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1.
澳大利亚东部地区一些酸性硫酸盐土壤磷的特征 总被引：1，自引：0，他引：1
Forty-five acid sulfate topsoil samples (depth < 0.5 m) from 15 soil cores were collected from 11 locations along the New South Wales coast, Australia. There was an overall trend for the concentration of the HC1-extractable P to increase along with increasing amounts of organic C and the HCl-extractable trivalent metals in the topsoils of some less-disturbed acid sulfate soils (pH < 4.5). This suggests that inorganic P in these soils probably accumulated via biological cycling and was retained by complexation with trivalent metals or their oxides and hydroxides. While there was no clear correlation between pH and the water-extractable P, the concentration of the water-extractable P tended to increase with increasing amounts of the HCl-extractable P. This disagrees with some established models which suggest that the concentration of solution P in acid soils is independent of total P and decreases with increasing acidity. The high concentration of sulfate present in acid sulfate soils appeared to affect the chemical behavior of Pin these soil systems. Comparison was made between a less disturbed wetland acid sulfate soil and a more intensively disturbed sugarcane acid sulfate soil. The results show that reclamation of wetland acid sulfate soils for sugarcane production caused a significant decrease in the HCl-extractable P in the topsoil layer as a result of the reduced bio-cycling of phosphorus following sugarcane farming. Simulation experiment shows that addition of hydrated lime had no effects on the immobilization of retained P in an acid sulfate soil sample within a pH range 3.54.6. When the pH was raised to above 4.6, soluble P in the soil extracts had a tendency to increase with increasing pH until the 15th extraction (pH 5.13). This, in combination with the poor pH-soluble P relationship observed from the less-disturbed acid sulfate soils, suggests that soluble P was not clearly pH-dependent in acid sulfate soils with pH < 4.5. 相似文献
2.
某极度酸化的酸性硫酸盐土壤中可溶性和交换性酸的特征 总被引：4，自引：0，他引：4
An extremely acidified acid sulfate soil(ASS) was investigated to characterise its soluble and exchangeable acidity,The results showed that soluble acidity of a sample dtermined by titration with a KOH soulution was much significantly greater than that indicated by pH measured using a pH meter,paricularly for the extremely acidic soil samples,This is because the total soluble acidity of the extremely acidic soil samples was mainly composed of various soluble Al and Fe species,possibly in forms of Al sulfate complexes(e.g.,AlSO4^ ) and feerous Fe(Fe^2 )_,It is therefore suggested not to use pH alone as an indicator of soluble acidity in ASS,particularly for extremely acidic ASS,It is also likely that AlSO4^ actively participated in cation exchange reactions.It appears that the possible involvement of this Al sulfate cation in the cation adsorption has significant effect on increasing the amount of acidity being adsorbed by the soils. 相似文献
3.
不同提取剂连续提取下某酸性硫酸盐土壤酸的释放 总被引：5，自引：3，他引：2
An acid sulfate soil sample was successively extracted with deionized water,1 molL^-1 KCl and 0.0005mol L^-1 Ca(OH)2 solutions.The results showed that only very small amounts of acidity were extracted by deionized water,possibly through slow jarosite hydrolysis.Acid release through jarosite hydrolysis was greatly enhanced by Ca(OH)2 extraction at the expense of the added OH^- being neutralized by the acid released.Successive extration of the sample with KCl removed the largest amounts of acidity from the sample.However,it is likely that the major form of acidity released by KCl extraction was exchangeable acidity.The results also show the occurrence of low or non charged Al and Fe species in water and Ca(OH)2 extracts after first a few extractions .It appears that such a phenomenon was related to a decreasing EC value with increasing number of extractions. 相似文献
4.
