamy, kaolinitic, thermic). Height and dry weight of corn (Zea mays L. Pioneer 3368A) (21 day), tall fescue (Festuca arundinacea Schreb. Kentucky 31) (45 day) immature soybean (Glycine max (L.) Merr. Altoona) (21 day) plant, mature soybean plant, and mature wheat (Triticum aestivum L. Butte) straw were not affected by phthalic acid applied to soil. In addition, soybean seed and wheat seed dry weight were unaffected. Immature wheat (40 day) height decreased at the 600 ppm rate. Plant uptake of phthalic acid ranged from 0 to 23 ppm and was significantly above background for all plants and plant materials except soybean pods. Fescue and immature plants exhibited the highest concentration of phthalic acid while mature wheat plants and wheat seeds exhibited the least. Most of the phthalic acid volatilized or was decomposed from the soil by the end of the study; an average of only 5.7% of the originally applied chemical was recovered in both soil or plants. An average of 0.02% of the originally applied phthalic acid leached out of the treated zone. Considering the low toxicity of phthalic acid and its relatively rapid disappearance from soil, it is unlikely to become a health hazard from contaminated plants. However, plant uptake of other toxic organics could potentially become a hazard on soils treated with sludge containing significant quantities of these substances

  4. Seasonal abundance of soil arthropods in relation to meteorological and edaphic factors in the agroecosystems of Faisalabad, Punjab, Pakistan

    Science.gov (United States)

    Shakir, Muhammad Mussadiq; Ahmed, Sohail

    2015-05-01

    Soil arthropods are an important component of agroecosystems, contributing significantly to their biodiversity and functioning. However, seasonal patterns, population dynamics, and significant roles of these soil arthropods in improvement of soil structures and functions are influenced by many factors. The objective of the current study was to investigate soil arthropod abundance in relation to a blend of meteorological and edaphic factors and to find out the difference in abundance among various crops (sugarcane, cotton, wheat, alfalfa fodder, and citrus orchards). The arthropod sampling was done by pitfall traps and Tullgren extractions on fortnightly intervals. Soil temperature and relative humidity were noted on the field sites while analysis for soil pH, organic matter, and soil moisture contents were done in the laboratory. The rainfall data was obtained from an observatory. Results showed that significant differences were found in soil arthropod abundance across different sampling months and crops. Out of total 13,673 soil arthropods sampled, 38 % belonged to Collembola, followed by 15 % Hymenoptera, 15 % Acarina, 11 % Myriapods, 6 % Coleoptera, 5 % Orthoptera, and 5 % Araneae. Mean abundance per sample was highest in summer months as compared to winter. Overall abundance per sample was significantly different between all crops ( p Aranae, Coleoptera), least abundant (Dermaptera, Hemiptera, Diptera), and rare (Blattaria, Isoptera, Diplura, Lepidoptera). Soil temperature and soil organic matter showed significant positive correlation with abundance, while relative humidity was significantly negatively correlated. Soil moisture and soil pH showed no significant correlations while no correlation was found with total rainfall. PCA analysis revealed that soil surface arthropods were the major contributors of variation in overall abundance in extreme temperature months while microarthropods in low-temperature months. CCA analysis revealed the occurrence of

  5. Seasonal abundance of soil arthropods in relation to meteorological and edaphic factors in the agroecosystems of Faisalabad, Punjab, Pakistan.

    Science.gov (United States)

    Shakir, Muhammad Mussadiq; Ahmed, Sohail

    2015-05-01

    Soil arthropods are an important component of agroecosystems, contributing significantly to their biodiversity and functioning. However, seasonal patterns, population dynamics, and significant roles of these soil arthropods in improvement of soil structures and functions are influenced by many factors. The objective of the current study was to investigate soil arthropod abundance in relation to a blend of meteorological and edaphic factors and to find out the difference in abundance among various crops (sugarcane, cotton, wheat, alfalfa fodder, and citrus orchards). The arthropod sampling was done by pitfall traps and Tullgren extractions on fortnightly intervals. Soil temperature and relative humidity were noted on the field sites while analysis for soil pH, organic matter, and soil moisture contents were done in the laboratory. The rainfall data was obtained from an observatory. Results showed that significant differences were found in soil arthropod abundance across different sampling months and crops. Out of total 13,673 soil arthropods sampled, 38 % belonged to Collembola, followed by 15 % Hymenoptera, 15 % Acarina, 11 % Myriapods, 6 % Coleoptera, 5 % Orthoptera, and 5 % Araneae. Mean abundance per sample was highest in summer months as compared to winter. Overall abundance per sample was significantly different between all crops (p arthropods according to abundance, i.e., highly abundant (Collembola, Acarina, Myripoda, Hymenoptera), moderately abundant (Orthoptera, Aranae, Coleoptera), least abundant (Dermaptera, Hemiptera, Diptera), and rare (Blattaria, Isoptera, Diplura, Lepidoptera). Soil temperature and soil organic matter showed significant positive correlation with abundance, while relative humidity was significantly negatively correlated. Soil moisture and soil pH showed no significant correlations while no correlation was found with total rainfall. PCA analysis revealed that soil surface arthropods were the major contributors of variation in overall

  6. TOLERANCE OF PEANUT GENOTYPES TO ACIDIC SOIL CONDITION

    Directory of Open Access Journals (Sweden)

    Astanto Kasno

    2013-06-01

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

  7. Effect of some soil amendments on soil properties and plant growth in Southern Thailand acid upland soil

    Directory of Open Access Journals (Sweden)

    Onthong, C.

    2007-01-01

    Full Text Available One of the major factors limiting plant growth is acid soil. In general lime is used for soil amendment in acid soil. However, It has been reported that gypsum or phosphogypsum can be used for ameliorating soilacidity. Pot experiment was conducted to study the effects of lime, phosphogypsum and kieserite on soil properties and plant growth in Kho Hong soil series (coarse loamy, kaolinitic,isohyperthermic, TypicKandiudults which was considered as acid upland soil (pH 5.07. Sweet corn variety INSEE 2 was used as the test crop. The experiment was a completely randomized design with 4 replications and 19 treatments asfollow : unamended, application of hydrated lime and dolomite to raise soil pH at 5.5, application of hydrated lime and dolomite combined with phosphogypsum at the rate that can supply calcium 0.25, 0.50,0.75 and 1 time of both limes, application of hydrated lime and dolomite combined with kieserite at the rate 0.25, 0.50,0.75 and 1 times of sulfur requirement for corn (40 kg S ha-1. The result showed that shoot and root dry weights of corn were increased when lime materials, phosphogypsum and kieserite were applied and the drymatter weights were increased according to the increasing of phosphogypsum and kieserite. The maximum shoot dry weight (18.98 g pot-1 was obtained when 1 times of kieserite was supplied with dolomite and wassignificantly (P<0.01 higher than those of the unamended treatment, only hydrated lime and dolomite treatments, which had dry weights of 12.64, 15.18 and 15.67 g pot-1 respectively. Phosphorus and K uptakewere not significantly different in all treatments and the lowest uptake of N, Ca, Mg and S was obtained in the unamended treatment. The maximum uptake of N (512.10 mg pot-1 was found when 0.5 times ofphosphogypsum was applied together with dolomite. Calcium and Mg uptake was likely to increase according to the increasing rate of soil amendment application. Highest uptake of Ca (42.51 mg pot-1 was obtainedwhen

  8. Acid-deposition research program. Volume 2. Effects of acid-forming emissions on soil microorganisms and microbially-mediated processes

    Energy Technology Data Exchange (ETDEWEB)

    Visser, S.; Danielson, R.M.; Parr, J.F.

    1987-02-01

    The interactions of soil physical, chemical, and biological processes are ultimately expressed in a soil's fertility and its capacity for plant production. Consequently, much of the research conducted to date regarding the impact of acid-forming pollutants on soil properties has been geared towards possible effects on plant productivity. This trend continues in this paper where the effects of acidic deposition on microbial communities are reviewed in relation to potential impact on plant growth. The objectives of the review are to discuss: (1) The effects of acid-forming emissions (primarily S-containing pollutants) on microbial community structure with emphasis on qualitative and quantitative aspects; (2) The effects of acidic deposition on microbially mediated processes (i.e., community functions); (3) Acidification effects of pollutants on symbiotic and disease-causing microorganisms. The symbionts discussed include ectomycorrhizal fungi, vesicular-arbuscular mycorrhizal fungi, and N/sub 2/-fixing bacteria, particularly Rhizobium, while the disease-causing microorganisms will include those responsible for foliage, stem, and root diseases.

  9. Carbon stabilization and microbial growth in acidic mine soils after addition of different amendments for soil reclamation

    Science.gov (United States)

    Zornoza, Raúl; Acosta, Jose; Ángeles Muñoz, María; Martínez-Martínez, Silvia; Faz, Ángel; Bååth, Erland

    2016-04-01

    The extreme soil conditions in metalliferous mine soils have a negative influence on soil biological activity and therefore on soil carbon estabilization. Therefore, amendments are used to increase organic carbon content and activate microbial communities. In order to elucidate some of the factors controlling soil organic carbon stabilization in reclaimed acidic mine soils and its interrelationship with microbial growth and community structure, we performed an incubation experiment with four amendments: pig slurry (PS), pig manure (PM) and biochar (BC), applied with and without marble waste (MW; CaCO3). Results showed that PM and BC (alone or together with MW) contributed to an important increment in recalcitrant organic C, C/N ratio and aggregate stability. Bacterial and fungal growths were highly dependent on pH and labile organic C. PS supported the highest microbial growth; applied alone it stimulated fungal growth, and applied with MW it stimulated bacterial growth. BC promoted the lowest microbial growth, especially for fungi, with no significant increase in fungal biomass. MW+BC increased bacterial growth up to values similar to PM and MW+PM, suggesting that part of the biochar was degraded, at least in short-term mainly by bacteria rather than fungi. PM, MW+PS and MW+PM supported the highest microbial biomass and a similar community structure, related with the presence of high organic C and high pH, with immobilization of metals and increased soil quality. BC contributed to improved soil structure, increased recalcitrant organic C, and decreased metal mobility, with low stimulation of microbial growth.

  10. The effect of oxygen on fatty acid composition of soil micromycetes

    Czech Academy of Sciences Publication Activity Database

    Jirout, Jiří

    2015-01-01

    Roč. 53, June (2015), s. 125-128 ISSN 1470-160X R&D Projects: GA ČR GPP504/12/P752 Institutional support: RVO:60077344 Keywords : soil micromycetes * oxygen depletion * fatty acids Subject RIV: EE - Microbiology, Virology Impact factor: 3.190, year: 2015

  11. Drainage, liming and fertilization of organic soils. 1. Long-term effects on acid/base relations

    International Nuclear Information System (INIS)

    Braekke, F.H.

    1999-01-01

    Long-term changes of the acid/base relations of organic soils after drainage, fertilization and/or liming at three experimental sites - two ombrogenous and one soligenous - in south-central Norway are discussed. These sites were drained, fertilized and/or limed in 1953-1956 and sampled in 1991-1992. Drainage at the ombrogenous sites caused: insignificant shifts of pH, higher bulk densities to 40 cm depth, higher ash percentage, higher contents of N and P to 20 cm depth and reduced concentrations of total Ca, K, Mg, Na, Al and Fe in soil layers deeper than 20 cm. The soligenous site was not effectively drained; despite this, pH dropped about 0.5 unit in the surface and subsurface soil layers of the control plots, while small changes were measured for most other soil variables. The suggested reason for the pH drop is limited sulphide oxidation in the upper 20 cm drained layer. Base saturation at actual soil pH, when all treatments were included, was estimated with good precision by four regressors: pH, extractable Al, extractable Fe and extractable Ca (R 2 = 0.90-0.95). Similar models explained 97-99% of the variation in base saturation at soil pH = 7.0. The lime effects at the properly drained oligotrophic sites were proportional to applied doses; for pH to 40 cm, base saturation to 60 cm, and Ca concentration to 60 cm depth. At the less well-drained soligenous site, effects were limited to the upper 30 cm layer. Both drainage and liming caused higher cation exchange capacities and proper drainage seems to be a prerequisite for the liming effect. Estimated recovery of calcium to 60 cm depth was 64-79% at the ombrogenous sites and 42-46% at the soligenous site 28 refs, 3 figs, 8 tabs

  12. Wheat genotypes differing in aluminum tolerance differ in their growth response to CO2 enrichment in acid soils

    OpenAIRE

    Tian, Qiuying; Zhang, Xinxin; Gao, Yan; Bai, Wenming; Ge, Feng; Ma, Yibing; Zhang, Wen-Hao

    2013-01-01

    Aluminum (Al) toxicity is a major factor limiting plant growth in acid soils. Elevated atmospheric CO2 [CO2] enhances plant growth. However, there is no report on the effect of elevated [CO2] on growth of plant genotypes differing in Al tolerance grown in acid soils. We investigated the effect of short-term elevated [CO2] on growth of Al-tolerant (ET8) and Al-sensitive (ES8) wheat plants and malate exudation from root apices by growing them in acid soils under ambient [CO2] and elevated [CO2]...

  13. Soil Chemistry Effect on Feasibility of Cr-decontamination by Acid-Washing

    OpenAIRE

    Isoyama, Masahiro; Wada, Shin-Ichiro

    2006-01-01

    Soil washing with sample acid jas been proven to be effective for removal of cationic heavy metals from contaminated soils. Since the obsorption of anitonic heavy metals is enhanced in acidic medium, the efficiency of acid-washing may not be guaranteed for soils that are doubly contaminated with cationic and anitonic heavy metals. To evaluate the efficiensy of acid-washing, nine soils are artifically contaminated with chromate and chromium was extracted with hydrochrolic acid of 0.5 mmol L[-1...

  14. The effect of simulated acid rain on the stabilization of cadmium in contaminated agricultural soils treated with stabilizing agents.

    Science.gov (United States)

    Zhu, Hao; Wu, Chunfa; Wang, Jun; Zhang, Xumei

    2018-04-16

    Stabilization technology is one of widely used remediation technologies for cadmium (Cd)-contaminated agricultural soils, but stabilized Cd in soil may be activated again when external conditions such as acid rain occurred. Therefore, it is necessary to study the effect of acid rain on the performance of different stabilizing agents on Cd-polluted agriculture soils. In this study, Cd-contaminated soils were treated with mono-calcium phosphate (MCP), mono-ammonium phosphate (MAP), and artificial zeolite (AZ) respectively and incubated 3 months. These treatments were followed by two types of simulated acid rain (sulfuric acid rain and mixed acid rain) with three levels of acidity (pH = 3.0, 4.0, and 5.6). The chemical forms of Cd in the soils were determined by Tessier's sequential extraction procedure, and the leaching toxicities of Cd in the soils were assessed by toxicity characteristic leaching procedure (TCLP). The results show that the three stabilizing agents could decrease the mobility of Cd in soil to some degree with or without simulated acid rain (SAR) treatment. The stabilization performances followed the order of AZ stabilized soil, and both anion composition and pH of acid rain were two important factors that influenced the stabilization effect of Cd.

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

    Directory of Open Access Journals (Sweden)

    Renata Wilma Vasconcelos

    2014-08-01

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

  16. Aluminium release from acidic forest soil following deforestation and ...

    African Journals Online (AJOL)

    Acidic tropical soils often have high Al3+ concentrations in soil solutions, which can be toxic to plants and, thereby, reduce agricultural yields. This study focuses on the impact of deforestation and cultivation on the short and long-term Al geochemistry of acidic soils in Ghana, West Africa. Site-specific investigations were ...

  17. Biodegradation and speciation of residual SS-ethylenediaminedisuccinic acid (EDDS) in soil solution left after soil washing.

    Science.gov (United States)

    Tandy, Susan; Ammann, Adrian; Schulin, Rainer; Nowack, Bernd

    2006-07-01

    This paper aims to investigate the degradation and speciation of EDDS-complexes (SS-ethylenediaminedisuccinic acid) in soil following soil washing. The changes in soil solution metal and EDDS concentrations were investigated for three polluted soils. EDDS was degraded after a lag phase of 7-11 days with a half-life of 4.18-5.60 days. No influence of EDDS-speciation on the reaction was observed. The decrease in EDDS resulted in a corresponding decrease in solubilized metals. Changes in EDDS speciation can be related to (1) initial composition of the soil, (2) temporarily anoxic conditions in the soil slurry after soil washing, (3) exchange of EDDS complexes with Cu even in soils without elevated Cu and (4) formation of NiEDDS. Dissolved organic matter is important for metal speciation at low EDDS concentrations. Our results show that even in polluted soils EDDS is degraded from a level of several hundred micromoles to below 1 microM within 50 days.

  18. Effect of EDTA and citric acid on phytoremediation of Cr- B[a]P-co-contaminated soil.

    Science.gov (United States)

    Chigbo, Chibuike; Batty, Lesley

    2013-12-01

    Polycyclic aromatic hydrocarbons and heavy metals in the environment are a concern, and their removal to acceptable level is required. Phytoremediation, the use of plants to treat contaminated soils, could be an interesting alternative to conventional remediation processes. This work evaluates the role of single and combined applications of chelates to single or mixed Cr + benzo[a]pyrene (B[a]P)-contaminated soil. Medicago sativa was grown in contaminated soil and was amended with 0.3 g citric acid, 0.146 g ethylenediaminetetraacetic acid (EDTA), or their combination for 60 days. The result shows that in Cr-contaminated soil, the application of EDTA + citric acid significantly (psoil. The soluble Cr concentration in single Cr or Cr + B[a]P-contaminated soil was enhanced with the amendment of all chelates; however, only the application of citric acid in Cr-contaminated soil (44 %) or EDTA and EDTA + citric acid in co-contaminated soil increased the removal of Cr from the soil (34 and 54 %, respectively). The dissipation of B[a]P in single B[a]P-contaminated soil was effective even without planting and amendment with chelates, while in co-contaminated soil, it was related to the application of either EDTA or EDTA + citric acid. This suggests that M. sativa with the help of chelates in single or co-contaminated soil can be effective in phytoextraction of Cr and promoting the biodegradation of B[a]P.

  19. Pore water sampling in acid sulfate soils: a new peeper method.

    Science.gov (United States)

    Johnston, Scott G; Burton, Edward D; Keene, Annabelle F; Bush, Richard T; Sullivan, Leigh A; Isaacson, Lloyd

    2009-01-01

    This study describes the design, deployment, and application of a modified equilibration dialysis device (peeper) optimized for sampling pore waters in acid sulfate soils (ASS). The modified design overcomes the limitations of traditional-style peepers, when sampling firm ASS materials over relatively large depth intervals. The new peeper device uses removable, individual cells of 25 mL volume housed in a 1.5 m long rigid, high-density polyethylene rod. The rigid housing structure allows the device to be inserted directly into relatively firm soils without requiring a supporting frame. The use of removable cells eliminates the need for a large glove-box after peeper retrieval, thus simplifying physical handling. Removable cells are easily maintained in an inert atmosphere during sample processing and the 25-mL sample volume is sufficient for undertaking multiple analyses. A field evaluation of equilibration times indicates that 32 to 38 d of deployment was necessary. Overall, the modified method is simple and effective and well suited to acquisition and processing of redox-sensitive pore water profiles>1 m deep in acid sulfate soil or any other firm wetland soils.

  20. Hydrochemistry of rivers in an acid sulphate soil hotspot area in western Finland

    Directory of Open Access Journals (Sweden)

    M. ROOS

    2008-12-01

    Full Text Available During heavy rains and snow melting, acid sulphate (AS soils on the coastal plains of Finland are flushed resulting in discharge of acidic and metal-rich waters that strongly affect small streams. In this study, the impact of AS soils occurrence and hydrological changes on water quality were determined for 21 rivers (catchment sizes between 96–4122 km2 running through an AS soil hotspot area in western central Finland. Water samples, collected at the outlet, during eight selected events, were analysed for pH, dissolved organic carbon, electrical conductivity (EC and 32 chemical elements. Based on the correlation with percentage arable land in the catchments (a rough estimate of AS soil occurrences, as up to 50% of the arable land is underlain with these soils, it was possible to categorize variables into those that are enriched in runoff from such land, depleted in runoff from such land (only one element, and not affected by land-use type in the catchments. Of the variables enriched in runoff from arable land, some were leached from AS soils during high-water flows, in particular (aluminium, boron, beryllium, cadmium, cobalt, copper, lithium, manganese, nickel, sulphur, silicon, thorium, thallium, uranium, and zinc and others occurred in highest concentrations during lower flows (calcium, EC, potassium, magnesium, sodium, rubidium and strontium. Molybdenum and phosphorus were not leached from AS soils in larger amounts than from other soils and thus related to other factors connected to the arable land. Based on the concentrations of potentially toxic metals derived from AS soils, the 21 rivers were ranked from the least (Lestijoki River, Lapväärtinjoki River and Perhonjoki River to the most (Sulvanjoki River, Vöyrinjoki River and Maalahdenjoki River heavily AS soil impacted. It has been decided that Vöyrinjoki is to be dredged along a ca. 20 km distance. This is quite alarming considering the high metal concentrations in the river.;

  1. Micronutrient Availability in Relation to Selected Soil Properties and landscape Position in Calcareous Soils of Golpayegan

    Directory of Open Access Journals (Sweden)

    Mojtaba Fathi

    2017-02-01

    Full Text Available Introduction: Variety of soil reactions govern the distribution of metal micronutrients that includes complexation with organic and inorganic ligands, ion exchange, adsorption and desorption processes, precipitation and dissolution of solids and acid-based equilibria. The relative importance of these reactions depends on many factors such as soil physical, chemical, and mineralogical properties and the nature of metal ions. Environmental factors such as climate, physiographic position, and soil development may affect variability of some soil properties and thereby nutrient availability. The present research was conducted to find relationships between Iron, manganese, zinc, and copper availability and some major soil properties, physiographic condition and soil development. Materials and Methods: Golpayegan region is located in northwest of Isfahan province in central Iran. The mean elevation of the studied area is 1790 above sea level. Annual precipitation was about 244mm and mean monthly temperature ranges from -6 in January to 34°C in August. The soils were developed on different physiographic conditions including piedmont plains, alluvial-fan, plateaus, and flood plains belonging to Entisols and Aridisols. Soil samples (0–60 cm were collected from 98 grid points with 2000m distance in the agricultural area of Golpayegan. Particle size distribution, calcium carbonate, organic carbon, available potassium and phosphorus of the soils were measured by SWRI standard methods. Available Zn, Cu, Mn, and Fe were determined by addition of 10 g soil to 20mL 0.005M diethylentriaminepentacetic‏. The solutions were shaken for 2 h at 25°C, centrifuged, filtered, and Fe, Mn, Zn, and Cu concentrations were measured by an atomic absorption spectrophotometer. Results Discussion: Studied soils were developed on calcareous material and about 60% of samples have more than 20% of calcium carbonate. Available Fe ranged from 1.4 to 6.5 mg kg-1 (mean 15.8 mg kg-1

  2. Relative age and age sequence of fractions of soil organic matter

    International Nuclear Information System (INIS)

    Scharpenseel, H.W.

    1975-01-01

    Natural radiocarbon measurements on soil fractions provide information regarding the chances of separating the ''old biologically inert carbon'' out of samples of recent soil material. Beyond this, the relative fraction ages are scrutinized for the sequential order of the origin of the fractions within the biosynthetic reaction chain of soil humic matter. Among all fractions compared (classic humic matter fractionation by alkali and acid treatment; successive extraction with organic solvents of increasing polarity; separation according to particle size by Sephadex gel filtration; hydrolysis residue) the 6 n HCl hydrolysis residue shows the most consistent significant age increment. Repeated exhaustive hydrolysis treatment of the same sample material is still pending. All other fraction types indicate an age pattern under strong predetermination by method of origin, e.g., existence or lack of hydromorphy, without an evident enrichment of the ''old biologically inert carbon''. Among the organic extracts, no persistent age hierarchy is noticeable, whereas the classical fractions follow an age sequence mainly parallel to an increase of the molecular weight. Hymatomelanic acids appear rejuvenated by relics of recent carbon derived from the extractant ethanol. Grey humic acids are older than the brown humic acids, humines from fully terrestrial soil environment are older than humic acids, while in hydromorphic soils, cold alkali insoluble young C-compounds seem to be conserved which are liable to falsify rejuvenation of the humines

  3. Potential origin and formation for molecular components of humic acids in soils

    Science.gov (United States)

    Hatcher, Patrick; DiDonato, Nicole; Waggoner, Derek

    2016-04-01

    Humification is defined as the process by which plant and microbial debris are transformed in to humic substances. Proposed pathways for the formation of humic substances, include the lignin and lignin decomposition theories, the lignin-polyphenol theory as well as the melanoidin pathway. It is generally accepted that a combination of several of these pathways with some modifications may be responsible for producing humic substances. The current study examines humic acids from numerous soil samples to demonstrate their molecular composition. In addition we provide an explanation for the formation of these molecules that introduces a new perspective of the humification process. Our work utilizes advanced analytical techniques such as ESI-FTICR-MS and solid state NMR to more completely characterize humic acids at the molecular level. Methods Humic acids were extracted from soils using 0.5 M NaOH followed by treatment with a Dowex™ ion-exchange resin to remove sodium ions. Solid State 13C NMR spectra were obtained on a Bruker 400 MHz Avance II spectrometer equipped with a 4 mm solid state MAS probe. ESI-FTICR-MS analysis was conducted in the negative ion mode on a Bruker Daltonics 12 Tesla Apex Qe FTICR-MS instrument equipped with an Apollo II ESI source. Results: Soil humic acids from numerous soils were investigated in this study. The molecular formulas calculated from ultrahigh resolution mass spectra of well humified soils fall clearly into two predominant regions consisting of condensed aromatic molecules as well as high H/C, low O/C carboxyl-containing aliphatic molecules (CCAM). In contrast, the spectral data for humic acids from a poorly humified spodosol soil show a less dramatic separation of these regions, with relatively more molecular formula plotting in the lignin-like region and relatively fewer condensed aromatic molecules. From the mass spectral observations made for the humic acids, we can readily discern a relationship based on degree of

  4. Ion activity and distribution of heavy metals in acid mine drainage polluted subtropical soils

    International Nuclear Information System (INIS)

    Li Yongtao; Becquer, Thierry; Dai Jun; Quantin, Cecile; Benedetti, Marc F.

    2009-01-01

    The oxidative dissolution of mine wastes gives rise to acidic, metal-enriched mine drainage (AMD) and has typically posed an additional risk to the environment. The poly-metallic mine Dabaoshan in South China is an excellent test site to understand the processes affecting the surrounding polluted agricultural fields. Our objectives were firstly to investigate metal ion activity in soil solution, distribution in solid constituents, and spatial distribution in samples, secondly to determine dominant environment factors controlling metal activity in the long-term AMD-polluted subtropical soils. Soil Column Donnan Membrane Technology (SC-DMT) combined with sequential extraction shows that unusually large proportion of the metal ions are present as free ion in the soil solutions. The narrow range of low pH values prevents any pH effects during the binding onto oxides or organic matter. The differences in speciation of the soil solutions may explain the different soil degradation observed between paddy and non-paddy soils. - First evidence of the real free metal ion concentrations in acid mine drainage context in tropical systems

  5. Retention of available P in acid soils of tropical and subtropical evergreen broad-leaved forests

    Institute of Scientific and Technical Information of China (English)

    CHEN Jianhui; ZOU Xiaoming; YANG Xiaodong

    2007-01-01

    Precipitation of mineral phosphate is often recognized as a factor of limiting the availability of P in acidic soils of tropical and subtropical forests.For this paper,we studied the extractable P pools and their transformation rates in soils of a tropical evergreen forest at Xishuangbanna and a subtropical montane wet forest at the Ailao Mountains in order to understand the biogeochemical processes regulating P availability in acidic soils.The two forests differ in forest humus layer;it is deep in the Ailao forest while little is present in the Xishuangbanna forest.The extractable P pools by resin and sodium-bicarbonate decreased when soil organic carbon content was reduced.The lowest levels of extractable P pools occurred in the surface (0-10 era) mineral soils of the Xishuangbanna forest.However,microbial P in the mineral soil of the Xishuangbauna forest was twice that in the Ailao forest.Potential rates of microbial P immobilization were greater than those of organic P mineralization in mineral soils for both forests.We suggest that microbial P immobilization plays an essential role in avoiding mineral P precipitation and retaining available P of plant in tropical acidic soils,whereas both floor mass accumulation and microbial P immobilization function benefit retaining plant available P in subtropical montane wet forests.

  6. Different low-molecular-mass organic acids specifically control leaching of arsenic and lead from contaminated soil.

    Science.gov (United States)

    Ash, Christopher; Tejnecký, Václav; Borůvka, Luboš; Drábek, Ondřej

    2016-04-01

    Low-molecular-mass organic acids (LMMOA) are of key importance for mobilisation and fate of metals in soil, by functioning as ligands that increase the amount of dissolved metal in solution or by dissociation of metal binding minerals. Column leaching experiments were performed on soil polluted with As and Pb, in order to determine the specificity of LMMOA related release for individual elements, at varying organic acid concentrations. Acetic, citric and oxalic acids were applied in 12h leaching experiments over a concentration range (0.5-25 mM) to soil samples that represent organic and mineral horizons. The leaching of As followed the order: oxalic>citric>acetic acid in both soils. Arsenic leaching was attributed primarily to ligand-enhanced dissolution of mineral oxides followed by As released into solution, as shown by significant correlation between oxalic and citric acids and content of Al and Fe in leaching solutions. Results suggest that subsurface mineral soil layers are more vulnerable to As toxicity. Leaching of Pb from both soils followed the order: citric>oxalic>acetic acid. Mineral soil samples were shown to be more susceptible to leaching of Pb than samples characterised by a high content of organic matter. The leaching efficiency of citric acid was attributed to formation of stable complexes with Pb ions, which other acids are not capable of. Results obtained in the study are evidence that the extent of As and Pb leaching in contaminated surface and subsurface soil depends significantly on the types of carboxylic acid involved. The implications of the type of acid and the specific element that can be mobilised become increasingly significant where LMMOA concentrations are highest, such as in rhizosphere soil. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. The role of organic acids exuded from roots in phosphorus nutrition and aluminium tolerance in acidic soils

    Energy Technology Data Exchange (ETDEWEB)

    Hocking, P J; Randall, P J; Delhaize, E [CSIRO Plant Industry, Canberra (Australia); Keerthisinghe, G [International Atomic Energy Agency, Vienna (Austria)

    2000-06-01

    Soil acidity is a major problem of large areas of arable land on a global scale. Many acid soils are low in plant-available phosphorus (P) or are highly P-fixing, resulting in poor plant growth. In addition, aluminium (Al) is soluble in acid soils in the toxic Al{sup 3+} form, which also reduces plant growth. There is considerable evidence that both P deficiency and exposure to Al{sup 3+} stimulate the efflux of organic acids from roots of a range of species. Organic acids such as citrate, malate and oxalate are able to desorb or solubilise fixed soil P, making it available for plant uptake. Organic acids also chelate Al{sup 3+} to render it non-toxic, and are, therefore, involved in Al tolerance mechanisms. In this review, we discuss the literature on the role of organic acids exuded from roots in improving plant P uptake and Al-tolerance in acid soils. Research is now attempting to understand how P deficiency or exposure to Al{sup 3+} activates or induces organic acid efflux at the molecular level, with the aim of improving P acquisition and Al tolerance by conventional plant breeding and by genetic engineering. At the agronomic level, it is desirable that existing crop and pasture plants with enhanced soil-P uptake and tolerance to Al due to organic acid exudation are integrated into farming systems. (author)

  8. The role of organic acids exuded from roots in phosphorus nutrition and aluminium tolerance in acidic soils

    International Nuclear Information System (INIS)

    Hocking, P.J.; Randall, P.J.; Delhaize, E.; Keerthisinghe, G.

    2000-01-01

    Soil acidity is a major problem of large areas of arable land on a global scale. Many acid soils are low in plant-available phosphorus (P) or are highly P-fixing, resulting in poor plant growth. In addition, aluminium (Al) is soluble in acid soils in the toxic Al 3+ form, which also reduces plant growth. There is considerable evidence that both P deficiency and exposure to Al 3+ stimulate the efflux of organic acids from roots of a range of species. Organic acids such as citrate, malate and oxalate are able to desorb or solubilise fixed soil P, making it available for plant uptake. Organic acids also chelate Al 3+ to render it non-toxic, and are, therefore, involved in Al tolerance mechanisms. In this review, we discuss the literature on the role of organic acids exuded from roots in improving plant P uptake and Al-tolerance in acid soils. Research is now attempting to understand how P deficiency or exposure to Al 3+ activates or induces organic acid efflux at the molecular level, with the aim of improving P acquisition and Al tolerance by conventional plant breeding and by genetic engineering. At the agronomic level, it is desirable that existing crop and pasture plants with enhanced soil-P uptake and tolerance to Al due to organic acid exudation are integrated into farming systems. (author)

  9. Relative influence of soil chemistry and topography on soil available micronutrients by structural equation modeling

    OpenAIRE

    Zhu, Hongfen; Zhao, Ying; Nan, Feng; Duan, Yonghong; Bi, Rutian

    2016-01-01

    Soil chemical and topographic properties are two important factors influencing available micronutrient distribution of soil in the horizontal dimension. The objective of this study was to explore the relative influence of soil chemistry (including soil pH, soil organic matter, total nitrogen, available phosphorus, and available potassium) and topography (including elevation, slope, aspect, and wetness index) on the availability of micronutrients (Fe, Mn, Cu, Zn, and B) using structural equati...

  10. Interaction between Al3+ and acrylic acid and polyacrylic acid in acidic aqueous solution: a model experiment for the behavior of Al3+ in acidified soil solution.

    Science.gov (United States)

    Etou, Mayumi; Masaki, Yuka; Tsuji, Yutaka; Saito, Tomoyuki; Bai, Shuqin; Nishida, Ikuko; Okaue, Yoshihiro; Yokoyama, Takushi

    2011-01-01

    From the viewpoint of the phytotoxicity and mobility of Al(3+) released from soil minerals due to soil acidification, the interaction between Al(3+) and acrylic acid (AA) and polyacrylic acid (PAA) as a model compound of fulvic acid was investigated. The interaction was examined at pH 3 so as to avoid the hydrolysis of Al(3+). The interaction between Al(3+) and AA was weak. However, the interaction between Al(3+) and PAA was strong and depended on the initial (COOH in PAA)/Al molar ratio (R(P)) of the solution. For the range of 1/R(P), the interaction between Al(3+) and PAA can be divided into three categories: (1) 1:1 Al-PAA-complex (an Al(3+) combines to a carboxyl group), (2) intermolecular Al-PAA-complex (an Al(3+) combines to more than 2 carboxyl groups of other Al-PAA-complexes) in addition to the 1:1 Al-PAA-complex and (3) precipitation of intermolecular complexes. In conclusion, R(P) is an important factor affecting the behavior of Al(3+) in acidic soil solution.

  11. Supplementing predictive mapping of acid sulfate soil occurrence with Vis-NIR spectroscopy

    DEFF Research Database (Denmark)

    Beucher, Amélie; Peng, Yi; Knadel, Maria

    , including geology, landscape type and terrain parameters. Visible-Near-Infrared (Vis-NIR) spectroscopy constitutes a rapid and cheap alternative to soil analysis, and was successfully utilized for the prediction of soil chemical, physical and biological properties. In particular, the Vis-NIR spectra contain......Releasing acidity and metals into watercourses, acid sulfate soils represent a critical environmental problem worldwide. Identifying the spatial distribution of these soils enables to target the strategic areas for risk management. In Denmark, the occurrence of acid sulfate soils was first studied...... during the 1980’s through conventional mapping (i.e. soil sampling and the subsequent determination of pH at the time of sampling and after incubation, the pyrite content and the acid-neutralizing capacity). Since acid sulfate soils mostly occur in wetlands, the survey specifically targeted these areas...

  12. Variability of the soil-to-plant radiocaesium transfer factor for Japanese soils predicted with soil and plant properties.

    Science.gov (United States)

    Uematsu, Shinichiro; Vandenhove, Hildegarde; Sweeck, Lieve; Van Hees, May; Wannijn, Jean; Smolders, Erik

    2016-03-01

    Food chain contamination with radiocaesium (RCs) in the aftermath of the Fukushima accident calls for an analysis of the specific factors that control the RCs transfer. Here, soil-to-plant transfer factors (TF) of RCs for grass were predicted from the potassium concentration in soil solution (mK) and the Radiocaesium Interception Potential (RIP) of the soil using existing mechanistic models. The mK and RIP were (a) either measured for 37 topsoils collected from the Fukushima accident affected area or (b) predicted from the soil clay content and the soil exchangeable potassium content using the models that had been calibrated for European soils. An average ammonium concentration was used throughout in the prediction. The measured RIP ranged 14-fold and measured mK varied 37-fold among the soils. The measured RIP was lower than the RIP predicted from the soil clay content likely due to the lower content of weathered micas in the clay fraction of Japanese soils. Also the measured mK was lower than that predicted. As a result, the predicted TFs relying on the measured RIP and mK were, on average, about 22-fold larger than the TFs predicted using the European calibrated models. The geometric mean of the measured TFs for grass in the affected area (N = 82) was in the middle of both. The TFs were poorly related to soil classification classes, likely because soil fertility (mK) was obscuring the effects of the soil classification related to the soil mineralogy (RIP). This study suggests that, on average, Japanese soils are more vulnerable than European soils at equal soil clay and exchangeable K content. The affected regions will be targeted for refined model validation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Role of organic acids on the bioavailability of selenium in soil: A review.

    Science.gov (United States)

    Dinh, Quang Toan; Li, Zhe; Tran, Thi Anh Thu; Wang, Dan; Liang, Dongli

    2017-10-01

    Organic Acids (OAs) are important components in the rhizosphere soil and influence Se bioavailability in soil. OAs have a bidirectional contrasting effect on Se bioavailability. Understanding the interaction of OAs with Se is essential to assessing Se bioavailability in soil and clarifying the role of OAs in controlling the behavior and fate of Se in soil. This review examines the mechanisms for the (im)mobilization of Se by OAs and discusses the practical implications of these mechanisms in relation to sequestration and bioavailability of Se in soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Spatio-temporal variability of acid sulphate soils in the plain of reeds, Vietnam : impact of soil properties, water management and crop husbandry on the growth and yield of rice in relation to microtopography

    NARCIS (Netherlands)

    Husson, O.

    1998-01-01

    Acid sulphate soils in the Mekong delta cover 1.6 million hectares, of which 400 000 ha are located in the Plain of Reeds. Due to the presence of pyrite that yields acid when oxidised, all acid sulphate soils are (potentially) strongly acidic. Reclamation of the 150 000 ha of severely acid

  15. Interactive effects of biochar ageing in soils related to feedstock, pyrolysis temperature, and historic charcoal production.

    Science.gov (United States)

    Heitkötter, Julian; Marschner, Bernd

    2015-04-01

    Biochar is suggested for soil amelioration and carbon sequestration, based on its assumed role as the key factor for the long-term fertility of Terra preta soils. Several studies have shown that certain biochar properties can undergo changes through ageing processes, especially regarding charge characteristics. However, only a few studies determined the changes of different biochars under the same incubation conditions and in different soils. The objective of this study was to characterize the changes of pine chip (PC)- and corn digestate (CD)-derived biochars pyrolyzed at 400 or 600 °C during 100 days of laboratory incubation in a historical kiln soil and an adjacent control soil. Separation between soil and biochar was ensured by using mesh bags. Especially, changes in charge characteristics depended on initial biochar properties affected by feedstock and pyrolysis temperature and on soil properties affected by historic charcoal production. While the cation exchange capacity (CEC) markedly increased for both CD biochars during incubation, PC biochars showed no or only slight increases in CEC. Corresponding to the changes in CEC, ageing of biochars also increased the amount of acid functional groups with increases being in average about 2-fold higher in CD biochars than in PC biochars. Further and in contrast to other studies, the surface areas of biochars increased during ageing, likely due to ash leaching and degradation of tar residues. Changes in CEC and surface acidity of CD biochars were more pronounced after incubation in the control soil, while surface area increase was higher in the kiln soil. Since the two acidic forest soils used in this this study did not greatly differ in physical or chemical properties, the main process for inducing these differences in the buried biochar most likely is related to the differences in dissolved organic carbon (DOC). Although the kiln soil contained about 50% more soil organic carbon due to the presence of charcoal

  16. Bioavailability of phosphorus from composts and struvite in acid soils

    Directory of Open Access Journals (Sweden)

    Carmo Horta

    Full Text Available ABSTRACT The objective of this study was to assess the type and fractions of phosphorus (P forms in composts and struvite and how these P forms affect the bioavailability of P in the soil. P fertilization was performed with compost from sewage sludge (CSS, compost from poultry litter (CPL and struvite (SV and compared with single superphosphate (SSP. P forms were quantified through a sequential fractionation scheme. The first extraction was performed with H2O, the second with 0.5 M NaHCO3, the third with 0.1 M NaOH and the fourth with 1 M HCl. The release of P over time, after soil P fertilization, was assessed by incubating the fertilizers with a low-P acid soil. P bioavailability was assessed through a micro-pot experiment with the incubated soils in a growth chamber using rye plants (Secale cereale L.. Inorganic P forms in the first two fractions represented ~50% (composts, 32% (SV and 86% (SSP of the total P; and in the HCl fraction, ~40% (composts, 26% (SV and 13% (SSP of the total P. Despite the variability of the P form fractions in the composts and struvite, the P release and bioavailability were similar among the fertilized treatments. The acidic nature of the soil, which improve solubility of Ca-P forms, and the high efficiency of rye, which favors P uptake, were factors that contributed to these results.

  17. Simultaneous Removal of Lindane, Lead and Cadmium from Soils by Rhamnolipids Combined with Citric Acid

    Science.gov (United States)

    Long, Tao; Ying, Rongrong; Ye, Mao; Zhang, Shengtian; Li, Qun; Zhou, Yan; Lin, Yusuo

    2015-01-01

    This study investigated the performance of rhamnolipids-citric acid mixed agents in simultaneous desorption of lindane and heavy metals from soils. The capacity of the mixed agents to solubilize lindane, lead and cadmium in aqueous solution was also explored. The results showed that the presence of citric acid greatly enhanced the solubilization of lindane and cadmium by rhamnolipids. A combined effect of the mixed agents on lindane and heavy metals removal from soils was observed. The maximum desorption ratios for lindane, cadmium and lead were 85.4%, 76.4% and 28.1%, respectively, for the mixed agents containing 1% rhamnolipidsand 0.1 mol/L citric acid. The results also suggest that the removal efficiencies of lead and cadmium were strongly related to their speciations in soils, and metals in the exchangeable and carbonate forms were easier to be removed. Our study suggests that the combining use of rhamnolipids and citric acid is a promising alternative to simultaneously remove organochlorine pesticides and heavy metals from soils. PMID:26087302

  18. Extraction of rare earth elements from a contaminated cropland soil using nitric acid, citric acid, and EDTA.

    Science.gov (United States)

    Tang, Hailong; Shuai, Weitao; Wang, Xiaojing; Liu, Yangsheng

    2017-08-01

    Rare earth elements (REEs) contamination to the surrounding soil has increased the concerns of health risk to the local residents. Soil washing was first attempted in our study to remediate REEs-contaminated cropland soil using nitric acid, citric acid, and ethylene diamine tetraacetic acid (EDTA) for soil decontamination and possible recovery of REEs. The extraction time, washing agent concentration, and pH value of the washing solution were optimized. The sequential extraction analysis proposed by Tessier was adopted to study the speciation changes of the REEs before and after soil washing. The extract containing citric acid was dried to obtain solid for the X-ray fluorescence (XRF) analysis. The results revealed that the optimal extraction time was 72 h, and the REEs extraction efficiency increased as the agent concentration increased from 0.01 to 0.1 mol/L. EDTA was efficient to extract REEs over a wide range of pH values, while citric acid was around pH 6.0. Under optimized conditions, the average extraction efficiencies of the major REEs in the contaminated soil were 70.96%, 64.38%, and 62.12% by EDTA, nitric acid, and citric acid, respectively. The sequential extraction analyses revealed that most soil-bounded REEs were mobilized or extracted except for those in the residual fraction. Under a comprehensive consideration of the extraction efficiency and the environmental impact, citric acid was recommended as the most suitable agent for extraction of the REEs from the contaminated cropland soils. The XRF analysis revealed that Mn, Al, Si, Pb, Fe, and REEs were the major elements in the extract indicating a possibile recovery of the REEs.

  19. Analysis of Factors Influencing Soil Salinity, Acidity, and Arsenic Concentration in a Polder in Southwest Bangladesh

    Science.gov (United States)

    Ayers, J. C.; Patton, B.; Fry, D. C.; Goodbred, S. L., Jr.

    2017-12-01

    Soil samples were collected on Polder 32 in the coastal zone of SW Bangladesh in wet (October) and dry (May) seasons from 2013-2017 and analyzed to characterize the problems of soil salinization and arsenic contamination and identify their causes. Soils are entisols formed from recently deposited, predominantly silt-sized sediments with low carbon concentrations typical of the local mangrove forests. Soluble (DI extract) arsenic concentrations were below the Government of Bangladesh limit of 50 ppb for drinking water. Soil acidity and extract arsenic concentrations exhibit spatial variation but no consistent trends. In October soil extract As is higher and S and pH are lower than in May. These observations suggest that wet season rainwater oxidizes pyrite, reducing soil S and releasing H+, causing pH to decrease. Released iron is oxidized to form Hydrous Ferric Oxyhydroxides (HFOs), which sorb As and increase extractable As in wet season soils. Changes in pH are small due to pH buffering by soil carbonates. Soil and rice paddy water salinities are consistently higher in May than October, reaching levels in May that reduce rice yields. Rice grown in paddies should be unaffected by salt concentrations in the wet season, while arsenic concentrations in soil may be high enough to cause unsafe As levels in produced rice.

  20. Acid phosphomonoesterase (E.C. 3.1.3.2) location in soil

    Czech Academy of Sciences Publication Activity Database

    Rejšek, K.; Vránová, V.; Pavelka, Marian; Formánek, P.

    2012-01-01

    Roč. 175, č. 5 (2012), s. 196-211 ISSN 1436-8730 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional research plan: CEZ:AV0Z60870520 Keywords : acid phosphomonoesterase * soil * roots * mycorrhizal fungi * location * extraction Subject RIV: EH - Ecology, Behaviour Impact factor: 1.380, year: 2012

  1. Potential microbial risk factors related to soil amendments and irrigation water of potato crops.

    Science.gov (United States)

    Selma, M V; Allende, A; López-Gálvez, F; Elizaquível, P; Aznar, R; Gil, M I

    2007-12-01

    This study assesses the potential microbial risk factors related to the use of soil amendments and irrigation water on potato crops, cultivated in one traditional and two intensive farms during two harvest seasons. The natural microbiota and potentially pathogenic micro-organisms were evaluated in the soil amendment, irrigation water, soil and produce. Uncomposted amendments and residual and creek water samples showed the highest microbial counts. The microbial load of potatoes harvested in spring was similar among the tested farms despite the diverse microbial levels of Listeria spp. and faecal coliforms in the potential risk sources. However, differences in total coliform load of potato were found between farms cultivated in the autumn. Immunochromatographic rapid tests and the BAM's reference method (Bacteriological Analytical Manual; AOAC International) were used to detect Escherichia coli O157:H7 from the potential risk sources and produce. Confirmation of the positive results by polymerase chain reaction procedures showed that the immunochromatographic assay was not reliable as it led to false-positive results. The potentially pathogenic micro-organisms of soil amendment, irrigation water and soil samples changed with the harvest seasons and the use of different agricultural practices. However, the microbial load of the produce was not always influenced by these risk sources. Improvements in environmental sample preparation are needed to avoid interferences in the use of immunochromatographic rapid tests. The potential microbial risk sources of fresh produce should be regularly controlled using reliable detection methods to guarantee their microbial safety.

  2. Efficiency of sulfuric acid, mined gypsum, and two gypsum by-products in soil crusting prevention and sodic soil reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Amezketa, E.; Aragues, R.; Gazol, R. [Gobierno Navarra, Pamplona (Spain). Agricultural Resources Evaluation Center

    2005-06-01

    We evaluated the efficiency of four amendments (sulfuric acid, mined-gypsum, and the by-products coal-gypsum and lacto-gypsum) in crusting prevention of two calcareous nonsodic and sodic soils and in sodic soil reclamation. Treatments for crust prevention consisted of surface-applied amendments at equivalent rates of 5 Mg pure-gypsum ha{sup -1}. Treatments for sodic soil reclamation consisted of surface-applied acid and soil-incorporated gypsums at rates of 1 pure-gypsum requirement. The efficiency of these amendments was evaluated by comparing the final infiltration rates (FIR) of the amended vs. the nonamended soils measured in disturbed-soil columns pounded with low-salinity irrigation water. Electrical conductivity (EC) and Na in the leachates of the sodic soil were measured. In the crusting prevention experiment, FIRs (mm h{sup -1) of the nonsodic soil were 21 (nonamended), 33 to 35 (gypsum materials), and 53 (sulfuric acid), whereas those for the sodic soil were 0 (nonamended), 9 (lacto-gypsum), 15 to 17 (coal- and mined-gypsum), and 21 (sulfuric acid). In the sodic-soil reclamation experiment, FIRs were 0 (nonamended), 8 to 9 (gypsum-materials), and 17 (sulfuric acid) mm h{sup -1}. All amendments were effective in crusting prevention and soil reclamation, but sulfuric acid was the most efficient due to the fastest EC and Na reductions in the leachates. The three gypsum-materials were equally effective in the reclamation process and in the nonsodic soil crusting-prevention, whereas lacto-gypsum was less efficient in the sodic-soil crusting-prevention.

  3. Plant adaptation to acid soils: the molecular basis for crop aluminum resistance

    Science.gov (United States)

    Aluminum (Al) toxicity on acid soils is a significant limitation to crop production worldwide, as approximately 50% of the world’s potentially arable soils are acidic. Because acid soils are such an important constraint to agriculture, understanding the mechanisms and genes conferring resistance to ...

