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1.
DING Chang-Pu 《土壤圈》1995,5(2):171-178
A greater part of water-soluble organic substances,accounting for 60-70% of the total,could be adsorbed by soils,which included strongly and weekly reducing substances,positively and negatively charged substances and substances containing amido.There existed a tendency of decrease in adsorption of the negatively charged organic substances by the soil from South China to North China,with expression as Coulombian adsorption.A simulatneous reduction of iron and manganese appeared with clear voltammertric behaviours upon oxidation of water-soluble organic substances,Complexation of organic ligands with ferrous iron and manganous manganee was proved by differential pulse voltammetric method,with disappearance of oxidation peaks of ferrous iron and manganous manganese at 0.00 V and 0.35 V and occurrence of Fe^2 -complex and Mn^2 -complex at 0l75 V and 1.2V respectively,whose peak potentials shifted backward. 相似文献
2.
Co,Ni,Cr and V in 25 typical soils of China were fractionated into exchangeable,carbonate bound (calcareous soils),Mn oxide bound,organically bound,amorphous Fe oxide bound,crystalline Fe oxide bound and residual forms using a seven-step sequential extraction procedure,so as to study the distribution of chemical forms of these metals as well as the effects of soil proiperties on the distribution.The results showed that most of soil Co,Ni,Cr and V were present in residual forms,and the distribution ratio averaged 48.2% for Co,53.0% for Ni,81.5% for Cr and 68.7% for V.The speciation of heavy metals was greatly influenced by soil physico-chemical properties and the chemistry of elements.The results also indicated that the recovery of metal elements by the sequential extraction procedure was satisfactory,with the relative difference between the sum of seven forms and the total content in soils averaging 9.5% for Co,12.8% for Ni,6.6% for Cr and 7.2% for V. 相似文献
3.
由石灰性冲积物发育而来的排水不良和排水良好的土壤中游离氧化物的分布 总被引：1，自引：0，他引：1
A study on the distribution of free iron and manganese oxides was conducted in soils developed on calcareous alluvial deposits under subhumid climatic conditions, in Western Greece. Soil samples from two well drained soils and from two poorly drained soils, classified as Alfisols, were collected and used in this study. After certification of soil homogeneity the acid ammonium oxalate and dithionite-citrate-bicaxbonate methods were used to extract free iron and manganese oxides from the samples. Iron oxides extracted by the dithionite-citrate-bicarbonate method (Fed) were significantly higher than the iron oxides extracted by the ammonium oxalate method (Feo), indicating that a considerable fraction is present in crystalline forms, independent of drainage status. A confirmation of free iron oxides and fine clay was detected. The ratios Feo/Fed and (Fed-Feo)/total Fe (Fet) could not be used to distinguish the well drained soils from the poorly drained soils. Manganese movement in a soluble form is independent of the fine clay. 相似文献
4.
钙盐诱导下土壤锰和铁的释放及其对胡椒的生物有效性 总被引：9，自引：7，他引：9
Releases of manganese and iron ions from an albic soil (Albic-Udic Luvisol), a yellow-red soil (Hap-Udic Ferrisol) and a yellow-brown soil (Arp-Udic Luvisol) induced by calcium salt addition and their bioavailability to pepper (Capsicum frutescens L.) were studied in a pot experiment. Addition of Ca(NO3)2 decreased soil pH and increased both exchangeable and DTPA (diethylenetriamine pentaacetic acid)-extractable Mn and Fe in soils. Meanwhile, total Mn accumulation in the shoots of Capsicum frutescens L. on the salt-treated soils increased significantly (P< 0.01) compared with the control, suggesting that salt addition to soil induced Mn toxicity in Capsicum frutescens L. Although exchangeable and DTPA-extractable Fe increased also in the salt-treated soils, Fe uptake by the shoots of Capsicum frutescens L. decreased. The effect of added salts in soils on dry matter weight of pepper varied with the soil characteristics, showing different buffer capacities of the soils for salt toxicity in an order of yellow-brown soil > albic soil > yellow-red soil. Fe/Mn ratio in shoots of Capsicum frutescens L. decreased with increasing salt addition for all the soils, which was ascribed to the antagonistic effect of Mn on Fe accumulation. The ratio of Fe/Mn in the tissue was a better indicator of the appearance of Mn toxicity symptoms than Mn concentration alone. 相似文献
5.
Combined application of a straw layer and flue gas desulphurization gypsum to reduce soil salinity and alkalinity 总被引：1，自引：0，他引：1
Burying a straw layer and applying flue gas desulphurization(FGD)gypsum are effective practices to ameliorate soil salinization or alkalization and to increase crop yield;however,little information exists on the effects of such integration in saline-alkali soils.A soil column experiment was conducted to investigate the effects of a straw layer plus FGD gypsum on soil salinity and alkalinity.We placed a straw layer(5 cm thick)at a depth of 30 cm and mixed FGD gypsum into the 0–20 cm soil layer at application rates of 7.5,15.0,22.5,and 30.0 t ha^-1,with no straw layer and FGD gypsum as a control(CK).The soil water content in the 0–30 cm soil layer was significantly higher(>7.8%)in the treated soil profiles after infiltration than in the CK,but decreased after evaporation.The electrical conductivity(EC)of the 10–30 cm soil layer was 230.2%and 104.9%higher in the treated soil profiles than in the CK after infiltration and evaporation,respectively,and increased with increasing rates of FGD gypsum application,with Ca^2+and SO4^2-being the main dissolved salts.Compared to those in the CK,the concentrations of Na^+,Cl^-,and HCO3-decreased in the treated soil profiles at depths above 55 cm,but the other soluble ions increased,after infiltration.A similar trend occurred after evaporation for all soluble ions except for HCO3-.The p H and exchangeable sodium percentage in the treated soil profiles were significantly lower than those in the CK over the entire profile,and decreased with increasing FGD gypsum application rates.Therefore,the incorporation of a straw layer plus FGD gypsum can reduce salinity and alkalinity,but the quantity of FGD gypsum should be controlled in saline-alkali soils. 相似文献
6.