有机配体、竞争阳离子和pH对土壤中Zn分解的影响 总被引：1，自引：0，他引：1
A series of experiments were conducted to examine the interactive effects of an organic ligand, a competing cation, and pH on the dissolution of zinc （Zn） from three California soils, Maymen sandy loam, Merced clay, and Yolo clay loam. The concentrations of soluble Zn of the three soils were low in a background solution of Ca（NO3）2. Citric acid, a common organic ligand found in the rhizosphere, was effective in mobilizing Zn in these soils; its presence enhanced the concentration of Zn in soil solution by citrate forming a complex with Zn. The ability of Zn to form a complex with citric acid in the soil solution was dependent on the concentration of citric acid, pH, and the concentration of the competing cation Ca^2＋. The pH of the soil solution determined the extent of desorption of Zn in solid phase in the presence of citric acid. The amounts of Zn released from the solid phase were proportional to the concentration of citric acid and inversely proportional to the concentration of Ca（NO3）2 background solution, which supplied the competing cation Ca^2＋ for the formation of a complex with citrate. When the soil suspension was spiked with Zn, the adsorption of Zn by the soils was retarded by citric acid via the formation of the soluble Zn-citrate complex. The dissolution of Zn in the presence of citric acid was pH dependent in both adsorption and desorption processes. 相似文献
5.
施用生物肥料，镁石灰石，玄武岩可改善马来西亚酸性硫酸盐土壤化学性质与水稻生长状况 总被引：1，自引：1，他引：0
Acid sulfate soils are normally not suitable for crop production unless they are appropriately ameliorated. An experiment was conducted in a glasshouse to enhance the growth of rice, variety MR219, planted on an acid sulfate soil using various soil amendments.The soil was collected from Semerak, Kelantan, Malaysia. Ground magnesium limestone（GML）, bio-fertilizer, and basalt（each 4t ha^-1） were added either alone or in combinations into the soil in pots 15 d before transplanting. Nitrogen, P and potash were applied at 150, 30, and 60 kg ha^-1, respectively. Three seven-day-old rice seedlings were transplanted into each pot. The soil had a p H of 3.8 and contained organic C of 21 g kg^-1, N of 1.2 g kg^-1, available P of 192 mg kg^-1, exchangeable K of 0.05 cmolc kg^-1,and exchangeable Al of 4.30 cmol c kg^-1, with low amounts of exchangeable Ca and Mg（0.60 and 0.70 cmol c kg^-1）. Bio-fertilizer treatment in combination with GML resulted in the highest p H of 5.4. The presence of high Al or Fe concentrations in the control soil without amendment severely affected the growth of rice. At 60 d of growth, higher plant heights, tiller numbers and leaf chlorophyll contents were obtained when the bio-fertilizer was applied individually or in combination with GML compared to the control. The presence of beneficial bacteria in bio-fertilizer might produce phytohormones and organic acids that could enhance plant growth and subsequently increase nutrient uptake by rice. Hence, it can be concluded that addition of bio-fertilizer and GML improved rice growth by increasing soil pH which consequently eliminated Al and/or Fe toxicity prevalent in the acid sulfate soil. 相似文献
6.
Recent research results suggest that acidification of acid sulfate soils may be inhibited in well-drained estuarine floodplains in eastern Australia by the absence of natural creek levees,The lack of natural levees has allowed the inuudation of the land by regular tidal flooding prior to the construction of flood mitigation work.Such physiographical conditions prevent the development of pre-draingae pyrite-derived soil acidifica-tion that possibly occurred at many levee-protected sites in eastern Australian estuarine floodplains during extremely dry spells.Pre-drainage acidification is considered as an important condition for accumulation of soluble Fe and consequently,the creation of favourable environments for catalysed pyrite oxidation.Under current intensively drained onditions,the acid materials produced by ongoing pyrite oxidation can be rapidly removed from soil pore water by lateral leaching and acid buffering,resulting in low concentrations of soluble Fe in the pyritic layer,which could reduce the rate of pyrite oxidation. 相似文献
7.