  4. Emission of nitrous acid from soil and biological soil crusts as a major source of atmospheric HONO on Cyprus

    Science.gov (United States)

    Meusel, Hannah; Tamm, Alexandra; Wu, Dianming; Kuhn, Uwe; Leifke, Anna-Lena; Weber, Bettina; Su, Hang; Lelieveld, Jos; Hoffmann, Thorsten; Pöschl, Ulrich; Cheng, Yafang

    2017-04-01

    Elucidation of the sources and atmospheric chemistry of nitrous acid (HONO) is highly relevant, as HONO is an important precursor of OH radicals. Up to 30% of the OH budget are formed by photolysis of HONO, whereas major fractions of HONO measured in the field derive from yet unidentified sources. Heterogeneous conversion of nitrogen dioxide (NO2) to HONO on a variety of surfaces (soot, humic acid aerosol) is assumed to be a major HONO source (Stemmler et al., 2007, Ammann et al., 1998). In rural regions, however, NO2 concentrations were found to be too low to explain observed HONO concentrations, as e.g., in the case of a recent field study on the Mediterranean island of Cyprus (Meusel et al., 2016). In this study a good correlation between missing sources of HONO and nitrogen oxide (NO) was found indicating a common origin of both reactive nitrogen compounds. Simultaneous emission of HONO and NO from soil was reported earlier (Oswald et al., 2013), and enhanced emission rates were found when soil was covered by biological soil crusts in arid and semi-arid ecosystems (Weber et al., 2015). In the present study we measured HONO and NO emissions of 43 soil and soil crust samples from Cyprus during full wetting and drying cycles under controlled laboratory conditions by means of a dynamic chamber system. The observed range of HONO and NO emissions was in agreement with earlier studies, but unlike the study of Weber et al. (2015), we found highest emission from bare soil, followed by soil covered by light and dark cyanobacteria-dominated biological soil crusts. Emission rates correlated well with the nitrite and nitrate contents of soil and biological soil crust samples, and higher nutrient contents of bare soil samples, as compared to the previous biological soil crust study, explain the higher bare soil emissions. Integrating the emission rates of bare soil and the different types of biological soil crusts, based on their local relative abundance, the calculated

  5. Dissipation of sulfamethoxazole in pasture soils as affected by soil and environmental factors.

    Science.gov (United States)

    Srinivasan, Prakash; Sarmah, Ajit K

    2014-05-01

    The dissipation of sulfamethoxazole (SMO) antibiotic in three different soils was investigated through laboratory incubation studies. The experiments were conducted under different incubation conditions such as initial chemical concentration, soil depth, temperature, and with sterilisation. The results indicate that SMO dissipated rapidly in New Zealand pasture soils, and the 50% dissipation times (DT50) in Hamilton, Te Kowhai and Horotiu soils under non-sterile conditions were 9.24, 4.3 and 13.33 days respectively. During the incubation period for each sampling event the soil dehydrogenase activity (DHA) and the variation in microbial community were monitored thorough phospholipid fatty acid extraction analysis (PLFA). The DHA data correlated well with the dissipation rate constants of SMO antibiotic, an increase in the DHA activity resulted in faster antibiotic dissipation. The PLFA analysis was indicative of higher bacterial presence as compared to fungal community, highlighting the type of microbial community responsible for dissipation. The results indicate that with increasing soil depth, SMO dissipation in soil was slower (except for Horotiu) while with increase in temperature the antibiotic loss was faster, and was noticeable in all the soils. Both the degree of biological activity and the temperature of the soil influenced overall SMO dissipation. SMO is not likely to persist more than 5-6 months in all three soils suggesting that natural biodegradation may be sufficient for the removal of these contaminants from the soil. Its dissipation in sterile soils indicated abiotic factors such as strong sorption onto soil components to play a role in the dissipation of SMO. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Column leaching of chromium and nickel from a contaminated soil using EDTA and citric acid

    International Nuclear Information System (INIS)

    Jean-Soro, Liliane; Bordas, François; Bollinger, Jean-Claude

    2012-01-01

    This study investigates the column leaching of a soil contaminated mainly with Cr and Ni by using two chelants: citric acid (biodegradable) and EDTA (non-biodegradable) followed with water rinse. The chelants lead to Cr and Ni leaching, in addition to major elements (Ca, Fe, Mg, Al, Mn and Zn) showing the dissolution of soil mineral constituents. EDTA leaches more major elements and Ni than citric acid related to the respective stability of metal–chelant complexes; citric acid leaches more Cr than EDTA, certainly because of a substitution reaction with Cr(VI). In the case of alternating chelant/water applications, leaching occurs during the chelant applications, but also during water applications. In the case of chelant/water applications followed by continuous water application, both Cr and Ni leach over time. This increased mobility could be due to the residual chelant present in soil as well as to the dissolution/mobilization of mineral or organic soil fractions. - Highlights: ► Column leaching of an industrial soil contaminated with chromium and nickel. ► Citric acid or EDTA were used alternatively or followed with water rinse. ► Chelants lead to Cr and Ni leaching and the dissolution of soil mineral constituents. ► Leaching of these two metals proceeds continuously during water rinse. ► Chelants deeply impacted Cr and Ni mobility. - Citric acid or EDTA application deeply impact Cr and Ni mobility during column leaching of a contaminated soil.

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

    Science.gov (United States)

    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 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.

  8. IMPACT OF BRACHIARIA, ARBUSCULAR MYCORRHIZA, AND POTASSIUM ENRICHED RICE STRAW COMPOST ON ALUMINIUM, POTASSIUM AND STABILITY OF ACID SOIL AGGREGATES

    Directory of Open Access Journals (Sweden)

    Bariot Hafif

    2013-04-01

    Full Text Available Acid soil is commonly grown with cassava, which in general, tolerate low soil  fertility and aluminum (Al toxicity. However, without any improvement efforts such soil will become worse. Intercropping cassava with Brachiaria decumbens (BD which adapts to acid soil and tolerates low fertility soils as well as application of arbuscular mycorrhiza (AM and organic matters are among the important efforts to rehabilitate this soil. The experiment was conducted to  examine the impact of BD, AM, and potassium (K enriched rice straw compost on exchangeable Al, available K, and stability of soil aggregates. Experiment was arranged in a completely randomized design with three factors and three replications. The first factor was BD as cassava intercropping, the second factor was AM, and the third factor was 2 t ha-1 rice straw compost enriched with 0 kg, 50 kg, 100 kg, and 200 kg KCl ha-1. Brick pots (1 m length x 1 m width x 0.45 m depth filled with Kanhapludult soil was used for growing cassava in which row of BD was planted at 60 cm from cassava stem. K-enriched rice straw compost and AM (10 g per stem were applied around cassava stem at 2 and 12 days after planting, respectively. BD was cut every 30 days and the cutting was returned to the soil. Soil exchangeable Al was analyzed at 0, 3, 6 and 9 months after planting (MAP, while Al and K contents as well as aggregate stability were measured at 6 MAP. The results showed that planting BD decreased 33% exchangeable Al, which means that the root exudates of this grass was effective in detoxifying Al3+. Treatment of BD and/or in combination with AM was effective in preserving K added to the soil, increasing total polysaccharides, and improving soil aggregate stability. This indicated that planting BD and applying AM and Kenriched rice straw compost improved acid soil fertility, and therefore can be recommended in cassava cultivation.

  9. Toxicity and tolerance of aluminum in plants: tailoring plants to suit to acid soils.

    Science.gov (United States)

    Sade, Hemalatha; Meriga, Balaji; Surapu, Varalakshmi; Gadi, Jogeswar; Sunita, M S L; Suravajhala, Prashanth; Kavi Kishor, P B

    2016-04-01

    Aluminum (Al) stress is one of the serious limiting factors in plant productivity in acidic soils, which constitute about 50 % of the world's potentially arable lands and causes anywhere between 25 and 80 % of yield losses depending upon the species. The mechanism of Al toxicity and tolerance has been examined in plants, which is vital for crop improvement and enhanced food production in the future. Two mechanisms that facilitate Al tolerance in plants are Al exclusion from the roots and the ability to tolerate Al in the symplast or both. Although efforts have been made to unravel Al-resistant factors, many aspects remain unclear. Certain gene families such as MATE, ALMT, ASR, and ABC transporters have been implicated in some plants for resistance to Al which would enhance the opportunities for creating crop plants suitable to grow in acidic soils. Though QTLs have been identified related to Al-tolerance, no crop plant that is tolerant to Al has been evolved so far using breeding or molecular approaches. The remarkable changes that plants experience at the physiological, biochemical and molecular level under Al stress, the vast array of genes involved in Al toxicity-tolerance, the underlying signaling events and the holistic image of the molecular regulation, and the possibility of creating transgenics for Al tolerance are discussed in this review.

  10. Bioaccumulation of perfluoroalkyl acids by earthworms (Eisenia fetida) exposed to contaminated soils.

    Science.gov (United States)

    Rich, Courtney D; Blaine, Andrea C; Hundal, Lakhwinder; Higgins, Christopher P

    2015-01-20

    The presence of perfluoroalkyl acids (PFAAs) in biosolids-amended and aqueous film-forming foam (AFFF)-impacted soils results in two potential pathways for movement of these environmental contaminants into terrestrial foodwebs. Uptake of PFAAs by earthworms (Eisenia fetida) exposed to unspiked soils with varying levels of PFAAs (a control soil, an industrially impacted biosolids-amended soil, a municipal biosolids-amended soil, and two AFFF-impacted soils) was measured. Standard 28 day exposure experiments were conducted in each soil, and measurements taken at additional time points in the municipal soil were used to model the kinetics of uptake. Uptake and elimination rates and modeling suggested that steady state bioaccumulation was reached within 28 days of exposure for all PFAAs. The highest concentrations in the earthworms were for perfluorooctane sulfonate (PFOS) in the AFFF-impacted Soil A (2160 ng/g) and perfluorododecanoate (PFDoA) in the industrially impacted soil (737 ng/g). Wet-weight (ww) and organic carbon (OC)-based biota soil accumulation factors (BSAFs) for the earthworms were calculated after 28 days of exposure for all five soils. The highest BSAF in the industrially impacted soil was for PFDoA (0.42 goc/gww,worm). Bioaccumulation factors (BAFs, dry-weight-basis, dw) were also calculated at 28 days for each of the soils. With the exception of the control soil and perfluorodecanoate (PFDA) in the industrially impacted soil, all BAF values were above unity, with the highest being for perfluorohexanesulfonate (PFHxS) in the AFFF-impacted Soil A (139 gdw,soil/gdw,worm). BSAFs and BAFs increased with increasing chain length for the perfluorocarboxylates (PFCAs) and decreased with increasing chain length for the perfluoroalkyl sulfonates (PFSAs). The results indicate that PFAA bioaccumulation into earthworms depends on soil concentrations, soil characteristics, analyte, and duration of exposure, and that accumulation into earthworms may be a potential

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

    International Nuclear Information System (INIS)

    Horst, W.J.

    2000-01-01

    One of the key elements of sustainable cropping systems is the integration of crops and/or crop cultivars with high tolerance of soil acidity and which make most efficient use of the nutrients supplied by soil and fertilizer. This paper is based mainly on on-going work within an EU-funded project combining basic research on plant adaptation mechanisms by plant physiologists, and field experimentation on acid soils in Brazil, Cameroon, Colombia and Guadeloupe by breeders, soil scientists and a agronomists. The results suggest that large genetic variability exists in adaptation of plants to acid soils. A range of morphological and physiological plant characteristics contribute to tolerance of acid soils, elucidation of which has contributed to the development of rapid techniques for screening for tolerance. Incorporation of acid-soil-tolerant species and cultivars into cropping systems contributes to improved nutrient efficiency overall, and thus reduces fertilizer needs. This may help to minimize maintenance applications of fertiliser through various pathways: (i) deeper root growth resulting in more-efficient uptake of nutrients from the sub-soil and less leaching, (ii) more biomass production resulting in less seepage and less leaching, with more intensive nutrient cycling, maintenance of higher soil organic-matter content, and, consequently, less erosion owing to better soil protection by vegetation and mulch. (author)

  12. Growth and Cd uptake by rice (Oryza sativa) in acidic and Cd-contaminated paddy soils amended with steel slag.

    Science.gov (United States)

    He, Huaidong; Tam, Nora F Y; Yao, Aijun; Qiu, Rongliang; Li, Wai Chin; Ye, Zhihong

    2017-12-01

    Contamination of rice (Oryza sativa) by Cd is of great concern. Steel slag could be used to amend Cd-contaminated soils and make them safe for cereal production. This work was conducted to study the effects of steel slag on Cd uptake and growth of rice plants in acidic and Cd-contaminated paddy soils and to determine the possible mechanisms behind these effects. Pot (rhizobag) experiments were conducted using rice plants grown on two acidic and Cd-contaminated paddy soils with or without steel slag amendment. Steel slag amendment significantly increased grain yield by 36-45% and root catalase activity, and decreased Cd concentrations in brown rice by 66-77% compared with the control, in both soils. Steel slag amendment also markedly decreased extractable soil Cd, Cd concentrations in pore-water and Cd translocation from roots to above-ground parts. It also significantly increased soil pH, extractable Si and Ca in soils and Ca concentrations in roots. Significant positive correlations were found between extractable soil Cd and Cd concentrations in rice tissues, but it was negatively correlated with soil pH and extractable Si. Calcium in root tissues significantly and negatively correlated with Cd translocation factors from roots to straw. Overall, steel slag amendment not only significantly promoted rice growth but decreased Cd accumulation in brown rice. These benefits appear to be related to improvements in soil conditions (e.g. increasing pH, extractable Si and Ca), a reduction in extractable soil Cd, and suppression of Cd translocation from roots to above-ground parts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

    Energy Technology Data Exchange (ETDEWEB)

    Kuperman, R.G. [Argonne National Lab., IL (United States). Environmental Assessment Div.

    1996-02-01

    Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

  14. An investigation of inorganic antimony species and antimony associated with soil humic acid molar mass fractions in contaminated soils

    International Nuclear Information System (INIS)

    Steely, Sarah; Amarasiriwardena, Dulasiri; Xing Baoshan

    2007-01-01

    The presence of antimony compounds is often suspected in the soil of apple orchards contaminated with lead arsenate pesticide and in the soil of shooting ranges. Nitric acid (1 M) extractable Sb from the shooting range (8300 μg kg -1 ) and the apple orchard (69 μg kg -1 ) had considerably higher surface Sb levels than the control site ( -1 ), and Sb was confined to the top ∼30 cm soil layer. Sb(V) was the principal species in the shooting range and the apple orchard surface soils. Size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) analysis of humic acids isolated from the two contaminated soils demonstrated that Sb has complexed to humic acid molar mass fractions. The results also indicate that humic acids have the ability to arrest the mobility of Sb through soils and would be beneficial in converting Sb(III) to a less toxic species, Sb(V), in contaminated areas. - The soil surface and depth distribution Sb(V) and Sb(III) species in a contaminated apple orchard and a shooting range, and the effect soil humic acids on inorganic antimony species is reported

  15. Factors impacting the electro conductivity variations of clayey soils

    International Nuclear Information System (INIS)

    Ouhadi, V. R.; Goodarzi, A. R.

    2007-01-01

    The variation of pore fluid properties in soil has a major effect on soil behaviour. This effect is a function of pore fluid properties and soil mineralogy. Such variation usually happens in the reservoirs of dams or in some geotechnical projects. The electro conductivity measurement is a simple method to monitor any variation in the pore fluid of soils. electro conductivity is the ability of a material to transmit (conduct) an electrical current. This paper focuses attention on the effect of soil-pore fluid interaction on the electro conductivity of clayey soils. A set of physico-chemical experiments are performed and the role of different factors including soil pH, soil mineralogy, soil: water ratio, cation and anion effects are investigated. The results of this study indicate that for soil that has a relatively low CEC, the anion type is an important factor, while the cation type does not noticeably affect the electro conductivity of the soil-solution. However, for such soil, an electrolyte property, i.e. its solubility, is much more effective than the CEC of the soil. In addition, it was observed that in the presence of neutral salts such as pore fluid, the pH of the soil-solution decreases causing an increase in the electro conductivity of the soil sample

  16. [Process and mechanism of plants in overcoming acid soil aluminum stress].

    Science.gov (United States)

    Zhao, Tian-Long; Xie, Guang-Ning; Zhang, Xiao-Xia; Qiu, Lin-Quan; Wang, Na; Zhang, Su-Zhi

    2013-10-01

    Aluminum (Al) stress is one of the most important factors affecting the plant growth on acid soil. Currently, global soil acidification further intensifies the Al stress. Plants can detoxify Al via the chelation of ionic Al and organic acids to store the ionic Al in vacuoles and extrude it from roots. The Al extrusion is mainly performed by the membrane-localized anion channel proteins Al(3+)-activated malate transporter (ALMT) and multi-drug and toxin extrusion (MATE). The genes encoding ABC transporter and zinc-finger protein conferred plant Al tolerance have also been found. The identification of these Al-resistant genes makes it possible to increase the Al resistance of crop plants and enhance their production by the biological methods such as gene transformation and mark-associated breeding. The key problems needed to be solved and the possible directions in the researches of plant Al stress resistance were proposed.

  17. Soil microbial community responses to acid exposure and neutralization treatment.

    Science.gov (United States)

    Shin, Doyun; Lee, Yunho; Park, Jeonghyun; Moon, Hee Sun; Hyun, Sung Pil

    2017-12-15

    Changes in microbial community induced by acid shock were studied in the context of potential release of acids to the environment due to chemical accidents. The responses of microbial communities in three different soils to the exposure to sulfuric or hydrofluoric acid and to the subsequent neutralization treatment were investigated as functions of acid concentration and exposure time by using 16S-rRNA gene based pyrosequencing and DGGE (Denaturing Gradient Gel Electrophoresis). Measurements of soil pH and dissolved ion concentrations revealed that the added acids were neutralized to different degrees, depending on the mineral composition and soil texture. Hydrofluoric acid was more effectively neutralized by the soils, compared with sulfuric acid at the same normality. Gram-negative ß-Proteobacteria were shown to be the most acid-sensitive bacterial strains, while spore-forming Gram-positive Bacilli were the most acid-tolerant. The results of this study suggest that the Gram-positive to Gram-negative bacterial ratio may serve as an effective bio-indicator in assessing the impact of the acid shock on the microbial community. Neutralization treatments helped recover the ratio closer to their original values. The findings of this study show that microbial community changes as well as geochemical changes such as pH and dissolved ion concentrations need to be considered in estimating the impact of an acid spill, in selecting an optimal remediation strategy, and in deciding when to end remedial actions at the acid spill impacted site. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. A conceptual framework: Redefining forest soil's critical acid loads under a changing climate

    International Nuclear Information System (INIS)

    McNulty, Steven G.; Boggs, Johnny L.

    2010-01-01

    Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it is believed to potentially impair forest health. The excess over the critical soil acid load is termed the exceedance, and the larger the exceedance, the greater the risk of ecosystem damage. This definition of critical soil acid load applies to exposure of the soil to a single, long-term pollutant (i.e., acidic deposition). However, ecosystems can be simultaneously under multiple ecosystem stresses and a single critical soil acid load level may not accurately reflect ecosystem health risk when subjected to multiple, episodic environmental stress. For example, the Appalachian Mountains of western North Carolina receive some of the highest rates of acidic deposition in the eastern United States, but these levels are considered to be below the critical acid load (CAL) that would cause forest damage. However, the area experienced a moderate three-year drought from 1999 to 2002, and in 2001 red spruce (Picea rubens Sarg.) trees in the area began to die in large numbers. The initial survey indicated that the affected trees were killed by the southern pine beetle (Dendroctonus frontalis Zimm.). This insect is not normally successful at colonizing these tree species because the trees produce large amounts of oleoresin that exclude the boring beetles. Subsequent investigations revealed that long-term acid deposition may have altered red spruce forest structure and function. There is some evidence that elevated acid deposition (particularly nitrogen) reduced tree water uptake potential, oleoresin production, and caused the trees to become more susceptible to insect colonization during the drought period

  19. Evaluation of soil saturation, soil chemistry, and early spring soil and air temperatures as risk factors in yellow-cedar decline.

    Science.gov (United States)

    D.V. D' Amore; P.E. Hennon

    2006-01-01

    Yellow-cedar (Callitropsis nootkatensis (D. Don) Oerst.) is a valuable tree species that is experiencing a widespread decline and mortality in southeast Alaska. This study evaluated the relative importance of several potential risk factors associated with yellow-cedar decline: soil saturation, soil aluminum (Al) toxicity or calcium (Ca) deficiency...

  20. Copper bioavailability and extractability as related to chemical properties of contaminated soils from a vine-growing area

    International Nuclear Information System (INIS)

    Chaignon, V.; Sanchez-Neira, I.; Herrmann, P.; Jaillard, B.; Hinsinger, P.

    2003-01-01

    Root Cu concentration is a good indicator of soil Cu bioavailability. - Vineyard soils have been contaminated by Cu as a consequence of the long-term use of Cu salts as fungicides against mildew. This work aimed at identifying which soil parameters were the best related to Cu bioavailability, as assessed by measuring the concentrations of Cu in shoots and roots of tomato cropped (in lab conditions) over a range of 29 (24 calcareous and five acidic) Cu-contaminated topsoils from a vine-growing area (22-398 mg Cu kg -1 ). Copper concentrations in tomato shoots remained in the adequate range and were independent of soil properties and soil Cu content. Conversely, strong, positive correlations were found between root Cu concentration, total soil Cu, EDTA- or K-pyrophosphate-extractable Cu and organic C contents in the 24 calcareous soils, suggesting a prominent role of organic matter in the retention and bioavailability of Cu. Such relations were not observed when including the five acidic soils in the investigated population, suggesting a major pH effect. Root Cu concentration appeared as a much more sensitive indicator of soil Cu bioavailability than shoot Cu concentration. Simple extractions routinely used in soil testing procedures (total and EDTA-extractable Cu) were adequate indicators of Cu bioavailability for the investigated calcareous soils, but not when different soil types were considered (e.g. acidic versus calcareous soils)

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

    Directory of Open Access Journals (Sweden)

    Guohua Liang

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

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

    Science.gov (United States)

    Liang, Guohua; Liu, Xingzhao; Chen, Xiaomei; Qiu, Qingyan; Zhang, Deqiang; Chu, Guowei; Liu, Juxiu; Liu, Shizhong; Zhou, Guoyi

    2013-01-01

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

  3. Adsorption and desorption dynamics of citric acid anions in soil

    KAUST Repository

    Oburger, E.

    2011-07-26

    The functional role of organic acid anions in soil has been intensively investigated, with special focus on (i) microbial respiration and soil carbon dynamics, (ii) nutrient solubilization or (iii) metal detoxification and reduction of plant metal uptake. Little is known about the interaction dynamics of organic acid anions with the soil matrix and the potential impact of adsorption and desorption processes on the functional significance of these effects. The aim of this study was to characterize experimentally the adsorption and desorption dynamics of organic acid anions in five agricultural soils differing in iron and aluminium oxide contents and using citrate as a model carboxylate. Results showed that both adsorption and desorption processes were fast in all soils, reaching a steady state within approximately 1 hour. However, for a given total soil citrate concentration (ct) the steady state was critically dependent on the starting conditions of the experiment, whether most of the citrate was initially present in solution (cl) or held on the solid phase (cs). Specifically, desorption-led processes resulted in significantly smaller steady-state solution concentrations than adsorption-led processes, indicating that hysteresis occurred. As it is not possible to distinguish between different adsorption and desorption pools in soil experimentally, a new dynamic hysteresis model that relies only on measured soil solution concentrations was developed. The model satisfactorily explained experimental data and was able to predict dynamic adsorption and desorption behaviour. To demonstrate its use, we applied the model to two relevant situations involving exudation and microbial degradation. The study highlighted the complex nature of citrate adsorption and desorption dynamics in soil. We conclude that existing models need to incorporate both temporal and hysteresis components to describe realistically the role and fate of organic acids in soil processes. © 2011 The

  4. Effect of decreasing acidity on the extractability of inorganic soil phosphorus

    Directory of Open Access Journals (Sweden)

    Helinä Hartikainen

    1981-01-01

    Full Text Available The extractability of P by the water and anion exchange resin methods and reactions of soil inorganic P were investigated with seven acid mineral soil samples incubated with KOH solutions of various concentrations. The results were compared with the analytical data obtained from three soil samples incubated in a prolonged liming experiment. The resin extraction method proved more effective than the water extraction method. The amounts of P desorbed by both methods seemed to increase exponentially as the pH in the soil suspensions rose. The factors involved were discussed. On the basis of fractionation analyses P reacting to changes in the pH and participating in desorption processes was supposed to originate from secondary NH4F and NaOH soluble reserves. In general, as the acidity decreased NH4F-P increased at the expense of NaOH-P. In heavily limed gyttja soil also H2SO4-P increased. This was possibly induced by the precipitation of mobilized P as a Ca compound. The significance of pH in the extractability of soil P seemed somewhat to lessen as the amount of secondary P increased. The results were in accordance with the conception that liming improves the availability of inorganic P to plants and reduces the need for P fertilization. However, increasing of the soil pH involves the risk that P is more easily desorbed to the recipient water by the eroded soil material carried into the watercourse. Therefore, intensive liming is not recommendable close to the shoreline. Further, it should be taken into account that liming of lakes may also result in eutrophication as desorption of sedimentary inorganic P is enhanced.

  5. The Influence of Soil Chemical Factors on In Situ Bioremediation of Soil Contamination

    Energy Technology Data Exchange (ETDEWEB)

    Breedveld, Gijs D.

    1997-12-31

    Mineral oil is the major energy source in Western society. Production, transport and distribution of oil and oil products cause serious contamination problems of water, air and soil. The present thesis studies the natural biodegradation processes in the soil environment which can remove contamination by oil products and creosote. The main physical/chemical processes determining the distribution of organic contaminants between the soil solid, aqueous and vapour phase are discussed. Then a short introduction to soil microbiology and environmental factors important for biodegradation is given. There is a discussion of engineered and natural bioremediation methods and the problems related to scaling up laboratory experiments to field scale remediation. Bioremediation will seldom remove the contaminants completely; a residue remains. Factors affecting the level of residual contamination and the consequences for contaminant availability are discussed. Finally, the main findings of the work are summarized and recommendations for further research are given. 111 refs., 41 figs., 19 tabs.

  6. Limiting Factors for Agricultural Production and Differentiation of Soil Management in Romania

    Science.gov (United States)

    Ioana Moraru, Paula; Rusu, Teodor; Bogdan, Ileana; Ioan Pop, Adrian; Pop, Horia

    2017-04-01

    Romania's land area is 23,839,100 ha; 0.16% of the world's surface. Worldwide, Romania is ranked #83 for areal extent, and it consitutes 4.81% of the Europe's surface (ranked #12). Romania has 14,856,800 ha of agricultural land which represents 62.3% of the total surface; 0.65 ha per capita. At the national level, 72.5% and 27.5% of soils in Romania can be broadly classed as very poor and good/very good, respectively, based on intrinsic soil characteristics, climate, topography, and ground water. Romania has a specific geographical situation, namely: i) Romanian territory is located in the southeast portion of Central Europe at the cross roads of several high and low pressure centers that form regularly at the borders. The influence of these air masses is altered by the presence in the central regions of the Carpathian mountain chain resulting in a diverse climate with average annual rain fall amounts between 350 to 1,400 mm and average annual temperatures between 2 and 11.5°C. ii) At the national level, almost all soils in the international classification system are present in Romania; each soil type having specific properties and characteristics. iii) On approximately 12.5 million ha (7.5 million ha arable), soil fertility is adversely affected by erosion, acidity, low humus content, extreme texture (clay, sand), excessive moisture, chemical pollution etc. These natural and anthropogenic factors dramatically influence agricultural production. Furthermore, soil, climate, topography, etc. vary widely not only across the country, but also on smaller scales, even across fields within the same farm. In Steppe zone limitative climatic factors, which require differentiation towards soil management use, include: long periods of drought, high temperatures, high frequency winds (wind erosion in area of sands), low relative air humidity, and harsh frosts during winter. Negative phenomena most commonly encountered in this area are salinization, excess water, temporary

  7. Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

    Directory of Open Access Journals (Sweden)

    Xiaochuang Cao

    Full Text Available Amino acids are important sources of soil organic nitrogen (N, which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N. On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine did not vary appreciably with elevation (p>0.10. The compositional

  8. The microbial communities and potential greenhouse gas production in boreal acid sulphate, non-acid sulphate, and reedy sulphidic soils

    Czech Academy of Sciences Publication Activity Database

    Šimek, Miloslav; Virtanen, S.; Simojoki, A.; Chroňáková, Alica; Elhottová, Dana; Krištůfek, Václav; Yli-Halla, M.

    2014-01-01

    Roč. 466, January (2014), s. 663-672 ISSN 0048-9697 R&D Projects: GA ČR GA526/09/1570; GA MŠk LC06066 Grant - others:GAJU(CZ) GAJU 138/2010/P Institutional support: RVO:60077344 Keywords : acid sulphate soil * carbon * CARD-FISH * microorganisms * nitrogen * PLFA Subject RIV: EE - Microbiology, Virology Impact factor: 4.099, year: 2014

  9. Soil remediation: humic acids as natural surfactants in the washings of highly contaminated soils

    International Nuclear Information System (INIS)

    Conte, Pellegrino; Agretto, Anna; Spaccini, Riccardo; Piccolo, Alessandro

    2005-01-01

    The remediation of the highly contaminated site around the former chemical plant of ACNA (near Savona) in Northern Italy is a top priority in Italy. The aim of the present work was to contribute in finding innovative and environmental-friendly technology to remediate soils from the ACNA contaminated site. Two soils sampled from the ACNA site (A and B), differing in texture and amount and type of organic contaminants, were subjected to soil washings by comparing the removal efficiency of water, two synthetic surfactants, sodium dodecylsulphate (SDS) and Triton X-100 (TX100), and a solution of a natural surfactant, a humic acid (HA) at its critical micelle concentration (CMC). The extraction of pollutants by sonication and soxhlet was conducted before and after the soil washings. Soil A was richer in polycyclic aromatic hydrocarbons, whereas soil B had a larger content of thiophenes. Sonication resulted more analytically efficient in the fine-textured soil B. The coarse-textured soil A was extracted with a general equal efficiency also by soxhlet. Clean-up by water was unable to exhaustively remove contaminants from the two soils, whereas all the organic surfactants revealed very similar efficiencies (up to 90%) in the removal of the contaminants from the soils. Hence, the use of solutions of natural HAs appears as a better choice for soil washings of highly polluted soils due to their additional capacity to promote microbial activity, in contrast to synthetic surfactants, for a further natural attenuation in washed soils. - Solutions of natural humic acids appear to be a better choice for washing highly polluted soils

  10. Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

    Science.gov (United States)

    Sullivan, Timothy J.; Lawrence, Gregory B.; Bailey, Scott W.; McDonnell, Todd C.; McPherson, G.T.

    2013-01-01

    This study documents the effects of acidic deposition and soil acid-base chemistry on the growth, regeneration, and canopy condition of sugar maple (SM) trees in the Adirondack Mountains of New York. Sugar maple is the dominant canopy species throughout much of the northern hardwood forest in the State. A field study was conducted in 2009 in which 50 study plots within 20 small Adirondack watersheds were sampled and evaluated for soil acid-base chemistry and SM growth, canopy condition, and regeneration. Atmospheric sulfur (S) and nitrogen (N) deposition were estimated for each plot. Trees growing on soils with poor acid-base chemistry (low exchangeable calcium and % base saturation) that receive relatively high levels of atmospheric S and N deposition exhibited little to no SM seedling regeneration, decreased canopy condition, and short-to long-term growth declines compared with study plots having better soil condition and lower levels of atmospheric deposition. These results suggest that the ecosystem services provided by SM in the western and central Adirondack Mountain region, including aesthetic, cultural, and monetary values, are at risk from ongoing soil acidification caused in large part by acidic deposition.

  11. Isotopic tracer studies to evaluate relative efficiency of different forms of P for growing rice on different soil types

    Energy Technology Data Exchange (ETDEWEB)

    Dash, R N; Mohanty, S K; Patnaik, S [Central Rice Research Inst., Cuttack (India)

    1977-12-01

    The relative efficiency of different forms of P in relation to their time of application for growing rice on different soil types has been studied by using /sup 32/P tagged mono-, di-, and tri-calcium phosphate, ammonium nitrate phosphate containing all the P in the citrate-soluble form and potassium meta-phosphate. P-deficient acid laterite soil from Burdwan, red loam soil from Peramanpur and calcareous black soil from Hyderabad were used in the study. The different P forms were found to be compatible in the acid, red and laterite soils when the phosphorus forms were primed to moist acid soils 2 weeks prior to flooding. On application at flooding, fertilizers containing citrate-soluble phosphate were found to be less effective as compared to those containing water-soluble phosphate. In the calcareous black soil, however, the fertilizers, containing insoluble or citrate-soluble phosphates were not as efficient as the water-soluble forms, possibly because of lack of dissolution process. Potassium meta-phosphate was found to be effective in all the soil types whether applied at flooding or primed to the moist soil.

  12. pH buffering capacity of acid soils from tropical and subtropical regions of China as influenced by incorporation of crop straw biochars

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ren-kou; Zhao, An-zhen; Yuan, Jin-hua; Jiang, Jun [Academy of Sciences, Nanjing (China). State Key Lab. of Soil and Sustainable Agriculture

    2012-04-15

    Purpose: The key factors influencing pH buffering capacity of acid soils from tropical and subtropical regions, and effects of soil evolution and incorporation of biochars on pH buffering capacity were investigated to develop suitable methods to increase pH buffering capacity of acid soils. Materials and methods: A total of 24 acid soils collected from southern China were used. The pH buffering capacity was determined using acid-base titration. The values of pH buffering capacity were obtained from the slope of titration curves of acid or alkali additions plotted against pH in the pH range 4.0-7.0. Two biochars were prepared from straws of peanut and canola using a low temperature pyrolysis method. After incubation of three acid soils, pH buffering capacity was then determined. Results and discussion: pH buffering capacity had a range of 9.1-32.1 mmol kg{sup -1} pH{sup -1} for 18 acid soils from tropical and subtropical regions of China. The pH buffering capacity was highly correlated (R{sup 2} = 0.707) with soil cation exchange capacity (CEC) measured with ammonium acetate method at pH 7.0 and decreased with soil evolution due to the decreased CEC. Incorporation of biochars at rates equivalent to 72 and 120 t ha{sup -1} increased soil pH buffering capacity due to the CEC contained in the biochars. Incorporation of peanut straw char which itself contained more CEC and alkalinity induced more increase in soil CEC, and thus greater increase in pH buffering capacity compared with canola straw char. At 5% of peanut straw char added, soil CEC increased by 80.2%, 51.3%, and 82.8% for Ultisol from Liuzhou, Oxisol from Chengmai and Ultisol from Kunlun, respectively, and by 19.8%, 19.6%, and 32.8% with 5% of canola straw char added, respectively; and correspondingly for these soils, the pH buffering capacity increased by 73.6%, 92.0%, and 123.2% with peanut straw char added; and by 31.3%, 25.6%, and 52.3% with canola straw char added, respectively. Protonation

  13. The impact of acid soil volume of reclaimed minespoils on plant growth in minilysimeters

    International Nuclear Information System (INIS)

    Shahandeh, H.; Hossner, L.R.; Birkhead, J.A.

    1996-01-01

    Limited data are available to assess the influence of randomly distributed acid soil, produced from acid forming materials (AFM), on growth and productivity of crops. This study evaluated the effect of amount and volume of acid soil on the growth of an acid tolerant plant (Coastal bermudga grass, Cynodon dactylon, L.) and an acid intolerant plant (Yuchi arrowleaf clover, Trifolium vesiculosum, Savi) in greenhouse lysimeters. Acid soil (pH=2.5) volumes up to 20% for Yuchi arrowleaf clover and up to 40% for Coastal bermuda grass did not significantly decrease dry matter yield. Concentrations of Al and Mn in plant tissue of clover and bermudagrass were below the toxicity level. In the presence of randomly distributed acid soil, plant roots continued to elongate in non-acid soil, by evading localized areas of low soil pH. These results suggest that the federally mandated zero tolerance for AFM in the top 1.2 m of reclaimed lands may not be reasonable. 18 refs., 7 figs., 2 tabs

  14. Sorption-desorption of imidacloprid onto a lacustrine Egyptian soil and its clay and humic acid fractions.

    Science.gov (United States)

    Kandil, Mahrous M; El-Aswad, Ahmed F; Koskinen, William C

    2015-01-01

    Sorption-desorption of the insecticide imidacloprid 1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine onto a lacustrine sandy clay loam Egyptian soil and its clay and humic acid (HA) fractions was investigated in 24-h batch equilibrium experiments. Imidacloprid (IMDA) sorption-desorption isotherms onto the three sorbents were found to belong to a non-linear L-type and were best described by the Freundlich model. The value of the IMDA adsorption distribution coefficient, Kd(ads), varied according to its initial concentration and was ranged 40-84 for HA, 14-58 for clay and 1.85-4.15 for bulk soil. Freundlich sorption coefficient, Kf(ads), values were 63.0, 39.7 and 4.0 for HA, clay and bulk soil, respectively. The normalized soil Koc value for imidacloprid sorption was ∼800 indicating its slight mobility in soils. Nonlinear sorption isotherms were indicated by 1/n(ads) values imidacloprid sorption process with all tested sorbents. Gibbs free energy (ΔG) values indicated a spontaneous and physicosorption process for IMDA and a more favorable sorption to HA than clay and soil. In conclusion, although the humic acid fraction showed the highest capacity and affinity for imidacloprid sorption, the clay fraction contributed to approximately 95% of soil-sorbed insecticide. Clay and humic acid fractions were found to be the major two factors controlling IMDA sorption in soils. The slight mobility of IMDA in soils and the hysteresis phenomenon associated with the irreversibility of its sorption onto, mainly, clay and organic matter of soils make its leachability unlikely to occur.

  15. Temporal and spatial variation in the status of acid rivers and potential prevention methods of AS soil-related leaching in peatland forestry

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, T.

    2013-06-01

    This thesis examines temporal and spatial variations in the status of different rivers and streams of western Finland in terms of acidity and sources of acid load derived from the catchment area. It also examines the monitoring of acid runoff water derived from maintenance drainage in peatland forestry and suggests potential mitigation methods. A total of 17 river basins of different sizes in western Finland were selected for study, including rivers affected by both drainage of agricultural AS soils and forested peatlands. Old data from 1911-1931 were available, but most data were from the 1960s onwards and were taken from the HERTTA database. During 2009-2011, pH and conductivity measurements and water sampling were conducted. Biological monitoring for ecological classification was conducted in the Sanginjoki river system during 2008 and 2009. Three peatland forestry sites were selected to study acid leaching via pH and EC measurements and water sampling. Fluctuations in groundwater level in different drainage conditions were simulated and acid leaching was investigated in laboratory experiments in order to replicate a situation where the groundwater level drops and allows oxidation of sulphidic materials. It was found that river pH decreased and metal concentrations increased with runoff. The highest acidity observed coincided with periods of intense drainage in the 1970s and after dry summers in the past decade. Together with pH, electric conductivity and sulphate in river water were identified as suitable indicators of AS soils in a catchment, because they directly respond to acid leaching derived from AS soils. Acidity derived from organic acids was clearly observed in catchments dominated by forested peatlands and wetlands. Temporal and spatial variations in ecological status were observed, but monitoring at whole-catchment scale and during consecutive years is needed to increase the reliability of the results. Simulations on the potential effects of

  16. Major controlling factors and predictions for cadmium transfer from the soil into spinach plants.

    Science.gov (United States)

    Liang, Zhenfei; Ding, Qiong; Wei, Dongpu; Li, Jumei; Chen, Shibao; Ma, Yibing

    2013-07-01

    Predicting the mobility, bioavailability and transfer of cadmium (Cd) in the soil-plant system is of great importance with regards to food safety and environmental management. In this study, the transfer characteristics of Cd (exogenous salts) from a wide range of Chinese soils to spinach (Spinacia oleracea L.) were investigated. The major controlling factors and prediction equations for Cd transfer in the soil-plant system were also investigated. The results showed that plant Cd concentration was positively correlated with soil Cd concentration. The maximum transfer factor (ratio of the Cd concentration in the plant to that in the soil) was found in acid soils. The extended Freundlich-type function was able to describe the Cd transfer from soil to spinach plants. Combining soil total Cd, pH and organic carbon (OC) content in the prediction equation greatly improved the correlation performance compared with predictions based on total Cd only. A slight protection effect of OC on Cd uptake was observed at low soil Cd concentrations. The results are a useful tool that can be used to predict Cd transfer from soil to plant. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. [Effects of Low-Molecular-Weight Organic Acids on the Speciation of Pb in Purple Soil and Soil Solution].

    Science.gov (United States)

    Liu, Jiang; Jiang, Tao; Huang, Rong; Zhang, Jin-zhong; Chen, Hong

    2016-04-15

    Lead (Pb) in purple soil was selected as the research target, using one-step extraction method with 0.01 mol · L⁻¹ sodium nitrate as the background electrolyte to study the release effect of citric acid (CA), tartaric acid (TA) and acetic acid (AC) with different concentrations. Sequential extraction and geochemical model (Visual Minteq v3.0) were applied to analyze and predict the speciation of Pb in soil solid phase and soil solution phase. Then the ebvironmental implications and risks of low-molecule weight organic acid (LMWOA) on soil Pb were analyzed. The results indicated that all three types of LMWOA increased the desorption capacity of Pb in purple soil, and the effect followed the descending order of CA > TA > AC. After the action of LMWOAs, the exchangeable Pb increased; the carbonate-bound Pb and Fe-Mn oxide bound Pb dropped in soil solid phase. Organic bound Pb was the main speciation in soil solution phase, accounting for 45.16%-75.05%. The following speciation of Pb in soil solution was free Pb, accounting for 22.71%-50.25%. For CA and TA treatments, free Pb ions and inorganic bound Pb in soil solution increased with increasing LMWOAs concentration, while organic bound Pb suffered a decrease in this process. An opposite trend for AC treatment was observed compared with CA and TA treatments. Overall, LMWOAs boosted the bioavailability of Pb in purple soil and had a potential risk to contaminate underground water. Among the three LMWOAs in this study, CA had the largest potential to activate soil Pb.

  18. Impacts of simulated acid rain on recalcitrance of two different soils.

    Science.gov (United States)

    Dai, Zhongmin; Liu, Xingmei; Wu, Jianjun; Xu, Jianming

    2013-06-01

    Laboratory experiments were conducted to estimate the impacts of simulated acid rain (SAR) on recalcitrance in a Plinthudult and a Paleudalfs soil in south China, which were a variable and a permanent charge soil, respectively. Simulated acid rains were prepared at pH 2.0, 3.5, 5.0, and 6.0, by additions of different volumes of H2SO4 plus HNO3 at a ratio of 6 to 1. The leaching period was designed to represent 5 years of local annual rainfall (1,200 mm) with a 33 % surface runoff loss. Both soils underwent both acidification stages of (1) cation exchange and (2) mineral weathering at SAR pH 2.0, whereas only cation exchange occurred above SAR pH 3.5, i.e., weathering did not commence. The cation exchange stage was more easily changed into that of mineral weathering in the Plinthudult than in the Paleudalfs soil, and there were some K(+) and Mg(2+) ions released on the stages of mineral weathering in the Paleudalfs soil. During the leaching, the release of exchangeable base cations followed the order Ca(2+) >K(+) >Mg(2+) >Na(+) for the Plinthudult and Ca(2+) >Mg(2+) >Na(+) >K(+) for the Paleudalfs soil. The SARs above pH 3.5 did not decrease soil pH or pH buffering capacity, while the SAR at pH 2.0 decreased soil pH and the buffering capacity significantly. We conclude that acid rain, which always has a pH from 3.5 to 5.6, only makes a small contribution to the acidification of agricultural soils of south China in the short term of 5 years. Also, Paleudalfs soils are more resistant to acid rain than Plinthudult soils. The different abilities to prevent leaching by acid rain depend upon the parent materials, types of clay minerals, and soil development degrees.

  19. Back to acid soil fields

    NARCIS (Netherlands)

    Carvalho, Geraldo; Schaffert, Robert Eugene; Malosetti Zunin, Marcos; Eeuwijk, van Fred

    2016-01-01

    Aluminum (Al) toxicity damages plant roots and limits crop production on acid soils, which comprise up to 50% of the world's arable lands. A major Al tolerance locus on chromosome 3, AltSB, controls aluminum tolerance in sorghum [Sorghum bicolor (L.) Moench] via SbMATE, an Al-activated plasma

  20. Uranium Leaching from Contaminated Soil Utilizing Rhamnolipid, EDTA, and Citric Acid

    Directory of Open Access Journals (Sweden)

    Sara Asselin

    2014-01-01

    Full Text Available Biosurfactants have recently gained attention as “green” agents that can be used to enhance the remediation of heavy metals and some organic matter in contaminated soils. The overall objective of this paper was to investigate rhamnolipid, a microbial produced biosurfactant, and its ability to leach uranium present in contaminated soil from an abandoned mine site. Soil samples were collected from two locations in northern Arizona: Cameron (site of open pit mining and Leupp (control—no mining. The approach taken was to first determine the total uranium content in each soil using a hydrofluoric acid digestion, then comparing the amount of metal removed by rhamnolipid to other chelating agents EDTA and citric acid, and finally determining the amount of soluble metal in the soil matrix using a sequential extraction. Results suggested a complex system for metal removal from soil utilizing rhamnolipid. It was determined that rhamnolipid at a concentration of 150 μM was as effective as EDTA but not as effective as citric acid for the removal of soluble uranium. However, the rhamnolipid was only slightly better at removing uranium from the mining soil compared to a purified water control. Overall, this study demonstrated that rhamnolipid ability to remove uranium from contaminated soil is comparable to EDTA and to a lesser extent citric acid, but, for the soils investigated, it is not significantly better than a simple water wash.

  1. Interactive effects of soil acidity and fluoride on soil solution aluminium chemistry and barley (Hordeum vulgare L.) root growth

    International Nuclear Information System (INIS)

    Manoharan, V.; Loganathan, P.; Tillman, R.W.; Parfitt, R.L.

    2007-01-01

    A greenhouse study was conducted to determine if concentrations of fluoride (F), which would be added to acid soils via P fertilisers, were detrimental to barley root growth. Increasing rates of F additions to soil significantly increased the soil solution concentrations of aluminium (Al) and F irrespective of the initial adjusted soil pH, which ranged from 4.25 to 5.48. High rates of F addition severely restricted root growth; the effect was more pronounced in the strongly acidic soil. Speciation calculations demonstrated that increasing rates of F additions substantially increased the concentrations of Al-F complexes in the soil. Stepwise regression analysis showed that it was the combination of the activities of AlF 2 1+ and AlF 2+ complexes that primarily controlled barley root growth. The results suggested that continuous input of F to soils, and increased soil acidification, may become an F risk issue in the future. - Addition of high rates of fluoride to strongly acidic soils can reduce barley root growth due to the toxicity of aluminium-fluoride complexes formed in soil solution

  2. Scale-location specific relations between soil nutrients and topographic factors in the Fen River Basin, Chinese Loess Plateau

    Science.gov (United States)

    Zhu, Hongfen; Bi, Rutian; Duan, Yonghong; Xu, Zhanjun

    2017-06-01

    Understanding scale- and location-specific variations of soil nutrients in cultivated land is a crucial consideration for managing agriculture and natural resources effectively. In the present study, wavelet coherency was used to reveal the scale-location specific correlations between soil nutrients, including soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), and available potassium (AK), as well as topographic factors (elevation, slope, aspect, and wetness index) in the cultivated land of the Fen River Basin in Shanxi Province, China. The results showed that SOM, TN, AP, and AK were significantly inter-correlated, and that the scales at which soil nutrients were correlated differed in different landscapes, and were generally smaller in topographically rougher terrain. All soil nutrients but TN were significantly influenced by the wetness index at relatively large scales (32-72 km) and AK was significantly affected by the aspect at large scales at partial locations, showing localized features. The results of this study imply that the wetness index should be taken into account during farming practices to improve the soil nutrients of cultivated land in the Fen River Basin at large scales.

  3. Bioleaching of heavy metals from soil using fungal-organic acids : bench scale testing

    Energy Technology Data Exchange (ETDEWEB)

    Cathum, S.J.; Ousmanova, D.; Somers, A.; Punt, M. [SAIC Canada, Ottawa, ON (Canada); Brown, C.E. [Environment Canada, Ottawa, ON (Canada). Emergencies Engineering Division]|[Environment Canada, Ottawa, ON (Canada). Environmental Technology Centre

    2006-07-01

    The ability of fungi to solubilize metals from solid materials may present new opportunities in environmental remediation. This paper presented details of a bench scale experiment that evaluated the leaching of heavy metals from contaminated soil using in situ fungal-generated organic acids. Rice was used as the growing media for organic acid production by A. foetidus. The cultivated fungus was placed on large pieces of potato-dextrose agar (PDA) plates and suspended in 5 L of sterilized water. The cooked rice was inoculated by pouring the 5 L spore suspension over the rice layer. Soil was obtained from a soil pile impacted with heavy metals at a private industrial site and augmented with Pb-contaminated soil. A polyethylene tub was used with a drain pipe leading to a leachate vessel. Crushed stone was spread over the bottom of the tub to assist leachate drainage. Approximately 45 kg of the contaminated soil was spread evenly over the stone layer to a depth of 10 cm. The concentrated spore suspension was sprinkled over the rice. Each week the leachate collection vessel was removed from the bioleaching system and the fine soil particles were allowed to settle. A control was run using the contaminated soil and solid substrate without fungus. Growth of A. foetidus was observed in both control experiment and test experiment after a period of 35 days. The pH of the leachate was measured as the fungal growth progressed. The process was assessed using ICP Mass Spectroscopy and electron spectroscopy, which showed that approximately 65 g of heavy metals were mobilized from 45 kg of soil, and that the biological leaching process resulted in greater mobilization of heavy metals relative to the control experiment. It was concluded that organic acids generated by A. foetidus were capable of leaching heavy metals from the soil. 30 refs., 4 tabs., 15 figs.

  4. Proportion of root-derived acid phosphomonoesterase in total soil acid phosphomonoesterase in different forests

    Directory of Open Access Journals (Sweden)

    Ladislav Holík

    2011-01-01

    Full Text Available Enzyme acid phosphomonoesterase (APM plays an important role in phosphorus mineralization in different type of terrestrial ecosystems. This enzyme is of great agronomic significance because it hydrolyses organic phosphorus to different forms of inorganic phosphorus which are assimilable by plants. APM may also indicate changes in the quantity and quality of phosphorylated substrates in soil and is a good indicator of its biological state as well as presence of pollutants. APM may be produced by plant roots and soil microorganisms and both of these sources may play different role in phosphorus mineralization in different ecosystems. The aim of this work was determine acid phosphomonoesterase (APM activity location in soil of different forest ecosystems. The APM activity location determination was performed on the basis of root-derived and soil-derived APM and expression of proportion of those root-derived in total soil APM up to 13 cm depth. The results of this preliminary study showed that root-derived APM formed 21–34 % of total soil APM in pine and oak forest.