The distribution of iron monosulifde (quantified as acid volatile sulfur:SAV) was compared with geochemical properties that are known to affect its formation and accumulation in three coastal Holocene acid sulfate soils (ASS) at Tuckean Swamp,Mc Leods Creek and Bungawalbyn Swamp respectively,These properties included pH,reactive iron(FeR),pore-water sulfate(SO4^2-) and organic carbon(OC).Iron monosulfide was concentrated at the oxic/anoxic boundary,the Tuckean Swamp and McLeods Creek sites are Holocene sediments,whereas the Bungawalbyn Swamp is a Holocene peat.The concentration of SAV averaged 0.2 g kg^-1 in a 0.5m thick soil layer at the Tuckean Swamp,but was an order of magnitude lower in the oxic/anoxic transition layers at McLeods Creek and Bungawalbyn Swamp,The SAV mineral greigite(Fe3S4) was identified in the Tuckean Swamp by X-ray diffraction and scanning electron microscopy with quantitative energy dispersive X-ray analysis(SEM-EDX),Very small concentrations of greigite were also observed in the McLeods Creek,based on crystal morphology and elemental composition.The concentration of SAV was a small fraction of the total reduced sulfur,representing at most 3% of the pyrite sulfur,However,the presence of this highly reactive sulfide mineral,distributed within pores where oxygen diffusion is most rapid,has important implications to the potential rate of acid production from these sediments. 相似文献
8.
Forty-five acid sulfate topsoil samples (depth < 0.5 m) from 15 soil cores at 11 locations along the New South Wales coast, Australia, were selected to investigate the chemical behavior of Zn, Mn, Cr, Co and Pb in these soils. The amount of HCl-extractable Mn was much smaller than the mean value of the total Mn documented for other soils. This may be attributed to enhanced mobilization of Mn from the soils under the extremely acidic and seasonally flooded conditions encountered in the investigated soils. The pH-dependency of soluble Zn and Mn was strongly affected by the availability of acid reactive Zn and Mn compounds. There were fairly good relationships between soluble Zn and acid reactive Zn compounds, and between soluble Mn and acid reactive Mn compounds. Soluble Zn and soluble Mn concentrations were important controls on exchangeable Zn and Mn concentrations, respectively. In contrast to the suggestion by other authors that adsorption of Co was closely associated with Mn oxides present in soils, the exchangeable Co in the investigated acid sulfate soils was not clearly related to the abundance of Mn minerals. In addition to the fact that there are few Mn minerals present in the soils, this might also be because the availability of cation exchange sites on the crystal surfaces of Mn oxides was reduced under extremely acidic conditions. 相似文献
9.
施用碱稳定污泥污水土壤经γ-辐照后土壤溶液中Cu和Zn 总被引：1，自引：0，他引：1
Soil samples collected from several acid soils in Guangdong, Fujian, Zhejiang and Anhui provinces of the southern China were employed to characterize the chemical species of aluminumions in the soils. The proportion of monomeric inorganic Al to total Al in soil solution was in the range of 19% to 70%, that of monomeric organic Al (Al-OM) to total Al ranged from 7.7% to 69%, and that of the acid-soluble Al to total Al was generally smaller and was lower than 20% in most of the acid soils studied. The Al-OM concentration in soil solution was positively correlated with the content of dissolved organic carbon (DOC) and also affected by the concentration of Al3+. The complexes of aluminum with fluoride (Al-F) were the predominant forms of inorganic Al, and the proportion of Al-F complexes to total inorganic Al increased with pH. Under strongly acid condition, Al3+ was also a major form of inorganic Al, and the proportion of Al3+ to total inorganic Al decreased with increasing pH. The proportions of Al-OH and Al-SO4 complexes to total inorganic Al were small and were not larger than 10% in the most acid soils. The concentration of inorganic Al in solution depended largely on pH and the concentration of total F in soil solution. The concentrat ions of Al-OM, Al3+, Al-F and Al-OH complexes in topsoil were higher than those in subsoil and decreased with the increase in soil depth. The chemical species of aluminumions were influenced by pH. The concentrations of Al-OM, Al3+, Al-F complexes and Al-OH complexes decreased with the increase in pH. 相似文献
10.