  5. Soil humic acids may favour the persistence of hexavalent chromium in soil

    International Nuclear Information System (INIS)

    Leita, Liviana; Margon, Alja; Pastrello, Arnold; Arcon, Iztok; Contin, Marco; Mosetti, Davide

    2009-01-01

    The interaction between hexavalent chromium Cr(VI), as K 2 CrO 4 , and standard humic acids (HAs) in bulk solution was studied using three complementary analytical methods: UV-Visible spectroscopy, X-ray absorption spectroscopy and differential pulse stripping voltammetry. The observed UV-Vis and X-ray absorption spectra showed that, under our experimental conditions, HAs did not induce reduction of Cr(VI) to its trivalent chemical form. The interaction between Cr(VI) and HAs has rather led to the formation of Cr(VI)-HAs micelles via supramolecular chemical processes. The reported results could contribute towards explaining the relative persistence of ecotoxic hexavalent chromium in soils. - Humic acids (HAs) did not induce reduction of Cr(VI) to its trivalent chemical form, as the interaction between Cr(VI) and HAs rather led to the formation of Cr(VI)-HAs micelles via supramolecular chemical processes.

  6. Temperature effects on protein depolymerization and amino acid immobilization rates in soils.

    Science.gov (United States)

    Noll, Lisa; Hu, Yuntao; Zhang, Shasha; Zheng, Qing; Wanek, Wolfgang

    2017-04-01

    Increasing N deposition, land use change, elevated atmospheric CO2 concentrations and global warming have altered soil nitrogen (N) cycling during the last decades. Those changes affected ecosystem services, such as C and N sequestration in soils, which calls for a better understanding of soil N transformation processes. The cleavage of macromolecular organic N by extracellular enzymes maintains an ongoing flow of new bioavailable organic N into biotic systems and is considered to be the bottle neck of terrestrial N cycling in litter and soils. Recent studies showed that protein depolymerization is susceptible to changes in C and N availabilities. Based on general biological observations the temperature sensitivity of soil organic N processes is expected to depend on whether they are rather enzyme limited (i.e. Q10=2) or diffusion limited (i.e. Q10= 1.0 - 1.3). However, temperature sensitivities of protein depolymerization and amino acid immobilization are still unknown. We therefore here report short-term temperature effects on organic N transformation rates in soils differing in physicochemical parameters but not in climate. Soil samples were collected from two geologically distinct sites close to the LFZ Raumberg-Gumpenstein, Styria, Austria, each from three different management types (arable land, grassland, forest). Four replicates of mineral soil were taken from every site and management type. The area provides a unique opportunity to study geological and management controls in soils without confounding effects of climate and elevation. The soils differ in several soil chemical parameters, such as soil pH, base saturation, soil C: N ratio and SOM content as well as in soil physical parameters, such as soil texture, bulk density and water holding capacity. Soils were pre-incubated at 5, 15 and 25˚ C for one day. Protein depolymerization rates and amino acid immobilization rates were assessed by an isotope pool dilution assay with 15N labeled amino acids at

  7. Soil infiltration based on bp neural network and grey relational analysis

    Directory of Open Access Journals (Sweden)

    Wang Juan

    2013-02-01

    Full Text Available Soil infiltration is a key link of the natural water cycle process. Studies on soil permeability are conducive for water resources assessment and estimation, runoff regulation and management, soil erosion modeling, nonpoint and point source pollution of farmland, among other aspects. The unequal influence of rainfall duration, rainfall intensity, antecedent soil moisture, vegetation cover, vegetation type, and slope gradient on soil cumulative infiltration was studied under simulated rainfall and different underlying surfaces. We established a six factor-model of soil cumulative infiltration by the improved back propagation (BP-based artificial neural network algorithm with a momentum term and self-adjusting learning rate. Compared to the multiple nonlinear regression method, the stability and accuracy of the improved BP algorithm was better. Based on the improved BP model, the sensitive index of these six factors on soil cumulative infiltration was investigated. Secondly, the grey relational analysis method was used to individually study grey correlations among these six factors and soil cumulative infiltration. The results of the two methods were very similar. Rainfall duration was the most influential factor, followed by vegetation cover, vegetation type, rainfall intensity and antecedent soil moisture. The effect of slope gradient on soil cumulative infiltration was not significant.

  8. Plant-induced changes in soil chemistry do not explain differences in uranium transfer

    International Nuclear Information System (INIS)

    Duquene, L.; Vandenhove, H.; Tack, F.; Avoort, E. van der; Hees, M. van; Wannijn, J.

    2006-01-01

    A greenhouse experiment was set up with maize, ryegrass, Indian mustard, wheat and pea to evaluate to what extent differences in uranium (U) transfer factors can be explained by root-mediated changes in selected soil properties. The experiment involved an acid and an alkaline soil contaminated with 238 U. U soil-to-shoot transfer factors (TFs) ranged between 0.0005 and 0.021 on the acid soil and between 0.007 and 0.179 on the alkaline soil. Indian mustard showed the highest U uptake in shoots and maize the lowest. The root TFs, only available for the acid soil, ranged from 0.58 for maize and Indian mustard to 1.38 for ryegrass. The difference in U uptake between the two soils and the five plants was only partially explained by the different initial U concentrations in soil solution or differences in soil properties in the two soils. However, we obtained a significant relation for differences in shoot TFs observed between the two soils when relating shoot TFs with concentration of UO 2 2+ and uranyl carbonate complexes in soil solution (R 2 = 0.88). The physiological mechanisms by which root-to-shoot U transfer is inhibited or promoted seemed at least as important as the plant-induced changes in soil characteristics in determining soil-to-shoot TFs

  9. The impact of acid soil volume of reclaimed minespoils on plant growth in minilysimeters

    Energy Technology Data Exchange (ETDEWEB)

    Shahandeh, H.; Hossner, L.R.; Birkhead, J.A. [Texas A & M University, College Station, TX (United States). College of Agriculture and Life Science

    1996-06-01

    Limited data are available to assess the influence of randomly distributed acid soil, produced from acid forming materials (AFM), on growth and productivity of crops. This study evaluated the effect of amount and volume of acid soil on the growth of an acid tolerant plant (Coastal bermudga grass, {ital Cynodon dactylon}, L.) and an acid intolerant plant (Yuchi arrowleaf clover, {ital Trifolium vesiculosum}, Savi) in greenhouse lysimeters. Acid soil (pH=2.5) volumes up to 20% for Yuchi arrowleaf clover and up to 40% for Coastal bermuda grass did not significantly decrease dry matter yield. Concentrations of Al and Mn in plant tissue of clover and bermudagrass were below the toxicity level. In the presence of randomly distributed acid soil, plant roots continued to elongate in non-acid soil, by evading localized areas of low soil pH. These results suggest that the federally mandated zero tolerance for AFM in the top 1.2 m of reclaimed lands may not be reasonable. 18 refs., 7 figs., 2 tabs.

  10. Effect of wood ash application on soil solution chemistry of tropical acid soils: incubation study.

    Science.gov (United States)

    Nkana, J C Voundi; Demeyer, A; Verloo, M G

    2002-12-01

    The objective of this study was to determine the effect of wood ash application on soil solution composition of three tropical acid soils. Calcium carbonate was used as a reference amendment. Amended soils and control were incubated for 60 days. To assess soluble nutrients, saturation extracts were analysed at 15 days intervals. Wood ash application affects the soil solution chemistry in two ways, as a liming agent and as a supplier of nutrients. As a liming agent, wood ash application induced increases in soil solution pH, Ca, Mg, inorganic C, SO4 and DOC. As a supplier of elements, the increase in the soil solution pH was partly due to ligand exchange between wood ash SO4 and OH- ions. Large increases in concentrations of inorganic C, SO4, Ca and Mg with wood ash relative to lime and especially increases in K reflected the supply of these elements by wood ash. Wood ash application could represent increased availability of nutrients for the plant. However, large concentrations of basic cations, SO4 and NO3 obtained with higher application rates could be a concern because of potential solute transport to surface waters and groundwater. Wood ash must be applied at reasonable rates to avoid any risk for the environment.

  11. Oxidation of phenolic acid derivatives by soil and its relevance to allelopathic activity.

    Science.gov (United States)

    Ohno, T

    2001-01-01

    Previous studies have suggested that phenolic acids from legume green manures may contribute to weed control through allelopathy. The objectives of this study were to investigate the oxidation reactions of phenolic acids in soil and to determine the subsequent effects of oxidation upon phytotoxicity. Soils were reacted for 18 h with 0.25 mmol L(-1) benzoic and cinnamic acid derivative solutions and Mn release from the suspension was used as a marker for phenolic acid oxidation. The extent of oxidation in soil suspensions was in the order of 3,4dihydroxy- > 4-hydroxy-3-methoxy- > 4-hydroxy-approximately 2-hydroxy-substituted benzoic and cinnamic acids. The same ranking was observed for cyclic voltammetry peak currents of the cinnamic acid derivatives. This suggests that the oxidation of phenolic acids is controlled by the electron transfer step from the sorbed phenolic acid to the metal oxide. A bioassay experiment showed that the 4-hydroxy-, 4-hydroxy-3-methoxy-, and 3,4-dihydroxy-substituted cinnamic acids were bioactive at 0.25 mmol L(-1) concentration. Reaction with soil for 18 h resulted in the elimination of bioactivity of these three cinnamic acids at the 5% significance level. The oxidative reactivity of phenolic acids may limit the potential of allelopathy as a component of an integrated weed management system. However, the initial phytotoxicity after soil incorporation may coincide with the early, critical stage of weed emergence and establishment, so that allelopathic phenolic acids may still play a role in weed management despite their reactivity in soil systems.

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

    Directory of Open Access Journals (Sweden)

    Christopher Ash

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

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

    Science.gov (United States)

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

    2016-01-01

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

  14. Decolorization of humic acids and alkaline lignin derivative by an anamorphic Bjerkandera adusta E59 strain isolated from soil

    Energy Technology Data Exchange (ETDEWEB)

    Kornillowicz-Kowalska, T.; Ginalska, G.; Belcarz, A.; Iglik, H. [University of Life Sciences, Lublin (Poland). Dept. of Microbiology

    2008-07-01

    An anamorphic Bjerkandera adusta R59 strain, isolated from soil, was found to decolorize post-industrial lignin alkaline fraction, humic acids isolated from two kinds of soil and from brown coal. The drop of methoxyphenolic compound levels in liquid B. adusta cultures containing lignin or humic acids was correlated with decolorization of studied biopolymers, which suggests their partial biodegradation. It was shown that this process was Coupled with the induction of secondary metabolism (idiophase), and highest peroxidase activity in culture medium and appearance of aerial mycelium. Decolorization of lignin and humic acids from lessive soil and brown coal depended on glucose presence (cometabolism). Decolorization of humic acid from chernozem was related partially to adsorption by fungal mycelium.

  15. Effects of EDTA and low molecular weight organic acids on soil solution properties of a heavy metal polluted soil.

    Science.gov (United States)

    Wu, L H; Luo, Y M; Christie, P; Wong, M H

    2003-02-01

    A pot experiment was conducted to study the effects of EDTA and low molecular weight organic acids (LMWOA) on the pH, total organic carbon (TOC) and heavy metals in the soil solution in the rhizosphere of Brassica juncea grown in a paddy soil contaminated with Cu, Zn, Pb and Cd. The results show that EDTA and LMWOA have no effect on the soil solution pH. EDTA addition significantly increased the TOC concentrations in the soil solution. The TOC concentrations in treatments with EDTA were significantly higher than those in treatments with LMWOA. Adding 3 mmol kg(-1) EDTA to the soil markedly increased the total concentrations of Cu, Zn, Pb and Cd in the soil solution. Compared to EDTA, LMWOA had a very small effect on the metal concentrations. Total concentrations in the soil solution followed the sequence: EDTA > citric acid (CA) approximately oxalic acid (OA) approximately malic acid (MA) for Cu and Pb; EDTA > MA > CA approximately OA for Zn; and EDTA > MA > CA > OA for Cd. The labile concentrations of Cu, Zn, Pb and Cd showed similar trends to the total concentrations.

  16. Remote sensing of acid sulfate soils using multispectral and gamma-ray data

    International Nuclear Information System (INIS)

    Bierwirth, P.N.; Graham, T.L.

    1998-01-01

    Acid sulfate soils are a significant environmental problem in coastal regions of Australia. Drainage and disturbance of coastal lands can result in acid soil degradation and the release of sulfuric acid and toxic metals into coastal waters. Remote sensing can provide a useful tool for detection of these soils and monitoring of their disturbance. As acid sulfate soils become oxidised with exposure to air, iron-minerals are produced and precipitate at the surface. This results from the breakdown of pyrite to form hydrated iron minerals and elemental sulfur, the oxidation of which produces acidity. The concentration of iron minerals at the surface can be an indicator of the level of acid sulfate soil activity in the near subsurface. These iron minerals include goethite, ferrihydrite and jarosite. Space-borne remote sensing scanners such as Landsat TM are capable of detecting iron minerals as a result of ferric ion absorption of solar radiation. Hyperspectral scanners are capable of further discrimination of individual minerals. This paper will discuss spectral characteristics of active acid sulfate soils and demonstrate the use of spectral unmixing algorithms on Landsat TM to detect problem areas at the surface. This method matches multispectral data to material reflectance-spectra known as end-members. These end-members or materials are then resolved mathematically as to their respective contributions to the overall reflectance (Bierwirth, 1990). In this way, abundances for particular materials can be derived.Digital elevation data was used to distinguish between the iron minerals due to weathering of bedrock in upland areas and acid sulfate soils on the plains. Also, the results of a high resolution (200m linespacing) airborne gamma-ray survey are presented. This data senses the concentration of radioelements down to about 40 cm depth and is largely unaffected by vegetation. Concentrations of gamma-emitting elements can indicate the type and depth of alluvium that

  17. Anaerobic N mineralization in paddy soils in relation to inundation management, physicochemical soil fractions, mineralogy and soil properties

    Science.gov (United States)

    Sleutel, Steven; Kader, Mohammed Abdul; Ara Begum, Shamim; De Neve, Stefaan

    2013-04-01

    Anaerobic N mineralization measured from (saturated) repacked soil cores from 25 paddy fields in Bangladesh and was previously found to negatively related to soil N content on a relative basis. This suggests that other factors like soil organic matter (SOM) quality or abiotic factors instead control the anaerobic N mineralization process. We therefore assessed different physical and chemical fractions of SOM, management factors and various soil properties as predictors for the net anaerobic N mineralization. 1° First, we assessed routinely analyzed soil parameters (soil N and soil organic carbon, texture, pH, oxalate- and pyrophosphate-extractable Fe, Al, and Mn, fixed-NH4 content). We found no significant influences of neither soil mineralogy nor the annual length of inundation on soil N mineralization. The anaerobic N mineralization correlated positively with Na-pyrophosphate-extractable Fe and negatively with pH (both at Presistant OM fraction, followed by extraction of mineral bound OM with 10%HF thereby isolating the HF-resistant OM. None of the physicochemical SOM fractions were found useful predictors anaerobic N mineralization. The linkage between these chemical soil N fractions and N supplying processes actually occurring in the soil thus appears to be weak. Regardless, we hypothesize that variation in strength of N-mineral and N-OM linkages is likely to explain variation in bio-availability of organic N and proneness to mineralization. Yet, in order to separate kinetically different soil N fractions we then postulated that an alternative approach would be required, which instead isolates soil N fractions on the basis of bonding strength. In this respect bonding strength should be seen as opposite of proneness to dissolution of released N into water, the habitat of soil microorganisms mediating soil N mineralization. We hypothesize that soil N extracted by water at increasing temperatures would reflect such N fractions with increasing bonding strength, in

  18. Effects of Organic Acids and Sylvite on Phytoextraction of 241Am Contaminated Soil.

    Science.gov (United States)

    Wang, Ping; Du, Liang; Tan, Zhaoyi; Su, Rongbo; Li, Taowen

    2017-03-01

    Contamination of soil with Americium ( 241 Am) at nuclear sites in China poses a serious problem. We screened six plants, from five families, for their 241 Am-enrichment potential. Europium (Eu), which is morphologically and chemically similar to the highly toxic 241 Am, was used in its place. Moreover, the effects of sylvite, citric acid (CA), malic acid (MA), and humic acid (HA) on the absorption of 241 Am by the plants, and its transport within them, were evaluated along with their effect on plant biomass and 241 Am extraction volume. Barley and cabbage showed relatively stronger Eu accumulation capacities. Citric acid promoted the absorption of 241 Am by barley roots and its transport within the plants. The effects of sylvite were not obvious and those of HA were the weakest in case of sunflower; HA, however, maximally increased the biomass of the plants. Our results could provide the basis for future radionuclide phytoremediation of contaminated soils.

  19. soil groups relative susceptibility to erosion in parts of south-eastern

    African Journals Online (AJOL)

    Dr Obe

    erosion by water determined based on the amount of soil lost during the various runs. Based on ... knowledge of the many factors of soil erosion .... Table 4: Relative erodibility levels of soil groups in lmo and Abia States under 'wet' conditions. Moderately Erodible. Highly Erodible. Very Highly Erodible. 1. Type Dystropepts.

  20. [Current situation and impact factors of acid deposition in main cites of Shandong Province].

    Science.gov (United States)

    Jia, Hong-yu; Zhang, Qiao-xian; Deng, Hong-bing; Zhao, Jing-zhu; Mu, Jin-bo; Zhang, De-zhi

    2006-12-01

    Based on the monitoring data for years in Shandong Province, current situation of acid rain in every city was assessed, and the temporal distribution of the dry, wet and total sulfur deposition in Jinan and Qingdao were studied. The results showed that Qingdao which had the largest precipitation acidity was the single city whose annul average precipitation pH was below 5. 60. The precipitation acidities in the main cities of Shandong Province were in a descent tendency. The total sulfur desposition in Jinan and Qingdao was basically stable or in a descent tendency, but also reached 10 t/(km(2)x a) or so. Among the total sulfur deposition flux, the dry deposition of sulfur had the greater contribution, and the contribution of SO2 dry deposition was higher than that of SO42- dry deposition. By analyzing the relation between the precipitation acidity and the SO2 discharge intensity, soil acidity and meteorological condition, the impact factors of acid precipitation in the cities of Shandong Province were revealed.

  1. Alleviating acid soil stress in cowpea with a local population of ...

    African Journals Online (AJOL)

    Alleviating acid soil stress in cowpea with a local population of arbuscular ... Roots of the cowpea lines were all heavily colonized by the fungi and their leaf P was ... Total dry weight of inoculated cowpea was not affected by soil acidity while it ...

  2. Isotopic tracer studies to evaluate relative efficiency of different forms of P for growing rice on different soil types

    International Nuclear Information System (INIS)

    Dash, R.N.; Mohanty, S.K.; Patnaik, S.

    1977-01-01

    The relative efficiency of different forms of P in relation to their time of application for growing rice on different soil types has been studied by using 32 P tagged mono-, di-, and tri-calcium phosphate, ammonium nitrate phosphate containing all the P in the citrate-soluble form and potassium meta-phosphate. P-deficient acid laterite soil from Burdwan, red loam soil from Peramanpur and calcareous black soil from Hyderabad were used in the study. The different P forms were found to be compatible in the acid, red and laterite soils when the phosphorus forms were primed to moist acid soils 2 weeks prior to flooding. On application at flooding, fertilizers containing citrate-soluble phosphate were found to be less effective as compared to those containing water-soluble phosphate. In the calcareous black soil, however, the fertilizers, containing insoluble or citrate-soluble phosphates were not as efficient as the water-soluble forms, possibly because of lack of dissolution process. Potassium meta-phosphate was found to be effective in all the soil types whether applied at flooding or primed to the moist soil. (M.G.B.)

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

    International Nuclear Information System (INIS)

    Atanasov, I.; Gribachev, P.

    1997-01-01

    This study assesses the damage of soils caused by spills of sulfuric acid solutions used for in situ leaching of uranium at eight uranium producing (by open-cast method) sites (total area of approximately 220 ha) in the region of Momino-Rakovski (South Bulgaria). The upper soil layer is cinnamonic pseudopodzolic ( or Eutric Planosols by FAO Legend, 1974). The results of the investigation show that the sulfuric acid spills caused strong acidification of upper (0-20 cm) and subsurface (20-60 cm) soil horizons which is expressed as decreasing of pH (H 2 O) to 2.9-3.5 and increasing of exchangeable H + and Al 3+ to 18 and 32% from CEC. Acid degradation of soils is combined with reducing of organic matter content. The average concentration of the total heavy metal content in the upper soil horizon (in ppm) is: Cd=1.5; Cu=30; Pb=25; Zn=40 and U=8. No significant differences were detected between the upper and subsurface soil layers . The heavy metal concentration did not exceed the Bulgarian standards for heavy metals and uranium content of soils. But the coarse texture of the top soil layers, the lack of carbonates, The low CEC and strong acidity determine a low buffering capacity of the investigated soils and this can be considered as hazardous for plants. This indicates that a future soil monitoring should be carried out in the region together with measures for neutralizing of soil acidity

  4. Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

    Science.gov (United States)

    Sullivan, Timothy J.; Lawrence, Gregory B.; Bailey, Scott W.; McDonnell, Todd C.; Beier, Colin M.; Weathers, K.C.; McPherson, G.T.; Bishop, Daniel A.

    2013-01-01

    We documented the effects of acidic atmospheric deposition and soil acidification on the canopy health, basal area increment, and regeneration of sugar maple (SM) trees across the Adirondack region of New York State, in the northeastern United States, where SM are plentiful but not well studied and where widespread depletion of soil calcium (Ca) has been documented. Sugar maple is a dominant canopy species in the Adirondack Mountain ecoregion, and it has a high demand for Ca. Trees in this region growing on soils with poor acid–base chemistry (low exchangeable Ca and % base saturation [BS]) that receive relatively high levels of atmospheric sulfur and nitrogen deposition exhibited a near absence of SM seedling regeneration and lower crown vigor compared with study plots with relatively high exchangeable Ca and BS and lower levels of acidic deposition. Basal area increment averaged over the 20th century was correlated (p < 0.1) with acid–base chemistry of the Oa, A, and upper B soil horizons. A lack of Adirondack SM regeneration, reduced canopy condition, and possibly decreased basal area growth over recent decades are associated with low concentrations of nutrient base cations in this region that has undergone soil Ca depletion from acidic deposition.

  5. Soil-to-potato transfer factors of elements

    International Nuclear Information System (INIS)

    Tsukada, Hirofumi; Watabe, Teruhisa.

    1996-01-01

    Transfer factors (TFs) of stable elements from soil to potato were determined for 26 pairs of samples which were collected at different sites in Aomori prefecture, Japan. The concentrations of 31 elements in both soil and potato samples were determined by neutron activation analysis. Several of these elements were divided into two groups, each having different TF characteristics. In the first group of elements, such as Cl, K, Ca, etc., an inverse correlation was seen between the TFs for each element and their concentrations in the soil. The relatively constant concentrations of these elements in potato were independent of the concentrations of the same elements in soil. However, in the second group, the TFs for other elements, such as Sc, Co and so on, in potato were independent of their concentrations in the soil. The fluctuation of TF observed in this study was smaller than that previously reported. It may be attributed to the fact that the experiment was done in a relatively narrow geographic area. In addition, the TFs for stable elements in this study were generally one to three orders of magnitude lower than those compiled for radioactive isotopes in IAEA publications. These differences should be precisely examined hereafter. (author)

  6. Isotopically exchangeable Al in coastal lowland acid sulfate soils

    Energy Technology Data Exchange (ETDEWEB)

    Yvanes-Giuliani, Yliane A.M. [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia); Centre Européen de Recherche et d' Enseignement des Géosciences de l' Environnement, Aix-Marseille Université, Aix en Provence (France); Fink, D. [Centre Européen de Recherche et d' Enseignement des Géosciences de l' Environnement, Aix-Marseille Université, Aix en Provence (France); Rose, J. [Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Waite, T. David [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia); Collins, Richard N., E-mail: richard.collins@unsw.edu.au [UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia, Sydney, NSW 2052 (Australia)

    2016-01-15

    Periodic discharges of high concentrations of aluminium (Al) causing fish kills and other adverse effects occur worldwide in waterways affected by coastal lowland acid sulfate soils (CLASS). The exchangeability — a metal's ability to readily transfer between the soil solid- and solution-phases — of Al in these soils is therefore of particular importance as it has implications for metal transport, plant availability and toxicity to living organisms. In the present study, the concentrations of isotopically exchangeable Al (E values) were measured in 27 CLASS and compared with common salt extractions (i.e. KCl and CuCl{sub 2}) used to estimate exchangeable soil pools of Al. E values of Al were high in the soils, ranging from 357 to 3040 mg·kg{sup −1}. Exchangeable concentrations estimated using 1 M KCl were consistently lower than measured E values, although a reasonable correlation was obtained between the two values (E = 1.68 × Al{sub KCl}, r{sup 2} = 0.66, n = 25). The addition of a 0.2 M CuCl{sub 2} extraction step improved the 1:1 agreement between extractable and isotopically exchangeable Al concentrations, but lead to significant mobilisation of non-isotopically exchangeable Al in surficial ‘organic-rich’ CLASS having E values < 1000 mg·kg{sup −1}. It was concluded that currently used (i.e. 1 M KCl) methodology severely underestimates exchangeable Al and total actual acidity values in CLASS and should be corrected by a factor similar to the one determined here. - Highlights: • Isotopically exchangeable Al was compared to 1 M KCl or 0.2 M CuCl{sub 2} extractable Al. • 1 M KCl always underestimated isotopically exchangeable Al concentrations. • 0.2 M CuCl{sub 2} mobilised non-isotopically exchangeable Al • 1 M KCl values require correction of ~ 1.7 to reflect exchangeable Al concentrations.

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

    Science.gov (United States)

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

    2013-03-01

    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.

  8. EDTA and HCl leaching of calcareous and acidic soils polluted with potentially toxic metals: remediation efficiency and soil impact.

    Science.gov (United States)

    Udovic, Metka; Lestan, Domen

    2012-07-01

    The environmental risk of potentially toxic metals (PTMs) in soil can be diminished by their removal. Among the available remediation techniques, soil leaching with various solutions is one of the most effective but data about the impact on soil chemical and biological properties are still scarce. We studied the effect of two common leaching agents, hydrochloric acid (HCl) and a chelating agent (EDTA) on Pb, Zn, Cd removal and accessibility and on physico-chemical and biological properties in one calcareous, pH neutral soil and one non-calcareous acidic soil. EDTA was a more efficient leachant compared to HCl: up to 133-times lower chelant concentration was needed for the same percentage (35%) of Pb removal. EDTA and HCl concentrations with similar PTM removal efficiency decreased PTM accessibility in both soils but had different impacts on soil properties. As expected, HCl significantly dissolved carbonates from calcareous soil, while EDTA leaching increased the pH of the acidic soil. Enzyme activity assays showed that leaching with HCl had a distinctly negative impact on soil microbial and enzyme activity, while leaching with EDTA had less impact. Our results emphasize the importance of considering the ecological impact of remediation processes on soil in addition to the capacity for PTM removal. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Tannic acid for remediation of historically arsenic-contaminated soils.

    Science.gov (United States)

    Gusiatin, Zygmunt Mariusz; Klik, Barbara; Kulikowska, Dorota

    2017-12-22

    Soil washing effectively and permanently decreases soil pollution. Thus, it can be considered for the removal of the most toxic elements, for example arsenic (As). In this study, historically As-contaminated soils (2041-4294 mg/kg) were remediated with tannic acid (TA) as the washing agent. The scope of this study included optimization of the operational conditions of As removal, determination of As distribution in soil before and after double soil washing, and measurement of TA loss during washing. The optimum conditions for As removal were 4% TA, pH 4 and 24 h washing time. The average As removal after single and double washings was 38% and 63%, respectively. TA decreased As content in amorphous and poorly crystalline oxides by >90%. Although TA increased the amount of As in the easily mobilizable As fraction, the stability of As in washed soils increased, with reduced partition indexes of 0.52-0.66 after washing. The maximum capacity of the soils to adsorb TA (q max ) was 50.2-70.4 g C/kg. TA sorption was higher at alkaline than at acidic conditions. Only TA removes As from soils effectively if the proportion of As in amorphous and poorly crystalline oxides is high. Thus, it can be considered for remediation of historically contaminated soils.

  10. Development of effective methods for determination of boron in soils and soil solutions

    Directory of Open Access Journals (Sweden)

    Мaruan Tanasheva

    2012-12-01

    Full Text Available This paper is related to serious ecological problem in agriculture: soil degradation in rice fields in South Kazakhstan and in particular, to boron toxicity in rice, which resulted in reduced crop yields. The following abiotic factors were studied to determine the ability of boron to accumulate in rice fields: soil type, soil properties like salinity and acidity', season (level of precipitation, water logging /water shortage. The results shows that the severity of boron excess for fertility of rice crop which depends on boron ionic composition in soil. Adverse impact of both boron deficiency and boron excess are discussed. The necessity of boron fertilizers is shown for soils with high boron mobility.

  11. Nitrous oxide emissions and soil mineral nitrogen status following application of hog slurry and inorganic fertilisers to acidic soils under forage grass

    International Nuclear Information System (INIS)

    Mkhabela, M.S.; Gordon, R.; Madani, A.; Burton, D.; Hart, W.

    2008-01-01

    This paper examined the influence of hog slurry and inorganic fertilizers on nitrous oxide (N 2 O) emissions and soil inorganic nitrogen (N) composition. Factors controlling N 2 O production were also identified. The study was comprised of 3 field experiments conducted during the summer months of 2005 on 2 acidic soils seeded with forage grass at a site in Nova Scotia. Treatments included hog slurry; ammonium sulphate; potassium nitrate; and an unamended control site. Emissions were measured using vented polyvinyl chloride static chambers. Gas fluxes and NO 2 measurements were analyzed using gas chromatography. Data were then subjected to analysis of variance (ANOVA). N 2 O flux and soil mineral N data from each sampling day were analyzed separately. Cumulative N 2 O losses were also calculated. Results demonstrated that the addition of hog slurry resulted in lower N 2 O emissions than the samples containing potassium nitrate fertilizer. The study also demonstrated that nitrate (NO 3 ) production drives NO 2 production in acidic soils. It was concluded that further research is needed to verify results obtained during the study. 29 refs., 3 tabs., 3 figs

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

    International Nuclear Information System (INIS)

    Zhang Jinbo; Cai Zucong; Zhu Tongbin

    2011-01-01

    To date, N 2 O production pathways are poorly understood in the humid subtropical and tropical forest soils. A 15 N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N 2 O production in four subtropical acid forest soils (pH 2 O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N 2 O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N 2 O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N 2 O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N 2 O product ratios from nitrification. The ratio of N 2 O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: → We studied N 2 O production pathways in subtropical acid forest soil under aerobic conditions. → Denitrification was the main source of N 2 O production in subtropical acid forest soils. → Heterotrophic nitrification accounted for 27.3%-41.8% of N 2 O production. → While, contribution of autotrophic nitrification to N 2 O production was little. → Ratios of N 2 O-N emission from nitrification were higher than those in most previous references.

  13. Predicting recovery from acid rain using the micro-spatial heterogeneity of soil columns downhill the infiltration zone of beech stemflow: introduction of a hypothesis.

    Science.gov (United States)

    Berger, Torsten W; Muras, Alexander

    Release of stored sulfur may delay the recovery of soil pH from Acid Rain. It is hypothesized that analyzing the micro-spatial heterogeneity of soil columns downhill of a beech stem enables predictions of soil recovery as a function of historic acid loads and time. We demonstrated in a very simplified approach, how these two different factors may be untangled from each other using synthetic data. Thereafter, we evaluated the stated hypothesis based upon chemical soil data with increasing distance from the stem of beech trees. It is predicted that the top soil will recover from acid deposition, as already recorded in the infiltration zone of stemflow near the base of the stem. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed.

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

    Science.gov (United States)

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

    2015-11-01

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

  15. Characterizing the release of different composition of dissolved organic matter in soil under acid rain leaching using three-dimensional excitation-emission matrix spectroscopy.

    Science.gov (United States)

    Liu, Li; Song, Cunyi; Yan, Zengguang; Li, Fasheng

    2009-09-01

    Although excitation-emission matrix spectroscopy (EEMS) has been widely used to characterize dissolved organic matter (DOM), there has no report that EEMS has been used to study the effects of acid rain on DOM and its composition in soil. In this work, we employed three-dimensional EEMS to characterize the compositions of DOM leached by simulated acid rain from red soil. The red soil was subjected to leaching of simulated acid rain of different acidity, and the leached DOM presented five main peaks in its EEMS: peak-A, related to humic acid-like (HA-like) material, at Ex/Em of 310-330/395-420nm; peak-B, related to UV fulvic acid-like (FA-like) material, at Ex/Em of 230-280/400-435nm; peak-C and peak-D, both related to microbial byproduct-like material, at Ex/Em of 250-280/335-355nm and 260-280/290-320nm, respectively; and peak-E, related to simple aromatic proteins, at Ex/Em of 210-240/290-340nm. EEMS analysis results indicated that most DOM could be lost from red soil in the early phase of acid rain leaching. In addition to the effects of the pH of acid rain, the loss of DOM also depended on the properties of its compositions and the solubility of their complexes with aluminum. HA-like and microbial byproduct-like materials could be more easily released from red soil by acid rain at both higher pH (4.5 and 5.6) and lower pH (2.5 and 3) than that at middle pH (3.5). On the contrary, FA-like material lost in a similar manner under the action of different acid rains with pH ranging from 2.5 to 5.6.

  16. Phospholipid fatty acid composition of microorganisms in pine forest soils of Central Siberia

    Czech Academy of Sciences Publication Activity Database

    Evgrafova, S.Yu.; Šantrůčková, H.; Shibistova, O.B.; Elhottová, Dana; Černá, B.; Zrazhevskaya, G.K.; Lloyd, D.

    2008-01-01

    Roč. 35, č. 5 (2008), s. 452-458 ISSN 1062-3590 Grant - others:Evropská unie(XE) 03-55-1344; Ministry of Education and Science of the Russian Federation(RU) RUX0-002-KR-06 Institutional research plan: CEZ:AV0Z60660521 Keywords : phospholipid fatty acid * microorganisms * pine forest soils Subject RIV: EH - Ecology, Behaviour Impact factor: 0.082, year: 2008

  17. Soil fauna and its relation with environmental variables in soil management systems

    Directory of Open Access Journals (Sweden)

    Dilmar Baretta

    Full Text Available The present study aims to generate knowledge about the soil fauna, its relation to other explanatory environmental variables, and, besides it, to select edaphic indicators that more contribute to separate the land use systems (LUS. Five different LUS were chosen: conventional tillage with crop rotation (CTCR; no-tillage with crop rotation (NTCR; conventional tillage with crop succession (CTCS; no-tillage with crop succession (NTCS and minimum tillage with crop succession (MTCS. The samples were made in the counties Chapecó, Xanxerê and Ouro Verde located in the state of Santa Catarina, Brazil, and were considered the true replicates of the LUS. In each site, nine points were sampled in a sampling grid of 3 x 3. At the same points, soil was sampled for the physical, chemical and biological attributes (environmental variables. Pitfall traps were used to evaluate the soil fauna. Data were analyzed using principal component analysis (PCA and canonical discriminant analysis (CDA. The soil fauna presented potential to be used as indictors of soil quality, since some groups proved to be sensible to changes of the environmental variables and to soil management and tillage. The soil management using crop rotation (NTCR and CTCR presented higher diversity, compared to the systems using crop succession (NTCS, MTCS and NTCS, evidencing the importance of the soil tillage, independent of the season (summer or winter. The variable that better contributed to explain these changes were the chemical variables (potassium, pH, calcium, organic matter, available phosphorus, potential acidity, and biological variables (Shannon diversity index, Collembola, Pielou equitability index and microbial biomass carbon, respectively.

  18. Plant Adaptation to Acid Soils: The Molecular Basis for Crop Aluminum Resistance.

    Science.gov (United States)

    Kochian, Leon V; Piñeros, Miguel A; Liu, Jiping; Magalhaes, Jurandir V

    2015-01-01

    Aluminum (Al) toxicity in acid soils is a significant limitation to crop production worldwide, as approximately 50% of the world's potentially arable soil is acidic. Because acid soils are such an important constraint to agriculture, understanding the mechanisms and genes conferring resistance to Al toxicity has been a focus of intense research interest in the decade since the last article on crop acid soil tolerance was published in this journal. An impressive amount of progress has been made during that time that has greatly increased our understanding of the diversity of Al resistance genes and mechanisms, how resistance gene expression is regulated and triggered by Al and Al-induced signals, and how the proteins encoded by these genes function and are regulated. This review examines the state of our understanding of the physiological, genetic, and molecular bases for crop Al tolerance, looking at the novel Al resistance genes and mechanisms that have been identified over the past ten years. Additionally, it examines how the integration of molecular and genetic analyses of crop Al resistance is starting to be exploited for the improvement of crop plants grown on acid soils via both molecular-assisted breeding and biotechnology approaches.

  19. Removal of heavy metals from contaminated soil by electrodialytic remediation enhanced with organic acids.

    Science.gov (United States)

    Merdoud, Ouarda; Cameselle, Claudio; Boulakradeche, Mohamed Oualid; Akretche, Djamal Eddine

    2016-11-09

    The soil from an industrial area in Algeria was contaminated with Cr (8370 mg kg -1 ), Ni (1135 mg kg -1 ) and zinc (1200 mg kg -1 ). The electrodialytic remediation of this soil was studied using citric acid and EDTA as facilitating agents. 0.1 M citric acid or EDTA was added directly to the soil before it was introduced in an electrodialytic cell in an attempt to enhance the heavy metal solubility in the interstitial fluid. The more acidic pH in the soil when citric acid was used as the facilitating agent was not enough to mobilize and remove the metals from the soil. Only 7.2% of Ni and 6.7% of Zn were removed from the soil in the test with citric acid. The best results were found with EDTA, which was able to solubilize and complex Zn and Ni forming negatively charged complexes that were transported and accumulated in the anolyte. Complete removal was observed for Ni and Zn in the electrodialytic treatment with EDTA. Minor amounts of Cr were removed with both EDTA and citric acid.

  20. Subcritical Water Extraction of Amino Acids from Atacama Desert Soils

    Science.gov (United States)

    Amashukeli, Xenia; Pelletier, Christine C.; Kirby, James P.; Grunthaner, Frank J.

    2007-01-01

    Amino acids are considered organic molecular indicators in the search for extant and extinct life in the Solar System. Extraction of these molecules from a particulate solid matrix, such as Martian regolith, will be critical to their in situ detection and analysis. The goals of this study were to optimize a laboratory amino acid extraction protocol by quantitatively measuring the yields of extracted amino acids as a function of liquid water temperature and sample extraction time and to compare the results to the standard HCl vapor- phase hydrolysis yields for the same soil samples. Soil samples from the Yungay region of the Atacama Desert ( Martian regolith analog) were collected during a field study in the summer of 2005. The amino acids ( alanine, aspartic acid, glutamic acid, glycine, serine, and valine) chosen for analysis were present in the samples at concentrations of 1 - 70 parts- per- billion. Subcritical water extraction efficiency was examined over the temperature range of 30 - 325 degrees C, at pressures of 17.2 or 20.0 MPa, and for water- sample contact equilibration times of 0 - 30 min. None of the amino acids were extracted in detectable amounts at 30 degrees C ( at 17.2 MPa), suggesting that amino acids are too strongly bound by the soil matrix to be extracted at such a low temperature. Between 150 degrees C and 250 degrees C ( at 17.2 MPa), the extraction efficiencies of glycine, alanine, and valine were observed to increase with increasing water temperature, consistent with higher solubility at higher temperatures, perhaps due to the decreasing dielectric constant of water. Amino acids were not detected in extracts collected at 325 degrees C ( at 20.0 MPa), probably due to amino acid decomposition at this temperature. The optimal subcritical water extraction conditions for these amino acids from Atacama Desert soils were achieved at 200 degrees C, 17.2 MPa, and a water- sample contact equilibration time of 10 min.

  1. Detailed predictive mapping of acid sulfate soil occurrence using electromagnetic induction data

    DEFF Research Database (Denmark)

    Beucher, Amélie; Boman, A; Mattbäck, S

    impact through the resulting corrosion of concrete and steel infrastructures, or their poor geotechnical qualities. Therefore, mapping acid sulfate soil occurrence constitutes a key step to target the strategic areas for subsequent environmental risk management and mitigation. Conventional mapping (i...... obtained from a EM38 proximal sensor enabled the refined mapping of acid sulfate soils over a field (Huang et al. 2014). The present study aims at developing an efficient and reliable method for the detailed predictive mapping of acid sulfate soil occurrence in a field located in western Finland. Different...

  2. Influence of ameliorating soil acidity with dolomite on the priming of soil C content and CO2 emission.

    Science.gov (United States)

    Shaaban, Muhammad; Wu, Lei; Peng, Qi-An; van Zwieten, Lukas; Chhajro, Muhammad Afzal; Wu, Yupeng; Lin, Shan; Ahmed, Muhammad Mahmood; Khalid, Muhammad Salman; Abid, Muhammad; Hu, Ronggui

    2017-04-01

    Lime or dolomite is commonly implemented to ameliorate soil acidity. However, the impact of dolomite on CO 2 emissions from acidic soils is largely unknown. A 53-day laboratory study was carried out to investigate CO 2 emissions by applying dolomite to an acidic Acrisol (rice-rapeseed rotation [RR soil]) and a Ferralsol (rice-fallow/flooded rotation [RF soil]). Dolomite was dosed at 0, 0.5, and 1.5 g 100 g -1 soil, herein referred to as CK, L, and H, respectively. The soil pH (H2O) increased from 5.25 to 7.03 and 7.62 in L and H treatments of the RR soil and from 5.52 to 7.27 and 7.77 in L and H treatments of the RF soil, respectively. Dolomite application significantly (p ≤ 0.001) increased CO 2 emissions in both RR and RF soils, with higher emissions in H as compared to L dose of dolomite. The cumulative CO 2 emissions with H dose of dolomite were greater 136% in the RR soil and 149% in the RF soil as compared to CK, respectively. Dissolved organic carbon (DOC) and microbial biomass carbon (MBC) increased and reached at 193 and 431 mg kg -1 in the RR soil and 244 and 481 mg kg -1 in the RF soil by H treatments. The NH 4 - -N and NO 3 - -N were also increased by dolomite application. The increase in C and N contents stimulated microbial activities and therefore higher respiration in dolomite-treated soil as compared to untreated. The results suggest that CO 2 release in dolomite-treated soils was due to the priming of soil C content rather than chemical reactions.

  3. A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

    Science.gov (United States)

    Pannatier, Elisabeth Graf; Thimonier, Anne; Schmitt, Maria; Walthert, Lorenz; Waldner, Peter

    2011-03-01

    Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

  4. Physical and chemical factors influencing radionuclide behaviour in arable soils

    International Nuclear Information System (INIS)

    Rauret, G.; Vidal, M.; Alexakhin, R.M.; Kruglov, S.V.; Cremers, A.; Wauters, J.; Valcke, E.; Ivanov, Y.

    1996-01-01

    Soil-to-plant transfer of radionuclides integrates plant physiological and soil chemical aspects. Therefore, it is necessary to study the factors affecting the equilibrium of the radionuclides between solid and soil solution phases. Desorption and adsorption studies were applied to the podsolic and peat soils considered in the ECP-2 project. In the desorption approach, both sequential extraction and 'infinite bath' techniques were used. In the adsorption approach, efforts were directed at predicting Cs and Sr-K D on the basis of soil properties and soil solution composition. Desorption approach predicts time-dynamics of transfer with time but it is un sufficient for comparatively predicting transfer. Adsorption studies informs about which are the key factors affecting radionuclide transfer. For Sr, availability depends on the CEC and on the concentration of the Ca + Mg in the soil solution. For Cs, availability is mainly dependent on the partitioning between FES -frayed edge sites-, which are highly specific and REC -regular exchange complex-, with low selectivity for Cs. Moreover, availability depends on the K and NH 4 , levels in the soil solution and fixation properties of the soil. Considering these factors, the calculation of the in situ K D values helps to predict the relative transfer of radionuclides. The calculation of the K D of the materials that could be used as countermeasures could permit the prediction of its suitability to decrease transfer and therefore to help in producing cleaner agricultural products

  5. A conceptual framework: redifining forests soil's critical acid loads under a changing climate

    Science.gov (United States)

    Steven G. McNulty; Johnny L. Boggs

    2010-01-01

    Federal agencies of several nations have or are currently developing guidelines for critical forest soil acid loads. These guidelines are used to establish regulations designed to maintain atmospheric acid inputs below levels shown to damage forests and streams. Traditionally, when the critical soil acid load exceeds the amount of acid that the ecosystem can absorb, it...

  6. Estimates of critical acid loads and exceedances for forest soils across the conterminous United States

    Science.gov (United States)

    Steven G. McNulty; Erika C. Cohen; Jennifer A. Moore Myers; Timothy J. Sullivan; Harbin Li

    2007-01-01

    Concern regarding the impacts of continued nitrogen and sulfur deposition on ecosystem health has prompted the development of critical acid load assessments for forest soils. A critical acid load is a quantitative estimate of exposure to one or more pollutants at or above which harmful acidification-related effects on sensitive elements of the environment occur. A...

  7. Organic acid enhanced electrodialytic extraction of lead from contaminated soil fines in suspension

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland; Ahring, Birgitte Kiær; Ottosen, Lisbeth M.

    2007-01-01

    for decontamination of the sludge was investigated. The ability of 11 organic acids to extract Pb from the fine fraction of contaminated soil (grains soil fines in suspension......The implementation of soil washing technology for the treatment of heavy metal contaminated soils is limited by the toxicity and unwieldiness of the remaining heavy metal contaminated sludge. In this work, the feasibility of combining electrodialytic remediation with heterotrophic leaching...... was tested. Five of the acids showed the ability to extract Ph from the soil fines in excess of the effect caused solely by pH changes. Addition of the acids, however, severely impeded EDR, hence promotion of EDR by combination with heterotrophic leaching was rejected. In contrast, enhancement of EDR...

  8. Electrochemical soil remediation - accelerated soil weathering?

    Energy Technology Data Exchange (ETDEWEB)

    Ottosen, L.M.; Villumsen, A.; Hansen, H.K.; Jensen, P.E.; Pedersen, A.J. [Dept. of Civil Engineering, Technical Univ. of Denmark, Lyngby (Denmark); Ribeiro, A.B. [Dept. of Environmental Sciences and Engineering, New Univ. of Lisbon, Monte da Caparica (Portugal)

    2001-07-01

    In electrochemical soil remediation systems, where enhancement solutions and complexing agents are not used, a developing acidic front is mobilizing the heavy metals and the electric current is removing the mobilized elements from the soil. The hypotheses investigated in this paper is whether this process may be comparable to the chemical soil weathering that occurs in the environment due to the acidic rain, where the mobilized elements are removed from the soil by the penetrating water. Even through the weathering process is highly accelerated in the electrochemical cell. This paper shows results from electrodialytic remediation experiments performed with four different Danish heavy metal polluted soils. The main emphasis is laid on the relation between the developing acidic front and electromigration of Cu, Zn, Mn, Mg, Fe and Ca. (orig.)

  9. Effects of Applying Lime and CalciumMontmorillonite on Nitrification Dynamics in Acidic Soil

    Directory of Open Access Journals (Sweden)

    WANG Mei

    2017-01-01

    Full Text Available Soil acidification is known as a natural and slow process along with clay mineral weathering. In recent years however, with inten sive soil utilization in agriculture, soil acidification has increased dramatically and nitrification of ammonium nitrogen fertilizer is one of the main contributors to soil acidification. Lime application is the traditional practice to improve acidic soils but it often makes the soil acidic a gain leading to soil compaction in most cases. Montmorillonite is the main clay mineral component of alkaline or neutral soils, more so it is known to undergo further weathering processes during soil acidification. The laboratory-based incubations were used in this study, and nitri fication was measured while kinetic curves were fitted to check the effects of decreasing soil acidity by lime(Ca-OHand montmorillonite (Ca-Mon nitrification of the acidic soil. The results showed that significant nitrification was observed both in Ca-OH and Ca-M treatments, and the nitrification process was fitted in the first-order kinetic model, NNO3=N0+Np(1-exp(-k1t(P-1·d-1was significantly higher than that of Ca-M treatment(2.381 mg·kg-1·d-1. The potential nitrifi cation rate(Vpwere 6.42, 8.58 mg N·kg-1·d-1 at pH 5.7 and 6.2 respectively, and the average nitrification rate(Vaof Ca-OH treatment were 2.71, 3.88 mg N·kg-1·d-1 respectively, which were significantly greater than those of Ca-M treatment(Vp were 3.40, 4.56 mg N·kg-1·d-1 and Va were 2.36, 3.04 mg N·kg-1·d-1 at pH 5.7 and 6.2 respectively. Therefore the net nitrification rate, potential nitrification rate(Vp and average nitrification rate(Vaof Ca-OH treatment were significantly higher than that of Ca-M treatment, suggesting that the possibili ty and degree of soil reacidification by using lime to improve acidic soil is greater than using calcium montmorillonite. This study will provide a new reference for the improvement of acid soils.

  10. Relative nitrogen mineralization and nitrification potentials in relation to soil chemistry in oak forest soils along a historical deposition gradient

    Science.gov (United States)

    Ralph E. J. Boerner; Elaine Kennedy Sutherland

    1996-01-01

    This study quantified soil nutrient status and N mineralization/nitrification potentials in soils of oak-dominated, unmanaged forest stands in seven USDA Forest Service experimental forests (EF) ranging along a historical and current acidic deposition gradient from southern Illinois to central West Virginia.

  11. 471 Soil Characterization and Land Use of Arondizogu Inland Valley ...

    African Journals Online (AJOL)

    User

    2010-10-16

    Oct 16, 2010 ... Effective cation exchange capacity was low (4.60-6.39 meg/100g). Similarly, exchangeable acidity was generally ... more fragile or even marginal lands where over exploitation has led to high rate of deforestation, soil erosion and declining productivity. Also, some soil related factors have contributed to the.

  12. Methylmercury production in soil in the water-level-fluctuating zone of the Three Gorges Reservoir, China: The key role of low-molecular-weight organic acids.

    Science.gov (United States)

    Yin, Deliang; Wang, Yongmin; Jiang, Tao; Qin, Caiqing; Xiang, Yuping; Chen, Qiuyu; Xue, Jinping; Wang, Dingyong

    2018-04-01

    As important parts of dissolved organic matter, low-molecular-weight organic acids (LMWOAs) typically play important roles in desorbing Hg(II) from the soil solid-phase, which may directly or indirectly impact methylmercury (MeHg) production. However, the mechanism of these processes remains unclear. To better understand the effects of LMWOAs on Hg methylation in the soil, a field study was conducted to investigate the distribution of LMWOAs and their relationship with soil MeHg in a seasonally inundated area in the Three Gorges Reservoir (TGR), China. Meanwhile, laboratory simulation experiments were performed to determine the potential mechanism of LMWOAs in Hg methylation. The field investigation detected considerable amounts of LMWOAs in soil, among which tartaric acid and oxalic acid were dominant components. Among which, tartaric acid and oxalic acid were dominant components. Also, a seasonally and spatially heterogeneous distribution of LMWOAs in soil was observed. Notably, a significant positive relationship was found between MeHg concentrations and LMWOA pools in soil (r = 0.969, p < .01), implying that LMWOAs could promote soil MeHg production. The simulation experiments confirmed that the MeHg levels in soil were largely elevated with the addition of LMWOAs, which occurred mainly in oxygen-deficient environment and was mediated by biotic factors. The soluble Hg-LMWOA complexes, which were formed by the enhanced desorption of Hg(II) from solid-phase, were mostly responsible for the elevated MeHg production in soil. Moreover, those LMWOAs with more carboxylic groups were believed to enhance the net production of MeHg. The generated MeHg in sediment could diffuse into the overlying water, which thus poses a potential threat to the aquatic food web. Therefore, the enhanced Hg methylation caused by LMWOAs should be given more attention, especially in a seasonally inundated ecosystem, where the MeHg exposure is usually related to fishery activities

  13. Alleviating soil acidity through plant organic compounds

    Directory of Open Access Journals (Sweden)

    Anderson R. Meda

    2001-06-01

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

  14. Ethylene limits abscisic acid- or soil drying-induced stomatal closure in aged wheat leaves.

    Science.gov (United States)

    Chen, Lin; Dodd, Ian C; Davies, William J; Wilkinson, Sally

    2013-10-01

    The mechanism of age-induced decreased stomatal sensitivity to abscisic acid (ABA) and soil drying has been explored here. Older, fully expanded leaves partly lost their ability to close stomata in response to foliar ABA sprays, and soil drying which stimulated endogenous ABA production, while young fully expanded leaves closed their stomata more fully. However, ABA- or soil drying-induced stomatal closure of older leaves was partly restored by pretreating plants with 1-methylcyclopropene (1-MCP), which can antagonize ethylene receptors, or by inoculating soil around the roots with the rhizobacterium Variovorax paradoxus 5C-2, which contains 1-aminocyclopropane-1-carboxylic acid (ACC)-deaminase. ACC (the immediate biosynthetic precursor of ethylene) sprays revealed higher sensitivity of stomata to ethylene in older leaves than younger leaves, despite no differences in endogenous ACC concentrations or ethylene emission. Taken together, these results indicate that the relative insensitivity of stomatal closure to ABA and soil drying in older leaves is likely due to altered stomatal sensitivity to ethylene, rather than ethylene production. To our knowledge, this is the first study to mechanistically explain diminished stomatal responses to soil moisture deficit in older leaves, and the associated reduction in leaf water-use efficiency. © 2013 John Wiley & Sons Ltd.

  15. Impact of acid atmosphere deposition on soils : field monitoring and aluminum chemistry

    NARCIS (Netherlands)

    Mulder, J.

    1988-01-01

    The effect of acid atmospheric deposition on concentrations and transfer of major solutes in acid, sandy soils was studied. Emphasis was given to mobilization and transport of potentially toxic aluminum. Data on solute concentrations and fluxes in meteoric water as well as soil solutions

  16. The Influence of Clay on the Rate of Decay of Amino Acid Metabolites Synthesized in Soils during Decomposition of Cellulose

    DEFF Research Database (Denmark)

    Sørensen, Lasse Holst

    1975-01-01

    caused by the treatments in the different soils was, however, not related to the amount of silt + clay, and a high content of this material did not protect organic material against the effect of the treatments. is concluded that the silt + clay fraction ensures stabilization of amino acid metabolites...... produced during the period of intense biological activity that follows the addition of decomposable, energy rich material to the soil. The amount of amino acid metabolites stabilized increased with increasing concentration of silt + clay, but the rate of decay of the amino acid material during later stages......14C-labelled cellulose was added to seven different soils containing silt + clay (particles

  17. The soil sulphate effect and maize plant (Zea mays L.) growth of sulphate reducing bacteria (SRB) inoculation in acid sulfate soils with the different soil water condition

    Science.gov (United States)

    Asmarlaili, S.; Rauf, A.; Hanafiah, D. S.; Sudarno, Y.; Abdi, P.

    2018-02-01

    The objective of the study was to determine the potential application of sulphate reducing bacteria on acid sulfate soil with different water content in the green house. The research was carried out in the Laboratory and Green House, Faculty of Agriculture, Universitas Sumatera Utara. This research used Randomized Block Design with two treatments factors, ie sulphate reducing bacteria (SRB) isolate (control, LK4, LK6, TSM4, TSM3, AP4, AP3, LK4 + TSM3, LK4 + AP4, LK4 + AP3, LK6 + TSM3, LK6 + AP4, LK6 + AP3, TSM4 + TSM3, TSM4 + AP4, TSM4 + AP3) and water condition (100% field capacity and 110% field capacity). The results showed that application of isolate LK4 + AP4 with water condition 110% field capacity decreased the soil sulphate content (27.38 ppm) significantly after 6 weeks. Application of isolate LK4 + AP3 with water condition 110% field capacity increased soil pH (5.58) after-week efficacy 6. Application of isolate LK4 with water condition 110% field capacity increased plant growth (140 cm; 25.74 g) significantly after week 6. The best treatment was application isolate LK4 with water condition 110% field Capacity (SRB population 2.5x108; soil sulphate content 29.10ppm; soil acidity 4.78; plant height 140cm; plant weight 25.74g).

  18. Integrated assessment of space, time, and management-related variability of soil hydraulic properties

    Energy Technology Data Exchange (ETDEWEB)

    Es, H.M. van; Ogden, C.B.; Hill, R.L.; Schindelbeck, R.R.; Tsegaye, T.

    1999-12-01

    Computer-based models that simulate soil hydrologic processes and their impacts on crop growth and contaminant transport depend on accurate characterization of soil hydraulic properties. Soil hydraulic properties have numerous sources of variability related to spatial, temporal, and management-related processes. Soil type is considered to be the dominant source of variability, and parameterization is typically based on soil survey databases. This study evaluated the relative significance of other sources of variability: spatial and temporal at multiple scales, and management-related factors. Identical field experiments were conducted for 3 yr. at two sites in New York on clay loam and silt loam soils, and at two sites in Maryland on silt loam and sandy loam soils, all involving replicated plots with plow-till and no-till treatments. Infiltrability was determined from 2054 measurements using parameters, and Campbell's a and b parameters were determined based on water-retention data from 875 soil cores. Variance component analysis showed that differences among the sites were the most important source of variability for a (coefficient of variation, CV = 44%) and b (CV = 23%). Tillage practices were the most important source of variability for infiltrability (CV = 10%). For all properties, temporal variability was more significant than field-scale spatial variability. Temporal and tillage effects were more significant for the medium- and fine-textured soils, and correlated to initial soil water conditions. The parameterization of soil hydraulic properties solely based on soil type may not be appropriate for agricultural lands since soil-management factors are more significant. Sampling procedures should give adequate recognition to soil-management and temporal processes at significant sources of variability to avoid biased results.

  19. Sorption of Tannin and Related Phenolic Compounds and Effects on Extraction of Soluble-N in Soil Amended with Several Carbon Sources

    Directory of Open Access Journals (Sweden)

    Javier M. Gonzalez

    2012-02-01

    Full Text Available Some tannins sorb to soil and reduce soluble-N. However, we know little about how they interact with organic amendments in soil. Soil (0–5 cm from plots, which were amended annually with various carbon substances, was treated with water (control or solutions containing tannins or related phenolic subunits. Treatments included a proanthocyanidin, catechin, tannic acid, β-1,2,3,4,6-penta-O-galloyl-D-glucose (PGG, gallic acid, and methyl gallate. We applied solutions of each of these materials to soil and measured soluble-C and -N in supernatants after application and following extraction with hot water (16 h, 80 °C. Sorption was low for non-tannin phenolics, methyl gallate, gallic acid, and catechin, and unaffected by amendment. Sorption of tannins, proanthocyanidin, tannic acid, and PGG, was higher and greater in plots amended with biosolids or manure. Extraction of soluble-N was not affected by amendment or by catechin, proanthocyanidin, or methyl gallate, but was reduced with PGG, tannic acid and gallic acid. Soil cation exchange capacity increased following treatment with PGG but decreased with gallic acid, irrespective of amendment. Tannins entering soil may thus influence soil organic matter dynamics and nutrient cycling but their impact may be influenced by the composition of soil organic matter.

  20. Impact of simulated acid rain on soil microbial community function in Masson pine seedlings

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2014-09-01

    Conclusion: The results obtained indicated that the higher acid load decreased the soil microbial activity and no effects on soil microbial diversity assessed by Biolog of potted Masson pine seedlings. Simulated acid rain also changed the metabolic capability of the soil microbial community.

  1. Adsorption and desorption dynamics of citric acid anions in soil

    KAUST Repository

    Oburger, E.; Leitner, D.; Jones, D. L.; Zygalakis, K. C.; Schnepf, A.; Roose, T.

    2011-01-01

    The functional role of organic acid anions in soil has been intensively investigated, with special focus on (i) microbial respiration and soil carbon dynamics, (ii) nutrient solubilization or (iii) metal detoxification and reduction of plant metal

  2. Characterization of the coal derived humic acids from Mukah, Sarawak as soil conditioner

    Directory of Open Access Journals (Sweden)

    Fong Sim Siong

    2006-01-01

    Full Text Available In Malaysia, abundant coal resources were found in Sarawak and Sabah. The utilization of coal resources, to date, is emphasized on the energy productions. The non-energy utilization as soil conditioner is unexplored. Therefore, this study attempted to characterize the coal humic acids extracted from Mukah coal and to evaluate its properties as soil conditioner. The coal humic acids from the regenerated sample were also assessed. The results revealed that different extractants and concentrations influenced the properties of humic acids. The extraction with KOH at 0.5 mol L-1 produced humic acids with low ash content and high acidic functional groups, which are substantial as soil conditioner. However, the yield was low. Regeneration of coal sample with 10% nitric acids improved the yield to an average of 83.45%. The acidic functional groups of nitrohumic acids were improved with the ash content remained at a low level.

  3. Soil acidification and liming in grassland production and grassland soil fertility in Slovenia

    Directory of Open Access Journals (Sweden)

    Jure ČOP

    2015-12-01

    Full Text Available This paper reviews the evidences on grassland soil acidity and liming in relation to soil processes and herbage production. There is also an outline of the present state of soil acidity and acidity-related traits – contents of organic matter (OM, phosphorus (P and potassium (K in Slovene grassland. In grassland, soil acidification is an ongoing process under humid climate conditions. It is mainly driven by leaching of nutrients, net loss of cations due to retention in livestock products, use of physiologically acid fertilizers, acid rain and N2 fixation. This process is reduced by strong pH buffering capacity of the soil and by physiologically basic fertilizers. Acid grassland soils in Slovenia are widely distributed in spite of the fact that 44% of the total land has developed from a carbonate parent material. Of the 1713 grassland soil samples analysed during 2005-2007 45% were regarded as acid ones (pH < 5.5; in KCl, 57% as soils with very low P status (˂ 6 mg P2O5/100 g soil and 22% as soils with very low K status (˂ 10 mg K2O/100 soil. Increased content of soil organic matter was identified for alpine pastures (˃ 10 % OM in 44% of samples, mainly as a result of low decomposition rate. Liming of acid grassland soils did not always reflect in a higher herbage yield. The cause for this inefficiency is plant composition of grassland. Thus, many grassland plants with relatively high production potential have adapted to acid soil conditions. To illustrate the inconsistent liming effect three researches are reviewed. In the first two researches liming along with fertilizer application did not increase the yield comparing to the fertilized control while in the third research the increase amounted 26 %. Liming improves considerably botanical composition of the acid grassland (e.g. sward where Common Bent – Agrostis tenuis Sibth. – prevails and thus indirectly affects palatability and nutritive value of herbage. Grassland liming has a weak

  4. Intensified Vegetation Water Use due to Soil Calcium Leaching under Acid Deposition

    Science.gov (United States)

    Lanning, M.; Wang, L.; Scanlon, T. M.; Vadeboncoeur, M. A.; Adams, M. B.; Epstein, H. E.; Druckenbrod, D.

    2017-12-01

    Despite the important role vegetation plays in the global water cycle, the exact controls of vegetation water use, especially the role of soil biogeochemistry, remain elusive. Nitrate and sulfate deposition from fossil fuel burning has caused significant soil acidification, leading to the leaching of soil base cations. From a physiological perspective, plants require various soil cations as signaling and regulatory ions as well as integral parts of structural molecules; a depletion of soil cations can cause reduced productivity and abnormal responses to environmental change. A deficiency in calcium could also potentially prolong stomatal opening, leading to increased transpiration until enough calcium had been acquired to stimulate stomatal closure. Based on the plant physiology and the nature of acidic deposition, we hypothesize that depletion of the soil calcium supply, induced by acid deposition, would intensify vegetation water use at the watershed scale. We tested this hypothesis by analyzing a long-term and unique data set (1989-2012) of soil lysimeter data along with stream flow and evapotranspiration data at the Fernow Experimental Forest. We show that depletion of soil calcium by acid deposition can intensify vegetation water use ( 10% increase in evapotranspiration and depletion in soil water) for the first time. These results are critical to understanding future water availability, biogeochemical cycles, and surficial energy flux and may help reduce uncertainties in terrestrial biosphere models.

  5. [Advance in researches on vegetation cover and management factor in the soil erosion prediction model].

    Science.gov (United States)

    Zhang, Yan; Yuan, Jianping; Liu, Baoyuan

    2002-08-01

    Vegetation cover and land management are the main limiting factors of soil erosion, and quantitative evaluation on the effect of different vegetation on soil erosion is essential to land use and soil conservation planning. The vegetation cover and management factor (C) in the universal soil loss equation (USLE) is an index to evaluate this effect, which has been studied deeply and used widely. However, the C factor study is insufficient in China. In order to strengthen the research of C factor, this paper reviewed the developing progress of C factor, and compared the methods of estimating C value in different USLE versions. The relative studies in China were also summarized from the aspects of vegetation canopy coverage, soil surface cover, and root density. Three problems in C factor study were pointed out. The authors suggested that cropland C factor research should be furthered, and its methodology should be unified in China to represent reliable C values for soil loss prediction and conservation planning.

  6. Micropore surface area of alkali-soluble plant macromolecules (humic acids) drives their decomposition rates in soil.

    Science.gov (United States)

    Papa, Gabriella; Spagnol, Manuela; Tambone, Fulvia; Pilu, Roberto; Scaglia, Barbara; Adani, Fabrizio

    2010-02-01

    Previous studies suggested that micropore surface area (MSA) of alkali-soluble bio-macromolecules of aerial plant residues of maize constitutes an important factor that explains their humification in soil, that is, preservation against biological degradation. On the other hand, root plant residue contributes to the soil humus balance, as well. Following the experimental design used in a previous paper published in this journal, this study shows that the biochemical recalcitrance of the alkali-soluble acid-insoluble fraction of the root plant material, contributed to the root maize humification of both Wild-type maize plants and its corresponding mutant brown midrib (bm3), this latter characterized by reduced lignin content. Humic acids (HAs) existed in root (root-HAs) were less degraded in soil than corresponding HAs existed in shoot (shoot-HAs): shoot-HAs bm3 (48%)>shoot-HAs Wild-type (37%)>root-HAs Wild-type (33%)>root-HAs bm3 (22%) (degradability shown in parenthesis). These differences were related to the MSA of HAs, that is, root-HAs having a higher MSA than shoot-HAs: shoot-HAs bm3 (41.43+/-1.2m(2)g(-1))soil.

  7. Molecular distributions of phospholipid ester-linked fatty acids in a soil profile of the Dinghushan Biosphere Reserve

    Directory of Open Access Journals (Sweden)

    Shengyi Mao

    2018-01-01

    Full Text Available Phospholipid ester-linked fatty acids (PLFA were used to investigate the microbial ecology and its association with carbon accumulation in one soil profile from the Dinghushan Biosphere Preserve in south China, in order to probe the mechanisms that control the carbon accumulation at the depth of 0 - 20 cm in the Dinghushan forest soil profile. The data show that sulfate reducing bacteria (SRB occur in the top 10 cm, and methanotrophic bacteria and fungi are not present below 10 cm, and the gram-negative bacteria are reduced with gram-positive bacteria dominating at that depth; all of which indicated that the activities of some of the microorganisms were inhibited, from which we infer that the available carbon source and oxygen content of micro environment may be reduced below 10 cm of the profile. The shallow depth (top 10 cm of the soil anaerobic zone at the Wukesong profile, compared to the normal soil anaerobic zone (top 20 - 30 cm, is considered to be mainly the result of the high precipitation of acidic rain. The physicochemical reactions caused by acid rain in the soil system result in a decreased soil porosity, and a correspondingly decreased porosity-dependent oxygen concentration, leading to the thriving of SRB in the shallow depth. Although the increase of soil organic carbon stock is attributed to numerous factors, the decreasing rate of litter decomposition in the topsoil layer, together with the rise of the depth of the anaerobic zone, may play key roles in the carbon accumulation in the depth of 0 - 20 cm in the soil profile from the Dinghushan Biosphere Preserve.

  8. Interactive effects of soil acidity and fluoride on soil solution aluminium chemistry and barley (Hordeum vulgare L.) root growth.

    Science.gov (United States)

    Manoharan, V; Loganathan, P; Tillman, R W; Parfitt, R L

    2007-02-01

    A greenhouse study was conducted to determine if concentrations of fluoride (F), which would be added to acid soils via P fertilisers, were detrimental to barley root growth. Increasing rates of F additions to soil significantly increased the soil solution concentrations of aluminium (Al) and F irrespective of the initial adjusted soil pH, which ranged from 4.25 to 5.48. High rates of F addition severely restricted root growth; the effect was more pronounced in the strongly acidic soil. Speciation calculations demonstrated that increasing rates of F additions substantially increased the concentrations of Al-F complexes in the soil. Stepwise regression analysis showed that it was the combination of the activities of AlF2(1+) and AlF(2+) complexes that primarily controlled barley root growth. The results suggested that continuous input of F to soils, and increased soil acidification, may become an F risk issue in the future.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

    The purpose of this study was to determine the ammonia-oxidizing activity and the phylogentic composition of microorganisms involved in acid tea (Camellia sinensis) orchard soil. All soil samples were collected from three sites located in Tahara and Toyohashi, Aichi Prefecture, Japan. The potential nitrification rate (PNR) was measured by the chlorate inhibition method. The soil pH of tea orchards studied ranged from 2.78 to 4.84, differing significantly from sample to sample, whereas that of meadow and unplanted fields ranged from 5.78 to 6.35. The PNR ranged from 0.050 to 0.193 μg NO 2 - -Ng -1 h -1 and were positively correlated with the soil pH (r 2 0.382, p 2 - -Ng -1 h -1 ) and subjected to PCR-aided clone library analyses targeting archaeal and bacterial amoA genes. The detected archaeal clones separated from the cluster of the 'Soil clones' and tightly clustered with the clones originating from other acidic soil environments including the Chinese tea orchard soil. These results suggest that the specific archaeal populations dominate as the ammonia oxidizers in acid tea-orchard soils and possibly other acid soils, independent of geographic locations, which results from the adaptation to specific ecological niches.

  10. Effects of reforestation on ammonia-oxidizing microbial community composition and abundance in subtropical acidic forest soils.

    Science.gov (United States)

    Wu, Ruo-Nan; Meng, Han; Wang, Yong-Feng; Gu, Ji-Dong

    2018-06-01

    Forest ecosystems have great ecological values in mitigation of climate change and protection of biodiversity of flora and fauna; re-forestry is commonly used to enhance the sequestration of atmospheric CO 2 into forest storage biomass. Therefore, seasonal and spatial dynamics of the major microbial players in nitrification, ammonia-oxidizing archaea (AOA) and bacteria (AOB), in acidic soils of young and matured revegetated forests were investigated to elucidate the changes of microbial communities during forest restoration, and compared to delineate the patterns of community shifts under the influences of environmental factors. AOA were more abundant than AOB in both young and matured revegetated forest soils in both summer and winter seasons. In summer, however, the abundance of amoA-AOA decreased remarkably (p < 0.01), ranging from 1.90 (± 0.07) × 10 8 copies per gram dry soil in matured forest to 5.04 (± 0.43) × 10 8 copies per gram dry soil in young forest, and amoA-AOB was below detection limits to obtain any meaningful values. Moreover, exchangeable Al 3+ and organic matter were found to regulate the physiologically functional nitrifiers, especially AOA abundance in acidic forest soils. AOB community in winter showed stronger correlation with the restoration status of revegetated forests and AOA community dominated by Nitrosotalea devanaterra, in contrast, was more sensitive to the seasonal and spatial variations of environmental factors. These results enrich the current knowledge of nitrification during re-forestry and provide valuable information to developmental status of revegetated forests for management through microbial analysis.

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

    Science.gov (United States)

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

    2012-03-01

    The purpose of this study was to determine the ammonia-oxidizing activity and the phylogentic composition of microorganisms involved in acid tea (Camellia sinensis) orchard soil. All soil samples were collected from three sites located in Tahara and Toyohashi, Aichi Prefecture, Japan. The potential nitrification rate (PNR) was measured by the chlorate inhibition method. The soil pH of tea orchards studied ranged from 2.78 to 4.84, differing significantly from sample to sample, whereas that of meadow and unplanted fields ranged from 5.78 to 6.35. The PNR ranged from 0.050 to 0.193 μg NO2--Ng-1 h-1 and were positively correlated with the soil pH (r2 = 0.382, p<0.001). Bulk DNA was extracted from a tea orchard soil (pH 4.8; PNR, 0.078 μg NO2--Ng-1 h-1) and subjected to PCR-aided clone library analyses targeting archaeal and bacterial amoA genes. The detected archaeal clones separated from the cluster of the 'Soil clones' and tightly clustered with the clones originating from other acidic soil environments including the Chinese tea orchard soil. These results suggest that the specific archaeal populations dominate as the ammonia oxidizers in acid tea-orchard soils and possibly other acid soils, independent of geographic locations, which results from the adaptation to specific ecological niches.

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

    International Nuclear Information System (INIS)

    Wan Zhaoliang; Liu Dayong

    1995-01-01

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

  13. Effect of Polylactic Acid-Degradable Film Mulch on Soil Temperature and Cotton Yield

    Directory of Open Access Journals (Sweden)

    ZHANG Ni

    2016-03-01

    Full Text Available Concern on biodegradable plastic film is increasing because of pollution problems caused by the plastic films currently used. The objective of this field experiment is to evaluate the effect of two thicknesses of polyactic acid-degradable film on soil temperature and cotton yield. The results showed that small holes appeared in the polyactic acid-degradable film at 17~22 d after it was installed. Burst period appeared about 60 d after installation. Splits were observed in the polyactic acid-degradable film at 130 d after installation. Soil temperatures rose slowly under polyactic acid-degradable film during the cotton seedling stage. Daytime soil temperatures were 0.8℃ and 6.2℃ lower under 18μm and 15μm thick polyactic acid-degradable film than non-degradable plastic film(CK, respectively. Nighttime soil temperatures under the polyactic acid-degradable film were about 1℃ warmer than CK. There was no significant difference in cotton yields between the 18μm polyactic acid degradable film treatment and CK. In contrast, yields in the 15μm degradable plastic film treatment were 8.9% less than that in CK. This study indicated that 18μm polyactic acid degradable plastic film had good degradability and no negative effect on cotton growth. The 18μm polyactic acid degradable plastic film can replace ordinary plastic film in agricultural production.

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

    Science.gov (United States)

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

    2016-04-01

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

  15. The response of soil solution chemistry in European forests to decreasing acid deposition.

    Science.gov (United States)

    Johnson, James; Graf Pannatier, Elisabeth; Carnicelli, Stefano; Cecchini, Guia; Clarke, Nicholas; Cools, Nathalie; Hansen, Karin; Meesenburg, Henning; Nieminen, Tiina M; Pihl-Karlsson, Gunilla; Titeux, Hugues; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Waldner, Peter; Jonard, Mathieu

    2018-03-31

    Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosystems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al tot ) and dissolved organic carbon were determined for the period 1995-2012. Plots with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10-20 cm, 104 plots) and subsoil (40-80 cm, 162 plots). There was a large decrease in the concentration of sulphate (SO42-) in soil solution; over a 10-year period (2000-2010), SO42- decreased by 52% at 10-20 cm and 40% at 40-80 cm. Nitrate was unchanged at 10-20 cm but decreased at 40-80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca 2+  + Mg 2+  + K + ) and Al tot over the entire dataset. The response of soil solution acidity was nonuniform. At 10-20 cm, ANC increased in acid-sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40-80 cm, ANC remained unchanged in acid-sensitive soils (base saturation ≤20%, pHCaCl2 ≤ 4.5) and decreased in better-buffered soils (base saturation >20%, pHCaCl2 > 4.5). In addition, the molar ratio of Bc to Al tot either did not change or decreased. The results suggest a long-time lag between emission abatement and changes in soil solution acidity and underline the importance of long-term monitoring in evaluating ecosystem response to decreases in deposition. © 2018 John Wiley & Sons

  16. Degradation and enantiomeric fractionation of mecoprop in soil previously exposed to phenoxy acid herbicides - New insights for bioremediation

    Czech Academy of Sciences Publication Activity Database

    Frková, Zuzana; Johansen, A.; de Jonge, L.W.; Olsen, P.; Gosewinkel, U.; Bester, K.

    2016-01-01

    Roč. 569, November (2016), s. 1457-1465 ISSN 0048-9697 Institutional support: RVO:60077344 Keywords : phenoxy acids * nitrate-reducing conditions * herbicide biodegradation * enantioselectivity * biostimulation Subject RIV: DK - Soil Contamination ; De-contamination incl. Pesticides Impact factor: 4.900, year: 2016

  17. Radiocesium storage in soil microbial biomass of undisturbed alpine meadow soils and its relation to 137Cs soil-plant transfer

    International Nuclear Information System (INIS)

    Stemmer, Michael; Hromatka, Angelika; Lettner, Herbert; Strebl, Friederike

    2005-01-01

    This study focuses on radiocesium storage in soil microbial biomass of undisturbed alpine meadow sites and its relation to the soil-to-plant transfer. Soil and plant samples were taken in August 1999 from an altitude transect (800-1600 m.a.s.l.) at Gastein valley, Austria. Soil samples were subdivided into 3-cm layers for analyses of total, K 2 SO 4 -extractable and microbially stored 137 Cs. Microbial biomass was measured by the fumigation extraction method, and fungal biomass was quantified using ergosterol as biomarker molecule. In general, the quantity of 137 Cs stored in the living soil microbial biomass was relatively small. At the high-altitude meadows, showing high amounts of fungal biomass, microbially stored 137 Cs amounted to 0.64 ± 0.14 kBq m -2 which corresponds to about 1.2-2.7% of the total 137 Cs soil inventory. At lower altitudes, microbial 137 Cs content was distinctly smaller and in most cases not measurable at all using the fumigation extraction method. However, a positive correlation between the observed soil-to-plant aggregated transfer factor, microbially stored 137 Cs and fungal biomass was found, which indicates a possible role of fungal biomass in the storage and turnover of 137 Cs in soils and in the 137 Cs uptake by plants

  18. Adaptation to acidic soil is achieved by increased numbers of cis-acting elements regulating ALMT1 expression in Holcus lanatus.

    Science.gov (United States)

    Chen, Zhi Chang; Yokosho, Kengo; Kashino, Miho; Zhao, Fang-Jie; Yamaji, Naoki; Ma, Jian Feng

    2013-10-01

    Yorkshire fog (Holcus lanatus), which belongs to the Poaceae family and is a close relative of the agronomic crop oat (Avena sativa), is a widely adaptable grass species that is able to grow on highly acidic soils with high levels of Al, but the mechanism underlying the high Al tolerance is unknown. Here, we characterized two accessions of H. lanatus collected from an acid plot (soil pH 3.6, HL-A) and a neutral plot (pH 7.1, HL-N) in terms of Al tolerance, organic acid anion secretion and related gene expression. In response to Al (pH 4.5), the HL-A roots secreted approximately twice as much malate as the HL-N roots, but there was no difference in citrate secretion. Cloning of the gene HlALMT1 responsible for malate secretion showed that the encoded amino acid sequence did not differ between two accessions, but the expression level in the outer cell layers of the HL-A roots was twice as high as in the HL-N roots. This difference was not due to the genomic copy number, but was due to the number of cis-acting elements for an Al-responsive transcription factor (HlART1) in the promoter region of HlALMT1, as demonstrated by both a yeast one-hybrid assay and a transient assay in tobacco protoplasts. Furthermore, introduction of HlALMT1 driven by the HL-A promoter into rice resulted in significantly more Al-induced malate secretion than introduction of HlALMT1 driven by the HL-N promoter. These findings indicate that the adaptation of H. lanatus to acidic soils may be achieved by increasing number of cis-acting elements for ART1 in the promoter region of the HlALMT1 gene, enhancing the expression of HlALMT1 and the secretion of malate. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  19. White poplar (Populus alba L. - Litter impact on chemical and biochemical parameters related to nitrogen cycle in contaminated soils

    Directory of Open Access Journals (Sweden)

    Paula Madejon

    2014-04-01

    Full Text Available Aim of study: The aim of this study was to determine the effect of litter from Populus alba on chemical and biochemical properties related to the N cycle in soils with different pH values and trace element contents. We hypothesized that this litter would influence several parameters related to the N cycle and consequently to soil health.Area of study: we collected two reforested contaminated soils of different pH values (AZ pH 7.23 and DO pH = 2.66 and a non-contaminated soil (RHU pH 7.19.Materials and methods: Soil samples were placed in 2,000 cm3 microcosms and were incubated for 40 weeks in controlled conditions. Each soil was mixed with its corresponding litter, and soils without litter were also tested for comparison. Ammonium (NH4+-N and nitrate (NO3–-N content, potential nitrification rate (PNR, microbial biomass nitrogen (MBN, protease activity, and several chemical properties such as pH, available trace element concentrations (extracted with 0.01 M CaCl2 were determined at different times of incubation.Main results: Values of available trace elements did not vary during the incubation and were always higher in acid soil. In neutral soils litter presence increased values of Kjeldahl-N, NO3–-N content, potential nitrification rate (PNR, microbial biomass nitrogen (MBN and protease activity. Presence of trace elements in neutral soils did not alter the parameters studied. However, acidic pH and high content of available trace elements strongly affected NH4+-N andNO3–-N, microbial biomass N and protease activity.Research highlights: Our results showed the negative effect of the acidity and trace element availability in parameters related with the N-cycle.Key words: microbial biomass N; protease activity; soil pH; N mineralization; nitrification; phytoremediation.

  20. Investigation of features in radon soil dynamics and search for influencing factors

    Science.gov (United States)

    Yakovlev, Grigorii; Cherepnev, Maxim; Nagorskiy, Petr; Yakovleva, Valentina

    2018-03-01

    The features in radon soil dynamics at two depths were investigated and the main influencing factors were revealed. The monitoring of radon volumetric activity in soil air was performed at experimental site of Tomsk Observatory of Radioactivity and Ionizing Radiation with using radon radiometers and scintillation detectors of alpha-radiation with 10 min sampling frequency. The detectors were installed into boreholes of 0.5 and 1 m depths. The analysis of the soil radon monitoring data has allowed revealing some dependencies at daily and annual scales and main influencing factors. In periods with clearly defined daily radon variations in the soil were revealed the next: 1) amplitude of the daily variations of the soil radon volumetric activity damps with the depth, that is related with the influence of convective fluxes in the soil; 2) temporal shift between times of occurrence of radon volumetric activity maximum (or minimum) values at 0.5 m and 1 m depths can reach 3 hours. In seasonal dynamics of the soil radon the following dependences were found: 1) maximal values are observed in winter, but minimal - in summer; 2) spring periods of snow melting are accompanied by anomaly increasing of radon volumetric activity in the soil up to about 3 times. The main influencing factors are atmospheric precipitations, temperature gradient in the soil and the state of upper soil layer.

  1. The microbial communities and potential greenhouse gas production in boreal acid sulphate, non-acid sulphate, and reedy sulphidic soils

    Energy Technology Data Exchange (ETDEWEB)

    Šimek, Miloslav, E-mail: misim@upb.cas.cz [Biology Centre AS CR, v. v. i., Institute of Soil Biology, 370 05 České Budějovice (Czech Republic); University of South Bohemia, Faculty of Science, 370 05 České Budějovice (Czech Republic); Virtanen, Seija; Simojoki, Asko [Department of Food and Environmental Sciences, University of Helsinki, FI-00014 Helsinki (Finland); Chroňáková, Alica; Elhottová, Dana; Krištůfek, Václav [Biology Centre AS CR, v. v. i., Institute of Soil Biology, 370 05 České Budějovice (Czech Republic); Yli-Halla, Markku [Department of Food and Environmental Sciences, University of Helsinki, FI-00014 Helsinki (Finland)

    2014-01-01

    Acid sulphate (AS) soils along the Baltic coasts contain significant amounts of organic carbon and nitrogen in their subsoils. The abundance, composition, and activity of microbial communities throughout the AS soil profile were analysed. The data from a drained AS soil were compared with those from a drained non-AS soil and a pristine wetland soil from the same region. Moreover, the potential production of methane, carbon dioxide, and nitrous oxide from the soils was determined under laboratory conditions. Direct microscopic counting, glucose-induced respiration (GIR), whole cell hybridisation, and extended phospholipid fatty acid (PLFA) analysis confirmed the presence of abundant microbial communities in the topsoil and also in the deepest Cg2 horizon of the AS soil. The patterns of microbial counts, biomass and activity in the profile of the AS soil and partly also in the non-AS soil therefore differed from the general tendency of gradual decreases in soil profiles. High respiration in the deepest Cg2 horizon of the AS soil (5.66 μg C g{sup − 1} h{sup − 1}, as compared to 2.71 μg C g{sup − 1} h{sup − 1} in a top Ap horizon) is unusual but reasonable given the large amount of organic carbon in this horizon. Nitrous oxide production peaked in the BCgc horizon of the AS and in the BC horizon of the non-AS soil, but the peak value was ten-fold higher in the AS soil than in the non-AS soil (82.3 vs. 8.6 ng N g{sup − 1}d{sup − 1}). The data suggest that boreal AS soils on the Baltic coast contain high microbial abundance and activity. This, together with the abundant carbon and total and mineral nitrogen in the deep layers of AS soils, may result in substantial gas production. Consequently, high GHG emissions could occur, for example, when the generally high water table is lowered because of arable farming. - Highlights: •Boreal acid sulphate soils contain large amounts of organic C and N in subsoils. •Microbial communities throughout the acid

  2. Microbiological aspects of determination of trichloroacetic acid in soil

    International Nuclear Information System (INIS)

    Matucha, M.; Rohlenová, J.; Forczek, S.T.; Gryndler, M.; Uhlířová, H.; Fuksová, K.; Schroder, P.

    2004-01-01

    Soils have been shown to possess a strong microbial trichloroacetic acid (TCA)-degrading activity. High TCA-degradation rate was also observed during soil extraction with water. For correct measurements of TCA levels in soil all TCA-degrading activities have to be inhibited immediately after sampling before analysis. We used rapid freezing of soil samples (optimally in liquid nitrogen) with subsequent storage and slow thawing before analysis as an efficient technique for suppressing the degradation. Frozen soil samples stored overnight at −20 °C and then thawed slowly exhibited very low residual TCA-degrading activity for several hours. Omitting the above procedure could lead to the confusing differences between the TCA levels previously reported in the literature

  3. Denitrification potential of riparian soils in relation to multiscale spatial environmental factors: a case study of a typical watershed, China.

    Science.gov (United States)

    Wei, Jianbing; Feng, Hao; Cheng, Quanguo; Gao, Shiqian; Liu, Haiyan

    2017-02-01

    The objective of this study was to test the hypothesis that environmental regulators of riparian zone soil denitrification potential differ according to spatial scale within a watershed; consequently, a second objective was to provide spatial strategies for conserving and restoring the purification function of runoff in riparian ecosystems. The results show that soil denitrification in riparian zones was more heterogeneous at the profile scale than at the cross-section and landscape scales. At the profile scale, biogeochemical factors (including soil total organic carbon, total nitrogen, and nitrate-nitrogen) were the major direct regulators of the spatial distribution of soil denitrification enzyme activity (DEA). At the cross-section scale, factors included distance from river bank and vegetation density, while landscape-scale factors, including topographic index, elevation, and land use types, indirectly regulated the spatial distribution of DEA. At the profile scale, soil DEA was greatest in the upper soil layers. At the cross-section scale, maximum soil DEA occurred in the mid-part of the riparian zone. At the landscape scale, soil DEA showed an increasing trend towards downstream sites, except for those in urbanized areas.

  4. Traffic-related trace elements in soils along six highway segments on the Tibetan Plateau: Influence factors and spatial variation.

    Science.gov (United States)

    Wang, Guanxing; Zeng, Chen; Zhang, Fan; Zhang, Yili; Scott, Christopher A; Yan, Xuedong

    2017-03-01

    The accumulation of traffic-related trace elements in soil as the result of anthropogenic activities raises serious concerns about environmental pollution and public health. Traffic is the main source of trace elements in roadside soil on the Tibetan Plateau, an area otherwise devoid of industrial emissions. Indeed, the rapid development of tourism and transportation in this region means it is becoming increasingly important to identify the accumulation levels, influence distance, spatial distribution, and other relevant factors influencing trace elements. In this study, 229 soil samples along six segments of the major transportation routes on the Tibetan Plateau (highways G214, S308, and G109), were collected for analysis of eight trace elements (Cr, Co, Ni, As, Cu, Zn, Cd, and Pb). The results of statistical analyses showed that of the eight trace elements in soils, Cu, Zn, Cd, and Pb were primarily derived from traffic. The relationship between the trace element accumulation levels and the distance from the roadside followed an exponential decline, with the exception of Segment 3, the only unpaved gravel road studied. In addition, the distance of influence from the roadside varied by trace element and segment, ranging from 16m to 144m. Background values for each segment were different because of soil heterogeneity, while a number of other potential influencing factors (including traffic volume, road surface material, roadside distance, land cover, terrain, and altitude) all had significant effects on trace-element concentrations. Overall, however, concentrations along most of the road segments investigated were at, or below, levels defined as low on the Nemero Synthesis index. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Acid-base buffering of soils in transitional and transitional-accumulative positions of undisturbed southern-taiga landscapes

    Science.gov (United States)

    Rusakova, E. S.; Ishkova, I. V.; Tolpeshta, I. I.; Sokolova, T. A.

    2012-05-01

    The method of continuous potentiometric titration (CPT) of soil water suspensions was used to evaluate the acid-base buffering of samples from the major genetic horizons of podzolic soils on a slope and soddy gley soils on the adjacent floodplain of a rivulet. In the soils of the slope, the buffering to acid upon titration from the pH of the initial titration point (ITP) to pH 3 in all the horizons was 1.5-2.0 times lower than that in the podzolic soils of the leveled interfluve, which could be due to the active leaching of exchangeable bases and oxalate-soluble aluminum and iron compounds with the later soil flows. In the soddy gley soils, the buffering to acid in the mineral horizons was 2-10 times higher than that in the podzolic soils. A direct dependence of the soil buffering to acid on the total content of exchangeable bases and on the content of oxalate-soluble aluminum compounds was found. A direct dependence of the buffering to basic upon titration from the ITP to pH 10 on the contents of the oxalate-soluble aluminum and organic matter was observed in the mineral horizons of all the studied soils. The soil treatment with Tamm's reagent resulted in the decrease of the buffering to acid in the soddy gley soils of the floodplain, as well as in the decrease of the buffering to basic in the soils on the slopes and in the soddy gley soils. It was also found that the redistribution of the mobile aluminum compounds between the eluvial, transitional, and transitional-accumulative positions in the undisturbed southern taiga landscapes leads to significant spatial differentiation of the acid-base buffering of the mineral soil horizons with a considerable increase in the buffer capacity of the soils within the transitional-accumulative terrain positions.

  6. The Value Range of Contact Stiffness Factor between Pile and Soil Based on Penalty Function

    Science.gov (United States)

    Chen, Sandy H. L.; Wu, Xinliu

    2018-03-01

    The value range of contact stiffness factor based on penalty function is studied when we use finite element software ANSYS to analyze contact problems, take single pile and soil of a certain project for example, the normal contact between pile and soil is analyzed with 2D simplified model in horizontal load. The study shows that when adopting linear elastic model to simulate soil, the maximum contact pressure and penetration approach steady value as the contact stiffness factor increases. The reasonable value range of contact stiffness factor reduces as the underlying element thickness decreases, but the rule reverses when refers to the soil stiffness. If choose DP model to simulate soil, the stiffness factor should be magnified 100 times compares to the elastic model regardless of the soil bears small force and still in elastic deformation stage or into the plastic deformation stage. When the soil bears big force and into plastic deformation stage, the value range of stiffness factor relates to the plastic strain range of the soil, and reduces as the horizontal load increases.

  7. Metal mobilization from metallurgical wastes by soil organic acids.

    Science.gov (United States)

    Potysz, Anna; Grybos, Malgorzata; Kierczak, Jakub; Guibaud, Gilles; Fondaneche, Patrice; Lens, Piet N L; van Hullebusch, Eric D

    2017-07-01

    Three types of Cu-slags differing in chemical and mineralogical composition (historical, shaft furnace, and granulated slags) and a matte from a lead recovery process were studied with respect to their susceptibility to release Cu, Zn and Pb upon exposure to organic acids commonly encountered in soil environments. Leaching experiments (24-960 h) were conducted with: i) humic acid (20 mg/L) at pH t 0  = 4.4, ii) fulvic acid (20 mg/L) at pH t 0  = 4.4, iii) an artificial root exudates (ARE) (17.4 g/L) solution at pH t 0  = 4.4, iv) ARE solution at pH t 0  = 2.9 and v) ultrapure water (pH t 0  = 5.6). The results demonstrated that the ARE contribute the most to the mobilization of metals from all the wastes analyzed, regardless of the initial pH of the solution. For example, up to 14%, 30%, 24% and 5% of Cu is released within 960 h from historical, shaft furnace, granulated slags and lead matte, respectively, when exposed to the artificial root exudates solution (pH 2.9). Humic and fulvic acids were found to have a higher impact on granulated and shaft furnace slags as compared to the ultrapure water control and increased the release of metals by a factor up to 37.5 (Pb) and 20.5 (Cu) for granulated and shaft furnace slags, respectively. Humic and fulvic acids amplified the mobilization of metals by a maximal factor of 13.6 (Pb) and 12.1 (Pb) for historical slag and lead matte, respectively. The studied organic compounds contributed to different release rates of metallic contaminants from individual metallurgical wastes under the conditions tested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Multivariate analysis of selected metals in tannery effluents and related soil.

    Science.gov (United States)

    Tariq, Saadia R; Shah, Munir H; Shaheen, N; Khalique, A; Manzoor, S; Jaffar, M

    2005-06-30

    Effluent and relevant soil samples from 38 tanning units housed in Kasur, Pakistan, were obtained for metal analysis by flame atomic absorption spectrophotometric method. The levels of 12 metals, Na, Ca, K, Mg, Fe, Mn, Cr, Co, Cd, Ni, Pb and Zn were determined in the two media. The data were evaluated towards metal distribution and metal-to-metal correlations. The study evidenced enhanced levels of Cr (391, 16.7 mg/L) and Na (25,519, 9369 mg/L) in tannery effluents and relevant soil samples, respectively. The effluent versus soil trace metal content relationship confirmed that the effluent Cr was strongly correlated with soil Cr. For metal source identification the techniques of principal component analysis, and cluster analysis were applied. The principal component analysis yielded two factors for effluents: factor 1 (49.6% variance) showed significant loading for Ca, Fe, Mn, Cr, Cd, Ni, Pb and Zn, referring to a tanning related source for these metals, and factor 2 (12.6% variance) with higher loadings of Na, K, Mg and Co, was associated with the processes during the skin/hide treatment. Similarly, two factors with a cumulative variance of 34.8% were obtained for soil samples: factor 1 manifested the contribution from Mg, Mn, Co, Cd, Ni and Pb, which though soil-based is basically effluent-derived, while factor 2 was found associated with Na, K, Ca, Cr and Zn which referred to a tannery-based source. The dendograms obtained from cluster analysis, also support the observed results. The study exhibits a gross pollution of soils with Cr at levels far exceeding the stipulated safe limit laid down for tannery effluents.

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

    Science.gov (United States)

    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

  10. Nucleic Acid Extraction from Synthetic Mars Analog Soils for in situ Life Detection

    Science.gov (United States)

    Mojarro, Angel; Ruvkun, Gary; Zuber, Maria T.; Carr, Christopher E.

    2017-08-01

    Biological informational polymers such as nucleic acids have the potential to provide unambiguous evidence of life beyond Earth. To this end, we are developing an automated in situ life-detection instrument that integrates nucleic acid extraction and nanopore sequencing: the Search for Extra-Terrestrial Genomes (SETG) instrument. Our goal is to isolate and determine the sequence of nucleic acids from extant or preserved life on Mars, if, for example, there is common ancestry to life on Mars and Earth. As is true of metagenomic analysis of terrestrial environmental samples, the SETG instrument must isolate nucleic acids from crude samples and then determine the DNA sequence of the unknown nucleic acids. Our initial DNA extraction experiments resulted in low to undetectable amounts of DNA due to soil chemistry-dependent soil-DNA interactions, namely adsorption to mineral surfaces, binding to divalent/trivalent cations, destruction by iron redox cycling, and acidic conditions. Subsequently, we developed soil-specific extraction protocols that increase DNA yields through a combination of desalting, utilization of competitive binders, and promotion of anaerobic conditions. Our results suggest that a combination of desalting and utilizing competitive binders may establish a "universal" nucleic acid extraction protocol suitable for analyzing samples from diverse soils on Mars.

  11. Use of radioactive 32P technique to study phosphate rock dissolution in acid soils

    International Nuclear Information System (INIS)

    Mahisarakul, J.; Mullins, G.L.; Chien, S.H.

    2002-01-01

    A laboratory experiment was conducted to evaluate the dissolution of six sources of phosphate rock in two acid soils (Ultisols): a sandy soil and a red clay soil. Labile P was determined using the radioactive 32 P technique for Pi extractable P and resin extractable P. Incubations were conducted for 0, 1, 2, 3, 4 and 5 weeks for 32 P exchangeable technique, 0 and 5 weeks for Pi technique and 5 weeks for resin technique. Rates of PR were 0 and 400 mgP/ha. The results showed that labile P in the sandy soil decreased from 0-1 weeks for all the PRs except Hahotoe PR and Hazara PR's. Between 1 and 5 weeks labile P remained relatively constant. The ranking of labile P from PRs was: North Carolina = Kouribga > Matam > Hahotoe = Hazara> Patos de Minas. In the red soil, labile P from all PRs appeared to be relatively unchanged during the 0-5 week incubation. Pi extractable P in sandy soil showed no significant differences due to incubation time. In the red clay soil, there was a significant decrease in Pi-P extracted from soil mixtures with PRs after 5 weeks as compared to 0 weeks. Results of the Resin-extractable P in both sandy and red soils were in agreement with labile P as measured by 32 P exchange technique. (author)

  12. Cadmium Phytoavailability and Enzyme Activity under Humic Acid Treatment in Fluvo-aquic Soil

    Science.gov (United States)

    Liu, Borui; Huang, Qing; Su, Yuefeng

    2018-01-01

    A pot experiment was conducted to investigate the cadmium (Cd) availability to pakchois (Brassica chinensis L.) as well as the enzyme activities in fluvo-aquic soil under humic acid treatment. The results showed that the phytoavailability of Cd in soil decreased gradually as humic acid concentration rose (0 to 12 g·kg-1), while the activities of urease (UE), alkaline phosphatase (ALP) and catalase (CAT) kept increasing (P enzymes due to the Cd pollution. In conclusion, humic acid is effective for the reduction of both Cd phytoavailability and the damage to enzyme activities due to Cd pollution in fluvo-aquic soil

  13. Copper Recovery from Polluted Soils Using Acidic Washing and Bioelectrochemical Systems

    Directory of Open Access Journals (Sweden)

    Karin Karlfeldt Fedje

    2015-07-01

    Full Text Available Excavation followed by landfilling is the most common method for treating soils contaminated by metals. However, as this solution is not sustainable, alternative techniques are required. Chemical soil washing is one such alternative. The aim of this experimental lab-scale study is to develop a remediation and metal recovery method for Cu contaminated sites. The method is based on the washing of soil or ash (combusted soil/bark with acidic waste liquids followed by electrolytic Cu recovery by means of bioelectrochemical systems (BES. The results demonstrate that a one- or two-step acidic leaching process followed by water washing removes >80 wt. % of the Cu. Copper with 99.7–99.9 wt. % purity was recovered from the acidic leachates using BES. In all experiments, electrical power was generated during the reduction of Cu. This clearly indicates that Cu can also be recovered from dilute solutions. Additionally, the method has the potential to wash co-pollutants such as polycyclic aromatic hydrocarbons (PAHs and oxy-PAHs.