The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variable charge soils, with different surface charge properties were studied. Under the conditions of the same pH and ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of Cl- > NO3- > ClO4-, indicating the difference of the nature among these three anions. For Ferralsol in the same concentration of chloride and perchloride solutions, the two sulfate adsorption-pH curves could intersect at certain pH value. When pH was higher than the intersecting point, more sulfate was adsorbed in the perchloride solution, while when it was lower than the intersecting point, more sulfate was adsorbed in the chloride solution. In different concentrations of electrolyte solution, the curves of the amount of oxy-acid anion adsorbed, which changed with pH, could intersect at a certain pH, which is termed point of zero salt effect (PZSE) on adsorption. The nature of electrolyte anions influenced obviously the appearance of PZSE for sulfate adsorption. For ferralsol the curves of adsorption converged to about pH 7 in NaCl solution seemed to intersect in NaNO3 solution and to have a typical PZSE for sulfate adsorption in NaClO4 solution. For Acrisol the three curves of adsorption were nearly parallel in NaCl and NaNO3 solutions and converged to pH 6.5 in NaClO4 solution. 相似文献
11.
Ion leaching in 3 sandy spruce forest soils of different origin and pH was investigated in the laboratory. Zero-tension lysimeters containing undisturbed soil columns of varying soil depth were subjected to H2SO4 loadings for a period of 9 weeks. The analysis of the resulting leachate supports the hypothesis that Al-sulphate minerals may form in acidic soils when exposed to acid (H2SO4) deposition. In the B horizon of a glaciofluvial sandy soil (pH 4.2), both H+ and sulphate ions were retained to maintain 2pH + PSO4 = 11.9 in the leachate solutions. This relation between H+ and sulphate activity may be due to an adsorption mechanism or a precipitation mechanism. The precipitation mechanism is favored by the good fit of leachate composition to the conditions for jurbanite [AlOHSO4] formation from gibbsite [Al(OH)3]. In the B horizon of a sandy till at pH 3.7, the Al in soil solution (0.5 mmol L?1) was leached with sulphate. As the sulphate load was increased, some sulphate was retained. This may also be due to the dissolution and precipitation of an Al-sulphate mineral. The ion activity products of leachate solutions from the B horizon of this soil were close to the pKs reported for jurbanite. The conditions for the possible existence and/or formation of Al-sulphate minerals in acidic soils are discussed. 相似文献
12.
《Communications in Soil Science and Plant Analysis》2012,43(9):873-882
Abstract A refined scheme for the semi micro chemical analysis of sulfur fractions in soils is presented. Pyrite is analyzed, as iron, after extraction in HNO3. Non‐pyrite iron is excluded by a pretreatment with HF/H2SO4. Water‐soluble sulfate and jarosite [KFe3(SO4)2(OH)6], the other dominant sulfur fractions in acid sulfate soils, are analyzed turbidimetrically, as sulfate, after successive extractions by EDTA.3Na (water soluble plus exchangeable SO4) and by hot 4 M HCl (jarosite). These methods are simpler, less bulky and more specific than most existing procedures. Introduction of elemental sulfur analysis permits estimation of organic sulfur fraction as well. Sums of individual sulfur fractions agree well with separate total sulfur determinations. The proposed analysis of pyrite permits also distinction of the components Fe2O3, FeO and FeS2 in soils and rocks2. 相似文献
13.