  14. Natural Arabidopsis brx loss-of-function alleles confer root adaptation to acidic soil.

    Science.gov (United States)

    Gujas, Bojan; Alonso-Blanco, Carlos; Hardtke, Christian S

    2012-10-23

    Soil acidification is a major agricultural problem that negatively affects crop yield. Root systems counteract detrimental passive proton influx from acidic soil through increased proton pumping into the apoplast, which is presumably also required for cell elongation and stimulated by auxin. Here, we found an unexpected impact of extracellular pH on auxin activity and cell proliferation rate in the root meristem of two Arabidopsis mutants with impaired auxin perception, axr3 and brx. Surprisingly, neutral to slightly alkaline media rescued their severely reduced root (meristem) growth by stimulating auxin signaling, independent of auxin uptake. The finding that proton pumps are hyperactive in brx roots could explain this phenomenon and is consistent with more robust growth and increased fitness of brx mutants on overly acidic media or soil. Interestingly, the original brx allele was isolated from a natural stock center accession collected from acidic soil. Our discovery of a novel brx allele in accessions recently collected from another acidic sampling site demonstrates the existence of independently maintained brx loss-of-function alleles in nature and supports the notion that they are advantageous in acidic soil pH conditions, a finding that might be exploited for crop breeding. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Bioavailability and soil-to-plant transfer factors as indicators of potentially toxic element contamination in agricultural soils

    Energy Technology Data Exchange (ETDEWEB)

    Adamo, Paola, E-mail: paola.adamo@unina.it [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); Iavazzo, Pietro [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); Albanese, Stefano [Dipartimento di Scienze della Terra, dell' Ambiente e delle Risorse, Università di Napoli Federico II, Via Mezzocannone 8, 80134 Napoli (Italy); Agrelli, Diana [Dipartimento di Agraria, Università di Napoli Federico II, via Università 100, 80055 Portici (Italy); De Vivo, Benedetto; Lima, Annamaria [Dipartimento di Scienze della Terra, dell' Ambiente e delle Risorse, Università di Napoli Federico II, Via Mezzocannone 8, 80134 Napoli (Italy)

    2014-12-01

    Soil pollution in agricultural lands poses a serious threat to food safety, and suggests the need for consolidated methods providing advisory indications for soil management and crop production. In this work, the three-step extraction procedure developed by the EU Measurement and Testing Programme and two soil-to-plant transfer factors (relative to total and bioavailable concentration of elements in soil) were applied on polluted agricultural soils from southern Italy to obtain information on the retention mechanisms of metals in soils and on their level of translocation to edible vegetables. The study was carried out in the Sarno river plain of Campania, an area affected by severe environmental degradation potentially impacting the health of those consuming locally produced vegetables. Soil samples were collected in 36 locations along the two main rivers flowing into the plain. In 11 sites, lettuce plants were collected at the normal stage of consumption. According to Italian environmental law governing residential soils, and on the basis of soil background reference values for the study area, we found diffuse pollution by Be, Sn and Tl, of geogenic origin, Cr and Cu from anthropogenic sources such as tanneries and intensive agriculture, and more limited pollution by Pb, Zn and V. It was found that metals polluting soils as a result of human activities were mainly associated to residual, oxidizable and reducible phases, relatively immobile and only potentially bioavailable to plants. By contrast, the essential elements Zn and Cu showed a tendency to become more readily mobile and bioavailable as their total content in soil increased and were more easily transported to the edible parts of lettuce than other pollutants. According to our results, current soil pollution in the studied area does not affect the proportion of metals taken up by lettuce plants and there is a limited health risk incurred. - Highlights: • Soil pollution in an intensively farmed area of

  16. Bioavailability and soil-to-plant transfer factors as indicators of potentially toxic element contamination in agricultural soils

    International Nuclear Information System (INIS)

    Adamo, Paola; Iavazzo, Pietro; Albanese, Stefano; Agrelli, Diana; De Vivo, Benedetto; Lima, Annamaria

    2014-01-01

    Soil pollution in agricultural lands poses a serious threat to food safety, and suggests the need for consolidated methods providing advisory indications for soil management and crop production. In this work, the three-step extraction procedure developed by the EU Measurement and Testing Programme and two soil-to-plant transfer factors (relative to total and bioavailable concentration of elements in soil) were applied on polluted agricultural soils from southern Italy to obtain information on the retention mechanisms of metals in soils and on their level of translocation to edible vegetables. The study was carried out in the Sarno river plain of Campania, an area affected by severe environmental degradation potentially impacting the health of those consuming locally produced vegetables. Soil samples were collected in 36 locations along the two main rivers flowing into the plain. In 11 sites, lettuce plants were collected at the normal stage of consumption. According to Italian environmental law governing residential soils, and on the basis of soil background reference values for the study area, we found diffuse pollution by Be, Sn and Tl, of geogenic origin, Cr and Cu from anthropogenic sources such as tanneries and intensive agriculture, and more limited pollution by Pb, Zn and V. It was found that metals polluting soils as a result of human activities were mainly associated to residual, oxidizable and reducible phases, relatively immobile and only potentially bioavailable to plants. By contrast, the essential elements Zn and Cu showed a tendency to become more readily mobile and bioavailable as their total content in soil increased and were more easily transported to the edible parts of lettuce than other pollutants. According to our results, current soil pollution in the studied area does not affect the proportion of metals taken up by lettuce plants and there is a limited health risk incurred. - Highlights: • Soil pollution in an intensively farmed area of

  17. Soil-plant transfer factors for Pu in the field and laboratory in relation to desorption from the solid phase

    International Nuclear Information System (INIS)

    Mudge, S.; Kelly, M.; Hamilton-Taylor, J.; Horrill, A.D.

    1990-01-01

    Laboratory hydroponics experiments using an environmentally contaminated sediment as source of Pu, were carried out to determine the soil-plant, soil solution-plant and root-plant transfer factors. Soil-plant transfer factors, calculated from field observations, varied according to the degree of animal usage and were more than two orders of magnitude larger than those from the laboratory experiments. The discrepancies between field and laboratory measurements are probably due to the complex sediment speciation and desorption chemistry of Pu. The transfer factors based on the solution or root activities are likely to provided a better estimate of the vegetation activity than those based on the solid phase activity. (author)

  18. Isolation and Characterization of Alfalfa-Nodulating Rhizobia Present in Acidic Soils of Central Argentina and Uruguay

    Science.gov (United States)

    del Papa, María F.; Balagué, Laura J.; Sowinski, Susana Castro; Wegener, Caren; Segundo, Eduardo; Abarca, Francisco Martínez; Toro, Nicolás; Niehaus, Karsten; Pühler, Alfred; Aguilar, O. Mario; Martínez-Drets, Gloria; Lagares, Antonio

    1999-01-01

    We describe the isolation and characterization of alfalfa-nodulating rhizobia from acid soils of different locations in Central Argentina and Uruguay. A collection of 465 isolates was assembled, and the rhizobia were characterized for acid tolerance. Growth tests revealed the existence of 15 acid-tolerant (AT) isolates which were able to grow at pH 5.0 and formed nodules in alfalfa with a low rate of nitrogen fixation. Analysis of those isolates, including partial sequencing of the genes encoding 16S rRNA and genomic PCR-fingerprinting with MBOREP1 and BOXC1 primers, demonstrated that the new isolates share a genetic background closely related to that of the previously reported Rhizobium sp. Or191 recovered from an acid soil in Oregon (B. D. Eardly, J. P. Young, and R. K. Selander, Appl. Environ. Microbiol. 58:1809–1815, 1992). Growth curves, melanin production, temperature tolerance, and megaplasmid profiles of the AT isolates were all coincident with these characteristics in strain Or191. In addition to the ability of all of these strains to nodulate alfalfa (Medicago sativa) inefficiently, the AT isolates also nodulated the common bean and Leucaena leucocephala, showing an extended host range for nodulation of legumes. In alfalfa, the time course of nodule formation by the AT isolate LPU 83 showed a continued nodulation restricted to the emerging secondary roots, which was probably related to the low rate of nitrogen fixation by the largely ineffective nodules. Results demonstrate the complexity of the rhizobial populations present in the acidic soils represented by a main group of N2-fixing rhizobia and a second group of ineffective and less-predominant isolates related to the AT strain Or191. PMID:10103231

  19. The tillage effect on the soil acid and alkaline phosphatase activity

    Directory of Open Access Journals (Sweden)

    Lacramioara Oprica

    2011-12-01

    Full Text Available Phosphatases (acid and alkaline are important in soils because these extracellular enzymes catalyze the hydrolysis of organic phosphate esters to orthophosphate; thus they form an important link between biologically unavailable and mineral phosphorous. Phosphatase activity is sensitive to environmental perturbations such as organic amendments, tillage, waterlogging, compaction, fertilizer additions and thus it is often used as an environmental indicator of soil quality in riparian ecosystems. The aim of the study was to assess the effect of tillage systems on phosphatases activity in a field experiment carried out in Ezăreni farm. The phosphatase activitiy were determined at two depths (7-10 cm and 15-25cm layers of a chernozem soil submitted to conventional tillage (CT in a fertilised and unfertilised experiment. Monitoring soil alkaline phosphatase activity showed, generally, the same in fertilized soil profiles collected from both depths; the values being extremely close. In unfertilized soils, alkaline phosphatase activity is different only in soils that were exposed to unconventional work using disc harrows and 30cm tillage. Both works type (no tillage and conventional tillage cause an intense alkaline phosphatase activity in 7-10 cm soil profile. Acid phosphatase activity is highly fluctuating in both fertilized as well unfertilized soil, this enzyme being influenced by the performed works.

  20. Nucleic Acid Extraction from Synthetic Mars Analog Soils for in situ Life Detection.

    Science.gov (United States)

    Mojarro, Angel; Ruvkun, Gary; Zuber, Maria T; Carr, Christopher E

    2017-08-01

    Biological informational polymers such as nucleic acids have the potential to provide unambiguous evidence of life beyond Earth. To this end, we are developing an automated in situ life-detection instrument that integrates nucleic acid extraction and nanopore sequencing: the Search for Extra-Terrestrial Genomes (SETG) instrument. Our goal is to isolate and determine the sequence of nucleic acids from extant or preserved life on Mars, if, for example, there is common ancestry to life on Mars and Earth. As is true of metagenomic analysis of terrestrial environmental samples, the SETG instrument must isolate nucleic acids from crude samples and then determine the DNA sequence of the unknown nucleic acids. Our initial DNA extraction experiments resulted in low to undetectable amounts of DNA due to soil chemistry-dependent soil-DNA interactions, namely adsorption to mineral surfaces, binding to divalent/trivalent cations, destruction by iron redox cycling, and acidic conditions. Subsequently, we developed soil-specific extraction protocols that increase DNA yields through a combination of desalting, utilization of competitive binders, and promotion of anaerobic conditions. Our results suggest that a combination of desalting and utilizing competitive binders may establish a "universal" nucleic acid extraction protocol suitable for analyzing samples from diverse soils on Mars. Key Words: Life-detection instruments-Nucleic acids-Mars-Panspermia. Astrobiology 17, 747-760.

  1. Partitioning of metals in a degraded acid sulfate soil landscape: influence of tidal re-inundation.

    Science.gov (United States)

    Claff, Salirian R; Sullivan, Leigh A; Burton, Edward D; Bush, Richard T; Johnston, Scott G

    2011-11-01

    The oxidation and acidification of sulfidic soil materials results in the re-partitioning of metals, generally to more mobile forms. In this study, we examine the partitioning of Fe, Cr, Cu, Mn, Ni and Zn in the acidified surface soil (0-0.1 m) and the unoxidised sub-soil materials (1.3-1.5 m) of an acid sulfate soil landscape. Metal partitioning at this acidic site was then compared to an adjacent site that was previously acidified, but has since been remediated by tidal re-inundation. Differences in metal partitioning were determined using an optimised six-step sequential extraction procedure which targets the "labile", "acid-soluble", "organic", "crystalline oxide", "pyritic" and "residual" fractions. The surficial soil materials of the acidic site had experienced considerable losses of Cr, Cu, Mn and Ni compared to the underlying parent material due to oxidation and acidification, yet only minor losses of Fe and Zn. In general, the metals most depleted from the acidified surface soil materials exhibited the greatest sequestration in the surface soil materials of the tidally remediated site. An exception to this was iron, which accumulated to highly elevated concentrations in the surficial soil materials of the tidally remediated site. The "acid-soluble", "organic" and "pyritic" fractions displayed the greatest increase in metals following tidal remediation. This study demonstrates that prolonged tidal re-inundation of severely acidified acid sulfate soil landscapes leads to the immobilisation of trace metals through the surficial accumulation of iron oxides, organic material and pyrite. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Study on Erosion Factors Affecting Kuroboku Soil Loss I. Water Permeability of Stratified Soil and Slope Gradient

    OpenAIRE

    田熊, 勝利; 猪迫, 耕二; 中原 恒,

    2005-01-01

    The authors examined the factors of bed soil affecting the loss of surface soil and the effects of these factors on the extent of the soil loss. They conducted a multivariate analysis using actual measurement value at a laboratory erosion experiment. They also conducted a simulation of erosion in soil loss using the bed soil factors. Soil loss quantity is dependent on the coefficient of permeability of bed soil; the steeper the latter is, the more the former increases. Lateral soil scattering...

  3. DEVELOPMENT OF ACID-SOIL TOLERANT CORN (Zea mays L. WITH HIGH-QUALITY PROTEIN

    Directory of Open Access Journals (Sweden)

    E.S. Halimi

    2011-06-01

    Full Text Available Corn is an important food crop in Indonesia. Plant expansion has been hampered by soil-acidity problem and the protein content of many corn varieties was low. This research initiates development of soil-acid-tolerant corn with high-quality-protein content. Research was done on 12 factorial treatments and 3 replications as blocks in RCBD. The first factor was corn populations: Toray-1(G1, Toray-2(G2, GS-5(G3 and GS-10(G4. The second factor was fertilizations: P1(69 kg N+36 kg P2O5+15 kg K2O per ha; P2(115 kg N+54 kg P2O5+30 kg K2O per ha; and P3(161 kg N+72 kg P2O5+45 kg K2O per ha. The observed variables consisted of several agronomic traits, including the protein content. Results indicated that the corn populations, in general, showed good agronomic traits. The differences were mostly between populations, not between fertilizations, and no interaction was observed. The yield potential ranged from 4.25 to 6.47 ton dry seeds per ha. The protein content of seed resulted from cross ranged from 9.84% to 11.30%, as compared to the parents of 9.11% and 12.62%. This research concludes that genetic factors play an important role as confirmed by heritability estimate (h2=0.75.

  4. White popular (Populus alba L.) - Litter impact on chemical and biochemical parameters related to nitrogen cycle in contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Ciadamidaro, L.; Madejon, P.; Cabrera, F.; Madejon, E.

    2014-06-01

    Aim of study: The aim of this study was to determine the effect of litter from Populus alba on chemical and biochemical properties related to the N cycle in soils with different pH values and trace element contents. We hypothesized that this litter would influence several parameters related to the N cycle and consequently to soil health. Area of study: we collected two reforested contaminated soils of different pH values (AZ pH 7.23 and DO pH 2.66) and a non-contaminated soil (RHU pH 7.19). Materials and methods: Soil samples were placed in 2,000 cm{sup 3} microcosms and were incubated for 40 weeks in controlled conditions. Each soil was mixed with its corresponding litter, and soils without litter were also tested for comparison. Ammonium (NH{sub 4}{sup 4}+-N) and nitrate (NO{sub 3}{sup -} -N) content, potential nitrification rate (PNR), microbial biomass nitrogen (MBN), protease activity, and several chemical properties such as pH, available trace element concentrations (extracted with 0.01 M CaCl{sub 2}) were determined at different times of incubation. Main results: Values of available trace elements did not vary during the incubation and were always higher in acid soil. In neutral soils litter presence increased values of Kjeldahl-N, NO{sub 3} –-N content, potential nitrification rate (PNR), microbial biomass nitrogen (MBN) and protease activity. Presence of trace elements in neutral soils did not alter the parameters studied. However, acidic pH and high content of available trace elements strongly affected NH{sub 4}{sup +}-N and NO{sub 3}{sup -} -N, microbial biomass N and protease activity. Research highlights: Our results showed the negative effect of the acidity and trace element availability in parameters related with the N-cycle. (Author)

  5. Soil geochemical factors regulate Cd accumulation by metal hyperaccumulating Noccaea caerulescens (J. Presl & C. Presl) F.K. Mey in field-contaminated soils.

    Science.gov (United States)

    Rosenfeld, Carla E; Chaney, Rufus L; Martínez, Carmen E

    2018-03-01

    Cadmium contamination in soil is a substantial global problem, and of significant concern due to high food-chain transfer. Cadmium hyperaccumulators are of particular interest because of their ability to tolerate and take up significant amounts of heavy metal pollution from soils. One particular plant, Noccaea caerulescens (formerly, Thlaspi caerulescens), has been extensively studied in terms of its capacity to accumulate heavy metals (specifically Zn and Cd), though these studies have primarily utilized hydroponic and metal-spiked model soil systems. We studied Cd and nutrient uptake by two N. caerulescens ecotypes, Prayon (Zn-only hyperaccumulator) and Ganges (Zn- and Cd-hyperaccumulator) in four long-term field-contaminated soils. Our data suggest that individual soil properties such as total soil Cd, Zn:Cd molar ratio, or soil pH do not accurately predict Cd uptake by hyperaccumulating plants. Additionally, total Cd uptake by the hyperaccumulating Ganges ecotype was substantially less than its physiological capacity, which is likely due to Cd-containing solid phases (primarily iron oxides) and pH that play an important role in regulating and limiting Cd solubility. Increased P accumulation in the Ganges leaves, and greater plant Fe accumulation from Cd-containing soils suggests that rhizosphere alterations via proton, and potentially organic acid, secretion may also play a role in nutrient and Cd acquisition by the plant roots. The current study highlights the role that soil geochemical factors play in influencing Cd uptake by hyperaccumulating plants. While these plants may have high physiological potential to accumulate metals from contaminated soils, individual soil geochemical factors and the plant-soil interactions in that soil will dictate the actual amount of phytoextractable metal. This underlines the need for site-specific understanding of metal-containing solid phases and geochemical properties of soils before undertaking phytoextraction efforts

  6. Initial root length in wheat is highly correlated with acid soil tolerance in the field

    Directory of Open Access Journals (Sweden)

    Jorge Fernando Pereira

    Full Text Available ABSTRACT: In acid soils, toxic aluminum ions inhibit plant root growth. In order to discriminate aluminum (Al tolerance, trustful screening techniques are required. In this study, 20 wheat cultivars, showing different levels of Al tolerance, were evaluated in a short-term soil experiment to access their relative root length (RRL. Moreover, the alleles of two important genes (TaALMT1 and TaMATE1B for Al tolerance in wheat were discriminated. Both of these genes encode membrane transporters responsible for the efflux of organic acids by the root apices that are thought to confer tolerance by chelating Al. Genotypes showing TaALMT1 alleles V and VI and an insertion at the TaMATE1B promoter were among the ones showing greater RRL. Mechanisms of Al tolerance, which are not associated with organic acid efflux, can be potentially present in two cultivars showing greater RRL among the ones carrying inferior TaALMT1 and TaMATE1B alleles. The RRL data were highly correlated with wheat performance in acid soil at three developmental stages, tillering (r = −0.93, p < 0.001, silking (r = −0.91, p < 0.001 and maturation (r = −0.90, p < 0.001, as well as with the classification index of aluminum toxicity in the field (r = −0.92, p < 0.001. Since the RRL was obtained after only six days of growth and it is highly correlated with plant performance in acid soil under field conditions, the short-term experiment detailed here is an efficient and rapid method for reliable screening of wheat Al tolerance.

  7. Effects of heating on composition, degree of darkness, and stacking nanostructure of soil humic acids

    Energy Technology Data Exchange (ETDEWEB)

    Katsumi, Naoya, E-mail: n-katsu@ishikawa-pu.ac.jp; Yonebayashi, Koyo; Okazaki, Masanori

    2016-01-15

    Wildfires and prescribed burning can affect both the quality and the quantity of organic matter in soils. In this study, we investigated qualitative and quantitative changes of soil humic substances in two different soils (an Entisol from a paddy field and an Inceptisol from a cedar forest) under several controlled heating conditions. Soil samples were heated in a muffle furnace at 200, 250, or 300 °C for 1, 3, 5, or 12 h. The humic acid and fulvic acid contents of the soil samples prior to and after heating were determined. The degree of darkness, elemental composition, carbon and nitrogen stable isotope ratios, {sup 13}C nuclear magnetic resonance spectra, and X-ray diffraction patterns of humic acids extracted from the soils before and after heating were measured. The proportion of humic acids in total carbon decreased with increasing heating time at high temperature (300 °C), but increased with increasing heating time at ≤ 250 °C. The degree of darkness of the humic acids increased with increasing heating time and temperature. During darkening, the H/C atomic ratios, the proportion of aromatic C, and the carbon and nitrogen stable isotope ratios increased, whereas the proportions of alkyl C and O-alkyl C decreased. X-ray diffraction analysis verified that a stacking nanostructure developed by heating. Changes in the chemical structure of the humic acids from the heated soils depended on the type of soil. The major structural components of the humic acids from the heated Entisol were aromatic C and carboxylic C, whereas aliphatic C, aromatic C, and carboxylic C structural components were found in the humic acids from the heated Inceptisol. These results suggest that the heat-induced changes in the chemical structure of the humic acids depended on the source plant. - Highlights: • Darkness of humic acids increased with increasing heating time and temperature. • Aromatic carbon content increased during darkening. • Carbon and nitrogen stable isotope

  8. Declining acidic deposition begins reversal of forest-soil acidification in the northeastern U.S

    Science.gov (United States)

    Gregory B. Lawrence; Paul W. Hazlett; Ivan J. Fernandez; Rock Ouimet; Scott W. Bailey; Walter C. Shortle; Kevin T. Smith; Michael R. Antidormi

    2015-01-01

    Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been...

  9. l-2-Oxothiazolidine-4-Carboxylic Acid or α-Lipoic Acid Attenuates Airway Remodeling: Involvement of Nuclear Factor-κB (NF-κB, Nuclear Factor Erythroid 2p45-Related Factor-2 (Nrf2, and Hypoxia-Inducible Factor (HIF

    Directory of Open Access Journals (Sweden)

    Heung Bum Lee

    2012-06-01

    Full Text Available Reactive oxygen species (ROS play a crucial role in the pathogenesis of acute and chronic respiratory diseases. Antioxidants have been found to ameliorate airway inflammation and hyperresponsiveness in animal models employing short-term exposure to allergen. However, little data are available on the effect of antioxidants on airway remodeling and signaling pathways in chronic asthma. In the present study, we used a long-term exposure murine model of allergic airway disease to evaluate the effects of an antioxidant, l-2-oxothiazolidine-4-carboxylic acid (OTC or α-lipoic acid (LA on airway remodeling, focusing on the ROS-related hypoxia-inducible signaling. Long-term challenge of ovalbumin (OVA increased ROS production, airway inflammation, and airway hyperresponsiveness, and developed features of airway remodeling such as excessive mucus secretion, subepithelial fibrosis, and thickening of the peribronchial smooth muscle layer. Administration of OTC or LA reduced these features of asthma, including airway remodeling, which was accompanied by suppression of transforming growth factor-β1, vascular endothelial growth factor, and T-helper 2 cytokines. In addition, OVA-induced activation of nuclear factor-κB (NF-κB, nuclear factor erythroid 2p45-related factor-2 (Nrf2, hypoxia-inducible factor (HIF-1α, and HIF-2α was reduced by OTC or LA. Our results also showed that OTC or LA down-regulated phosphoinositide 3-kinase activity and decreased phosphorylation of p38 mitogen-activated protein kinase but not extracellular signal-regulated kinase 1/2 or c-Jun N-terminal kinase. These findings demonstrate that OTC and LA can inhibit activation of NF-κB, Nrf2, and HIF, leading to attenuate allergen-induced airway remodeling.

  10. Persistence of glyphosate and aminomethylphosphonic acid in loess soil under different combinations of temperature, soil moisture and light/darkness

    NARCIS (Netherlands)

    Martins Bento, Celia; Yang, Xiaomei; Gort, Gerrit; Xue, Sha; Dam, van Ruud; Zomer, Paul; Mol, Hans G.J.; Ritsema, Coen J.; Geissen, Violette

    2016-01-01

    The dissipation kinetics of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) were studied in loess soil, under biotic and abiotic conditions, as affected by temperature, soil moisture (SM) and light/darkness. Nonsterile and sterile soil samples were spiked with 16 mg kg

  11. Effect of three Electron Shuttles on Bioreduction of Ferric Iron in two Acidic and Calcareous soils

    Directory of Open Access Journals (Sweden)

    Setareh Sharifi

    2017-01-01

    Full Text Available Introduction: Iron cycle is one of the most important biogeochemical processes which affect the availability of iron in soils. Ferric iron oxides are the most abundant forms of iron in soils and sediments. Ferric iron is highly insoluble at circumneutral pH. Present investigations have shown that the structural ferric iron bound in clay minerals is reduced by some microorganisms. Anaerobic bacteria reduce ferric iron which bound to soil clay minerals under anaerobic conditions. They have the ability to use ferric iron as a terminal electron acceptor. Many studies presented that dissimilatory iron reducing bacteria (DIRB mediate the transfer of electrons from small organic molecules like acetate and glucose to various humic materials (electron shuttles which then pass electrons abiotically to ferric iron oxyhydroxide and phyllosilicate minerals. Electron shuttles like AQDS, a tricyclic quinone, increase the rate of iron reduction by iron reducing bacteria on sites of iron oxides and oxyhydroxides. By increasing the rate of bioreduction of ferric iron, the solubility and availability of iron enhanced meaningfully. Royer et al. (2002 showed that bioreduction of hematite (common iron mineral in soils increased more than three times in the presence of AQDS and Shewanella putrefaciens comparedto control treatments. Previous works have mostly used synthetic minerals as electron acceptor in bioreduction process. Furthermore, the effect of quinones as electron acceptor for microorganisms were studied with poorly crystalline ferric iron oxides . The main objective of this study was to study the effect of AQS, humic acid and fulvic acid (as electron shuttle and Shewanella sp. and Pseudomonas aeruginosa, on bioreduction of native ferric iron in two acidic and calcareous soils. Materials and Methods: An experiment was conducted in a completely randomized design with factorial arrangement and three replications in vitro condition. The soil samples collected

  12. Aspect-related Vegetation Differences Amplify Soil Moisture Variability in Semiarid Landscapes

    Science.gov (United States)

    Yetemen, O.; Srivastava, A.; Kumari, N.; Saco, P. M.

    2017-12-01

    Soil moisture variability (SMV) in semiarid landscapes is affected by vegetation, soil texture, climate, aspect, and topography. The heterogeneity in vegetation cover that results from the effects of microclimate, terrain attributes (slope gradient, aspect, drainage area etc.), soil properties, and spatial variability in precipitation have been reported to act as the dominant factors modulating SMV in semiarid ecosystems. However, the role of hillslope aspect in SMV, though reported in many field studies, has not received the same degree of attention probably due to the lack of extensive large datasets. Numerical simulations can then be used to elucidate the contribution of aspect-driven vegetation patterns to this variability. In this work, we perform a sensitivity analysis to study on variables driving SMV using the CHILD landscape evolution model equipped with a spatially-distributed solar-radiation component that couples vegetation dynamics and surface hydrology. To explore how aspect-driven vegetation heterogeneity contributes to the SMV, CHILD was run using a range of parameters selected to reflect different scenarios (from uniform to heterogeneous vegetation cover). Throughout the simulations, the spatial distribution of soil moisture and vegetation cover are computed to estimate the corresponding coefficients of variation. Under the uniform spatial precipitation forcing and uniform soil properties, the factors affecting the spatial distribution of solar insolation are found to play a key role in the SMV through the emergence of aspect-driven vegetation patterns. Hence, factors such as catchment gradient, aspect, and latitude, define water stress and vegetation growth, and in turn affect the available soil moisture content. Interestingly, changes in soil properties (porosity, root depth, and pore-size distribution) over the domain are not as effective as the other factors. These findings show that the factors associated to aspect-related vegetation

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

    Science.gov (United States)

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

    2015-05-01

    Acid rain is an environmental problem of increasing concern in China. In this study, a laboratory leaching column experiment with acid forest soil was set up to investigate the responses of soil and soil solution chemistry to simulated acid rain (SAR). Five pH levels of SAR were set: 2.5, 3.0, 3.5, 4.0, and 4.5 (as a control, CK). The results showed that soil acidification would occur when the pH of SAR was ≤3.5. The concentrations of NO₃(-)and Ca(2+) in the soil increased significantly when the pH of SAR fell 3.5. The concentration of SO₄(2-) in the soil increased significantly when the pH of SAR was soil solution chemistry became increasingly apparent as the experiment proceeded (except for Na(+) and dissolved organic carbon (DOC)). The net exports of NO₃(-), SO₄(2-), Mg(2+), and Ca(2+) increased about 42-86% under pH 2.5 treatment as compared to CK. The Ca(2+) was sensitive to SAR, and the soil could release Ca(2+) through mineral weathering to mitigate soil acidification. The concentration of exchangeable Al(3+) in the soil increased with increasing the acidity of SAR. The releases of soluble Al and Fe were SAR pH dependent, and their net exports under pH 2.5 treatment were 19.6 and 5.5 times, respectively, higher than that under CK. The net export of DOC was reduced by 12-29% under SAR treatments as compared to CK. Our results indicate the chemical constituents in the soil are more sensitive to SAR than those in the soil solution, and the effects of SAR on soil solution chemistry depend not only on the intensity of SAR but also on the duration of SAR addition. The soil and soil solution chemistry in this region may not be affected by current precipitation (pH≈4.5) in short term, but the soil and soil leachate chemistry may change dramatically if the pH of precipitation were below 3.5 and 3.0, respectively.

  14. Intrinsic factors of Peltigera lichens influence the structure of the associated soil bacterial microbiota.

    Science.gov (United States)

    Leiva, Diego; Clavero-León, Claudia; Carú, Margarita; Orlando, Julieta

    2016-11-01

    Definition of lichens has evolved from bi(tri)partite associations to multi-species symbioses, where bacteria would play essential roles. Besides, although soil bacterial communities are known to be affected by edaphic factors, when lichens grow upon them these could become less preponderant. We hypothesized that the structure of both the lichen microbiota and the microbiota in the soil underneath lichens is shaped by lichen intrinsic and extrinsic factors. In this work, intrinsic factors corresponded to mycobiont and cyanobiont identities of Peltigera lichens, metabolite diversity and phenoloxidase activity and extrinsic factors involved the site of the forest where lichens grow. Likewise, the genetic and metabolic structure of the lichen and soil bacterial communities were analyzed by fingerprinting. Among the results, metabolite diversity was inversely related to the genetic structure of bacterial communities of lichens and soils, highlighting the far-reaching effect of these substances; while phenoloxidase activity was inversely related to the metabolic structure only of the lichen bacterial microbiota, presuming a more limited effect of the products of these enzymes. Soil bacterial microbiota was different depending on the site and, strikingly, according to the cyanobiont present in the lichen over them, which could indicate an influence of the photobiont metabolism on the availability of soil nutrients. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Magnetic and chemical parameters of andic soils and their relation to selected pedogenesis factors

    Czech Academy of Sciences Publication Activity Database

    Grison, Hana; Petrovský, Eduard; Kapička, Aleš; Stejskalová, Šárka

    2016-01-01

    Roč. 139, April (2016), s. 179-190 ISSN 0341-8162 R&D Projects: GA ČR GA13-10775S Institutional support: RVO:67985530 Keywords : andosols * magnetic susceptibility * basalts * iron oxides * frequency-dependent susceptibility Subject RIV: DF - Soil Science Impact factor: 3.191, year: 2016

  16. Subcritical water extraction of amino acids from Mars analog soils.

    Science.gov (United States)

    Noell, Aaron C; Fisher, Anita M; Fors-Francis, Kisa; Sherrit, Stewart

    2018-01-18

    For decades, the Martian regolith has stymied robotic mission efforts to catalog the organic molecules present. Perchlorate salts, found widely throughout Mars, are the main culprit as they breakdown and react with organics liberated from the regolith during pyrolysis, the primary extraction technique attempted to date on Mars. This work further develops subcritical water extraction (SCWE) as a technique for extraction of amino acids on future missions. The effect of SCWE temperature (185, 200, and 215°C) and duration of extraction (10-120 min) on the total amount and distribution of amino acids recovered was explored for three Mars analog soils (JSC Mars-1A simulant, an Atacama desert soil, and an Antarctic Dry Valleys soil) and bovine serum albumin (as a control solution of known amino acid content). Total amounts of amino acids extracted increased with both time and temperature; however, the distribution shifted notably due to the destruction of the amino acids with charged or polar side chains at the higher temperatures. The pure bovine serum albumin solution and JSC Mars 1A also showed lower yields than the Atacama and Antarctic extractions suggesting that SCWE may be less effective at hydrolyzing large or aggregated proteins. Changing solvent from water to a dilute (10 mM) HCl solution allowed total extraction efficiencies comparable to the higher temperature/time combinations while using the lowest temperature/time (185°C/20 min). The dilute HCl extractions also did not lead to the shift in amino acid distribution observed at the higher temperatures. Additionally, adding sodium perchlorate salt to the extraction did not interfere with recoveries. Native magnetite in the JSC Mars-1A may have been responsible for destruction of glycine, as evidenced by its uncharacteristic decrease as the temperature/time of extraction increased. This work shows that SCWE can extract high yields of native amino acids out of Mars analog soils with minimal disruption of the

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

    Science.gov (United States)

    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. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Relating environmental availability to bioavailability: soil-type-dependent metal accumulation in the oligochaete Eisenia andrei.

    Science.gov (United States)

    Peijnenburg, W J; Baerselman, R; de Groot, A C; Jager, T; Posthuma, L; Van Veen, R P

    1999-11-01

    Body residues are often better estimates of the amount of a chemical at the sites of toxic action in an organism than ambient soil concentrations, because bioavailability differences among soils are explicitly taken into account in considerations of body residues. Often, however, insufficient attention is paid to the rate and extent at which tissue concentrations respond to soil concentrations and soil characteristics. In this contribution the impact of soil characteristics on the environmental bioavailability of heavy metals for the oligochaete worm Eisenia andrei is reported. Uptake of As, Cd, Cr, Cu, Ni, Pb, and Zn in 20 Dutch field soils and in OECD artificial soil was quantified as a function of time. Internal metal concentrations varied less than the corresponding external levels. Metal uptake and elimination were both metal- and species-dependent. Worms typically attained steady-state concentrations rapidly for Cr, Cu, Ni, and Zn. Internal concentrations similar to those in the cultivation medium, linearly increasing body concentrations, or steady-state internal concentrations well above those in the cultivation medium were found for As, Cd, and Pb. Multivariate expressions were derived to describe uptake rate constants, steady-state concentrations, and bioaccumulation factors as a function of soil characteristics. Soil acidity is the most important solid-phase characteristic modulating the availability of As, Cd, and Pb. Although additional semimechanistic calculations yielded evidence of pore-water-related uptake of Cd and Pb modulated by competition between H(+) and metal ions at the active sites of the membranes, the findings for Cr, Cu, Ni, and Zn point to additional influences, among which is probably regulation. Copyright 1999 Academic Press.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    We applied three different doses of crushed mussel shell (CMS) on two Cu-polluted acid soils to study the effect of these amendments on the growth of the bacterial community during 730 days. Soil pH increased in the short and medium term due to CMS addition. In a first stage, bacterial growth...... was lower in the CMS-amended than in the un-amended samples. Thereafter, bacterial growth increased slowly. The soil having the highest initial pH value (4.5) showed the first significant increase in bacterial growth 95 days after the CMS amendment. However, in the soil with the lowest initial pH value (3...... as an agronomic sound practice for strongly acid soils (pH

  20. Available nitrogen is the key factor influencing soil microbial functional gene diversity in tropical rainforest.

    Science.gov (United States)

    Cong, Jing; Liu, Xueduan; Lu, Hui; Xu, Han; Li, Yide; Deng, Ye; Li, Diqiang; Zhang, Yuguang

    2015-08-20

    Tropical rainforests cover over 50% of all known plant and animal species and provide a variety of key resources and ecosystem services to humans, largely mediated by metabolic activities of soil microbial communities. A deep analysis of soil microbial communities and their roles in ecological processes would improve our understanding on biogeochemical elemental cycles. However, soil microbial functional gene diversity in tropical rainforests and causative factors remain unclear. GeoChip, contained almost all of the key functional genes related to biogeochemical cycles, could be used as a specific and sensitive tool for studying microbial gene diversity and metabolic potential. In this study, soil microbial functional gene diversity in tropical rainforest was analyzed by using GeoChip technology. Gene categories detected in the tropical rainforest soils were related to different biogeochemical processes, such as carbon (C), nitrogen (N) and phosphorus (P) cycling. The relative abundance of genes related to C and P cycling detected mostly derived from the cultured bacteria. C degradation gene categories for substrates ranging from labile C to recalcitrant C were all detected, and gene abundances involved in many recalcitrant C degradation gene categories were significantly (P rainforest. Soil available N could be the key factor in shaping the soil microbial functional gene structure and metabolic potential.

  1. [Seasonal variation of soil heat conduction in a larch plantation and its relations to environmental factors].

    Science.gov (United States)

    Wang, Wen-Jie; Cui, Song; Liu, Wei; Zu, Yuan-Gang; Sun, Wei; Wang, Hui-Min

    2008-10-01

    Based on a 3-year (2003-2005) observation of soil heat flux (SHF) in a larch (Larix gmelinii) plantation, the characteristics of soil heat conduction in the plantation and their relationships with environment factors were analyzed. The results showed that there was an obvious seasonal variation of SHF in different years and sampling sites. The SHF was positive from April to August and mostly negative from September to next March, with an almost balance between heat income and outcome at annual scale. Solar net radiation had significant effects on the SHF and soil heat conductance (k), and an obvious time-lag effect was found, with 4-5 hours' time-lag in winter and 2-3 hours' time-lag in summer. Based on the real-time measurement of SHF and soil temperature difference at the study sites, the k value was significantly higher in early spring (P 0.05). Therefore, when we use the observation data of soil temperature from weather stations to estimate soil heat flux, the k value in spring (from March to May) could induce a bias estimation.

  2. Citric acid facilitated thermal treatment: An innovative method for the remediation of mercury contaminated soil

    International Nuclear Information System (INIS)

    Ma, Fujun; Peng, Changsheng; Hou, Deyi; Wu, Bin; Zhang, Qian; Li, Fasheng; Gu, Qingbao

    2015-01-01

    Highlights: • Hg content was reduced to <1.5 mg/kg when treated at 400 °C with citric acid. • The treated soil retained most of its original soil physicochemical properties. • Proton provided by citric acid facilitates thermal removal of mercury. • This thermal treatment method is expected to reduce energy input by 35%. - Abstract: Thermal treatment is a promising technology for the remediation of mercury contaminated soils, but it often requires high energy input at heating temperatures above 600 °C, and the treated soil is not suitable for agricultural reuse. The present study developed a novel method for the thermal treatment of mercury contaminated soils with the facilitation of citric acid (CA). A CA/Hg molar ratio of 15 was adopted as the optimum dosage. The mercury concentration in soils was successfully reduced from 134 mg/kg to 1.1 mg/kg when treated at 400 °C for 60 min and the treated soil retained most of its original soil physiochemical properties. During the treatment process, CA was found to provide an acidic environment which enhanced the volatilization of mercury. This method is expected to reduce energy input by 35% comparing to the traditional thermal treatment method, and lead to agricultural soil reuse, thus providing a greener and more sustainable remediation method for treating mercury contaminated soil in future engineering applications.

  3. Citric acid facilitated thermal treatment: An innovative method for the remediation of mercury contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Fujun [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Peng, Changsheng [The Key Lab of Marine Environmental Science and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100 (China); Hou, Deyi [Geotechnical and Environmental Research Group, Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom); Wu, Bin; Zhang, Qian; Li, Fasheng [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Gu, Qingbao, E-mail: guqb@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China)

    2015-12-30

    Highlights: • Hg content was reduced to <1.5 mg/kg when treated at 400 °C with citric acid. • The treated soil retained most of its original soil physicochemical properties. • Proton provided by citric acid facilitates thermal removal of mercury. • This thermal treatment method is expected to reduce energy input by 35%. - Abstract: Thermal treatment is a promising technology for the remediation of mercury contaminated soils, but it often requires high energy input at heating temperatures above 600 °C, and the treated soil is not suitable for agricultural reuse. The present study developed a novel method for the thermal treatment of mercury contaminated soils with the facilitation of citric acid (CA). A CA/Hg molar ratio of 15 was adopted as the optimum dosage. The mercury concentration in soils was successfully reduced from 134 mg/kg to 1.1 mg/kg when treated at 400 °C for 60 min and the treated soil retained most of its original soil physiochemical properties. During the treatment process, CA was found to provide an acidic environment which enhanced the volatilization of mercury. This method is expected to reduce energy input by 35% comparing to the traditional thermal treatment method, and lead to agricultural soil reuse, thus providing a greener and more sustainable remediation method for treating mercury contaminated soil in future engineering applications.

  4. The Relation between Soil Parameters and Growth Characteristics of Tamarix ramosissima in Abyaneh, Isfahan Province

    Directory of Open Access Journals (Sweden)

    SayedHamid Matinkhah

    2017-12-01

    Full Text Available Vegetative characteristics of plant species are strongly dependent on habitat environmental conditions. Most Salt cedar (Tamarix ramosissima individuals grow on unsuitable soil and climate conditions. One of the important habitats of this species is near Abyaneh in Isfahan Province. To investigate the relation of edaphic factors on the growth of T. ramosissima, three plots 400m2 in area were randomly placed in this region. In each plot, crown cover and mean height of each tree were measured. Chemical and physical properties of soil were evaluated in two depths (0-20, 20-40cm. The relation between soil and vegetation was assessed using ordination method and RDA. The results suggest that in the upper depth, organic matter and saturation percentage (%SP have a strong positive correlation with vegetative factors of T. ramosissima including canopy cover and mean height. On the other hand, in lower depth pH, %CaSO4 factors have higher correlation with plants factors compared to upper depth. Therefore, organic matter in upper layer and saturation percentage (%SP have more correlation with vegetative factors. This suggests the importance of studying these two soil depths. In the restoration projects on this species, it is necessary to consider the abovementioned soil factors.

  5. Mycorrhizas and tropical soil fertility

    NARCIS (Netherlands)

    Cardoso, I.M.; Kuyper, T.W.

    2006-01-01

    Major factors that constrain tropical soil fertility and sustainable agriculture are low nutrient capital, moisture stress, erosion, high P fixation, high acidity with aluminium toxicity, and low soil biodiversity. The fragility of many tropical soils limits food production in annual cropping

  6. The Effect of EDTA and Citric acid on Soil Enzymes Activity, Substrate Induced Respiration and Pb Availability in a Contaminated Soil

    Directory of Open Access Journals (Sweden)

    seyed sajjad hosseini

    2017-03-01

    Full Text Available Introduction: Application of EDTA may increase the heavy metal availability and phytoextraction efficiency in contaminated soils. In spite of that, it might also have some adverse effects on soil biological properties. Metals as freeions are considered to be severely toxic, whereas the complexed form of these metalswith organic compounds or Fe/Mn oxides may be less available to soil microbes. However, apart from this fact, some of these compounds like EDTA and EDTA-metal complexes have low bio- chemo- and photo-degradablity and high solubility in their own characteristics andable to cause toxicity in soil environment. So more attentions have been paid to use of low molecular weight organic acids (LMWOAs such as Citric acid because of having less unfavorable effects to the environment. Citric acid increases heavy metals solubility in soils and it also improves soil microbial activity indirectly. Soil enzymes activity is a good indicator of soil quality, and it is more suitable for monitoring the soil quality compared to physical or chemical indicators. The aims of this research were to evaluate the changes of dehydrogenase, urease and alkaline phosphomonoesterase activities, substrate-induced respiration (SIR and Pb availability after EDTA and citric acid addition into a contaminated soil with PbCl2. Materials and Methods: An experiment was conducted in a completely randomized design with factorial arrangement and three replications in greenhouse condition. The soil samples collected from surface horizon (0-20 cm of the Typic haplocalsids, located in Mashhad, Iran. Soil samples were artificially contaminated with PbCl2 (500 mg Pb per kg of soil and incubated for one months in 70 % of water holding capacity at room temperature. The experimental treatments included control, 3 and 5 mmol EDTA (EDTA3 and EDTA5 and Citric acid (CA3 and CA5 per kg of soil. Soil enzymes activity, substrate-induced respiration and Pb availability of soil samples were

  7. Influence of humic-acid complexing on the mobility of Americium in the soil aquatic environment

    International Nuclear Information System (INIS)

    Sheppard, J.C.; Campbell, M.J.; Kittrick, J.A.

    1982-03-01

    Diffusion data indicate the Am, Cm and Np migrate 1.2, 0.8, and 26 centimeters, respectively, in a thousand years. Thus, excluding mass transport by moving water or wind, actinide elements, such as Cm, Am, and Np that find their way to the soil-aquatic environment are relatively immobile. Measured diffusion coefficients, corrected for distribution between the aqueous and soil phases, tortuosity, negative absorption, and relative fluidity are in reasonable agreement with aqueous diffusion coefficients. However, agreement depends strongly on measurement method used to determine distribution ratios. Two sets of experiments with 241 Am and 152 Eu tracers have been done to measure distribution ratios as a function of the aqueous humic acid concentration. In the first experiments the solid phase was kaolinite and in the second series of distribution ratios were measured with Burbank sandy loam. Both of these experiments indicated that Am(III) and Eu(III) form very strong humic acid complexes with formation constants of approximately 10 5 . Additional experiments are being done to establish the average number of Am(III)s or Eu(III)s bound to the humic acid polymer

  8. Spatial Data Mining for Estimating Cover Management Factor of Universal Soil Loss Equation

    Science.gov (United States)

    Tsai, F.; Lin, T. C.; Chiang, S. H.; Chen, W. W.

    2016-12-01

    Universal Soil Loss Equation (USLE) is a widely used mathematical model that describes long-term soil erosion processes. Among the six different soil erosion risk factors of USLE, the cover-management factor (C-factor) is related to land-cover/land-use. The value of C-factor ranges from 0.001 to 1, so it alone might cause a thousandfold difference in a soil erosion analysis using USLE. The traditional methods for the estimation of USLE C-factor include in situ experiments, soil physical parameter models, USLE look-up tables with land use maps, and regression models between vegetation indices and C-factors. However, these methods are either difficult or too expensive to implement in large areas. In addition, the values of C-factor obtained using these methods can not be updated frequently, either. To address this issue, this research developed a spatial data mining approach to estimate the values of C-factor with assorted spatial datasets for a multi-temporal (2004 to 2008) annual soil loss analysis of a reservoir watershed in northern Taiwan. The idea is to establish the relationship between the USLE C-factor and spatial data consisting of vegetation indices and texture features extracted from satellite images, soil and geology attributes, digital elevation model, road and river distribution etc. A decision tree classifier was used to rank influential conditional attributes in the preliminary data mining. Then, factor simplification and separation were considered to optimize the model and the random forest classifier was used to analyze 9 simplified factor groups. Experimental results indicate that the overall accuracy of the data mining model is about 79% with a kappa value of 0.76. The estimated soil erosion amounts in 2004-2008 according to the data mining results are about 50.39 - 74.57 ton/ha-year after applying the sediment delivery ratio and correction coefficient. Comparing with estimations calculated with C-factors from look-up tables, the soil erosion

  9. Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition

    Science.gov (United States)

    Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

    2017-06-01

    Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO4 2- to NO3 - ratios, and where the invasive ( Amaranthus retroflexus L.) and the native species ( Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO4 2- to NO3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO4 2- to NO3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH-) between SO4 2- and NO3 -. As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

  10. Fatty acids linked to cardiovascular mortality are associated with risk factors

    Directory of Open Access Journals (Sweden)

    Sven O. E. Ebbesson

    2015-08-01

    Full Text Available Background: Although saturated fatty acids (FAs have been linked to cardiovascular mortality, it is not clear whether this outcome is attributable solely to their effects on low-density lipoprotein cholesterol (LDL-C or whether other risk factors are also associated with FAs. The Western Alaskan Native population, with its rapidly changing lifestyles, shift in diet from unsaturated to saturated fatty acids and dramatic increase in cardiovascular disease (CVD, presents an opportunity to elucidate any associations between specific FAs and known CVD risk factors. Objective: We tested the hypothesis that the specific FAs previously identified as related to CVD mortality are also associated with individual CVD risk factors. Methods: In this community-based, cross-sectional study, relative proportions of FAs in plasma and red blood cell membranes were compared with CVD risk factors in a sample of 758 men and women aged ≥35 years. Linear regression analyses were used to analyze relations between specific FAs and CVD risk factors (LDL-C, high-density lipoprotein cholesterol, triglycerides, C-reactive protein, systolic blood pressure, diastolic blood pressure, heart rate, body mass index, fasting glucose and fasting insulin, 2-hour glucose and 2-hour insulin. Results: The specific saturated FAs previously identified as related to CVD mortality, the palmitic and myristic acids, were adversely associated with most CVD risk factors, whereas unsaturated linoleic acid (18:2n-6 and the marine n-3 FAs were not associated or were beneficially associated with CVD risk factors. Conclusions: The results suggest that CVD risk factors are more extensively affected by individual FAs than hitherto recognized, and that risk for CVD, MI and stroke can be reduced by reducing the intake of palmitate, myristic acid and simple carbohydrates and improved by greater intake of linoleic acid and marine n-3 FAs.

  11. Interrelationships of metal transfer factor under wastewater reuse and soil pollution.

    Science.gov (United States)

    Papaioannou, D; Kalavrouziotis, I K; Koukoulakis, P H; Papadopoulos, F; Psoma, P

    2018-06-15

    The transfer of heavy metals under soil pollution wastewater reuse was studied in a Greenhouse experiment using a randomized block design, including 6 treatments of heavy metals mixtures composed of Zn, Mn, Cd, Co, Cu, Cr, Ni, and Pb, where each metal was taking part in the mixture with 0, 10, 20, 30, 40, 50 mg/kg respectively, in four replications. The Beta vulgaris L (beet) was used as a test plant. It was found that the metal transfer factors were statistically significantly related to the: (i) DTPA extractable soil metals, (ii) the soil pollution level as assessed by the pollution indices, (iii) the soil pH, (iv) the beet dry matter yield and (v) the interactions between the heavy metals in the soil. It was concluded that the Transfer Factor is subjected to multifactor effects and its real nature is complex, and there is a strong need for further study for the understanding of its role in metal-plant relationships. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Comparison of the Soil Dynamic Amplification Factor and Soil Amplification by Using Microtremor and MASW Methods Respectively

    Science.gov (United States)

    Tuncel, Aykut; Cevdet Özdag, Özkan; Pamuk, Eren; Akgün, Mustafa

    2017-12-01

    Single Station Microtremor method, which is widely used nowadays, is an effective and easy applicable method. In this study, dynamic amplification factor distributions of the study area were obtained using scenario earthquake parameters with single station microtremor data gathered at 112 points. In addition, a surface wave active method, which is known as MASW (Multichannel Analysis of Surface Waves), was applied at 43 profiles to calculate the soil amplification values. Dynamic amplification factor (DAF), soil amplification, the predominant soil period (PSP), geology and topography data of the study area were analysed together. Dynamic amplification factor and soil amplification values were obtained 2 or higher at about sea level parts of the study area which are generally composed of alluvial units. Additionally, in high altitude regions that are composed of volcanic rocks, relatively lower dynamic amplification factor and soil amplification values were obtained. The minimum amplification value in the study area was 1.15, while the maximum amplification value was 3.05 according to the dynamic amplification results and the soil amplification values were between 1.16 and 3.85 in harmony. It is seen that the obtained DAF values and the soil amplification values calculated from the seismic velocities are very similar to each other numerically and regionally. Because of this, it is concluded that the values of the soil amplification obtained by the MASW method and the calculated DAF values in this study are in harmony with each other. Although the depths of research in these two calculation methods are different from each other, the similarity of the results allows us to arrive at the result of how effective the ground layer is on the amplification. It has a great importance to calculate the amplification values and other dynamic parameters by in situ measurements for a planned plot because geological units can vary even at very short distances in heterogeneously

  13. Enhanced Soil Chemical Properties and Rice Yield in Acid Sulphate Soil by Application of Rice Straw

    Directory of Open Access Journals (Sweden)

    Siti Nurzakiah

    2012-01-01

    Full Text Available Swampland development such as acid sulphate soil for agricultural cultivation has various problem, including highsoil acidity, fluctuated and unpredictable water flooding and the presence of toxic elements such as Fe whichresulting in low crop yields. The research was conducted at the experimental station Belandean, Barito Kualaregency in dry season 2007. The objective of research was to study the effect of rice straw on the dynamic of soilpH, the concentration of iron and sulphate and yield on tidal land acid sulphate soil at two different water inletchannel. This research was designed in RCBD (Randomized Completely Block Design with five treatments (0, 2.5,5.0, 7.5 and 10 Mg ha-1 and four replications. Dolomite as much as 1 Mg ha-1 was also applied. This research wasdivided into two sub-units experiment i.e. two conditions of different water inlet channel. The first water channelswere placed with limestone and the second inlet was planted with Eleocharis dulcis. The results showed that (i ricestraw application did not affect the dynamic of soil pH, concentration of iron and sulphate, and (ii the highest yieldwas obtained with 7.5 Mg ha-1 of rice straw.

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

    Science.gov (United States)

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

    2016-03-01

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

  15. Nonlinear binding of phenanthrene to the extracted fulvic acid fraction in soil in comparison with other organic matter fractions and to the whole soil sample

    International Nuclear Information System (INIS)

    Liu Wenxin; Xu, Shanshan; Xing, Baoshan; Pan, Bo; Tao, Shu

    2010-01-01

    Fractions of soil organic matter in a natural soil were extracted and sorption (or binding) characteristics of phenanthrene on each fraction and to the whole sample were investigated. The organic carbon normalized single point sorption (or binding) coefficient followed lipid > humin (HM) > humic acid (HA) > fulvic acid (FA) > whole soil sample, while the nonlinear exponent exhibited lipid > FA > HA > whole soil sample > HM. FA showed nonlinear binding of phenanthrene as it often does with other fractions. HM and HA contributed the majority of organic carbon in the soil. The calculated sorption coefficients of the whole soil were about two times greater than the measured values at different equilibrium phenanthrene concentrations. As for phenanthrene, the sorption capacity and nonlinearity of the physically mixed HA-HM mixtures were stronger as compared to the chemically reconstituted HA-HM composite. This was attributed to (besides the conditioning effect of the organic solvents) interactions between HA and HM and acid-base additions during fractionation. - Nonlinear binding of phenanthrene to fulvic acid extracted from soil organic matter was found.

  16. Impact of Environmental Factors and Biological Soil Crust Types on Soil Respiration in a Desert Ecosystem

    Science.gov (United States)

    Feng, Wei; Zhang, Yuqing; Jia, Xin; Wu, Bin; Zha, Tianshan; Qin, Shugao; Wang, Ben; Shao, Chenxi; Liu, Jiabin; Fa, Keyu

    2014-01-01

    The responses of soil respiration to environmental conditions have been studied extensively in various ecosystems. However, little is known about the impacts of temperature and moisture on soils respiration under biological soil crusts. In this study, CO2 efflux from biologically-crusted soils was measured continuously with an automated chamber system in Ningxia, northwest China, from June to October 2012. The highest soil respiration was observed in lichen-crusted soil (0.93±0.43 µmol m−2 s−1) and the lowest values in algae-crusted soil (0.73±0.31 µmol m−2 s−1). Over the diurnal scale, soil respiration was highest in the morning whereas soil temperature was highest in the midday, which resulted in diurnal hysteresis between the two variables. In addition, the lag time between soil respiration and soil temperature was negatively correlated with the soil volumetric water content and was reduced as soil water content increased. Over the seasonal scale, daily mean nighttime soil respiration was positively correlated with soil temperature when moisture exceeded 0.075 and 0.085 m3 m−3 in lichen- and moss-crusted soil, respectively. However, moisture did not affect on soil respiration in algae-crusted soil during the study period. Daily mean nighttime soil respiration normalized by soil temperature increased with water content in lichen- and moss-crusted soil. Our results indicated that different types of biological soil crusts could affect response of soil respiration to environmental factors. There is a need to consider the spatial distribution of different types of biological soil crusts and their relative contributions to the total C budgets at the ecosystem or landscape level. PMID:25050837

  17. Impact of environmental factors and biological soil crust types on soil respiration in a desert ecosystem.

    Science.gov (United States)

    Feng, Wei; Zhang, Yuqing; Jia, Xin; Wu, Bin; Zha, Tianshan; Qin, Shugao; Wang, Ben; Shao, Chenxi; Liu, Jiabin; Fa, Keyu

    2014-01-01

    The responses of soil respiration to environmental conditions have been studied extensively in various ecosystems. However, little is known about the impacts of temperature and moisture on soils respiration under biological soil crusts. In this study, CO2 efflux from biologically-crusted soils was measured continuously with an automated chamber system in Ningxia, northwest China, from June to October 2012. The highest soil respiration was observed in lichen-crusted soil (0.93 ± 0.43 µmol m-2 s-1) and the lowest values in algae-crusted soil (0.73 ± 0.31 µmol m-2 s-1). Over the diurnal scale, soil respiration was highest in the morning whereas soil temperature was highest in the midday, which resulted in diurnal hysteresis between the two variables. In addition, the lag time between soil respiration and soil temperature was negatively correlated with the soil volumetric water content and was reduced as soil water content increased. Over the seasonal scale, daily mean nighttime soil respiration was positively correlated with soil temperature when moisture exceeded 0.075 and 0.085 m3 m-3 in lichen- and moss-crusted soil, respectively. However, moisture did not affect on soil respiration in algae-crusted soil during the study period. Daily mean nighttime soil respiration normalized by soil temperature increased with water content in lichen- and moss-crusted soil. Our results indicated that different types of biological soil crusts could affect response of soil respiration to environmental factors. There is a need to consider the spatial distribution of different types of biological soil crusts and their relative contributions to the total C budgets at the ecosystem or landscape level.

  18. Phosphate fertilisers and management for sustainable crop production in tropical acid soils

    International Nuclear Information System (INIS)

    Chien, S.H.; Friesen, D.K.

    2000-01-01

    Extensive research has been conducted over the past 25 years on the management of plant nutrients, especially N and P, for crop production on acidic infertile tropical soils. Under certain conditions, the use of indigenous phosphate rock (PR) and modified PR products, such as partially acidulated PR or compacted mixtures of PR with superphosphates, are attractive alternatives, both agronomically and economically, to the use of conventional water-soluble P fertilisers for increasing crop productivity on Oxisols and Ultisols. A combination of the effects of proper P and N management including biological N 2 fixation, judicious use of lime, and the use of acid-soil tolerant and/or P-efficient cultivars in cropping systems that enhance nutrient cycling and use efficiency, can provide an effective technology to sustainably increase crop productivity and production in tropical agro-ecosystems dominated by these acid soils. (author)

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

    Science.gov (United States)

    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.

  20. The response of soil solution chemistry in European forests to decreasing acid deposition

    DEFF Research Database (Denmark)

    Johnson, James; Pannatier, Elisabeth Graf; Carnicelli, Stefano

    2018-01-01

    to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Altot) and dissolved organic carbon were determined for the period 1995–2012. Plots...... with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10–20 cm, 104 plots) and subsoil (40–80 cm, 162 plots). There was a large decrease in the concentration of sulphate () in soil solution; over a 10‐year period (2000...... over the entire dataset. The response of soil solution acidity was nonuniform. At 10–20 cm, ANC increased in acid‐sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40–80 cm, ANC remained unchanged in acid‐sensitive soils (base...

  1. Back to Acid Soil Fields: The Citrate Transporter SbMATE Is a Major Asset for Sustainable Grain Yield for Sorghum Cultivated on Acid Soils

    Directory of Open Access Journals (Sweden)

    Geraldo Carvalho Jr

    2016-02-01

    Full Text Available Aluminum (Al toxicity damages plant roots and limits crop production on acid soils, which comprise up to 50% of the world’s arable lands. A major Al tolerance locus on chromosome 3, AltSB, controls aluminum tolerance in sorghum [Sorghum bicolor (L. Moench] via SbMATE, an Al-activated plasma membrane transporter that mediates Al exclusion from sensitive regions in the root apex. As is the case with other known Al tolerance genes, SbMATE was cloned based on studies conducted under controlled environmental conditions, in nutrient solution. Therefore, its impact on grain yield on acid soils remains undetermined. To determine the real world impact of SbMATE, multi-trait quantitative trait loci (QTL mapping in hydroponics, and, in the field, revealed a large-effect QTL colocalized with the Al tolerance locus AltSB, where SbMATE lies, conferring a 0.6 ton ha–1 grain yield increase on acid soils. A second QTL for Al tolerance in hydroponics, where the positive allele was also donated by the Al tolerant parent, SC283, was found on chromosome 9, indicating the presence of distinct Al tolerance genes in the sorghum genome, or genes acting in the SbMATE pathway leading to Al-activated citrate release. There was no yield penalty for AltSB, consistent with the highly localized Al regulated SbMATE expression in the root tip, and Al-dependent transport activity. A female effect of 0.5 ton ha–1 independently demonstrated the effectiveness of AltSB in hybrids. Al tolerance conferred by AltSB is thus an indispensable asset for sorghum production and food security on acid soils, many of which are located in developing countries.

  2. Factor value determination and applicability evaluation of universal soil loss equation in granite gneiss region

    Directory of Open Access Journals (Sweden)

    Wen-hai Zhang

    2009-06-01

    Full Text Available Six types of runoff plots were set up and an experimental study was carried out to examine natural rate of soil and water loss in the granite gneiss region of northern Jiangsu Province in China. Through correlation analysis of runoff and soil loss during 364 rainfall events, a simplified and convenient mathematical formula suitable for calculating the rainfall erosivity factor (R for the local region was established. Other factors of the universal soil loss equation (USLE model were also determined. Relative error analysis of the soil loss of various plots calculated by the USLE model on the basis of the observed values showed that the relative error ranged from -3.5% to 9.9% and the confidence level was more than 90%. In addition, the relative error was 5.64% for the terraced field and 12.36% for the sloping field in the practical application. Thus, the confidence level was above 87.64%. These results provide a scientific basis for forecasting and monitoring soil and water loss, for comprehensive management of small watersheds, and for soil and water conservation planning in the region.

  3. Dependence of soil-to-plant transfer factors of elements on their concentrations in soil

    International Nuclear Information System (INIS)

    Tsukada, Hirofumi; Watabe, Teruhisa.

    1996-01-01

    Transfer factors (TFs) of 31 stable elements from soil to plant were determined by neutron activation analysis. Soil and plant samples were collected from 112 farm fields in Aomori prefecture, Japan. The elements described are those that could be detected by this method, which include essential elements for plant growth and nonessential elements. Several of these elements were divided into two groups, each having different TF characteristics. In the first group of elements there was an inverse correlation between the TFs and the soil concentrations of the elements, especially for Cl, K and Ca. The concentrations of these elements in plants were independent of their soil concentrations. However, in the second group, especially Sc and Co, the TFs were independent of the soil concentrations of the elements. The fluctuation of TFs observed in this study was smaller than that previously reported. This may be attributed to the relatively narrow geographic area of the present study. In addition, the TFs for the stable elements in this study were generally one to three orders of magnitude lower than those compiled for radioactive isotopes in previous publications. (author)

  4. Can liming reduce cadmium (Cd) accumulation in rice (Oryza sativa) in slightly acidic soils? A contradictory dynamic equilibrium between Cd uptake capacity of roots and Cd immobilisation in soils.

    Science.gov (United States)

    Yang, Yongjie; Chen, Jiangmin; Huang, Qina; Tang, Shaoqing; Wang, Jianlong; Hu, Peisong; Shao, Guosheng

    2018-02-01

    Cadmium (Cd) accumulation in rice is strongly controlled by liming, but information on the use of liming to control Cd accumulation in rice grown in slightly acidic soils is inconsistent. Here, pot experiments were carried out to investigate the mechanisms of liming on Cd accumulation in two rice varieties focusing on two aspects: available/exchangeable Cd content in soils that were highly responsive to liming, and Cd uptake and transport capacity in the roots of rice in terms of Cd accumulation-relative gene expression. The results showed that soil availability and exchangeable iron, manganese, zinc and Cd contents decreased with increased liming, and that genes related to Cd uptake (OsNramp5 and OsIRT1) were sharply up-regulated in the roots of the two rice varieties. Thus, iron, manganese, zinc and Cd contents in rice plants increased under low liming applications but decreased in response to high liming applications. However, yield and rice quantities were only slightly affected. These results indicated that Cd accumulation in rice grown in slightly acidic soils presents a contradictory dynamic equilibrium between Cd uptake capacity by roots and soil Cd immobilisation in response to liming. The enhanced Cd uptake capacity under low liming dosages increases risks to human health. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Determination of water-soluble forms of oxalic and formic acids in soils by ion chromatography

    Science.gov (United States)

    Karicheva, E.; Guseva, N.; Kambalina, M.

    2016-03-01

    Carboxylic acids (CA) play an important role in the chemical composition origin of soils and migration of elements. The content of these acids and their salts is one of the important characteristics for agrochemical, ecological, ameliorative and hygienic assessment of soils. The aim of the article is to determine water-soluble forms of same carboxylic acids — (oxalic and formic acids) in soils by ion chromatography with gradient elution. For the separation and determination of water-soluble carboxylic acids we used reagent-free gradient elution ion-exchange chromatography ICS-2000 (Dionex, USA), the model solutions of oxalate and formate ions, and leachates from soils of the Kola Peninsula. The optimal gradient program was established for separation and detection of oxalate and formate ions in water solutions by ion chromatography. A stability indicating method was developed for the simultaneous determination of water-soluble organic acids in soils. The method has shown high detection limits such as 0.03 mg/L for oxalate ion and 0.02 mg/L for formate ion. High signal reproducibility was achieved in wide range of intensities which correspond to the following ion concentrations: from 0.04 mg/g to 10 mg/L (formate), from 0.1 mg/g to 25 mg/L (oxalate). The concentration of formate and oxalate ions in soil samples is from 0.04 to 0.9 mg/L and 0.45 to 17 mg/L respectively.

  6. Role of amino acid metabolites in the formation of soil organic matter

    DEFF Research Database (Denmark)

    Sørensen, Lasse Holst

    1972-01-01

    Carbon-14 labelled cellulose or glucose were added to a medium loam and two sandy soils. The soils were incubated at 20°C for about 6 yr under laboratory conditions. Six to 12 per cent of the labelled carbon added to the soils was transformed into metabolites hydrolysable to amino acids during th...

  7. Soil chemical factors and grassland species density in Emas National Park (central Brazil).

    Science.gov (United States)

    Amorim, P K; Batalha, M A

    2008-05-01

    Studies of grasslands on specific soil types suggest that different nutrients can limit biomass production and, hence, species composition and number. The Brazilian cerrado is the major savanna region in America and once covered about 2 million km(2), mainly in the Brazilian Central Plateau, under seasonal climate, with wet summer and dry winter. In view of the importance of soil chemical factors in the distribution of the vegetation forms within the Cerrado domain and which may influence the number of species, we analyzed some soil characteristics in three herbaceous vegetation forms -- hyperseasonal cerrado, seasonal cerrado, and wet grassland -- in Emas National Park, a core cerrado site, to investigate the relationship between number of species and soil characteristics. We collected vegetation and soil samples in these three vegetation forms and submitted the obtained data to multiple linear regression. We found out that aluminum and pH were the best predictors of species density, the former positively related to species density and the latter negatively related. Since the predictable variation in species density is important in determining areas of conservation, we can postulate that these two soil factors are indicators of high species density areas in tropical grasslands, which could be used in selecting priority sites for conservation.

  8. Improving the management of infertile acid soils in Southeast Asia: The approach of the IBSRAM Acid-Soils network

    International Nuclear Information System (INIS)

    Lefroy, R.D.B.

    2000-01-01

    The IBSRAM ASIALAND Management of Acid Soils network aims to improve the understanding of the broad range of biophysical and socio-economic production limitations on infertile acid soils of Southeast Asia, and to lead to development and implementation of sustainable land-management strategies for these important marginal areas. The main activities of the network are in Indonesia, Myanmar, Philippines, and Vietnam, with associated activity in Thailand, and minor involvement in Brunei, Cambodia, Laos, and Malaysia. The main experimental focus is through researcher-managed on-farm trials, to improve the management of phosphorus nutrition with inorganic and organic amendments. A generic design is used across the eight well characterised sites that form the core of the network. The results will be analysed across time and across sites. Improved methods for laboratory analyses, experimental management, socio-economic data collection, and data analysis and interpretation are critical components. Three important initiatives are associated with the core activities. These aim to establish a broader network on maintenance of quality laboratory analyses, to assess the potential for implementation of improved strategies through farmer-managed on-farm trials, and to improve our understanding of, and ways of estimating, nutrient budgets for diverse farming systems. (author)

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

    DEFF Research Database (Denmark)

    Sørensen, Lasse Holst; Paul, E. A.

    1971-01-01

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

  10. Soil microbiome responses to the short-term effects of Amazonian deforestation.

    Science.gov (United States)

    Navarrete, Acacio A; Tsai, Siu M; Mendes, Lucas W; Faust, Karoline; de Hollander, Mattias; Cassman, Noriko A; Raes, Jeroen; van Veen, Johannes A; Kuramae, Eiko E

    2015-05-01

    Slash-and-burn clearing of forest typically results in increase in soil nutrient availability. However, the impact of these nutrients on the soil microbiome is not known. Using next generation sequencing of 16S rRNA gene and shotgun metagenomic DNA, we compared the structure and the potential functions of bacterial community in forest soils to deforested soils in the Amazon region and related the differences to soil chemical factors. Deforestation decreased soil organic matter content and factors linked to soil acidity and raised soil pH, base saturation and exchangeable bases. Concomitant to expected changes in soil chemical factors, we observed an increase in the alpha diversity of the bacterial microbiota and relative abundances of putative copiotrophic bacteria such as Actinomycetales and a decrease in the relative abundances of bacterial taxa such as Chlamydiae, Planctomycetes and Verrucomicrobia in the deforested soils. We did not observe an increase in genes related to microbial nutrient metabolism in deforested soils. However, we did observe changes in community functions such as increases in DNA repair, protein processing, modification, degradation and folding functions, and these functions might reflect adaptation to changes in soil characteristics due to forest clear-cutting and burning. In addition, there were changes in the composition of the bacterial groups associated with metabolism-related functions. Co-occurrence microbial network analysis identified distinct phylogenetic patterns for forest and deforested soils and suggested relationships between Planctomycetes and aluminium content, and Actinobacteria and nitrogen sources in Amazon soils. The results support taxonomic and functional adaptations in the soil bacterial community following deforestation. We hypothesize that these microbial adaptations may serve as a buffer to drastic changes in soil fertility after slash-and-burning deforestation in the Amazon region. © 2015 John Wiley & Sons Ltd.

  11. Evaluation of the potential of pentachlorophenol degradation in soil by pulsed corona discharge plasma from soil characteristics.

    Science.gov (United States)

    Wang, Tie Cheng; Lu, Na; Li, Jie; Wu, Yan

    2010-04-15

    Chlorinated organics are frequently found as harmful soil contaminants and persisted for extended periods of time. A novel approach, named pulsed corona discharge plasma (PCDP), was employed for the degradation of pentachlorophenol (PCP) in soil. Experimental results showed that 87% of PCP could be smoothly removed in 60 min. Increasing pulse voltage, enhancing soil pH, lowering humic acid (HA) in soil and reducing granular size of the soil were found to be favorable for PCP degradation efficiency. Oxidation and physical processes simultaneously contributed to PCP removal in soil and ozone was the main factor in PCDP treatment. C-Cl bonds in PCP were cleaved during PCDP treatment by Fourier transform infrared spectroscopy (FTIR) analysis. The mineralization of PCP was confirmed by total organic carbon (TOC) and dechlorination analyses. The main intermediate products such as tetrachlorocatechol, tetrachlorohydroquinone, acetic acid, formic acid, and oxalic acid were identified by HPLC/MS and ion chromatography. A possible pathway of PCP degradation in soil in such a system was proposed.

  12. Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes

    OpenAIRE

    Ch’ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab.

    2014-01-01

    In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixt...

  13. Impact of acid atmospheric deposition on soils : quantification of chemical and hydrologic processes

    NARCIS (Netherlands)

    Grinsven, van J.J.M.

    1988-01-01

    Atmospheric deposition of SO x , NOx and NHx will cause major changes in the chemical composition of solutions in acid soils, which may affect the biological functions of the soil. This thesis deals with quantification of soil acidification by means of chemical

  14. Effects of cadmium amendments on low-molecular-weight organic acid exudates in rhizosphere soils of tobacco and sunflower.

    Science.gov (United States)

    Chiang, Po-Neng; Wang, Ming Kuang; Chiu, Chih Yu; Chou, Shu-Yen

    2006-10-01

    To recognize physiological response of plants to cadmium (Cd) toxicity in rhizosphere of plants, the pot experiments were employed to investigate how low-molecular-weight organic acids (LMWOAs) were exudated from tobacco and sunflower roots of Cd-amended soils. The aims of this study were to assess the effect of LMWOAs on uptake of Cd by tobacco and sunflower under pot experiments, thus comparing the ability of tobacco and sunflower for phytoremediation. Surface soils (0-20 cm) were collected from Taichung Experiment Station (TC) (silty loam). Cadmium chloride (CdCl(2)) was amended into TC soil, giving Cd concentrations of 1, 5, 10 mg kg(-1) soil. Soils with different concentrations of Cd were put into 12 cm (i.d.) pots for incubation, and then 2-week-old tobacco and sunflower seedlings were transplanted into the pots. Tobacco and sunflower were grown in greenhouse for 50 days, respectively. The rhizosphere and bulk soils, and fresh plant tissues were collected after harvest. The Cd concentrations in the plant and transfer factor values in the sunflower were higher than that in the tobacco. No LMWOAs were detected by gas chromatograph in bulk soils, and low amounts of LMWOAs were found in uncontaminated rhizosphere soils. Acetic, lactic, glycolic, malic, maleic, and succinic acids were found in the tobacco and sunflower rhizosphere soils. Concentrations of LMWOAs increased with increasing amendment of Cd concentrations in tobacco and sunflower rhizosphere soils. Correlation coefficient (r) of concentrations of Cd amendment versus LMWOAs exudates of tobacco and sunflower were 0.85 and 0.98, respectively. These results suggest that the different levels of LMWOAs present in the rhizosphere soil play an important role in the solubilization of Cd that bound with soil particle into soil solution and then uptake by plants.

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

    Science.gov (United States)

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

    2016-02-15

    With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. EFFECTS OF ALKALINE SANDY LOAM ON SULFURIC SOIL ACIDITY AND SULFIDIC SOIL OXIDATION

    Directory of Open Access Journals (Sweden)

    Patrick S. Michael

    2015-08-01

    Full Text Available  In poor soils, addition of alkaline sandy loam containing an adequate proportion of sand, silt and clay would add value by improving the texture, structure and organic matter (OM for general use of the soils. In acid sulfate soils (ASS, addition of alkaline sandy would improve the texture and leach out salts as well as add a sufficient proportion of OM for vegetation establishment. In this study, addition of alkaline sandy loam into sulfuric soil effectively increased the pH, lowered the redox and reduced the sulfate content, the magnitude of the effects dependent on moisture content. Addition of alkaline sandy loam in combination with OM was highly effective than the effects of the lone alkaline sandy loam. When alkaline sandy was added alone or in combination with OM into sulfidic soil, the effects on pH and the redox were similar as in the sulfuric soil but the effect on sulfate content was variable. The effects under aerobic conditions were higher than under anaerobic conditions. The findings of this study have important implications for the general management of ASS where lime availability is a concern and its application is limited.International Journal of Environment Volume-4, Issue-3, June-August 2015Page: 42-54

  17. Decontamination of Soils Contaminated with Co and Cs by Using an Acid Leaching Process

    International Nuclear Information System (INIS)

    Jung-Joon, Lee; Gye-Nam, Kim; Jei-Kwon, Moon; Kune-Woo, Lee

    2009-01-01

    Acid leaching process has been adapted for the remediation of soils contaminated with heavy metals and radionuclides. This method has been reported to be simple, and economically promising. Moreover it can be applicable for on-site and off-site remediations as well. Investigations were conducted on an acid leaching process using surrogate contaminated soils. Size sieving, agglomeration and column leaching were carried out with soils artificially contaminated with Co and Cs, respectively. Size distribution was analyzed for a determination of the particle size required to be agglomerated. Because of the low water permeability of the soils due to their fine particles, they were sieved by using a sieve with a 0.075 mm size (No. 200 mesh) for an agglomeration. The soils with a size smaller than 0.075 mm were agglomerated by using 2 % sodium silicate (Na 2 SiO 3 ), while the soils with a size larger than 0.075 mm were used directly for the column leaching test. From the preliminary test (the batch scale leaching test), 0.1 M of HCl was determined as the effective leaching agent for Co and Cs. Finally, the soils mixed with the coarse soil and the agglomerated soil were decontaminated with 0.1 M HCl within 11.3 days and the removal efficiencies of Co and Cs were 94.0 % and 82.8 %, respectively. In conclusion, an acid leaching process could be applied for a remediation of soils contaminated with radionuclides such as Co and Cs. (authors)

  18. Acid drainage from coal mining: Effect on paddy soil and productivity of rice.

    Science.gov (United States)

    Choudhury, Burhan U; Malang, Akbar; Webster, Richard; Mohapatra, Kamal P; Verma, Bibhash C; Kumar, Manoj; Das, Anup; Islam, Mokidul; Hazarika, Samarendra

    2017-04-01

    Overburden and acid drainage from coal mining is transforming productive agricultural lands to unproductive wasteland in some parts of Northeast India. We have investigated the adverse effects of acid mine drainage on the soil of rice paddy and productivity by comparing them with non-mined land and abandoned paddy fields of Jaintia Hills in Northeast India. Pot experiments with a local rice cultivar (Myngoi) as test crop evaluated biological productivity of the contaminated soil. Contamination from overburden and acid mine drainage acidified the soil by 0.5 pH units, increased the exchangeable Al 3+ content 2-fold and its saturation on clay complexes by 53%. Available sulfur and extractable heavy metals, namely Fe, Mn and Cu increased several-fold in excess of critical limits, while the availability of phosphorus, potassium and zinc contents diminished by 32-62%. The grain yield of rice was 62% less from fields contaminated with acid mine drainage than from fields that have not suffered. Similarly, the amounts of vegetation, i.e. shoots and roots, in pots filled with soil from fields that received acid mine drainage were 59-68% less than from uncontaminated land (average shoot weight: 7.9±2.12gpot -1 ; average root weight: 3.40±1.15gpot -1 ). Paddy fields recovered some of their productivity 4years after mining ceased. Step-wise multiple regression analysis affirmed that shoot weight in the pots and grain yield in field were significantly (p<0.01) and positively influenced by the soil's pH and its contents of K, N and Zn, while concentration of S in excess of threshold limits in contaminated soil significantly (p<0.01) reduced the weight of shoots in the pots and grain yield in the field. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Evaluation of plant species for use in the control of acid sulfated soils in Paipa, Boyacá

    Directory of Open Access Journals (Sweden)

    Andrea Angélica Bernal Figueroa

    2014-07-01

    Full Text Available Acid sulfated soils are characterized by high amounts of iron and sulfur, which in presence of air are oxidized and form sulfuric horizons extremely acidic, generating environmental changes ranging from water pollution to problems associated with fertility and crop production, among others. This research was conducted in order to identify suitable plant species to control the acidity of these soils in the town of Paipa, Boyacá, Colombia. A completely randomized experimental design with 6 treatments and 3 replications was implemented in potting shed; there, the response of Beta vulgaris L. (forage beet, Brassica rapa L. (forage turnip and Raphanus sativus L. (forage radish on the acidity of sulfated acid soil, contrasted with a non-sulfated soil, was evaluated, after correction with liming. To assess the effects, pH and exchangeable acidity (H+ + Al+3 cmolc/kg were measured in the two types of soil before and after seeding ; the agronomic response of plants in each treatment was determined at the end of the growing season (120 days after seeding . On acid sulfated soils, species B. rapa, R. sativus and B. vulgaris along with the complementary use of liming as corrective induced a reduction in exchangeable acidity; B. rapa and R. sativus showed better growth potential and resistance, while B. vulgaris was affected in height and root diameter.

  20. Nestedness in Arbuscular Mycorrhizal Fungal Communities along Soil pH Gradients in Early Primary Succession: Acid-Tolerant Fungi Are pH Generalists.

    Science.gov (United States)

    Kawahara, Ai; An, Gi-Hong; Miyakawa, Sachie; Sonoda, Jun; Ezawa, Tatsuhiro

    2016-01-01

    Soil acidity is a major constraint on plant productivity. Arbuscular mycorrhizal (AM) fungi support plant colonization in acidic soil, but soil acidity also constrains fungal growth and diversity. Fungi in extreme environments generally evolve towards specialists, suggesting that AM fungi in acidic soil are acidic-soil specialists. In our previous surveys, however, some AM fungi detected in strongly acidic soils could also be detected in a soil with moderate pH, which raised a hypothesis that the fungi in acidic soils are pH generalists. To test the hypothesis, we conducted a pH-manipulation experiment and also analyzed AM fungal distribution along a pH gradient in the field using a synthesized dataset of the previous and recent surveys. Rhizosphere soils of the generalist plant Miscanthus sinensis were collected both from a neutral soil and an acidic soil, and M. sinensis seedlings were grown at three different pH. For the analysis of field communities, rhizosphere soils of M. sinensis were collected from six field sites across Japan, which covered a soil pH range of 3.0-7.4, and subjected to soil trap culture. AM fungal community compositions were determined based on LSU rDNA sequences. In the pH-manipulation experiment the acidification of medium had a significant impact on the compositions of the community from the neutral soil, but the neutralization of the medium had no effect on those of the community from the acidic soil. Furthermore, the communities in lower -pH soils were subsets of (nested in) those in higher-pH soils. In the field communities a significant nestedness pattern was observed along the pH gradient. These observations suggest that the fungi in strongly acidic soils are pH generalists that occur not only in acidic soil but also in wide ranges of soil pH. Nestedness in AM fungal community along pH gradients may have important implications for plant community resilience and early primary succession after disturbance in acidic soils.

  1. Nestedness in Arbuscular Mycorrhizal Fungal Communities along Soil pH Gradients in Early Primary Succession: Acid-Tolerant Fungi Are pH Generalists

    Science.gov (United States)

    Kawahara, Ai; An, Gi-Hong; Miyakawa, Sachie; Sonoda, Jun

    2016-01-01

    Soil acidity is a major constraint on plant productivity. Arbuscular mycorrhizal (AM) fungi support plant colonization in acidic soil, but soil acidity also constrains fungal growth and diversity. Fungi in extreme environments generally evolve towards specialists, suggesting that AM fungi in acidic soil are acidic-soil specialists. In our previous surveys, however, some AM fungi detected in strongly acidic soils could also be detected in a soil with moderate pH, which raised a hypothesis that the fungi in acidic soils are pH generalists. To test the hypothesis, we conducted a pH-manipulation experiment and also analyzed AM fungal distribution along a pH gradient in the field using a synthesized dataset of the previous and recent surveys. Rhizosphere soils of the generalist plant Miscanthus sinensis were collected both from a neutral soil and an acidic soil, and M. sinensis seedlings were grown at three different pH. For the analysis of field communities, rhizosphere soils of M. sinensis were collected from six field sites across Japan, which covered a soil pH range of 3.0–7.4, and subjected to soil trap culture. AM fungal community compositions were determined based on LSU rDNA sequences. In the pH-manipulation experiment the acidification of medium had a significant impact on the compositions of the community from the neutral soil, but the neutralization of the medium had no effect on those of the community from the acidic soil. Furthermore, the communities in lower -pH soils were subsets of (nested in) those in higher-pH soils. In the field communities a significant nestedness pattern was observed along the pH gradient. These observations suggest that the fungi in strongly acidic soils are pH generalists that occur not only in acidic soil but also in wide ranges of soil pH. Nestedness in AM fungal community along pH gradients may have important implications for plant community resilience and early primary succession after disturbance in acidic soils. PMID

  2. Bioavailable concentrations of germanium and rare earth elements in soil as affected by low molecular weight organic acids and root exudates

    Science.gov (United States)

    Wiche, Oliver; Székely, Balázs; Kummer, Nicolai-Alexeji; Heinemann, Ute; Tesch, Silke; Heilmeier, Hermann

    2014-05-01

    Availability of elements in soil to plant is generally dependent on the solubility and mobility of elements in soil solution which is controlled by soil, elemental properties and plant-soil interactions. Low molecular organic acids or other root exudates may increase mobility and availability of certain elements for plants as an effect of lowering pH in the rhizosphere and complexation. However, these processes take place in a larger volume in soil, therefore to understand their nature, it is also important to know in which layers of the soil what factors modify these processes. In this work the influence of citric acid and root exudates of white lupin (Lupinus albus L.) on bioavailable concentrations of germanium, lanthan, neodymium, gadolinium and erbium in soil solution and uptake in root and shoot of rape (Brassica napus L.), comfrey (Symphytum officinale L.), common millet (Panicum milliaceum L.) and oat (Avena sativa L.) was investigated. Two different pot experiments were conducted: (1) the mentioned plant species were treated with nutrient solutions containing various amount of citric acid; (2) white lupin was cultivated in mixed culture (0 % lupin, 33 % lupin) with oat (Avena sativa L.) and soil solution was obtained by plastic suction cups placed at various depths. As a result, addition of citric acid significantly increased germanium concentrations in plant tissue of comfrey and rape and increased translocation of germanium, lanthan, neodymium, gadolinium and erbium from root to shoot. The cultivation of white lupin in mixed culture with oat led to significantly higher concentrations of germanium and increasing concentrations of lanthan, neodymium, gadolinium and erbium in soil solution and aboveground plant tissue. In these pots concentrations of citric acid in soil solution were significantly higher than in the control. The results show, that low molecular organic acids exuded by plant roots are of great importance for the mobilization of germanium

  3. Verrucomicrobial community structure and abundance as indicators for changes in chemical factors linked to soil fertility.

    Science.gov (United States)

    Navarrete, Acacio Aparecido; Soares, Tielle; Rossetto, Raffaella; van Veen, Johannes Antonie; Tsai, Siu Mui; Kuramae, Eiko Eurya

    2015-09-01

    Here we show that verrucomicrobial community structure and abundance are extremely sensitive to changes in chemical factors linked to soil fertility. Terminal restriction fragment length polymorphism fingerprint and real-time quantitative PCR assay were used to analyze changes in verrucomicrobial communities associated with contrasting soil nutrient conditions in tropical regions. In case study Model I ("Slash-and-burn deforestation") the verrucomicrobial community structures revealed disparate patterns in nutrient-enriched soils after slash-and-burn deforestation and natural nutrient-poor soils under an adjacent primary forest in the Amazonia (R = 0.819, P = 0.002). The relative proportion of Verrucomicrobia declined in response to increased soil fertility after slash-and-burn deforestation, accounting on average, for 4 and 2 % of the total bacterial signal, in natural nutrient-poor forest soils and nutrient-enriched deforested soils, respectively. In case study Model II ("Management practices for sugarcane") disparate patterns were revealed in sugarcane rhizosphere sampled on optimal and deficient soil fertility for sugarcane (R = 0.786, P = 0.002). Verrucomicrobial community abundance in sugarcane rhizosphere was negatively correlated with soil fertility, accounting for 2 and 5 % of the total bacterial signal, under optimal and deficient soil fertility conditions for sugarcane, respectively. In nutrient-enriched soils, verrucomicrobial community structures were related to soil factors linked to soil fertility, such as total nitrogen, phosphorus, potassium and sum of bases, i.e., the sum of calcium, magnesium and potassium contents. We conclude that community structure and abundance represent important ecological aspects in soil verrucomicrobial communities for tracking the changes in chemical factors linked to soil fertility under tropical environmental conditions.

  4. Relations between variously available fractions of trace metals in the soil and their actual plant-uptake

    International Nuclear Information System (INIS)

    Bujtas, K.; Csillag, J.

    1999-01-01

    In a pot experiment, availabilities of Cd, Cr, Ni, Pb, and Zn added to the soil as metal nitrates or as enrichment of sewage sludge were evaluated by comparing concentrations of their total potentially available, presumably plant-available and directly plant-available forms in the soil. At excessively increasing soil contamination, the plant-available concentrations increased more than the total soil contents, thus the relative availabilities of the metals increased. This was reflected in the amounts taken up by the young maize test plants and in the plant/soil transfer factors. Transfer factors calculated for the 'plant-available' soil metal contents depended less on the contamination level than those based on total soil metal contents. Refs. 8 (author)

  5. Simulated acid rain effects on soil chemistry and microbiology

    International Nuclear Information System (INIS)

    Gigliotti, C.; Falappi, D.; Farini, A.; Sorlini, C.; Milan Univ.; Molise Univ.

    1992-01-01

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

  6. The role of tolerant genotypes and plant nutrients in the management of acid soil infertility in upland rice

    International Nuclear Information System (INIS)

    Sahrawat, K.L.; Jones, M.P.; Diatta, S.

    2000-01-01

    As in other parts of the humid tropics, acid-related problems are the major constraint to crop production on low-activity clay soils in the humid and sub-humid zones of West Africa. The upland ecosystem of West Africa is very important to rice production. About 70% of upland rice is grown in the humid zone of the sub-region. To increase and stabilize rice productivity of the acid uplands at reasonable levels, a strategy is needed that integrates the use of tolerant cultivars with soil and plant-nutrient management. Research conducted on Alfisols and Ultisols of the humid-forest and savannah zones in West Africa showed that upland rice is a robust crop, possessing a wide range of tolerance to acid-soil conditions. Recent research at WARDA showed also that acid-soil tolerance can be enhanced through interspecific Oryza sativa x O. glaberrima progenies, which not only possess increased tolerance of acid-soil conditions, but also have superior overall adaptability to diverse upland environments in the sub-region. Our research on the diagnosis of acid-soil infertility problems on the Ultisols and Alfisols of the humid savannah and forest zones indicates that P deficiency is the most important nutrient disorder for upland rice. In the forest zone, response to N depended on the application of P. In the savannah and forest-savannah transition zones, N deficiency was more important than P deficiency. Among other plant nutrients, the application of Ca and Mg (as plant nutrients) did not appear initially to improve the performance of acid-tolerant upland rice cultivars. The results from a long-term study on an Ultisol with four acid-tolerant rice cultivars, revealed that they differed in agronomic and physiological P efficiencies, and the efficiencies were higher at lower rates of P. The amounts of total P removed in three successive crops were similar for all four cultivars although P-harvest index was 10 to 12% higher in the P-efficient than the inefficient cultivars. The

  7. Effect of biodegradable amendments on uranium solubility in contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Duquene, L. [Belgian Nuclear Research Centre, Environment Health and Safety, Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium)], E-mail: lduquene@sckcen.be; Tack, F.; Meers, E. [Ghent University, Laboratory for Analytical Chemistry and Applied Ecochemistry, Coupure Links 653, B-9000 Gent (Belgium); Baeten, J. [Katholieke Hogeschool Kempen, Departement of Health-Care and Chemistry, Kleinhoefstraat 4, B-2440 Geel (Belgium); Wannijn, J.; Vandenhove, H. [Belgian Nuclear Research Centre, Environment Health and Safety, Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium)

    2008-02-25

    Chelate-assisted phytoextraction has been proposed as a potential tool for phytoremediation of U contaminated sites. In this context, the effects of five biodegradable amendments on U release in contaminated soils were evaluated. Three soils were involved in this study, one with a relatively high background level of U, and two which were contaminated with U from industrial effluents. Soils were treated with 5 mmol kg{sup -1} dry weight of either citric acid, NH{sub 4}-citrate/citric acid, oxalic acid, S,S-ethylenediamine disuccinic acid or nitrilotriacetic acid. Soil solution concentration of U was monitored during 2 weeks. All amendments increased U concentration in soil solution, but citric acid and NH{sub 4}-citrate/citric acid mixture were most effective, with up to 479-fold increase. For oxalic acid, S,S-ethylenediamine disuccinic acid and nitrilotriacetic acid, the increase ranged from 10-to 100-fold. The highest concentrations were observed 1 to 7 days after treatment, after which U levels in soil solution gradually decreased. All amendments induced a temporary increase of soil solution pH and TOC that could not be correlated with the release of U in the soil solution. Thermodynamic stability constants (log K) of complexes did not predict the relative efficiency of the selected biodegradable amendments on U release in soil solution. Amendments efficiency was better predicted by the relative affinity of the chelate for Fe compared to U.

  8. Phospholipid fatty acid patterns of microbial communities in paddy soil under different fertilizer treatments

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi-chun; WANG Guang-huo; YAO Huai-ying

    2007-01-01

    The microbial communities under irrigated rice cropping with different fertilizer treatments, including control (CK), PK, NK, NP, NPK fertilization, were investigated using phospholipid fatty acid (PLFA) profile method. The results of this study revealed that the fertilizer practice had an impact on the community structure of specific microbial groups. The principal components analysis (PCA) showed that proportion of the actinomycete PLFAs (10Me 18:0 and 10Me 16:0) were the lowest in the PK treatment and the highest in the NPK treatment, which means that soil nitrogen status affected the diversity of actinomycetes, whereas nitrogen cycling was related to the actinomycets. Under CK treatment, the ratio of Gram-positive to Gram-negative bacteria was lower compared with that in fertilizer addition treatments, indicating that fertilizer application stimulated Gram-positive bacterial population in paddy soil. The fatty acid 18:2ω6, 9, which is considered to be predominantly of fungal origin, was at low level in all the treatments. The ratio of cy19:0 to 18:1ω7, which has been proposed as an indicator of stress conditions, decreased in PK treatment. Changes of soil microbial community under different fertilizer treatments of paddy soil were detected in this study; however, the causes that lead to changes in the microbial community still needs further study.

  9. Influence of multi-step washing using Na2EDTA, oxalic acid and phosphoric acid on metal fractionation and spectroscopy characteristics from contaminated soil.

    Science.gov (United States)

    Wei, Meng; Chen, Jiajun

    2016-11-01

    A multi-step soil washing test using a typical chelating agent (Na 2 EDTA), organic acid (oxalic acid), and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated with heavy metals near an arsenic mining area. The aim of the test was to improve the heavy metal removal efficiency and investigate its influence on metal fractionation and the spectroscopy characteristics of contaminated soil. The results indicated that the orders of the multi-step washing were critical for the removal efficiencies of the metal fractions, bioavailability, and potential mobility due to the different dissolution levels of mineral fractions and the inter-transformation of metal fractions by XRD and FT-IR spectral analyses. The optimal soil washing options were identified as the Na 2 EDTA-phosphoric-oxalic acid (EPO) and phosphoric-oxalic acid-Na 2 EDTA (POE) sequences because of their high removal efficiencies (approximately 45 % for arsenic and 88 % for cadmium) and the minimal harmful effects that were determined by the mobility and bioavailability of the remaining heavy metals based on the metal stability (I R ) and modified redistribution index ([Formula: see text]).

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

    International Nuclear Information System (INIS)

    Wang, H.F.; Ambe, S.; Takematsu, N.; Ambe, F.

    1998-01-01

    Using a radioactive multitracer and model acid rain (HCl or H 2 SO 4 solution), batch experiments were performed to examine the pH effect on the adsorption-desorption equilibrium of 16 elements on soils as a model study of an acid rain effect. Kaolin, black soil (original and with organic matter almost removed) and Kureha soil (original and with organic matter almost removed) were used as adsorbents. Characteristic dependence on the pH value of the suspension was observed for the adsorption of the elements on kaolin and the soils. The results of this model study indicate that acid rain decreases the retention of cations, while it increases or does not change the adsorption of anions on soils. Organic matter in soils has a positive effect on the extent of adsorption of most elements investigated. (author)

  11. Studies on 14C-extractable residue, 14C-bound residue and mineralization of 14C-labeled chlorsulfuron in soils

    International Nuclear Information System (INIS)

    Ye Qingfu; Sun Jinhe; Qi Wenyuan; Wu Jianmin

    2003-01-01

    The purpose of the present study was to investigate 14 C-extractable residue ( 14 C-ER), 14 C-bound residue ( 14 C-BR) and mineralization of 14 C-labeled chlorsulfuron in soils by using isotope technique. The main factors affecting 14 C-BR formation and the distribution pattern of 14 C-BR in humus were also discussed in details. The results were as follows: (1) The 14 C-ER content of 14 C-chlorsulfuron in seven kinds of soil was positively related to soil pH and negatively related to clay content and organic matter content significantly. Moreover. the decrease rate of 14 C-chlorsulfuron parent compound derived from 14 C-ER in soils followed the first order rate reaction, the half-life in Soil 1-Soil 7 were 13.0, 13.1, 17.7, 133.3, 21.8, 22.1, 33.2 days, respectively. It was concluded that soil pH was the main factor affecting the degradation of 14 C-chlorsulfuron. (2) The 14 C-BR content of 14 C-chlorsulfuron in soils increased sharply with the incubation time during the initial 20 days, then changed slowly with time. However, 14 C-BR content during the whole incubation depended on soil types. The order of 14 C-BR content followed Soil 1 > Soil 2, Soil 5 and Soil 6 > Soil 3 > Soil 7 > Soil 4. The maximum values of 14 C-BR content of 14 C-chlorsulfuron in Soil 1-Soil 7 were 53.3%, 40.9%, 37.8%, 16.4%, 42.5%, 41.0% and 31.3% of applied amount. In addition, the 14 C-BR content of 14 C-chlorsulfuron in soils was negatively related to soil pH significantly, and positively related to the clay content. The soil pH was found to be the main factor affecting BR formation of 14 C-chlorsulfuron among the basic properties of soil. (3) During the whole periods of the incubation, the 14 C-BR of 14 C-chlorsulfuron in soils was mainly distributed in fulvic acid and humin. The relative percent of 14 C-BR in fulvic acid was higher than in humin. While the relative percentage of the 14 C-BR in humic acid only account for 2%. It was suggested that fulvic acid played an important role

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

    International Nuclear Information System (INIS)

    Oostra, Swantje; Majdi, Hooshang; Olsson, Mats

    2006-01-01

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

  13. Roles of Organic Acid Anion Secretion in Aluminium Tolerance of Higher Plants

    Science.gov (United States)

    Yang, Lin-Tong; Qi, Yi-Ping; Jiang, Huan-Xin; Chen, Li-Song

    2013-01-01

    Approximately 30% of the world's total land area and over 50% of the world's potential arable lands are acidic. Furthermore, the acidity of the soils is gradually increasing as a result of the environmental problems including some farming practices and acid rain. At mildly acidic or neutral soils, aluminium(Al) occurs primarily as insoluble deposits and is essentially biologically inactive. However, in many acidic soils throughout the tropics and subtropics, Al toxicity is a major factor limiting crop productivity. The Al-induced secretion of organic acid (OA) anions, mainly citrate, oxalate, and malate, from roots is the best documented mechanism of Al tolerance in higher plants. Increasing evidence shows that the Al-induced secretion of OA anions may be related to the following several factors, including (a) anion channels or transporters, (b) internal concentrations of OA anions in plant tissues, (d) temperature, (e) root plasma membrane (PM) H+-ATPase, (f) magnesium (Mg), and (e) phosphorus (P). Genetically modified plants and cells with higher Al tolerance by overexpressing genes for the secretion and the biosynthesis of OA anions have been obtained. In addition, some aspects needed to be further studied are also discussed. PMID:23509687

  14. Spatial pattern of heavy metals accumulation risk in urban soils of Beijing and its influencing factors

    International Nuclear Information System (INIS)

    Liu, Rui; Wang, Meie; Chen, Weiping; Peng, Chi

    2016-01-01

    Accumulations of heavy metals in urban soils are highly spatial heterogeneity and affected by multiple factors including soil properties, land use and pattern, population and climatic conditions. We studied accumulation risks of Cd, Cu, Pb and Zn in unban soils of Beijing and their influencing based on the regression tree analysis and a GIS-based overlay model. Result shows that Zinc causes the most extensive soil pollution and Cu result in the most acute soil pollution. The soil's organic carbon content and CEC and population growth are the most significant factors affecting heavy metal accumulation. Other influence factors in land use pattern, urban landscape, and wind speed also contributed, but less pronounced. The soils in areas with higher degree of urbanization and surrounded by intense vehicular traffics have higher accumulation risk of Cd, Cu, Pb, and Zn. - Highlights: • Zn accumulations were the most extensive and Cu accumulations were the most acute. • Accumulations of Cd, Cu, Pb and Zn in urban soils were caused by different sets of influence factors. • Soil's organic carbon content and CEC and population growth were the most significant factors. • Accumulation risks were highly related with urbanization level and human activities. - A combined approach of employing geographical information systems and regression tree analyses identify the potential risks of accumulation Cd, Cu, Pb, and Zn in urban soils according to soil properties, urban land use patterns, urban landscape, demographics, and microclimatic conditions.

  15. Detailed predictive mapping of acid sulfate soil occurrence using electromagnetic induction data

    DEFF Research Database (Denmark)

    Beucher, Amélie; Boman, A; Mattbäck, S

    impact through the resulting corrosion of concrete and steel infrastructures, or their poor geotechnical qualities.Mapping acid sulfate soil occurrence thus constitutes a key step to target the strategic areas for subsequent environmental risk management and mitigation. Conventional mapping (i.e. soil...

  16. Effect of Rain Acidity Upon Mobility of Cs-134 and Co-60 in Soil

    International Nuclear Information System (INIS)

    Ruangchuay, S.; Harvey, N.W.; Sriyotha, P.

    1998-01-01

    This research was aimed to study the effects of groundwater and acid rain upon the mobility of radionuclides (Cs-134 and Co-60) in contaminated top soil. Clay soil was homogeneously packed in columns with dimension φ.12.5 cm. * 50 cm.. At the top 5 cm. of the columns, soil contaminated with radionuclides was added with the same consistency. Column were kept standing for 4 months in an artificial water table kept at 3 cm. from the bottom. During this period artificial acid rain with pH3, 4.5 and 6 was applied weekly at the top. Soil samples were taken every 30 days for examination of total and extracable radioactivity. It was shown that with the aide of the rain radionuclide movement down the profile was greater, with Co-60 > Cs-134. However acidity of the rain shown no effect on their movement

  17. Tree species is the major factor explaining C:N ratios in European forest soils

    DEFF Research Database (Denmark)

    Cools, Nathalie; Vesterdal, Lars; De Vos, Bruno

    2014-01-01

    The C:N ratio is considered as an indicator of nitrate leaching in response to high atmospheric nitrogen (N) deposition. However, the C:N ratio is influenced by a multitude of other site-related factors. This study aimed to unravel the factors determining C:N ratios of forest floor, mineral soil...... mineral soil layers it was the humus type. Deposition and climatic variables were of minor importance at the European scale. Further analysis for eight main forest tree species individually, showed that the influence of environmental variables on C:N ratios was tree species dependent. For Aleppo pine...... and peat top soils in more than 4000 plots of the ICP Forests large-scale monitoring network. The first objective was to quantify forest floor, mineral and peat soil C:N ratios across European forests. Secondly we determined the main factors explaining this C:N ratio using a boosted regression tree...