A computer simulation was done to illustrate how the equilibrium solubility and speciation of Al in well-aerated soil solutions may be affected by pH (from 2.0 to 10.0), organic acids (citric, oxalic, phthalic, and salicylic acid), metal ions (K, Mg, Ca, Al, Fe), inorganic ligands (F, OH, SO4, PO4, CO3, and SiO3), and type of Al-containing solid [kaolinite, gibbsite, or amorphous Al(OH)3] thought to be present. The simulation indicated that the type of Al-oxide/hydroxide considered has a substantial influence on the inorganic and organic equilibrium composition of the soil solution, and on the occurrence (or non-occurrence) of other Al-minerals such as KA13(SO4)2(OH)6 (alunite) and Al(SO4)(OH)-5H2O (jurbanite). 相似文献
14.
《Communications in Soil Science and Plant Analysis》2012,43(11-12):1947-1955
Abstract To evaluate conventional calcium dihydrogen phospahte [Ca(H2PO4)2] solution containing 500 mg P/L as an extractant for soluble plus adsorbed sulfate (SO4), we added known amounts of SO4 to 10 soil samples differed in clay mineral composition and extracted with Ca(H2PO4)2 solution. The experimental results showed that the five successive extractions at a soihsolution ratio of 1:10 could quantitatively recover the added SO4, and there was little effect of air‐drying the soils after addition of SO4. Based upon these experimental results, we concluded that the Ca(H2PO4)2 extraction is an excellent method for determining soluble plus adsorbed inorganic SO4 in soils. 相似文献
15.
《Communications in Soil Science and Plant Analysis》2012,43(5):841-851
Abstract The indirect procedure for sulfate determination by Ba absorption spectroscopy was modified so that low concentrations of SO4 in small volumes of solutions could be determined rapidly and precisely. Major modifications consisted of seeding the sample with BaSO4, precipitating in ethanol solutions to lower BaSO4 solubility, and determining Ba in a N2O‐acetylene flame using the absorption mode. The results showed: complete SO4 precipitation as BaSO4 after 15 min of shaking, little or no effect from solution Al on SO4 determination, quantitative recovery of SO4 from 0.01 M Ca(H2PO4)2 soil extracts, and greater precision of SO4 measurement with indirect method than with turbidimetric method. 相似文献
16.
Effects of phosphogypsum or calcium sulfate on aluminon reactive aluminum in solutions at varying pH
《Communications in Soil Science and Plant Analysis》2012,43(15):1715-1730
Abstract Growing evidence of positive crop responses to gypsum or phosphogypsum (PG) application in acid soils strongly support the use of these amendments as an ameliorant of subsoil acidity. Although gypsum improves Ca availability in subsoils, its role in alleviation of Al toxicity needs careful attention. In the current study, either PG, CaSO4.2H2O or CaCl2.2H2O was added (to supply 12 mM Ca) to solutions containing 40 μM Al at pH 4.1 + 0.1. Solution pH was gradually raised to 4.5, 4.8 and then to 5.3 at various time intervals during 25 d aging of the solutions at 25 + 1OC. Concentration of Al measured by aluminon method without preacidification and preheating, referred to as “reactive Al”; in this paper, was 16 μM in 2 g L‐1PG solution without added Al. This accounted 38% of total soluble Al in PG solution. Addition of 2 g L‐1PG to solution containing 40 μM Al, resulted in only 42% of total Al in solution present in forms reactive with aluminon. According to MINTEQ speciation model, Al in solution was present as an entirely complexed form with F‐. An increase in solution pH up to 5.3 had no effect on measured concentration of reactive Al or predicted distribution of Al species. Addition of CaSO4.2H2O to 40 μMAl solutions had no effect on the concentration of reactive Al within pH 4.1 ‐4.8, however, up to 62% of total Al was in a form complexed with SO4 2‐, as predicted by MINTEQ model. The concentration of reactive Al decreased by 60% at pH 5.3. Addition of CaCl2.2H2O also had no effect on the concentration of reactive Al within pH 4.1 ‐ 4.8. Nearly 73 ‐ 94% of total Al was present in Al3+form. An increase in pH to 5.3, decreased the concentration of reactive Al by 27%. The results suggest that ion‐pairing of Al with F‐would appear to be a possible mechanism for alleviation of Al toxicity by PG at pH range 4.1 ‐ 5.3. With regard to CaSO4.2H2O, at pH 4.1 ‐ 4.8 ion‐pairing with SO.4 2‐appears to be possible mechanism for the alleviation of Al toxicity. In addition, at pH 5.3 a considerable decrease in reactive Al was evident which would further alleviate Al toxicity. 相似文献
17.