  18. Pinus pinaster seedlings and their fungal symbionts show high plasticity in phosphorus acquisition in acidic soils.

    Science.gov (United States)

    Ali, M A; Louche, J; Legname, E; Duchemin, M; Plassard, C

    2009-12-01

    Young seedlings of maritime pine (Pinus pinaster Soland in Aït.) were grown in rhizoboxes using intact spodosol soil samples from the southwest of France, in Landes of Gascogne, presenting a large variation of phosphorus (P) availability. Soils were collected from a 93-year-old unfertilized stand and a 13-year-old P. pinaster stand with regular annual fertilization of either only P or P and nitrogen (N). After 6 months of culture in controlled conditions, different morphotypes of ectomycorrhiza (ECM) were used for the measurements of acid phosphatase activity and molecular identification of fungal species using amplification of the ITS region. Total biomass, N and P contents were measured in roots and shoots of plants. Bicarbonate- and NaOH-available inorganic P (Pi), organic P (Po) and ergosterol concentrations were measured in bulk and rhizosphere soil. The results showed that bulk soil from the 93-year-old forest stand presented the highest Po levels, but relatively higher bicarbonate-extractable Pi levels compared to 13-year-old unfertilized stand. Fertilizers significantly increased the concentrations of inorganic P fractions in bulk soil. Ergosterol contents in rhizosphere soil were increased by fertilizer application. The dominant fungal species was Rhizopogon luteolus forming 66.6% of analysed ECM tips. Acid phosphatase activity was highly variable and varied inversely with bicarbonate-extractable Pi levels in the rhizosphere soil. Total P or total N in plants was linearly correlated with total plant biomass, but the slope was steep only between total P and biomass in fertilized soil samples. In spite of high phosphatase activity in ECM tips, P availability remained a limiting nutrient in soil samples from unfertilized stands. Nevertheless young P. pinaster seedlings showed a high plasticity for biomass production at low P availability in soils.

  19. FATTY ACID STABLE ISOTOPE INDICATORS OF MICROBIAL CARBON SOURCE IN TROPICAL SOILS

    Science.gov (United States)

    The soil microbial community plays an important role in tropical ecosystem functioning because of its importance in the soil organic matter (SOM) cycle. We have measured the stable carbon isotopic ratio (delta13C) of individual phospholipid fatty acids (PLFAs) in a variety of tr...

  20. Effects of poly-γ-glutamic acid biopreparation (PGAB) on nitrogen conservation in the coastal saline soil

    Science.gov (United States)

    Chen, Lihua; Xu, Xianghong; Zhang, Huan; Han, Rui; Cheng, Yao; Tan, Xueyi; Chen, Xuanyu

    2017-04-01

    Water leaching is the major method to decrease soil salinity of the coastal saline soil. Conservation of soil nutrition in the soil ameliorating process is helpful to maintain soil fertility and prevent environment pollution. In the experiment, glutamic acid and poly-γ-glutamic acid (PGA) producing bacteria were isolated for manufacturing the PGA biopreparation (PGAB), and the effect of PGAB on the soil nitrogen (N) conservation was assayed. The glutamic acid and PGA producing bacteria were identified as Brevibacterium flavum and Bacillus amyloliquefaciens. After soil leached with water for 90 days, compared to control treatment, salt concentration of 0-30cm soil with PGAB treatment was lowered by 39.93%, however the total N loss was decreased by 65.37%. Compared to control, the microbial biomass N increased by 1.19 times at 0-30 cm soil with PGAB treatment. The populations of soil total bacteria, fungi, actinomyces, nitrogen fixing bacteria, ammonifying bacteria, nitrifying bacteria and denitrifying bacteria and biomass of soil algae were significantly increased in PGAB treatment, while anaerobic bacteria decreased (P 0.25 mm and 0.02 mm < diameter <0.25 mm were increased by 2.93 times and 26.79% respectively in PGAB treatment. The soil erosion-resistance coefficient of PGAB treatment increased by 50%. All these suggested that the PGAB conserved the soil nitrogen effectively in the process of soil water leaching and improved the coastal saline soil quality.

  1. Assessing the dynamics of the upper soil layer relative to soil management practices

    Science.gov (United States)

    Hatfield, J.; Wacha, K.; Dold, C.

    2017-12-01

    The upper layer of the soil is the critical interface between the soil and the atmosphere and is the most dynamic in response to management practices. One of the soil properties most reflective to changes in management is the stability of the aggregates because this property controls infiltration of water and exchange of gases. An aggregation model has been developed based on the factors that control how aggregates form and the forces which degrade aggregates. One of the major factors for this model is the storage of carbon into the soil and the interaction with the soil biological component. To increase soil biology requires a stable microclimate that provides food, water, shelter, and oxygen which in turn facilitates the incorporation of organic material into forms that can be combined with soil particles to create stable aggregates. The processes that increase aggregate size and stability are directly linked the continual functioning of the biological component which in turn changes the physical and chemical properties of the soil. Soil aggregates begin to degrade as soon as there is no longer a supply of organic material into the soil. These processes can range from removal of organic material and excessive tillage. To increase aggregation of the upper soil layer requires a continual supply of organic material and the biological activity that incorporates organic material into substances that create a stable aggregate. Soils that exhibit stable soil aggregates at the surface have a prolonged infiltration rate with less runoff and a gas exchange that ensures adequate oxygen for maximum biological activity. Quantifying the dynamics of the soil surface layer provides a quantitative understanding of how management practices affect aggregate stability.

  2. The acid-labile subunit of the ternary insulin-like growth factor complex in cirrhosis: relation to liver dysfunction

    DEFF Research Database (Denmark)

    Møller, S; Juul, A; Becker, U

    2000-01-01

    BACKGROUND/AIMS: In the circulation, insulin-like growth factor-I (IGF-I) is bound in a trimeric complex of 150 kDa with IGF binding protein-3 (IGFBP-3) and the acid-labile subunit (ALS). Whereas circulating IGF-I and IGFBP-3 are reported to be low in patients with chronic liver failure, the leve...... with significant relations to liver dysfunction and other components of the IGF complex. A small hepatic extraction was found in controls, which suggests extrahepatic production of ALS. Future studies should focus on organ-specific removal of ALS.......BACKGROUND/AIMS: In the circulation, insulin-like growth factor-I (IGF-I) is bound in a trimeric complex of 150 kDa with IGF binding protein-3 (IGFBP-3) and the acid-labile subunit (ALS). Whereas circulating IGF-I and IGFBP-3 are reported to be low in patients with chronic liver failure, the level...... of ALS has not been described in relation to hepatic dysfunction. The aim of the present study was therefore to measure circulating and hepatic venous concentrations of ALS in relation to hepatic function and the IGF axis. METHODS: Twenty-five patients with cirrhosis (Child class A/B/C:5/10/10) and 30...

  3. Elemental stoichiometry indicates predominant influence of potassium and phosphorus limitation on arbuscular mycorrhizal symbiosis in acidic soil at high altitude.

    Science.gov (United States)

    Khan, Mohammad Haneef; Meghvansi, Mukesh K; Gupta, Rajeev; Veer, Vijay

    2015-09-15

    The functioning of high-altitude agro-ecosystems is constrained by the harsh environmental conditions, such as low temperatures, acidic soil, and low nutrient supply. It is therefore imperative to investigate the site-specific ecological stoichiometry with respect to AM symbiosis in order to maximize the arbuscular mycorrhizal (AM) benefits for the plants in such ecosystems. Here, we assess the elemental stoichiometry of four Capsicum genotypes grown on acidic soil at high altitude in Arunachal Pradesh, India. Further, we try to identify the predominant resource limitations influencing the symbioses of different Capsicum genotypes with the AM fungi. Foliar and soil elemental stoichiometric relations of Capsicum genotypes were evaluated with arbuscular mycorrhizal (AM) colonization and occurrence under field conditions. AM fungal diversity in rhizosphere, was estimated through PCR-DGGE profiling. Results demonstrated that the symbiotic interaction of various Capsicum genotypes with the AM fungi in acidic soil was not prominent in the study site as evident from the low range of root colonization (21-43.67%). In addition, despite the rich availability of carbon in plant leaves as well as in soil, the carbon-for-phosphorus trade between AMF and plants appeared to be limited. Our results provide strong evidences of predominant influence of the potassium-limitation, in addition to phosphorus-limitation, on AM symbiosis with Capsicum in acidic soil at high altitude. We also conclude that the potassium should be considered in addition to carbon, nitrogen, and phosphorus in further studies investigating the stoichiometric relationships with the AMF symbioses in high altitude agro-ecosystems. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. Assessing the effects of soil liming with dolomitic limestone and sugar foam on soil acidity, leaf nutrient contents, grape yield and must quality in a Mediterranean vineyard

    Energy Technology Data Exchange (ETDEWEB)

    Olego, M.A.; Visconti, F.; Quiroga, M.J.; Paz, J.M. De; Garzón-Jimeno, E.

    2016-11-01

    Aluminium toxicity has been recognized as one of the most common causes of reduced grape yields in vineyard acid soils. The main aim of this study was to evaluate the effect of two liming materials, i.e. dolomitic lime and sugar foam, on a vineyard cultivated in an acid soil. The effects were studied in two soil layers (0-30 and 30-60 cm), as well as on leaf nutrient contents, must quality properties and grape yield, in an agricultural soil dedicated to Vitis vinifera L. cv. ‘Mencía’ cultivation. Data management and analysis were performed using analysis of variance (ANOVA). As liming material, sugar foam was more efficient than dolomitic limestone because sugar foam promoted the highest decrease in soil acidity properties at the same calcium carbonate equivalent dose. However, potassium contents in vines organs, including leaves and berries, seemed to decrease as a consequence of liming, with a concomitant increase in must total acidity. Soil available phosphorus also decreased as a consequence of liming, especially with sugar foam, though no effects were observed in plants. For these reasons fertilization of this soil with K and P is recommended along with liming. Grape yields in limed soils increased, although non-significantly, by 30%. This research has therefore provided an important opportunity to advance in our understanding of the effects of liming on grape quality and production in acid soils. (Author)

  5. Dissolved organic carbon and nitrogen mineralization strongly affect co2 emissions following lime application to acidic soil

    International Nuclear Information System (INIS)

    Shaaban, M.; Peng, Q.; Lin, S.; Wu, Y.

    2014-01-01

    Emission of greenhouse gases from agricultural soils has main contribution to the climatic change and global warming. Dynamics of dissolved organic carbon (DOC) and nitrogen mineralization can affect CO/sub 2/ emission from soils. Influence of DOC and nitrogen mineralization on CO/sub 2/ emissions following lime application to acidic soil was investigated in current study. Laboratory experiment was conducted under aerobic conditions with 25% moisture contents (66% water-filled pore space) at 25 degree C in the dark conditions. Different treatments of lime were applied to acidic soil as follows: CK (control), L (low rate of lime: 0.2g lime / 100 g soil) and H (high rate of lime: 0.5g lime /100g soil). CO/sub 2/ emissions were measured by gas chromatography and dissolved organic carbon, NH4 +-N, NO/sub 3/ --N and soil pH were measured during incubation study. Addition of lime to acidic soil significantly increased the concentration of DOC and N mineralization rate. Higher concentrations of DOC and N mineralization, consequently, increased the CO/sub 2/ emissions from lime treated soils. Cumulative CO/sub 2/ emission was 75% and 71% higher from L and H treatments as compared to CK. The results of current study suggest that DOC and N mineralization are critical in controlling gaseous emissions of CO/sub 2/ from acidic soils following lime application. (author)

  6. Novel Technique to improve the pH of Acidic Barren Soil using Electrokinetic-bioremediation with the application of Vetiver Grass

    Science.gov (United States)

    Azhar, A. T. S.; Nabila, A. T. A.; Nurshuhaila, M. S.; Zaidi, E.; Azim, M. A. M.; Zahin, A. M. F.

    2016-11-01

    Residual acidic slopes which are not covered by vegetation greatly increases the risk of soil erosion. In addition, low soil pH can bring numerous problems such as Al and Fe toxicity, land degradation issues and some problems related to vegetation. In this research, a series of electrokinetic bioremediation (EK-Bio) treatments using Bacillus sphaericus, Bacillus subtilis and Pseudomonas putida with a combination of Vetiver grass were performed in the laboratory. Investigations were conducted for 14 days and included the observation of changes in the soil pH and the mobilization of microorganism cells through an electrical gradient of 50 V/m under low pH. Based on the results obtained, this study has successfully proven that the pH of soil increases after going through electrokinetic bioremediation (EK-Bio). The treatment using Bacillus sphaericus increases the pH from 2.95 up to 4.80, followed by Bacillus subtilis with a value of 4.66. Based on the overall performance, Bacillus sphaericus show the highest number of bacterial cells in acidic soil with a value of 6.6 × 102 cfu/g, followed by Bacillus subtilis with a value of 5.7 × 102 cfu/g. In conclusion, Bacillus sphaericus and Bacillus subtilis show high survivability and is suitable to be used in the remediation of acidic soil.

  7. Lack of A-factor production induces the expression of nutrient scavenging and stress-related proteins in Streptomyces griseus.

    Science.gov (United States)

    Birkó, Zsuzsanna; Swiatek, Magdalena; Szájli, Emília; Medzihradszky, Katalin F; Vijgenboom, Erik; Penyige, András; Keseru, Judit; van Wezel, Gilles P; Biró, Sándor

    2009-10-01

    The small gamma-butyrolactone A-factor is an important autoregulatory signaling molecule for the soil-inhabiting streptomycetes. Starvation is a major trigger for development, and nutrients are provided by degradation of the vegetative mycelium via a process of programmed cell death, reusing proteins, nucleic acids, and cell wall material. The A-factor regulon includes many extracellular hydrolases. Here we show via proteomics analysis that many nutrient-scavenging and stress-related proteins were overexpressed in an A-factor non-producing mutant of Streptomyces griseus B-2682. Transcript analysis showed that this is primarily due to differential transcription of the target genes during early development. The targets include proteins relating to nutrient stress and environmental stress and an orthologue of the Bacillus sporulation control protein Spo0M. The enhanced expression of these proteins underlines the stress that is generated by the absence of A-factor. Wild-type developmental gene expression was restored to the A-factor non-producing mutant by the signaling protein Factor C in line with our earlier observation that Factor C triggers A-factor production.

  8. Opportunities and limitations related to the application of plant-derived lipid molecular proxies in soil science

    Directory of Open Access Journals (Sweden)

    B. Jansen

    2017-11-01

    Full Text Available The application of lipids in soils as molecular proxies, also often referred to as biomarkers, has dramatically increased in the last decades. Applications range from inferring changes in past vegetation composition, climate, and/or human presence to unraveling the input and turnover of soil organic matter (SOM. The molecules used are extractable and non-extractable lipids, including ester-bound lipids. In addition, the carbon or hydrogen isotopic composition of such molecules is used. While holding great promise, the application of soil lipids as molecular proxies comes with several constraining factors, the most important of which are (i variability in the molecular composition of plant-derived organic matter both internally and between individual plants, (ii variability in (the relative contribution of input pathways into the soil, and (iii the transformation and/or (selective degradation of (some of the molecules once present in the soil. Unfortunately, the information about such constraining factors and their impact on the applicability of molecular proxies is fragmented and scattered. The purpose of this study is to provide a critical review of the current state of knowledge with respect to the applicability of molecular proxies in soil science, specifically focusing on the factors constraining such applicability. Variability in genetic, ontogenetic, and environmental factors influences plant n-alkane patterns in such a way that no unique compounds or specific molecular proxies pointing to, for example, plant community differences or environmental influences, exist. Other components, such as n-alcohols, n-fatty acids, and cutin- and suberin-derived monomers, have received far less attention in this respect. Furthermore, there is a high diversity of input pathways offering both opportunities and limitations for the use of molecular proxies at the same time. New modeling approaches might offer a possibility to unravel such mixed input

  9. Factors affecting the long-term response of surface waters to acidic deposition: state-of-the-science

    Energy Technology Data Exchange (ETDEWEB)

    Turner, R.S.; Johnson, D.W.; Elwood, J.N.; Van Winkle, W.; Clapp, R.B.; Jones, M.L.; Marmarek, D.R.; Thornton, K.W.; Gherinig, S.A.; Schnoor, J.L.

    1986-01-01

    Recent intensive study of the causes of surface water acidification has led to numerous hypothesized controlling mechanisms. Among these are the salt-effect reduction of alkalinity, the base cation buffering and sulfate adsorption capacities of soils, availability of weatherable minerals (weathering rates), depth of till, micropore flow, and type of forest cover. Correlative and predictive models have been developed to show the relationships (if any) between hypothesized controlling mechanisms and surface water acidity, and to suggest under what conditions additional surface water might become acid. This document (Part A) is a review of our current knowledge of factors and processes controlling soil and surface water acidification, as well as an assessment of the adequacy of that knowledge for making predictions of future acidification. Section 2 is a data extensive, conceptual overview of how watersheds function. Section 3 is a closer look at the theory and evidence for the key hypotheses. Section 4 is a review of existing methods of assessing system response to acidic deposition.

  10. Evidence of rich microbial communities in the subsoil of a boreal acid sulphate soil conducive to greenhouse gas emissions

    Czech Academy of Sciences Publication Activity Database

    Šimek, Miloslav; Virtanen, S.; Krištůfek, Václav; Simojoki, A.; Yli-Halla, M.

    2011-01-01

    Roč. 140, 1-2 (2011), s. 113-122 ISSN 0167-8809 R&D Projects: GA ČR GA526/09/1570; GA MŠk LC06066 Institutional research plan: CEZ:AV0Z60660521 Keywords : acid sulphate soil * microorganisms * carbon Subject RIV: EH - Ecology, Behaviour Impact factor: 3.004, year: 2011

  11. Decay characteristics and erosion-related transport of glyphosate in Chinese loess soil under field conditions

    NARCIS (Netherlands)

    Yang, X.; Wang, Fei; Martins Bento, Celia; Meng, L.; Dam, van R.C.J.; Mol, J.G.J.; Liu, Guobin; Ritsema, C.J.; Geissen, V.

    2015-01-01

    The decay characteristics and erosion-related transport of glyphosate and aminomethylphosphonic acid (AMPA) were monitored for 35 d at different slope gradients and rates of application in plots with loess soil on the Loess Plateau, China. The initial glyphosate decayed rapidly (half-life of 3.5 d)

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

    Directory of Open Access Journals (Sweden)

    Alfred Obia

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

  13. Factors Related to Soil Transmitted Helminth Infection on Primary School Children

    Directory of Open Access Journals (Sweden)

    Liena Sofiana

    2018-01-01

    Full Text Available ABSTRACT Infeksi Soil Transmitted Helminth (STH is the third ranks of the top 10 common infectious diseases in the world with an incidence rate of about 1.4 billion per year. The incidence of STH in Indonesia is still quite high. This figure occurs in primary school students of 60-80%, while for all ages of 40% -60%. The purpose of this study was to determine factors related to STH infection in elementary school children at primary school of Moyudan Sleman. The type of research used was analytic observational with the cross-sectional design. The population in this study were all students of class I, II, and III in Moyudan Sleman primary school with total sampling technique of 60 respondents. Data analysis used chi-square. The test results showed that the habit of hand washing before eating (sig= 0.010; RP= 3.850, the habit of hand washing  after defecating(sig= 0.007; RP= 4.571, nail hygiene (sig= 0.179; RP= 2.138, the habit of wearing footwear (sig= 0.008; RP= 3.714, and bowel habits (sig= 0.004; RP= 4.000. It can be concluded that there was a relationship between hand washing before eating, hand washing after defecating, the habit of wearing footwear, bowel habits and STH infection on the students of Moyudan Sleman primary school but there was no relationship between nail hygiene and STH infection. ABSTRAK Infeksi Soil Transmitted Helminth (STH adalah penyakit yang menempati urutan ketiga dari 10 penyakit menular di dunia dengan tingkat kejadian sekitar 1,4 miliar per tahun. Insiden STH di Indonesia masih cukup tinggi. Angka tersebut terjadi pada siswa di sekolah dasar mencapai 60-80%, sedangkan untuk semua usia berkisar antara 40%-60%. Tujuan dari penelitian ini adalah untuk mengetahui faktor yang berhubungan dengan infeksi STH pada anak sekolah dasar di SD Negeri Moyudan Sleman. Penelitian ini adalah observasional analitik dengan rancangan cross sectional. Populasi dalam penelitian ini adalah semua siswa kelas I, II, dan III di SD Moyudan

  14. Natural radionuclides in soils - relation between soil properties and the activities

    International Nuclear Information System (INIS)

    Fujiyoshi, Ryoko; Nakayama, Masashi; Sawamura, Sadashi

    2000-01-01

    Vertical profiles of natural radionuclides (K-40 and Ra-226) have been investigated in a soil core with 8 m in depth to elucidate its relation to the bed rock activity and to several soil properties. Pattern of the Ra-226 activity with soil depth suggests inhomogeneity of this nuclide during the accumulating process. Radiometric sorption experiments with Pb-210 as a tracer gave the result that almost all Pb(II) in the soil solution disappeared to be sorbed to the soil components

  15. A possible mechanism relating increased soil temperature to forest decline

    International Nuclear Information System (INIS)

    Tomlinson, G.H.

    1993-01-01

    Nutrient cations are removed from the soil by uptake in biomass, and by leaching as a result of soil acidification. Such acidification results from acid deposition and/or from HNO 3 formed by mineralization and nitrification of humus, when at a rate in excess of the tree's nutritional requirements. This has been found to occur during and following periods of increased temperature and reduced rainfall. The cumulative loss of either Ca 2+ , Mg 2+ or K + by one or more of these processes, if greater than the amount released from the specific minerals in that soil, leads to nutrient deficiency, fine root mortality, poor growth, and eventually to die-back. Trees growing in soils derived from specific minerals in which there is a strong imbalance in the elements from which the exchangeable nutrients are formed, are vulnerable to nutrient deficiency. This paper discusses the relevance of earlier studies, when considered in relation to more recent findings. In Hawaii there have been frequent periods of increased temperature and drought resulting from the El Nino Southern Oscillation. This fact, when considered in relation to the relatively low K content, and its imbalance with Ca and Mg in the lava and volcanic ash on which the trees have grown, could result in K deficiency in the declining ohia trees. It is possible that the unusual periods of increased temperature and drought which have occurred in certain other localized areas may have led to the decline symptoms recently observed. In view of the threat of global warming, this possibility should be investigated. 39 refs., 3 figs., 2 tabs

  16. LEACHING AND DEGRADATION OF 2,4-DICHLOROPHENOXIACETIC ACID, IN COLOMBIA RICE FLOODED SOIL.

    Science.gov (United States)

    Huertas, J; Guerrero, J A; Martinez-Cordon, M J

    2015-01-01

    Rice is mostly cultivated on soil held under flooded conditions. Under these conditions pesticides undergo reductive transformations which are characteristic to rice fields and other anaerobic systems. The present study was undertaken to evaluate the mobility and persistence of 2,4-dichlorophenoxy acetic acid (2,4-D) under laboratory conditions for the rice crop in Espinal, Colombia. A displacement study was performed on a hand packed soil column 30 cm length. After leaching experiment, the soil from column was sliced into six successive sections (5 cm). Methanol acidified (H3PO4 0.25%) extraction was used to determine the herbicide residues in each section. 2,4-D experimental breakthrough curve was analyzed using Stanmod program (inverse problem) to obtain transport parameters. The non-equilibrium physical model fitted well the experimental breakthrough curve. The recovery percent of 2,4-D in leachates was 36.44% after 3.4 pore volumes, and retardation factor was 2.1, indicating low adsorption in that conditions. 2,4-D was rapidly degraded, with DT50 = 11.4 days. The results suggest that 2,4-D under flooded conditions have a high potential for leaching through the soil profile, although the elevated rate of degradation reduced the ground water contamination risk.

  17. Soil-to-plant concentration factors for radiological assessments

    International Nuclear Information System (INIS)

    Ng, Y.C.; Thompson, S.E.; Colsher, C.S.

    1982-09-01

    This report presents the results of a literature review to derive soil-to-plant concentration factors to predict the concentration of a radionuclide in plants from that in soil. The concentration factor, B/sub v/ is defined as the ratio of the concentration of a nuclide in the edible plant part to that in dry soil. CR (the concentration ratio) is similarly defined to denote the concentration factor for dry feed consumed by livestock. B/sub v/ and CR values are used to assess the dose from radionuclides deposited onto soil and transferred into crop plants via roots. Approaches for deriving B/sub v/ and CR values are described, and values for food and feed are tabulated for individual elements. The sources of uncertainty are described, and the factors that contribute to the inherent variability of the B/sub v/ and CR values are discussed. Summary tables of elemental B/sub v/ and CR values and statistical parameters that characterize their distributions provide a basis for a systematic updating of many of the B/sub v/ values in Regulatory Guide 1.109. They also provide a basis for selecting B/sub v/ and CR values for other applications that involve the use of equilibrium models to predict the concentration of radionuclides in plants from that in soil

  18. [Variation characteristics of farmland soil pH in the past 30 years of Enshi Autonomous Prefecture, Hubei, China].

    Science.gov (United States)

    Hu, Min; Xiang, Yong Sheng; Zhang, Zhi; Cong, Ri Huan; Huang, Fei Yue; Zhang, Jun Qiang; Shang, Li Li; Lu, Jian Wei

    2017-04-18

    In order to explore temporal-spatial variability of farmland soil pH at Enshi Antonomous Prefecture, Hubei, China, soil pH during the past three decades was analyzed, using the datasets of the Second National Soil Survey (1980-1983) and the Cultivated Land Quality Evaluation (2010-2013). The natural and human factors inducing the change of soil pH were evaluated to provide theoretical guidance for further soil acidification management. Results showed that acidic soil (i.e., pH<6.5) and neutral and alkaline soil (i.e., pH 6.5-8.5) were accounted for 98.4% and 1.6% in the farmland during the period of 2010-2013, respectively. The ratio increased 61.4% for the acidic soil but decreased 61.2% for the neutral and alkaline soil as compared with the period of 1980-1983. In addition, there was no alkaline soil (pH>8.5) in the region in 2010-2013. According to the dataset of the Second National Soil Survey (1980-1983), acidic soil was mainly distributed at Laifeng, Lichuan, Xuanen and Xianfeng counties, with the area ratio of 74.4%, 63.5%, 61.3% and 60.7%, respectively. For the period of 2010-2013, the ratio of acidic soil enhanced widely which was above 96% for each county. At Enshi Autonomous Prefecture, farmland soil showed an obvious acidification trend during the past three decades, with spatial variation of higher in the eastern part and lower in the western part of the region. Furthermore, soil pH decline occurred among different land use types in different areas. Overall, farmland soil pH declined 0.90 on average, with 1.14 decrease for upland and 0.87 for paddy soil, respectively. Clearly, upland soil acidification was severe than paddy soil. Factors related to soil acidification in the Enshi Autonomous Prefecture were mainly human factors such as unreasonable fertilizer combination, fertilizer ratio change, and more base cations taking away by high crop yield.

  19. Soil Burial of Polylactic Acid/Paddy Straw Powder Biocomposite

    Directory of Open Access Journals (Sweden)

    Noorulnajwa Diyana Yaacob

    2015-12-01

    Full Text Available The objective of this work was to study the biodegradability of polylactic acid (PLA/paddy straw powder (PSP biocomposites. Environmental degradation was evaluated by composting the biocomposite samples into the soil. Different techniques, including mechanical tests and scanning electron microscopy (SEM, were used to obtain a view of the degradation that occurred during the soil burial of the biocomposites. Results of the mechanical tests showed that an increasing content of PSP in the biocomposites decreased the tensile strength and elongation at break (EB, while it increased the modulus of elasticity after six months of exposure. Scanning electron microscopy on the surface after soil burial showed that the filler was poorly wetted by the matrix. This explains the reduction in tensile strength and the elongation at break after soil burial. Differential scanning calorimetry results indicated that the crystallinity of the biocomposites increased with longer composting periods.

  20. Recycling stabilised/solidified drill cuttings for forage production in acidic soils.

    Science.gov (United States)

    Kogbara, Reginald B; Dumkhana, Bernard B; Ayotamuno, Josiah M; Okparanma, Reuben N

    2017-10-01

    Stabilisation/solidification (S/S), which involves fixation and immobilisation of contaminants using cementitious materials, is one method of treating drill cuttings before final fate. This work considers reuse of stabilised/solidified drill cuttings for forage production in acidic soils. It sought to improve the sustainability of S/S technique through supplementation with the phytoremediation potential of plants, eliminate the need for landfill disposal and reduce soil acidity for better plant growth. Drill cuttings with an initial total petroleum hydrocarbon (TPH) concentration of 17,125 mg kg -1 and low concentrations of metals were treated with 5%, 10%, and 20% cement dosages. The treated drill cuttings were reused in granular form for growing a forage, elephant grass (Pennisetum purpureum), after mixing with uncontaminated soil. The grasses were also grown in uncontaminated soil. The phytoremediation and growth potential of the plants was assessed over a 12-week period. A mix ratio of one part drill cuttings to three parts uncontaminated soil was required for active plant growth. The phytoremediation ability of elephant grass (alongside abiotic losses) reduced the TPH level (up to 8795 mg kg -1 ) in the soil-treated-drill cuttings mixtures below regulatory (1000 mg kg -1 ) levels. There were also decreased concentrations of metals. The grass showed better heights and leaf lengths in soil containing drill cuttings treated with 5% cement dosage than in uncontaminated soil. The results suggest that recycling S/S treated drill cuttings for forage production may be a potential end use of the treated waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Amelioration of acidic soil increases the toxicity of the weak base carbendazim to the earthworm Eisenia fetida.

    Science.gov (United States)

    Liu, Kailin; Wang, Shaoyun; Luo, Kun; Liu, Xiangying; Yu, Yunlong

    2013-12-01

    Ameliorating acidic soils is a common practice and may affect the bioavailability of an ionizable organic pollutant to organisms. The toxicity of the weak base carbendazim to the earthworm (Eisenia fetida) was studied in an acidic soil (pH-H₂O, 4.6) and in the ameliorated soil (pH-H₂O, 7.5). The results indicated that the median lethal concentration of carbendazim for E. fetida decreased from 21.8 mg/kg in acidic soil to 7.35 mg/kg in the ameliorated soil. To understand why the amelioration increased carbendazim toxicity to the earthworm, the authors measured the carbendazim concentrations in the soil porewater. The authors found increased carbendazim concentrations in porewater, resulting in increased toxicity of carbendazim to earthworms. The increased pore concentrations result from decreased adsorption because of the effects of pH and calcium ions. © 2013 SETAC.

  2. Comparison of methods for the determination of reduced inorganic sulphur in acid sulphate soils

    International Nuclear Information System (INIS)

    Santomartino, S.L.

    1999-01-01

    Full text: The management of acid sulphate soils requires analytical methods that provide accurate data on the quantity of reduced inorganic sulphur within a soil, as it is this fraction that produces acid upon oxidation. This study uses sulphidic Coode Island Silt samples to compare common analytical methods including POCAS (Peroxide Oxidation-Combined Acidity and Sulphate) which consists of TSA (Total Sulphidic Acidity), S pos (Peroxide Oxidisable Sulphur), TOS (Total Oxidisable Sulphur) and chromium-reducible sulphur. The determination of total sulphur by Leco sulphur is strongly correlated with, but slightly less than, that analysed by XRF. Comparison of soil sulphide content by chromium-reducible sulphur, TSA and TOS methods indicates that TOS values are substantially higher than both other methods. The problem with the TOS method lies in the sulphate extraction procedure. Hot distilled water and HCI are commonly used as extractants, however hot distilled water fails to remove organic sulphur, thereby overestimating the sulphide content of the soil. Leco carbon analyses verify that a substantial proportion of organic matter exists within the samples. The HCI extraction process, which uses Ion Chromatography to analyse for sulphate, produces highly inaccurate results due to the interference of the sulphate peak by the chloride peak during analysis. An alternative method involving HCI extraction and XRF analysis of the soil residue is currently being undertaken. The use of KCI to extract sulphate generally produces values similar to the hot distilled water method. The sulphidic content measured by TSA is strongly correlated with, but slightly higher than that determined by the chromium-reducible sulphur method. This is attributed to the use of hydrogen peroxide in the TSA method, which oxidises organic matter to organic acids in addition to oxidising sulphides. These preliminary findings indicate that the chromium-reducible sulphur method is the most suitable

  3. Modification of degradation-resistant soil organic matter by soil saprobic microfungi

    Czech Academy of Sciences Publication Activity Database

    Řezáčová, Veronika; Hršelová, Hana; Gryndlerová, Hana; Mikšík, Ivan; Gryndler, Milan

    2006-01-01

    Roč. 38, - (2006), s. 2292-2299 ISSN 0038-0717 R&D Projects: GA ČR GA526/03/0188 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z50110509 Keywords : soil microfungi * fulvic acid * humic acid Subject RIV: EE - Microbiology, Virology Impact factor: 2.623, year: 2006

  4. Biochar Application in Malaysian Sandy and Acid Sulfate Soils: Soil Amelioration Effects and Improved Crop Production over Two Cropping Seasons

    Directory of Open Access Journals (Sweden)

    Theeba Manickam

    2015-12-01

    Full Text Available The use of biochar as an agricultural soil improvement was tested in acid sulfate and sandy soils from Malaysia, cropped with rice and corn. Malaysia has an abundance of waste rice husks that could be used to produce biochar. Rice husk biochar was produced in a gasifier at a local mill in Kelantan as well as in the laboratory using a controlled, specially designed, top lift up draft system (Belonio unit. Rice husk biochar was applied once to both soils at two doses (2% and 5%, in a pot set up that was carried out for two cropping seasons. Positive and significant crop yield effects were observed for both soils, biochars and crops. The yield effects varied with biochar type and dosage, with soil type and over the cropping seasons. The yield increases observed for the sandy soil were tentatively attributed to significant increases in plant-available water contents (from 4%–5% to 7%–8%. The yield effects in the acid sulfate soil were likely a consequence of a combination of (i alleviation of plant root stress by aluminum (Ca/Al molar ratios significantly increased, from around 1 to 3–5 and (ii increases in CEC. The agricultural benefits of rice husk biochar application to Malaysian soils holds promise for its future use.

  5. Soil Response to Global Change: Soil Process Domains and Pedogenic Thresholds (Invited)

    Science.gov (United States)

    Chadwick, O.; Kramer, M. G.; Chorover, J.

    2013-12-01

    The capacity of soil to withstand perturbations, whether driven by climate, land use change, or spread of invasive species, depends on its chemical composition and physical state. The dynamic interplay between stable, well buffered soil process domains and thresholds in soil state and function is a strong determinant of soil response to forcing from global change. In terrestrial ecosystems, edaphic responses are often mediated by availability of water and its flux into and through soils. Water influences soil processes in several ways: it supports biological production, hence proton-donor, electron-donor and complexing-ligand production; it determines the advective removal of dissolution products, and it can promote anoxia that leads microorganisms to utilize alternative electron acceptors. As a consequence climate patterns strongly influence global distribution of soil, although within region variability is governed by other factors such as landscape age, parent material and human land use. By contrast, soil properties can vary greatly among climate regions, variation which is guided by the functioning of a suite of chemical processes that tend to maintain chemical status quo. This soil 'buffering' involves acid-base reactions as minerals weather and oxidation-reduction reactions that are driven by microbial respiration. At the planetary scale, soil pH provides a reasonable indicator of process domains and varies from about 3.5 to10, globally, although most soils lie between about 4.5 and 8.5. Those that are above 7.5 are strongly buffered by the carbonate system, those that are characterized by neutral pH (7.5-6) are buffered by release of non-hydrolyzing cations from primary minerals and colloid surfaces, and those that are buffered by hydrolytic aluminum on colloidal surfaces. Alkali and alkaline (with the exception of limestone parent material) soils are usually associated with arid and semiarid conditions, neutral pH soils with young soils in both dry and wet

  6. Improving phosphorus availability in an acid soil using organic amendments produced from agroindustrial wastes.

    Science.gov (United States)

    Ch'ng, Huck Ywih; Ahmed, Osumanu Haruna; Majid, Nik Muhamad Ab

    2014-01-01

    In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments.

  7. Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes

    Directory of Open Access Journals (Sweden)

    Huck Ywih Ch’ng

    2014-01-01

    Full Text Available In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp. to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus, and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments.

  8. A New European Slope Length and Steepness Factor (LS-Factor for Modeling Soil Erosion by Water

    Directory of Open Access Journals (Sweden)

    Panos Panagos

    2015-04-01

    Full Text Available The Universal Soil Loss Equation (USLE model is the most frequently used model for soil erosion risk estimation. Among the six input layers, the combined slope length and slope angle (LS-factor has the greatest influence on soil loss at the European scale. The S-factor measures the effect of slope steepness, and the L-factor defines the impact of slope length. The combined LS-factor describes the effect of topography on soil erosion. The European Soil Data Centre (ESDAC developed a new pan-European high-resolution soil erosion assessment to achieve a better understanding of the spatial and temporal patterns of soil erosion in Europe. The LS-calculation was performed using the original equation proposed by Desmet and Govers (1996 and implemented using the System for Automated Geoscientific Analyses (SAGA, which incorporates a multiple flow algorithm and contributes to a precise estimation of flow accumulation. The LS-factor dataset was calculated using a high-resolution (25 m Digital Elevation Model (DEM for the whole European Union, resulting in an improved delineation of areas at risk of soil erosion as compared to lower-resolution datasets. This combined approach of using GIS software tools with high-resolution DEMs has been successfully applied in regional assessments in the past, and is now being applied for first time at the European scale.

  9. Soil water status under perennial and annual pastures on an acid duplex soil

    International Nuclear Information System (INIS)

    Heng, L.K.; White, R.E.; Chen, D.

    2000-01-01

    A comprehensive field study of soil water balance, nitrogen (N) cycling, pasture management and animal production was carried out on an acid duplex soil at Book Book near Wagga Wagga in southern New South Wales. The experiment, carried out over a 3-year period, tested the hypothesis that sown perennial grass pastures improve the sustainability of a grazing system through better use of water and N. The treatments were: annual pastures without lime (AP-), annual pastures with lime (AP+), perennial pastures without lime (PP-) and perennial pastures with lime (PP+). Soil water measurement was made using a neutron probe on one set of the treatments comprising four adjacent paddocks. Over three winter and spring periods, the results showed that perennial grass pastures, especially PP+, consistently extracted about 40 mm more soil water each year than did the annual grass pastures. As a result, surface runoff, sub-surface flow and deep drainage (percolation below 180 cm depth) were about 40 mm less from the perennial pastures. The soil water status of the four pasture treatments was simulated reasonably well using a simple soil water model. Together with the long-term simulation of deep drainage, using past meteorological records, it is shown that proper management of perennial pastures can reduce recharge to groundwater and make pastoral systems more sustainable in the high rainfall zone. However, to completely reduce recharge, more-deeply rooted plants or trees are needed. (author)

  10. Titanium Mass-balance Analysis of Paso Robles Soils: Elemental Gains and Losses as Affected by Acid Alteration Fluids

    Science.gov (United States)

    Sutter, Brad; Ming, Douglas W.

    2010-01-01

    The Columbia Hills soils have been exposed to aqueous alteration in alkaline [1] as well as acid conditions [2,3]. The Paso Robles class soils are bright soils that possess the highest S concentration of any soil measured on Mars [2]. Ferric-sulfate detection by Moessbauer analysis indicated that acid solutions were involved in forming these soils [4]. These soils are proposed to have formed by alteration of nearby rock by volcanic hydrothermal or fumarolic activity. The Paso Robles soils consist of the original Paso Robles-disturbed-Pasadena (PR-dist), Paso Robles- PasoLight (PR-PL), Arad-Samra, Arad-Hula, Tyrone- Berker Island1 and Tyrone-MountDarwin [2 ,3. ]Chemical characteristics indicate that the PR-dist and PR-PL soils could be derived from acid weathering of local Wishstone rocks while the Samra and Hula soils are likely derived from local Algonquin-Iroquet rock [3]. The Paso Robles soils were exposed to acidic sulfur bearing fluids; however, little else is known about the chemistry of the alteration fluid and its effects on the alteration of the proposed parent materials. The objectives of this work are to conduct titanium normalized mass-balance analysis to1) assess elemental gains and losses from the parent materials in the formation of the Paso Robles soils and 2) utilize this information to indicate the chemical nature of the alteration fluids.

  11. Diphenylarsinic acid contaminated soil remediation by titanium dioxide (P25) photocatalysis: Degradation pathway, optimization of operating parameters and effects of soil properties

    International Nuclear Information System (INIS)

    Wang, A-nan; Teng, Ying; Hu, Xue-feng; Wu, Long-hua; Huang, Yu-juan; Luo, Yong-ming; Christie, Peter

    2016-01-01

    Diphenylarsinic acid (DPAA) is formed during the leakage of arsenic chemical weapons in sites and poses a high risk to biota. However, remediation methods for DPAA contaminated soils are rare. Here, the photocatalytic oxidation (PCO) process by nano-sized titanium dioxide (TiO_2) was applied to degrade DPAA in soil. The degradation pathway was firstly studied, and arsenate was identified as the final product. Then, an orthogonal array experimental design of L_9(3)"4, only 9 experiments were needed, instead of 81 experiments in a conventional one-factor-at-a-time, was used to optimize the operational parameters soil:water ratio, TiO_2 dosage, irradiation time and light intensity to increase DPAA removal efficiency. Soil:water ratio was found to have a more significant effect on DPAA removal efficiency than other properties. The optimum conditions to treat 4 g soil with a DPAA concentration of 20 mg kg"−"1 were found to be a 1:10 soil: water ratio, 40 mW cm"−"2 light intensity, 5% TiO_2 in soil, and a 3-hour irradiation time, with a removal efficiency of up to 82.7%. Furthermore, this method (except for a change in irradiation time from 3 to 1.5 h) was validated in nine different soils and the removal efficiencies ranged from 57.0 to 78.6%. Removal efficiencies were found to be negatively correlated with soil electrical conductivity, organic matter content, pH and total phosphorus content. Finally, coupled with electron spin resonance (ESR) measurement, these soil properties affected the generation of OH• by TiO_2 in soil slurry. This study suggests that TiO_2 photocatalytic oxidation is a promising treatment for removing DPAA from soil. - Highlights: • DPAA was degraded into arsenate through TiO_2 (P25) photocatalytic oxidation. • Soil/water ratio was more influential on the removal of DPAA in soil by TiO_2 (P25). • Soil properties affected the adsorption of DPAA and the generation of OH• by TiO_2.

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

    Science.gov (United States)

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. The microbial communities and potential greenhouse gas production in boreal acid sulphate, non-acid sulphate, and reedy sulphidic soils.

    Science.gov (United States)

    Šimek, Miloslav; Virtanen, Seija; Simojoki, Asko; Chroňáková, Alica; Elhottová, Dana; Krištůfek, Václav; Yli-Halla, Markku

    2014-01-01

    Acid sulphate (AS) soils along the Baltic coasts contain significant amounts of organic carbon and nitrogen in their subsoils. The abundance, composition, and activity of microbial communities throughout the AS soil profile were analysed. The data from a drained AS soil were compared with those from a drained non-AS soil and a pristine wetland soil from the same region. Moreover, the potential production of methane, carbon dioxide, and nitrous oxide from the soils was determined under laboratory conditions. Direct microscopic counting, glucose-induced respiration (GIR), whole cell hybridisation, and extended phospholipid fatty acid (PLFA) analysis confirmed the presence of abundant microbial communities in the topsoil and also in the deepest Cg2 horizon of the AS soil. The patterns of microbial counts, biomass and activity in the profile of the AS soil and partly also in the non-AS soil therefore differed from the general tendency of gradual decreases in soil profiles. High respiration in the deepest Cg2 horizon of the AS soil (5.66 μg Cg(-1)h(-1), as compared to 2.71 μg Cg(-1)h(-1) in a top Ap horizon) is unusual but reasonable given the large amount of organic carbon in this horizon. Nitrous oxide production peaked in the BCgc horizon of the AS and in the BC horizon of the non-AS soil, but the peak value was ten-fold higher in the AS soil than in the non-AS soil (82.3 vs. 8.6 ng Ng(-1)d(-1)). The data suggest that boreal AS soils on the Baltic coast contain high microbial abundance and activity. This, together with the abundant carbon and total and mineral nitrogen in the deep layers of AS soils, may result in substantial gas production. Consequently, high GHG emissions could occur, for example, when the generally high water table is lowered because of arable farming. © 2013.

  14. Influence of the Amino Acid Sequence on Protein-Mineral Interactions in Soil

    Science.gov (United States)

    Chacon, S. S.; Reardon, P. N.; Purvine, S.; Lipton, M. S.; Washton, N.; Kleber, M.

    2017-12-01

    The intimate associations between protein and mineral surfaces have profound impacts on nutrient cycling in soil. Proteins are an important source of organic C and N, and a subset of proteins, extracellular enzymes (EE), can catalyze the depolymerization of soil organic matter (SOM). Our goal was to determine how variation in the amino acid sequence could influence a protein's susceptibility to become chemically altered by mineral surfaces to infer the fate of adsorbed EE function in soil. We hypothesized that (1) addition of charged amino acids would enhance the adsorption onto oppositely charged mineral surfaces (2) addition of aromatic amino acids would increase adsorption onto zero charged surfaces (3) Increase adsorption of modified proteins would enhance their susceptibility to alterations by redox active minerals. To test these hypotheses, we generated three engineered proxies of a model protein Gb1 (IEP 4.0, 6.2 kDA) by inserting either negatively charged, positively charged or aromatic amino acids in the second loop. These modified proteins were allowed to interact with functionally different mineral surfaces (goethite, montmorillonite, kaolinite and birnessite) at pH 5 and 7. We used LC-MS/MS and solution-state Heteronuclear Single Quantum Coherence Spectroscopy NMR to observe modifications on engineered proteins as a consequence to mineral interactions. Preliminary results indicate that addition of any amino acids to a protein increase its susceptibility to fragmentation and oxidation by redox active mineral surfaces, and alter adsorption to the other mineral surfaces. This suggest that not all mineral surfaces in soil may act as sorbents for EEs and chemical modification of their structure should also be considered as an explanation for decrease in EE activity. Fragmentation of proteins by minerals can bypass the need to produce proteases, but microbial acquisition of other nutrients that require enzymes such as cellulases, ligninases or phosphatases

  15. Preparative yield and properties of humic acids obtained by sequential alkaline extractions

    Science.gov (United States)

    Kholodov, V. A.; Yaroslavtseva, N. V.; Konstantinov, A. I.; Perminova, I. V.

    2015-10-01

    The preparative yield, composition, and structure of humic acids obtained by sequential alkaline extractions from two soils (a soddy-podzolic soil under forest and a typical chernozem in treatment with permanent black fallow of a long-term experiment since 1964) have been studied. The preparative yield of humic acids from the first extraction is 0.40 and 0.94% for the soddy-podzolic soil (Retisols) and the chernozem, respectively. The preparative yield from the second extraction is lower by several times, and the yield from the third extraction is lower by an order of magnitude. The study of the obtained preparations by elemental analysis, gel-permeation chromatography, and 13C NMR spectroscopy has shown insignificant changes in the elemental, molecular-weight, and structural-group composition of humic acids among the extractions. It has been supposed that this is related to the soil features: typical climatic factors for the formation of soil subtype in the case of soddy-podzolic soil and the land use in the long-term experiment in the case of typical chernozem. It has been concluded that that a single extraction is sufficient for the separation of humic acids and the preparation of a representative sample.

  16. Elevated uric acid and obesity-related cardiovascular disease risk factors among hypertensive youth.

    Science.gov (United States)

    Reschke, Lauren D; Miller, Edgar R; Fadrowski, Jeffrey J; Loeffler, Lauren F; Holmes, Kathryn W; Appel, Lawrence J; Brady, Tammy M

    2015-12-01

    Uric acid (UA) is associated with high blood pressure in adolescents and with left ventricular hypertrophy (LVH) and cardiovascular disease (CVD) in adults. We sought to determine if UA is independently associated with CVD risk factors and left ventricular mass (LVM) over time in hypertensive youth. This was a 1-year prospective observational study of hypertensive children aged 3-19 years. Cross-sectional and longitudinal associations of serum UA with CVD risk factors and LVM were explored. Of the 49 children who completed both the baseline and 12-month assessments, at baseline the mean age was 13.8 years and mean UA was 5.5 mg/dL; 24% had elevated UA, 51% were overweight/obese and 39% had LVH. Measures of adiposity, low high-density lipoprotein cholesterol, high-sensitivity C-reactive protein, LVM and LVH were all significantly associated with elevated UA at baseline, but not with change over time. Each 1 mg/dL increase in baseline UA was associated with a 2.5 g/m(2.7) increase in the LVM index at follow-up (95% confidence interval 0.64, 4.39; p = 0.01); after adjustment for age, sex, race, body mass index z-score, change in UA, time, blood pressure and medication use, this association was no longer significant. Hypertensive children with elevated UA have a higher prevalence of obesity-related CVD risk factors. Among hypertensive children, UA may be a marker of adiposity and not an independent CVD risk factor.

  17. Al-Fe interactions and growth enhancement in Melastoma malabathricum and Miscanthus sinensis dominating acid sulphate soils.

    Science.gov (United States)

    Watanabe, Toshihiro; Jansen, Steven; Osaki, Mitsuru

    2006-12-01

    Plants growing in acid sulphate soils are subject to high levels of Al availability, which may have effects on the growth and distribution of these species. Although Fe availability is also high in acid sulphate soils, little is known about the effect of Fe on the growth of native plants in these soils. Two species dominating this soil type in Asia, viz. Melastoma malabathricum and Miscanthus sinensis were grown hydroponically in a nutrient solution with different concentrations of Al and Fe. Melastoma malabathricum is found to be sensitive to Fe (40 and 100 microm). Application of 500 microm Al, however, completely ameliorates Fe toxicity and is associated with a decrease of Fe concentration in shoots and roots. The primary reason for the Al-induced growth enhancement of M. malabathricum is considered to be the Al-induced reduction of toxic Fe accumulation in roots and shoots. Therefore, Al is nearly essential for M. malabathricum when growing in acid sulphate soils. In contrast, application of both Fe and Al does not reduce the growth of M. sinensis, and Al application does not result in lower shoot concentrations of Fe, suggesting that this grass species has developed different mechanisms for adaptation to acid sulphate soils.

  18. A Study on the Removal of Cesium in Soil Contaminated with Radiation Using a Soil Washing Process

    International Nuclear Information System (INIS)

    Park, Ukryang; Kim, Gyenam; Kim, Seungsoo; Park, Hyemin; Kim, Wansuk; Moon, Jaikwon

    2013-01-01

    The first principle is related with the washing process which is carried out to transfer the contaminated mass from the soil to water by dissolving it with a cleansing solution. The second is concerned with the size of the separation process which focuses on the reduction of the volume by separating the subject matters based on the different sizes of the soil. The complex agents used in the soil washing process include HCl, Oxalic acid, Citric acid, CaCl 2 , BaCl 2 , NH 4 NO 3 , and NaOH. It is known that the complex-forming capacity of such complex agents and radionuclides influences the decontamination from the soil. Also, since the forms of the chemical species related with the complex agents and the surface potential of the soil vary based on the changes of acidity observed in the cleansing solution, the level of acidity in the cleansing solution can be regarded as a factor that influences the decontamination. Therefore, in this study, H 2 SO 4 was selected as the complex agent and used to check the influence of the temperature when the subject contaminated soil was washed. Then, by applying the sieve grading process with a sieve-shaker, the size separation process was carried out to measure the level of radiation for each size. By washing the contaminated soil separated into different sizes with the complex agent H 2 SO 4 , the different removal tendencies for each size were considered. After selecting the complex agent H 2 SO 4 and checking the influence of temperature when the contaminated soil was washed based on the solid-liquid ratio of 1g:2ml, it was found that the heat washing process at a temperature of 95 .deg. C showed a higher level of efficiency for the removal of Cs compared to the case of the non-heat washing process. Also, according to the results given by the process of considering the different removal tendencies for each size based on the heat washing process after the sieve grading process was applied with the sieve-shaker prior for the size

  19. Environment and geographic distance differ in relative importance for determining fungal community of rhizosphere and bulk soil.

    Science.gov (United States)

    Zhang, Kaoping; Adams, Jonathan M; Shi, Yu; Yang, Teng; Sun, Ruibo; He, Dan; Ni, Yingying; Chu, Haiyan

    2017-09-01

    Rhizospheric fungi play major roles in both natural and agricultural ecosystems. However, little is known about the determinants of their diversity and biogeographic patterns. Here, we compared fungal communities in rhizosphere and bulk soils of wheat fields in the North China Plain. The rhizosphere had a lower fungal diversity (observed OTUs and Chao1) than bulk soil, and a distinct fungal community structure in rhizosphere compared with bulk soil. The relative importance of environmental factors and geographic distance for fungal distribution differed between rhizosphere and bulk soil. Environmental factors were the primary cause of variations in total fungal community and major fungal phyla in bulk soil. By contrast, fungal communities in soils loosely attached to roots were predictable from both environmental factors and influences of geographic distance. Communities in soils tightly attached to roots were mainly determined by geographic distance. Our results suggest that both contemporary environment processes (present-day abiotic and biotic environment characters) and historical processes (spatial isolation, dispersal limitation occurred in the past) dominate variations of fungal communities in wheat fields, but their relative importance of all these processes depends on the proximity of fungal community to the plant roots. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Some geomedical problems in relation to soil science

    International Nuclear Information System (INIS)

    Laag, J.

    1988-01-01

    Geomedicine may be defined as the science dealing with the influence of ordinary environmental factors on geographical distribution of health problems in man and animals. An important group of geomedical problems is connected to nutrition. These problems may either be caused by deficiency or surplus of certain matters. Many questions concerning the pollution of nature are classified under the latter group Radioactive pollutants are regarded as important special occurrences under this group. In order to be able to solve complicated geomedical problems, knowledge is needed on the circulation processes rocks-soils-water-plants-animals-man, and waste products back to the soils. The registration of locations of different radioactive elements can give basic material for special geomedical conclusions. Many chemical reactions in which radioactive matter are involved, depend on properties of the soils. Humus and clay minerals have, generally speaking, a high capacity for the absorbtion of soluble matter, but great variations occur. The reactions of radioactive isotopes supplied from the atmosphere, depend on properties of the soil. Radioactive substances are leached relatively rapidly from a soil with low absorption capacity, and may thus be taken away from the circulation in which terrestrial plants, animals and man take part. If the substances is strongly absorbed (fixed), they can also to some extent be withdrawn from the circulation processes

  1. Handbook of methods for acid-deposition studies. Laboratory analyses for soil chemistry

    International Nuclear Information System (INIS)

    Blume, L.J.; Schumacher, P.W.; Schaffer, K.A.; Cappo, K.A.; Papp, M.L.

    1990-09-01

    The handbook describes methods used to process and analyze soil samples. It is intended as a guidance document for groups involved in acid deposition monitoring activities similar to those implemented by the Aquatic Effects Research Program of the National Acid Precipitation Assessment Program. These methods were developed for use in the Direct/Delayed Response Project, a component project of the Aquatic Effects Research Program within the Office of Ecological Processes and Effects Research. The program addresses the following issues relating to the effects of acid deposition on aquatic ecosystems: The extent and magnitude of past change; The change to be expected in the future under various deposition scenarios; The maximum rates of deposition below which further change is not expected; and The rate of change or recovery of aquatic ecosystems if deposition rates are decreased. Chemical and physical parameters were measured during the Direct/Delayed Response Project and are described in the document

  2. Root exudate as major player on soil-water retention dynamics

    Science.gov (United States)

    Albalasmeh, A. A.; Sweet, J. R.; Gebrenegus, T. B.; Ghezzehei, T. A.

    2012-12-01

    Plant roots and soil microbes release 5-60% of the entirety of photosynthetically fixed carbon in to the soil as exudates to adapt to their surrounding. There is indirect evidence suggesting that these exudates play a major role in altering the of the soil water retention properties. In this study, we used a uniformly sized (40 μm) glass beads and various concentrations (0, 2, 10, 20 and 29 g/L) of polygalacutronic acid (PGA) to mimic sandy soil and the organic exudates from plant roots, respectively. The samples were subjected to periods of drying and subsequent equilibration. At each stage, the water potential was measured using WP4C Dewpoint PotentiaMeter. The effect of root exudates on soil water retention can be attributed t at least two factors. The most widely speculated effect is through enhanced of soil aggregation. This effect is primarily due to capillary adhesion in fine pores within aggregates and is consistent was visual observation of pronounced aggregation in many rhizosphere soils. The second factor is related to osmotic effect of the exudate solution. Our observations show that the capillary effect is mostly to higher water potential regime (> -1 bar suction). Whereas the osmotic effect dominates in plant-soil relations.

  3. Elucidating key factors affecting radionuclide aging in soils

    Energy Technology Data Exchange (ETDEWEB)

    Roig, M. [Universitat Politecnica Catalunya, Institut de Tecniques Energetiques, Barcelona (Spain); Rigola, A.; Vidal, M.; Rauret, G. [Barcelona Univ., Dept. de Quimica Analitica (Spain)

    2004-07-01

    Mechanistic studies allow at present to describe the processes governing the short-term interaction of radiostrontium and radiocaesium in soils. The initial sorption step can be described through the estimation of the soil-soil solution distribution coefficient from soil parameters, as cationic exchange capacity, radiocaesium interception potential and concentration of competing ions in the soil solution. After the initial soil-radionuclide interaction, a fraction of radionuclide is no longer available for exchange with the solution, and it remains fixed in the solid fraction. At present, the initial fixed fraction of a radionuclide in a given soil cannot be predicted from soil properties. Besides, little is known about soil and environmental factors (e.g., temperature; hydric regime) provoking the increase in the fixed fraction with time, the so-called aging process. This process is considered to control the reduction of food contamination with time at contaminated scenarios. Therefore, it is crucial to be able to predict the radionuclide aging in the medium and long term for a better risk assessment, especially when a decision has to be made between relying on natural attenuation versus implementing intervention actions. Here we study radiostrontium and radiocaesium aging in a set of soils, covering a wide range of soil types of contrasting properties (e.g., loamy calcareous; podzol; chernozem, organic). Three factors are separately and simultaneously tested: time elapsed since contamination, temperature and hydric regime. Changes in the radionuclide fixed fraction are estimated with a leaching test based on the use of a mild extractant solution. In addition to this, secondary effects on the radiocaesium interception potential in various soils are also considered. (author)

  4. Soil washing of chromium- and cadmium-contaminated sludge using acids and ethylenediaminetetra acetic acid chelating agent.

    Science.gov (United States)

    Gitipour, Saeid; Ahmadi, Soheil; Madadian, Edris; Ardestani, Mojtaba

    2016-01-01

    In this research, the effect of soil washing in the removal of chromium- and cadmium-contaminated sludge samples collected from Pond 2 of the Tehran Oil Refinery was investigated. These metals are considered as hazardous substances for human health and the environment. The carcinogenicity of chromate dust has been established for a long time. Cadmium is also a potential environmental toxicant. This study was carried out by collecting sludge samples from different locations in Pond 2. Soil washing was conducted to treat the samples. Chemical agents, such as acetic acid, ethylenediaminetetra acetic acid (EDTA) and hydrochloric acid, were used as washing solutions to remove chromium and cadmium from sludge samples. The results of this study indicated that the highest removal efficiencies from the sludge samples were achieved using a 0.3 M HCl solution with 82.69% and 74.47% for chromium and cadmium, respectively. EDTA (0.1 M) in the best condition extracted 66.81% of cadmium and 72.52% of chromium from the sludges. The lowest efficiency values for the samples, however, were achieved using 3 M acetic acid with 41.7% and 46.96% removals for cadmium and chromium, respectively. The analysis of washed sludge indicated that the heavy metals removal decreased in the order of 3 M acetic acid < 0.1 M EDTA<0.3 M HCl, thus hydrochloric acid appears to offer a greater potential as a washing agent in remediating the sludge samples.

  5. Chemical stabilization of cadmium in acidic soil using alkaline agronomic and industrial by-products.

    Science.gov (United States)

    Chang, Yao-Tsung; Hsi, Hsing-Cheng; Hseu, Zeng-Yei; Jheng, Shao-Liang

    2013-01-01

    In situ immobilization of heavy metals using reactive or stabilizing materials is a promising solution for soil remediation. Therefore, four agronomic and industrial by-products [wood biochar (WB), crushed oyster shell (OS), blast furnace slag (BFS), and fluidized-bed crystallized calcium (FBCC)] and CaCO3 were added to acidic soil (Cd = 8.71 mg kg(-1)) at the rates of 1%, 2%, and 4% and incubated for 90 d. Chinese cabbage (Brassica chinensis L.) was then planted in the soil to test the Cd uptake. The elevation in soil pH caused by adding the by-products produced a negative charge on the soil surface, which enhanced Cd adsorption. Consequently, the diethylenetriamine pentaacetic acid (DTPA)-extractable Cd content decreased significantly (P soil. These results from the sequential extraction procedure indicated that Cd converted from the exchangeable fraction to the carbonate or Fe-Mn oxide fraction. The long-term effectiveness of Cd immobilization caused by applying the 4 by-products was much greater than that caused by applying CaCO3. Plant shoot biomass clearly increased because of the by-product soil amendment. Cd concentration in the shoots was soil.

  6. Toxicity of perfluorooctanoic acid towards earthworm and enzymatic activities in soil.

    Science.gov (United States)

    He, Wenxiang; Megharaj, Mallavarapu; Naidu, Ravi

    2016-07-01

    Perfluorooctanoic acid (PFOA) is a widespread persistent organic contaminant in the environment that has recently raised much of regulatory and public concern. Therefore, assessment of its ecological risk is a top priority research. Hence, this study investigated the toxicity of PFOA to beneficial microbial processes in the soil such as activities of dehydrogenase, urease and potential nitrification in addition to earthworm survival, weight loss and PFOA bioaccumulation in two contrasting soils. In general, PFOA caused inhibition of all the measured microbial processes in a dose-dependent manner and the inhibition was higher in Williamtown (WT) soil than Edinburgh (EB) soil. Thus, WT soil being sandy in nature with low clay content showed higher PFOA bioavailability and hence showed higher toxicity. There was no mortality in earthworms exposed up to 100 mg PFOA/kilogram soil in both the soils; however, there was a significant weight loss from 25 mg/kg onwards. This study clearly demonstrates that soil contamination of PFOA can lead to adverse effects on soil health.

  7. fractionation of lead-acid battery soil amended with biochar 36

    African Journals Online (AJOL)

    USER

    Biochar has a high surface area, highly porous, variable – charge organic material that has the potential to ... Keywords: Biochar, Lead–acid Battery, Fractionation and Heavy metals. INTRODUCTION .... toxicity of heavy metal ions in the soils.

  8. Plant-conservative agriculture of acid and degraded Raña-grassland enhances diversity of the common soil mites (Oribatida)

    Energy Technology Data Exchange (ETDEWEB)

    Jorrín, J.; González-Fernández, P.

    2016-11-01

    The seminatural prairie of the Raña of Cañamero (Spain) is a degraded and unproductive agrosystem with acid and stony soils, and low coverage of xerophytic grasses. In a project about secondary reconversion of the raña-prairie to a more productive cropland, an experimental field (EF) was established to assess the effect on plot-productivity of the interaction between correction of soil pH (liming) with three cropping systems: a no-tilled and annually fertilized and improved prairies, and a conventionally-tilled forage crop. The EF model of management was designed as plant-conservative, because no herbicide was applied after seeding to preserve the post-emergence of wild herbs and the natural grass diversity of the prairie. Between 2008 and 2012, we analysed the effect of managing factors (initial conventional-tillage, fertilization, liming and cropping) and agricultural predictors (pH, C:N ratio, soil bulk density and herbaceous biomass) on the alpha(α)-diversity of one of the major group of soil animals, the oribatids. In relation to the raña-prairie, all EF-plots improved their soil bulk density (ρs) and herbaceous biomass (t/ha), and enhanced desirable α-diversity values (richness, abundance and community equity). We conclude that the plant-conservative model: i) do not affect statistically the species richness of the prairie; ii) the desirable α-diversity responses are negatively correlated with soil bulk density and positively with herbaceous biomass, and iii) the low input or minimum intervention model, of an initial and conventional till and annual fertilisation, is the threshold and optimal model of agricultural management to improving oribatids diversity of the raña-soil. (Author)

  9. Size and shape of soil humic acids estimated by viscosity and molecular weight.

    Science.gov (United States)

    Kawahigashi, Masayuki; Sumida, Hiroaki; Yamamoto, Kazuhiko

    2005-04-15

    Ultrafiltration fractions of three soil humic acids were characterized by viscometry and high performance size-exclusion chromatography (HPSEC) in order to estimate shapes and hydrodynamic sizes. Intrinsic viscosities under given solute/solvent/temperature conditions were obtained by extrapolating the concentration dependence of reduced viscosities to zero concentration. Molecular mass (weight average molecular weight (M (w)) and number average molecular weight (M (n))) and hydrodynamic radius (R(H)) were determined by HPSEC using pullulan as calibrant. Values of M (w) and M (n) ranged from 15 to 118 x 10(3) and from 9 to 50 x 10(3) (g mol(-1)), respectively. Polydispersity, as indicated by M (w)/M (n), increased with increasing filter size from 1.5 to 2.4. The hydrodynamic radii (R(H)) ranged between 2.2 and 6.4 nm. For each humic acid, M (w) and [eta] were related. Mark-Houwink coefficients calculated on the basis of the M (w)-[eta] relationships suggested restricted flexible chains for two of the humic acids and a branched structure for the third humic acid. Those structures probably behave as hydrated sphere colloids in a good solvent. Hydrodynamic radii of fractions calculated from [eta] using Einstein's equation, which is applicable to hydrated sphere colloids, ranged from 2.2 to 7.1 nm. These dimensions are fit to the size of nanospaces on and between clay minerals and micropores in soil particle aggregates. On the other hand, the good agreement of R(H) values obtained by applying Einstein's equation with those directly determined by HPSEC suggests that pullulan is a suitable calibrant for estimation of molecular mass and size of humic acids by HPSEC.

  10. Experimental Study of Factors Affecting Soil Erodibility

    Science.gov (United States)

    Larionov, G. A.; Bushueva, O. G.; Gorobets, A. V.; Dobrovolskaya, N. G.; Kiryukhina, Z. P.; Krasnov, S. F.; Litvin, L. F.; Maksimova, I. A.; Sudnitsyn, I. I.

    2018-03-01

    The effect of different factors and preparation conditions of monofraction samples from the arable horizon of leached chernozem on soil erodibility and its relationship with soil tensile strength (STS) has been studied. The exposure of samples at 38°C reduces their erodibility by two orders of magnitude. The drying of samples, on the contrary, increases their erodibility. It has been shown that erodibility decreases during the experiment. It has been found that the inoculation of soil with yeast cultures ( Naganishia albida, Lipomyces tetrasporus) reliably increases the STS value in 1.5-1.9 times. The sterile soil is eroded more intensively than the unsterile soil: at 4.9 and 0.3 g/(m2 s), respectively. The drying of soil followed by wetting to the initial water content (30%) has no significant effect on the STS value in almost all experimental treatments.

  11. Priming Effect Induced by the Use of Different Fertilizers on Soil Functional Diversity

    Directory of Open Access Journals (Sweden)

    Bogdan Mihai ONICA

    2017-11-01

    Full Text Available Agricultural practices, such as the use of fertilizers, can change the structure and function of soil microbial community. Monitoring and assessing the soil microbiota and its dynamics related to different factors can be a powerful tool for understanding basic and applied ecological contexts. The main objective of this paper was to assess the changes of carbon turnover rate and the microbial metabolic activity, when different types of fertilizers were used, process called priming effect. A microcosm experiment was designed and performed under controlled temperature and humidity and the soil samples were analyzed using the MicroResp technique. Results show that the integration in soil of different carbon sources, such as green manure, can lead to a positive priming effect and integration of mineral fertilizers can lead to negative priming effect. The carbon sources with the highest respiratory activity were α-ketoglutaric acid, malic acid, oxalic acid, citric acid, while the lowest respiratory activity was obtained in case of arginine.

  12. Microwave Acid Extraction to Analyze K and Mg Reserves in the Clay Fraction of Soils

    Directory of Open Access Journals (Sweden)

    Araína Hulmann Batista

    Full Text Available ABSTRACT: Extraction of K and Mg with boiling 1 mol L-1 HNO3 in an open system for predicting K and Mg uptake by plants is a method of low reproducibility. The aim of this study was to compare the extraction capacity of different acid methods relative to hydrofluoric acid extraction for K and Mg. A further objective was to develop a chemical extraction method using a closed system (microwave for nonexchangeable and structural forms of these nutrients in order to replace the traditional method of extraction with boiling HNO3 on a hot plate (open system. The EPA 3051A method can be used to estimate the total content of K in the clay fraction of soils developed from carbonate and phyllite/mica schist rocks. In the clay fraction of soils developed from basalt, recoveries of K by the EPA 3051A (pseudo-total method were higher than for the EPA 3052 (total hydrofluoric extraction method. The relative abundance of K and Mg for soils in carbonate rocks, phyllite/mica schist, granite/gneiss, and basalt determined by aqua regia digestion is unreliable. The method using 1 mol L-1 HNO3 in an closed system (microwave showed potential for replacing the classical method of extraction of nonexchangeable forms of K (boiling 1 mol L-1 HNO3 in an open system - hot plate and reduced the loss of Si by volatilization.

  13. Influence of Soil Humic and Fulvic Acid on the Activity and Stability of Lysozyme and Urease

    NARCIS (Netherlands)

    Li, Yan; Tan, WenFeng; Koopal, Luuk K.; Wang, MingXia; Liu, Fan; Norde, Willem

    2013-01-01

    Humic substances (HS), including humic acids (HA) and fulvic acids (FA), are important components of soil systems. HS form strong complexes with oppositely charged proteins, which will lead to changes in the enzyme activity. The effect of soil HS on the activity and stability of two enzymes was

  14. Tillage and water management for riceland productivity in acid sulfate soils of the Mekong delta, Vietnam.

    NARCIS (Netherlands)

    Minh, L.Q.; Tuong, T.P.; Mensvoort, van M.E.F.; Bouma, J.

    1997-01-01

    Acid sulfate soils are characterized by low pH and high concentrations of aluminum, sulfate, iron and hydrogen sulfide. Removal of at least part of these substances is a prerequisite for land use, at least in severely acid soils. In this study, the effectiveness of harrowing and flushing with

  15. A new approach to study cadmium complexes with oxalic acid in soil solution.

    Science.gov (United States)

    Dytrtová, Jana Jaklová; Jakl, Michal; Sestáková, Ivana; Zins, Emilie-Laure; Schröder, Detlef; Navrátil, Tomáš

    2011-05-05

    This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI-MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH(2)) were observed. In order to verify the possible formation of complexes with OAH(2), aqueous solutions of OAH(2) with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI-MS, which follow the general formula [Cd(n)(X,Y)((2n+1))](-), where n is the number of cadmium atoms, X=Cl(-), and Y=OAH(-). Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. A new approach to study cadmium complexes with oxalic acid in soil solution

    International Nuclear Information System (INIS)

    Jaklova Dytrtova, Jana; Jakl, Michal; Sestakova, Ivana; Zins, Emilie-Laure; Schroeder, Detlef; Navratil, Tomas

    2011-01-01

    This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI-MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH 2 ) were observed. In order to verify the possible formation of complexes with OAH 2 , aqueous solutions of OAH 2 with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI-MS, which follow the general formula [Cd n (X,Y) (2n+1) ] - , where n is the number of cadmium atoms, X = Cl - , and Y = OAH - . Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions.

  17. A new approach to study cadmium complexes with oxalic acid in soil solution

    Energy Technology Data Exchange (ETDEWEB)

    Jaklova Dytrtova, Jana, E-mail: dytrtova@uochb.cas.cz [Institute of Organic Chemistry and Biochemistry of the AS CR, v.v.i., Flemingovo namesti 2, 16610 Prague 6 (Czech Republic); Jakl, Michal [Department of Agro-Environmental Chemistry and Plant Nutrition, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamycka 129, 16521 Prague - Suchdol (Czech Republic); Sestakova, Ivana [J. Heyrovsky Institute of Physical Chemistry of the AS CR, v.v.i., Dolejskova 3, 182 23 Prague 8 (Czech Republic); Zins, Emilie-Laure; Schroeder, Detlef [Institute of Organic Chemistry and Biochemistry of the AS CR, v.v.i., Flemingovo namesti 2, 16610 Prague 6 (Czech Republic); Navratil, Tomas [J. Heyrovsky Institute of Physical Chemistry of the AS CR, v.v.i., Dolejskova 3, 182 23 Prague 8 (Czech Republic)

    2011-05-05

    This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI-MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH{sub 2}) were observed. In order to verify the possible formation of complexes with OAH{sub 2}, aqueous solutions of OAH{sub 2} with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI-MS, which follow the general formula [Cd{sub n}(X,Y){sub (2n+1)}]{sup -}, where n is the number of cadmium atoms, X = Cl{sup -}, and Y = OAH{sup -}. Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions.

  18. Citric-acid preacidification enhanced electrokinetic remediation for removal of chromium from chromium-residue-contaminated soil.

    Science.gov (United States)

    Meng, Fansheng; Xue, Hao; Wang, Yeyao; Zheng, Binghui; Wang, Juling

    2018-02-01

    Electrokinetic experiments were conducted on chromium-residue-contaminated soils collected from a chemical plant in China. Acidification-electrokinetic remediation technology was proposed in order to solve the problem of removing inefficient with ordinary electrokinetic. The results showed that electrokinetic remediation removal efficiency of chromium from chromium-contaminated soil was significantly enhanced with acidizing pretreatment. The total chromium [Cr(T)] and hexavalent chromium [Cr(VI)] removal rate of the group acidized by citric acid (0.9 mol/L) for 5 days was increased from 6.23% and 19.01% in the acid-free experiments to 26.97% and 77.66% in the acidification-treated experiments, respectively. In addition, part of chromium with the state of carbonate-combined will be converted into water-soluble state through acidification to improve the removal efficiency. Within the appropriate concentration range, the higher concentration of acid was, the more chromium was released. So the removal efficiency of chromium depended on the acid concentration. The citric acid is also a kind of complexing agent, which produced complexation with Cr that was released by the electrokinetic treatment and then enhanced the removal efficiency. The major speciation of chromium that was removed from soils by acidification-electrokinetics remediation was acid-soluble speciation, revivification speciation and oxidation speciation, which reduced biological availability of chromium.

  19. Adsorption of 2,4-Dichlorophenoxyacetic Acid onto Volcanic Ash Soils:

    Directory of Open Access Journals (Sweden)

    Ei Ei Mon

    2009-01-01

    Full Text Available The quantification of the linear adsorption coefficient (Kd for soils plays a vital role to predict fate and transport of pesticides in the soil-water environment. In this study, we measured Kd values for 2,4-Dichlorophenoxyacetic acid (2,4-D adsorption onto Japanese volcanic ash soils with different amount of soil organic matter (SOM in batch experiments under different pH conditions. All measurements followed well both linear and Freundlich adsorption isotherms. Strong correlations were found between measured Kd values and pH as well as SOM. The 2,4-D adsorption increased with decreasing pH and with increasing SOM. Based on the data, a predictive Kd equation for volcanic ash soils, log (Kd = 2.04 - 0.37 pH + 0.91 log (SOM, was obtained by the multiple regression analysis. The predictive Kd equation was tested against measured 2,4-D sorption data for other volcanic ash soils and normal mineral soils from literature. The proposed Kd equation well predicted Kd values for other volcanic ash soils and slightly over- or under-predicted Kd values for normal mineral soils. The proposed Kd equation performed well against volcanic ash soils from different sites and countries, and is therefore recommended for predicting Kd values at different pH and SOM conditions for volcanic ash soils when calculating and predicting 2,4-D mobility and fate in soil and groundwater.

  20. Phosphatase activity in relation to key litter and soil properties in mature subtropical forests in China.

    Science.gov (United States)

    Hou, Enqing; Chen, Chengrong; Wen, Dazhi; Liu, Xian

    2015-05-15

    Phosphatase-mediated phosphorus (P) mineralization is one of the critical processes in biogeochemical cycling of P and determines soil P availability in forest ecosystems; however, the regulation of soil phosphatase activity remains elusive. This study investigated the potential extracellular activities of acid phosphomonoesterase (AcPME) and phosphodiesterase (PDE) and how they were related to key edaphic properties in the L horizon (undecomposed litter) and F/H horizon (fermented and humified litter) and the underlying mineral soil at the 0-15cm depth in eight mature subtropical forests in China. AcPME activity decreased significantly in the order of F/H horizon>L horizon>mineral soil horizon, while the order for PDE activity was L horizon=F/H horizon>mineral soil horizon. AcPME (X axis) and PDE (Y axis) activities were positively correlated in all horizons with significantly higher slope in the L and F/H horizons than in the mineral soil horizon. Both AcPME and PDE activities were positively related to microbial biomass C, moisture content and water-holding capacity in the L horizon, and were positively related to soil C:P, N:P and C:N ratios and fine root (diameter≤2mm) biomass in the mineral soil horizon. Both enzyme activities were also interactively affected by forest and horizon, partly due to the interactive effect of forest and horizon on microbial biomass. Our results suggest that modulator(s) of the potential extracellular activity of phosphatases vary with horizon, depending on the relative C, P and water availability of the horizon. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Respiration rates in forest soil organic horizon materials treated with simulated acid rain

    Energy Technology Data Exchange (ETDEWEB)

    Salonius, P O

    1990-01-01

    The entire organic horizon above the mineral soil was collected under a mature black spruce (Picea mariana) stand in central New Brunswick. The organic horizon consisted of litter, fermentation, and humus layers of 1.5, 4.0, and 1.0 cm depths respectively. In concert with a series of simulated rain experiments, which dealt with the effects of acid precipitation of pH 4.6, 3.6, and 2.6 compared with controls at pH 5.6 on germination and early growth of forest tree seedlings, 30 randomly distributed, unplanted tubes in each rain chamber were exposed to treatment during each of the 5-week treatments of the various tree species. During the experiments, ca 315 mm of simulated rain was deposited on the soil surfaces in the tube containers. Marked decreases in soil microbial activity were found only with pH 2.6 rain, but responsiveness to increasing temperature was lower as rain of greater acidity was applied to the soil. Ammonium nitrogen mineralization rates were not affected by treatment of soil with acidified precipitation. 26 refs., 3 figs., 1 tab.

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

    International Nuclear Information System (INIS)

    Esther Phillip; Muhamad Samudi Yasir

    2012-01-01

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

  3. Effect of humic acid on the underpotential deposition-stripping voltammetry of copper in acetic acid soil extract solutions at mercaptoacetic acid-modified gold electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Herzog, Gregoire; Beni, Valerio; Dillon, Patrick H.; Barry, Thomas; Arrigan, Damien W.M

    2004-05-24

    Electrochemical measurements were undertaken for the investigation of the underpotential deposition-stripping process of copper at bare and modified gold electrodes in 0.11 M acetic acid, the first fraction of the European Union's Bureau Communautaire de References (BCR) sequential extraction procedure for fractionating metals within soils and sediments. Gold electrodes modified with mercaptoacetic acid showed higher sensitivity for the detection of copper than bare gold electrodes, both in the absence and in the presence of humic acid in acetic acid solutions, using the underpotential deposition-stripping voltammetry (UPD-SV) method. In the presence of 50 mg l{sup -1} of humic acid, the mercaptoacetic acid modified electrode proved to be 1.5 times more sensitive than the bare gold electrode. The mercaptoacetic acid monolayer formed on the gold surface provided efficient protection against the adsorption of humic acid onto the gold electrode surface. Variation of the humic acid concentration in the solution showed little effect on the copper stripping signal at the modified electrode. UPD-SV at the modified electrode was applied to the analysis of soil extract samples. Linear correlation of the electrochemical results with atomic spectroscopic results yielded the straight-line equation y ({mu}g l{sup -1}) = 1.10x - 44 (ppb) (R=0.992, n=6), indicating good agreement between the two methods.

  4. Progresses on Amelioration of Red Soil Acidity with Crop Straw Biochar: A Review

    OpenAIRE

    XU Ren-kou

    2016-01-01

    The research progresses on amelioration of red soil acidity and immobilization of heavy metals in red soils with the biochars generated from crop straws were summarized in this review paper. The developing trends of the research in these areas in future were also predicted.

  5. Phthalic acid and benzo[a]pyrene in soil-plant-water systems amended with contaminated sewage sludge

    DEFF Research Database (Denmark)

    Mougin, C.; Dappozze, F.; Brault, A.

    2006-01-01

    We studied the fate of C-14-labelled phthalic acid and benzo[a]pyrene applied to the soil by the way of contaminated sewage sludge in model ecosystems allowing the simultaneous assessment of physicochemical and biological descriptors. Here we show that the mineralisation of phthalic acid is highe......[a]pyrene is recalcitrant to biodegradation whatever the type of soil contamination. We show also that the chemicals present in the sludge are poorly transferred to soil leachates and plant seedlings....

  6. Discriminating impacts of geomorphological and human factors on vineyard soil erosion (Burgundy, France)

    Science.gov (United States)

    Chevigny, Emmanuel; Quiquerez, Amélie; Petit, Christophe; Curmi, Pierre

    2014-05-01

    The Burgundy vineyards have been recognized for the high diversity of Terroirs, controlled by complex interactions between natural features, historical parameters and soil management practices. Vineyards are known to undergo substantial soil loss in comparison with other types of agricultural land. Hydric erosion on vineyards is controlled by complex interactions of natural and anthropogenic factors leading to intra-plot spatial heterogeneities of topsoil at a scale of a metre. Studying the relationship between soils and their degradation is crucial in this situation where soil sustainability is threatened. This study explores the relative influences of historical and present-day anthropogenic factors and geomorphological processes controlling soil erosion on vineyard hillslopes. The selected area was located in the Monthelie vineyard (Côte de Beaune, France) where intensive erosion occurred during high-intensity rainfall events. Soil erosion quantification was performed at a square-metre scale using dendrogeomorphology. This method is based on the measurement of the unearthing of the stock located on the vine plants, considered as a passive marker of soil-surface vertical displacement since the year of plantation. The obtained maps, together with various complementary datasets, such as geological and geomorphological data, but also historical documents (cadastral plans, cadastral matrices and old aerial photographs) allow landscape evolution to be assessed. The combination of all these data shows that spatial distribution and intensity of erosion are controlled mainly by lithology and slope value. However, our study highlights that the sediment dynamics in this vineyard plot is highly related to historical former plot limits and present-day management practices. Nonetheless, quantification of sediment dynamic for the last decade reveals that the impacts of historical structures are disappearing gradually, in response to present-day management practices and

  7. Behavior of phenolic substances in the decaying process of plants. V. Elution of heavy metals with phenolic acids from soil

    Energy Technology Data Exchange (ETDEWEB)

    Shindo, H; Kuwatsuka, S

    1977-01-01

    The relationship between the elution of heavy metals with phenolic substances and the chemical structure of phenolic substances, as well as the interaction between phenolic substances and metals were studied using batch and column methods. The elution of 3 metals (Fe, Al and Mn) with 4 phenolic acids (rho-hydroxybenzoic, salicylic, ..cap alpha..-resorcylic, and protocatechuic acids) and phthalic acid were investigated using 3 different soils. The results are as follows: (1) The elution of heavy metals was largely influenced by the chemical structures of the phenolic acids. Protocatechuic, salicylic, and phthalic acids which had different chelating sites easily extracted iron, aluminum, and manganese from the soils. Hydroxybenzoic and ..cap alpha..-resorcylic acids which had no chelating sites contributed little to the elution process. (2) In many cases protocatechuic acid showed a stronger affinity to iron than to aluminum, but salicylic acid showed the opposite trend. The affinity of phthalic acid to metals was much less than that of both phenolic acids. (3) The elution of heavy metals was also influenced by the soil pH. The amounts of heavy metals eluted with protocatechuic acid increased as the soil pH increased. The amounts eluted with salicylic and phthalic acids increased as the soil pH decreased. (4) The results suggested that chelating phenolics such as protocatechuic and salicylic acids, which were exuded from plant residues or produced during the decaying process of plant residues, eluted heavy metals such as iron, aluminum and manganese from soil particles and accelerated the downward movement of these metal ions.

  8. Using DTPA-extractable soil fraction to assess the bioconcentration factor of plants in phytoremediation of urban soils

    Science.gov (United States)

    Rodríguez-Bocanegra, Javier; Roca, Núria; Tume, Pedro; Bech, Jaume

    2017-04-01

    Urban soils may be highly contaminated with potentially toxic metals, as a result of intensive anthropogenic activities. Developing cities are increasing the number of lands where is practiced the urban agriculture. In this way, it is necessary to assess the part of heavy metals that is transferred to plants in order to a) know the potential health risk that represent soils and b) know the relation soil-plant to assess the ability of these plants to remove heavy metals from soil. Nowadays, to assess the bioconcentration factor (BF) of plants in phytoremediation, the pseudototal o total concentration has been used by many authors. Two different urban soils with similar pH and carbonates content but with different pollution degree were phytoremediated with different plant species. Urban soil from one Barcelona district (Spain), the most contaminated soil, showed an extractability of Cu, Pb and Zn of 9.6, 6.7 and 5.8% of the total fraction respectively. The soil from Talcahuano city (Chile), with contents of heavy metals slightly above the background upper limit, present values of 15.5, 13.5 and 12% of the total fraction of studied heavy metals. Furthermore, a peri-urban analysed soil from Azul (Argentina) also showed an elevated extractability with values of 24, 13.5 and 14% of the Cu, Pb and Zn contents respectively. These soils presented more extractability than other disturbed soils, like for example, soils from mine areas. The urban soils present more developed soil with an interaction between solution and solid phase in polluted systems. The most important soil surface functional groups include the basal plane of phyllosilicates and metal hydroxyls at edge sites of clay minerals, iron oxyhydroxides, manganese oxyhydroxides and organic matter. The interaction between solution and solid phase in polluted urban systems tends to form labile associations and pollutants are more readily mobilized because their bonds with soil particles are weaker. Clay and organic

  9. Soil Erodibility under Natural Rainfall Conditions as the K Factor of the Universal Soil Loss Equation and Application of the Nomograph for a Subtropical Ultisol

    Directory of Open Access Journals (Sweden)

    Elemar Antonino Cassol

    2018-05-01

    Full Text Available ABSTRACT: Erodibility represents the intrinsic susceptibility of the soil to the erosion process, represented by the K factor in the Universal Soil Loss Equation (USLE. In Brazil, there are few field experiments determined with a series larger than ten years of data, which are the most reliable for quantifying the K factor. The aim of this study was to determine the K factor of the USLE by the direct method, relating soil losses determined in the field under standard conditions to erosivity of rains, and by the analytic method, applying the Wischmeier nomograph. The data on soil loss by water erosion were obtained in a field experiment under natural rainfall conditions from 1976 to 1989 in an Ultisol at the Agronomic Experimental Station in Eldorado do Sul, RS, Brazil. The value of the K factor by the direct method was 0.0338 Mg ha h ha-1 MJ-1 mm-1, which is high, showing considerable susceptibility of the soil to erosion. From the analytical method, the K factor obtained was 0.0325 Mg ha h ha-1 MJ-1 mm-1, a value very close to that determined experimentally. Thus, the Wischmeier nomograph proved to be valid for determination of the K factor of the Ultisol under study. This method proved to be valid for this type of soil. These results can be used for calibration models based on the USLE.

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

    International Nuclear Information System (INIS)

    Abou-Assaf, N.; Coats, J.R.

    1987-01-01

    The effects of three soil pH's, three soil temperatures, and three soil moistures on [ 14 C]isofenphos degradation were investigated. All three factors interacted strongly and significantly affected the persistence of isofenphos as well as the formation of the degradation products (p less than 1%). Isofenphos degradation was greatest at the higher temperatures 35 0 C greater than 25 0 C greater than 15 0 C (except under alkaline pH's), medium moisture 25% greater than 30% greater than 15%, and in both alkaline (pH = 8) and acidic soils (pH = 6) compared with neutral soil (pH = 7). Isofenphos oxon formation was greatest at higher temperatures 35 0 C compared with 25 0 C and 15 0 C, in acidic soil greater than neutral soil greater than alkaline soil, and under high moisture (30%) compared with the 15% and 22.5% moistures. The formation of soil-bound residues was greatest at higher temperatures 35 0 C greater than 25 0 C greater than 15 0 C, higher moisture 30% compared with 15% and 22.5%, and in alkaline soil compared with neutral and acidic soils

  11. Long term field evaluation of phosphate rock and superphosphate in acid soils of Hungary; Incubation and pot experiments

    International Nuclear Information System (INIS)

    Nemeth, T.; Osztoics, E.; Csatho, P.; Radimszky, L.; Baczo, G.Y.

    2002-01-01

    A series of experiments was conducted to compare the agronomic effectiveness of phosphate rock (from Algeria) and of single superphosphate (from Russia, Kola) on a moderately acidic pseudogley brown forest soil (Szentgyoergyvoelgy) and on a slightly acidic chernozem brown forest soil (Kompolt). Dynamics of water-soluble and ammonium lactate-soluble P-contents (AL-P) and soil pH-H 2 O changes were studied in a half-year long incubation experiment. A follow-up pot experiment with the same soils was carried out with winter rape as test plants. Both experiments were set up with similar P fertilizer sources and P rates (100, 200, and 400 mg mineral acid soluble P 2 O 5 per kg soil). At the beginning of incubation experiment, the water-soluble P content of the pseudogley brown forest soil was influenced by both the sources of P and the experimental conditions. The water-soluble P content decreased with time. After the 15 th to 20 th day of incubation, when the fast binding process of the water-soluble P ended, the effects of the P forms decreased. In this stage, the effects of environmental conditions depended on the form of the P fertilizer. The water-soluble P content of the phosphate rock-treated samples was affected to a great extent by soil water content, while the incubation temperature had a greater effect in soils treated with superphosphate. The AL-P content of soils was increased similarly by addition of equal rates of phosphate rock and super-phosphate at the beginning of incubation. The AL-P content of phosphate rock-treated soils was higher throughout the incubation period than of the superphosphate-treated soils -treated. Temperature had a greater effect on the AL-P content of soils than soil water content. As the AL-extraction may dissolve a substantial amount of the undecomposed phosphate rock, this method is not applicable to soil testing of available P forms from phosphate rock-treated soils. Initial soil pH decreased on average by 0.5 units in the

  12. Heavy metals content in degraded agricultural soils of a mountain region related to soil properties

    Science.gov (United States)

    Navarro-Pedreño, José; Belén Almendro-Candel, María; Gómez, Ignacio; Jordán, Manuel M.; Bech, Jaume; Zorpas, Antonis

    2017-04-01

    Agriculture has been practiced for long time in Mediterranean regions. Intensive agriculture and irrigation have developed mainly in the valleys and coastal areas. In the mountainous areas, dry farming has been practiced for centuries. Soils have been fertilized using mainly organic amendments. Plants extracted nutrients and other elements like heavy metals presented in soils and agricultural practices modified soil properties that could favor the presence of heavy metals. In this work, it has been checked the content of heavy metals in 100 agricultural soils samples of the NorthWest area of the province of Alicante (Spain) which has been long cultivated with cereals and olive trees, and now soils are abandoned and degraded because of the low agricultural yields. European policy has the aim to improve the sustainable agriculture and recover landscapes of mountain regions. So that, it is important to check the state of the soils (Marques et al. 2007). Soils samples (arable layer) were analyzed determining: pH (1:5, w/v, water extract), equivalent calcium carbonate content, organic matter by Walkley-Black method (Nelson and Sommers 1996), micronutrients (Cu, Fe, Mn, Zn) extracted with DTPA (Lindsay and Norvell, 1978) and measured by atomic absorption spectrometry, and total content of metals (Cd, Cr, Ni, Pb) measured in soil samples after microwave acid digestion (Moral et al. 1996), quantifying the content of metals by ICP analysis. The correlation between soil properties and metals. The results indicated that pH and carbonates are the most important properties of these soils correlated with the metals (both micronutrients and heavy metals). The available micronutrients (all of them) are close correlated with the pH and carbonates in soils. Moreover, heavy metals like Pb and Ni are related to available Mn and Zn. Keywords: pH, carbonates, heavy metals, abandoned soils. References: Lindsay,W.L., andW.A. Norvell. 1978. "Development of a DTPA Soil Test for Zinc, Iron

  13. Effects of soil depth and plant-soil interaction on microbial community in temperate grasslands of northern China.

    Science.gov (United States)

    Yao, Xiaodong; Zhang, Naili; Zeng, Hui; Wang, Wei

    2018-07-15

    Although the patterns and drivers of soil microbial community composition are well studied, little is known about the effects of plant-soil interactions and soil depth on soil microbial distribution at a regional scale. We examined 195 soil samples from 13 sites along a climatic transect in the temperate grasslands of northern China to measure the composition of and factors influencing soil microbial communities within a 1-m soil profile. Soil microbial community composition was measured using phospholipid fatty acids (PLFA) analysis. Fungi predominated in topsoil (0-10 cm) and bacteria and actinomycetes in deep soils (40-100 cm), independent of steppe types. This variation was explained by contemporary environmental factors (including above- and below-ground plant biomass, soil physicochemical and climatic factors) >58% in the 0-40 cm of soil depth, but soils. Interestingly, when we considered the interactive effects between plant traits (above ground biomass and root biomass) and soil factors (pH, clay content, and soil total carbon, nitrogen, phosphorous), we observed a significant interaction effect occurring at depths of 10-20 cm soil layer, due to different internal and external factors of the plant-soil system along the soil profile. These results improve understanding of the drivers of soil microbial community composition at regional scales. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Divergence of dominant factors in soil microbial communities and functions in forest ecosystems along a climatic gradient

    Science.gov (United States)

    Xu, Zhiwei; Yu, Guirui; Zhang, Xinyu; He, Nianpeng; Wang, Qiufeng; Wang, Shengzhong; Xu, Xiaofeng; Wang, Ruili; Zhao, Ning

    2018-03-01

    Soil microorganisms play an important role in regulating nutrient cycling in terrestrial ecosystems. Most of the studies conducted thus far have been confined to a single forest biome or have focused on one or two controlling factors, and few have dealt with the integrated effects of climate, vegetation, and soil substrate availability on soil microbial communities and functions among different forests. In this study, we used phospholipid-derived fatty acid (PLFA) analysis to investigate soil microbial community structure and extracellular enzymatic activities to evaluate the functional potential of soil microbes of different types of forests in three different climatic zones along the north-south transect in eastern China (NSTEC). Both climate and forest type had significant effects on soil enzyme activities and microbial communities with considerable interactive effects. Except for soil acid phosphatase (AP), the other three enzyme activities were much higher in the warm temperate zone than in the temperate and the subtropical climate zones. The soil total PLFAs and bacteria were much higher in the temperate zone than in the warm temperate and the subtropical zones. The soil β-glucosidase (BG) and N-acetylglucosaminidase (NAG) activities were highest in the coniferous forest. Except for the soil fungi and fungi-bacteria (F/B), the different groups of microbial PLFAs were much higher in the conifer broad-leaved mixed forests than in the coniferous forests and the broad-leaved forests. In general, soil enzyme activities and microbial PLFAs were higher in primary forests than in secondary forests in temperate and warm temperate regions. In the subtropical region, soil enzyme activities were lower in the primary forests than in the secondary forests and microbial PLFAs did not differ significantly between primary and secondary forests. Different compositions of the tree species may cause variations in soil microbial communities and enzyme activities. Our results

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

    Directory of Open Access Journals (Sweden)

    Stanislava Vondráčková

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

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

    International Nuclear Information System (INIS)

    Wang, H.F.; Ambe, S.; Takematsu, N.; Ambe, F.

    2001-01-01

    Using a multitracer technique, the effects of acid rain pH on the adsorption of 15 trace elements on soil were studied. Kaolin, forest soil (original and with partially removed oxides), black soil (original and without organic matter) and Kureha soil (original, with partially removed oxides, and without organic matter) were employed as the adsorbents. Instead of H 2 SO 4 solution, HCl solution was selected as the model acid rain based on the results of adsorption experiments on kaolin. In general, the percentage adsorption of cationic elements on three original soils and kaolin increased with increasing pH. The adsorption of oxyanionic elements, As and Se, on three soils was high over the entire pH range studied, while that on kaolin was low and decreased with an increase in pH. The differences in the physical and chemical properties of soils were reflected on the adsorption. The organic matter in soil had positive effects on the extent of adsorption of most elements studied, while the oxides apparently showed positive effects only for Fe and Se adsorption. The results indicate that acid rain decreases the retention of cations in soil and that it increases or does not change the adsorption of anions. (orig.)

  17. [Characteristics of Phthalic Acid Esters in Agricultural Soils and Products in Areas of Zhongshan City, South China].

    Science.gov (United States)

    Li, Bin; Wu, Shan; Liang, Jin-ming; Liang, Wen-li; Chen, Gui-xian; Li, Yong-jun; Yang, Guo-yi

    2015-06-01

    In order to investigate and assess the pollution level of phthalic acid esters (PAEs) in farm soils and products from typical agricultural fields in areas of Zhongshan City, Guangdong Province, South China, 65 topsoil and 37 agricultural product samples were collected and contents of 6 PAEs compounds that classified by the U. S. Environmental Protection Agency (EPA) as priority pollutants were determined by the GC-FID. The results indicated that total contents of the PAEs (∑ PAEs) in soils ranged from 0. 14 to 1. 14 mg x kg(-1), and the mean value was 0.43 mg x kg(-1), with the detected ratio of 100%. Various concentrations of PAEs differed in three land-use types were ordered by vegetable soil > orchard soil > paddy soil. Comparing with six U.S. EPA priority pollutants of PAEs, the contents of Di-n-butyl phthalate (DBP) and Dimethyl phthalate ( DMP) in soils exceeded the control limits of PAEs in the American soil by 93.85% and 27.69% respectively, but the rest four PAEs compounds were lower than the control limits. Generally, the pollution level of soils contaminated by PAEs in agricultural fields of Zhongshan City was relatively low. The contents of 3 PAEs in agricultural products ranged from 0.15 to 3.15 mg x kg(-1) with the average of 1.12 mg x kg(-1), which was lower than the suggested standards in USA and Europe and with low health risk. Meanwhile, ∑ PAEs concentrations in vegetables were higher than those both in rice and fruits. DBP and DEHP were the main components of PAEs both in agricultural soils and products, with higher percentage contents and detected ratio. ∑ PAEs and DBP contents in various agricultural products-soils had a significantly positive correlation, with Pearson coefficients (r) in vegetables-vegetable soils were 0.81 (P = 0.000), 0.75 (P = 0.000), and corresponding r among rice-paddy soil and fruits-fruit soils were 0.74 (P = 0.036), 0.65 (P = 0.041) and 0.66 (P = 0.029), 0.78 (P = 0.045), respectively. Although there existed a

  18. 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

    Science.gov (United States)

    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.

  19. Sensitivity Analysis of b-factor in Microwave Emission Model for Soil Moisture Retrieval: A Case Study for SMAP Mission

    Directory of Open Access Journals (Sweden)

    Dugwon Seo

    2010-05-01

    Full Text Available Sensitivity analysis is critically needed to better understand the microwave emission model for soil moisture retrieval using passive microwave remote sensing data. The vegetation b-factor along with vegetation water content and surface characteristics has significant impact in model prediction. This study evaluates the sensitivity of the b-factor, which is function of vegetation type. The analysis is carried out using Passive and Active L and S-band airborne sensor (PALS and measured field soil moisture from Southern Great Plains experiment (SGP99. The results show that the relative sensitivity of the b-factor is 86% in wet soil condition and 88% in high vegetated condition compared to the sensitivity of the soil moisture. Apparently, the b-factor is found to be more sensitive than the vegetation water content, surface roughness and surface temperature; therefore, the effect of the b-factor is fairly large to the microwave emission in certain conditions. Understanding the dependence of the b-factor on the soil and vegetation is important in studying the soil moisture retrieval algorithm, which can lead to potential improvements in model development for the Soil Moisture Active-Passive (SMAP mission.

  20. Influence of environmental factors on the spatial distribution and diversity of forest soil in Latvia

    Directory of Open Access Journals (Sweden)

    Raimonds Kasparinskis

    2012-02-01

    Full Text Available This study was carried out to determine the spatial relationships between environmental factors (Quaternary deposits, topographical situation, land cover, forest site types, tree species, soil texture and soil groups, and their prefix qualifiers (according to the international Food and Agricultural Organization soil classification system World Reference Base for Soil Resources [FAO WRB]. The results show that it is possible to establish relationships between the distribution of environmental factors and soil groups by applying the generalized linear models in data statistical analysis, using the R 2.11.1 software for processing data from 113 sampling plots throughout the forest territory of Latvia.A very high diversity of soil groups in a relatively similar geological structure was revealed. For various reasons there is not always close relationship between the soil group, their prefix qualifiers and Quaternary deposits, as well as between forest site types, the dominant tree species and specific soil group and its prefix qualifiers. Close correlation was established between Quaternary deposits, forest site types, dominant tree species and soil groups within nutrient-poor sediments and very rich deposits containing free carbonates. No significant relationship was detected between the CORINE Land Cover 2005 classes, topographical situation and soil group.