Solubility characteristics of proto-imogolite sols: how silicic acid can de-toxify aluminium solutions 总被引：1，自引：0，他引：1
Proto-imogolite sols can be considered as highly dispersed forms of proto-imogolite allophane, the most widespread type of allophane in volcanic and non-volcanic soils world-wide. The solubility characteristics of such sols define the conditions of precipitation of allophanes in soils, and the maximum concentrations of aluminium released during acidic episodes from soils, such as podzols, that contain allophane. Direct measurement of Al, Si and pH values in equilibrium with proto-imogolite sols, approached from higher and lower pH, indicated a solubility equation: where log*Kso lay in the range 7.14 to 7.23 after equilibration for 4–24 weeks at 22 + 2°C in 17 of the 20 systems studied. The mean value of log *KSO at 298 K was calculated as 7.02. This value indicates that proto-imogolite will be more stable than amorphous aluminium hydroxides at H4SiO4 concentrations above 5 × 10?6m , but less stable than bayerite below 10?3m H4SiO4, and than gibbsite below 10?2m . Proto-imogolite is more stable than micro-crystalline gibbsite in 10?4m H4SiO4, a typical minimum concentration in soil solutions and streams in landscapes where podzols are present. The rapid formation of proto-imogolite effectively prevents the formation of gibbsite seeds in soil, except in highly leached and warm environments, i.e. in older landscapes in the tropics. Although the presence of 10?4m silicic acid has been found to eliminate the acute toxicity to fish exhibited by solutions containing 6–7 μm Al at pH 4.96, little or no proto-imogolite would form under these conditions. Silicic acid would, however, prevent the precipitation of aluminium hydroxides, and could inhibit the formation of the A113 polycation. These polymeric species are a likely cause of the increased toxicity exhibited by partially neutralized aluminium solutions. 相似文献
18.
Paul A. Arp Catherine Akerley Kajetan Mellerowicz 《Water, air, and soil pollution》1989,48(1-2):277-297
Two adjacent soils with contrasting sulfate sorption were examined in terms of (i) water-soluble and ion-exchangeable Al, Fe, Ca, Mg, K, Mn and Zn, (ii), water- and bicarbonate-extractable sulfate, (iii) Truog-extractable P, (iv) dithionite-extractable Al, Mn and Fe and (v) treatment response to irrigation with simulated acid precipitation. The biomass of 8 year old black spruce saplings growing on the soils, and the distributions of Al, Fe, Ca, Mg, K, Mn, P and Zn within these plants, were also examined. The soils were well to moderately-well drained, with the mineral soil exposed by site preparation prior to planting. The exposed soil underneath individual saplings was treated with acid sulfate solutions (75 mm containing 2 to 50 mg L?1 H2SO4) applied during each of three consecutive growing seasons. The results indicate that Al, much like Fe, Ca, Mn and Zn, accumulated with time in the foliage, but K, Mg and P were highest in young plant tissues. Much of Al and Fe taken up remained in the fine roots. Aluminum uptake increased with the amount of dithionite-extractable Al (free Al oxide) in the soil. Growth of the black spruce saplings was not visibly affected by readily accessed Al in each soil, or by acid irrigation.Instead, growth was restricted by factors other than soil Al and acid irrigation in spite of (i) low soil pH, (ii) high levels of exchangeable Al, and (iii) high levels of Al in fine roots. Sulfate retention across and within the two soils was positively correlated with free Al oxide. The two soils responded to acid irrigation by accelerated silicate weathering and enhanced ion leaching. Sulfate sorption reduced these effects. 相似文献