喷灌和畦灌对冬小麦农田表层土壤结构的影响 总被引：3，自引：0，他引：3
A two-year experiment was carried out on the effect of sprinkler irrigation on the topsoil structure in a winter wheat field. A border-irrigated field was used as the control group. The total soil porosity, pore size distribution, pore shape distribution, soil cracks and soil compaction were measured. The sprinkler irrigation brought significant changes to the total soil porosity, capillary porosity, air-filled porosity and pore shape of topsoil layers in comparison with the border irrigation. The total porosity and air-filled porosity of the topsoil in the sprinkler irrigation were higher than those in the border irrigation. The changes in the air-filled and elongated pores were the main reasons for the changes in total porosity. The porosities of round and irregular pores in topsoil under sprinkler irrigation were lower than those under border irrigation. Sprinkler irrigation produced smaller soil cracks than border irrigation did, so sprinkler irrigation may restrain the development of macropore flow in comparison with border irrigation. The topsoil was looser under sprinkler irrigation than under border irrigation. According to the conditions of topsoil structure, it is preferable for crops to grow under sprinkler irrigation than under border irrigation. 相似文献
7.
The present paper deals mainly with the relationships between the distribution of rare earth elements (REE) in different forms in soils and the atomic number and with the odd-even phenomenon in the distribution of ionic lanthanides in soils.The enrichment tendency of light REE relative to heavy REE in soils was pointed out on the experimental results about the proportions of Ce-group and Y-group elements in different REE forms in soils.Meanwhile,the differentiation of Tm in different soil REE forms was compared and the reasons why Tm is enriched in soils were preliminarily discussed. 相似文献
8.
施用碱稳定固体的酸性土壤的Cu和Zn的形态分布 总被引：2，自引：1，他引：2
LUO Yong-Ming 《土壤圈》2002,12(2):165-170
Fractionation of metals in a granite-derived acid sandy loam soil amended with alkaline-stabilised sewagesIudge biosolids was conducted in order to assess metal bioavailability and environmental mobility soil solution was extracted by a centrifugation and filtration technique. Metal speciation in the soil solution wasdetermined by a cation exchange resin method. Acetic acid and EDTA extracting solutions were used forextraction of metals in soil solid surfaces. Metal distribution in different fractions of soil solid phase was determined using a three-step sequential extraction scheme. The results show that the metals in the soilsolution existed in different fractions with variable lability and metals in the soil solid phase were also presentin various chemical forms with potentially different bioavail ability and environmental mobility Alkaline-stabilised biosolids could elevate solubility of Cu and proportion of Cu in organically complexed fractionsboth in soil liquid and solid phases, and may therefore increase Cu mobility. In contrast, the biosolids lowered the concentrations of water-soluble Zn (labile fraction) and exchangeable Zn and may hence decrease bioavailability and mobility of Zn. However, Fe and Mn oxides bound and organic matter bound fractions are likely to be Zn pools in the sludge-amended soil. These consequences possibly result from the liming effect and metal speciation of the sludge product and the difference in the chemistry between the metals in soil. 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.
Addition of clay-rich subsoil to sandy soil results in heterogeneous soil with clay peds(2-mm) or finely ground( 2 mm) clay soil(FG), which may affect the nutrient availability. The aim of this study was to assess the effect of clay soil particle size(FG or peds)and properties on nutrient availability and organic C binding in sandy soil after addition of residues with low(young kikuyu grass,KG) or high(faba bean, FB) C/N ratio. Two clay soils with high and low smectite percentage, clay and exchangeable Fe and Al were added to a sandy soil at a rate of 20%(weight/weight) either as FG or peds. Over 45 d, available N and P as well as microbial biomass N and P concentrations and cumulative respiration were greater in soils with residues of KG than FB. For soils with KG residues,clay addition increased available N and initial microbial biomass C and N concentrations, but decreased cumulative respiration and P availability compared to sandy soil without clay. Differences in measured parameters between clay type and size were inconsistent and varied with time except the increase in total organic C in the 53 μm fraction during the experiment, which was greater for soils with FG than with peds. We concluded that the high exchangeable Fe and Al concentrations in the low-smectite clay soil can compensate a lower clay concentration and proportion of smectite with respect to binding of organic matter and nutrients. 相似文献
11.
12.
淹水还原条件下红壤中葡萄糖及腐殖酸对铁锰形态的影响 总被引：2，自引：0，他引：2
通过设置不同的葡萄糖/腐殖酸配比模拟还原性土壤体系,考察长期(约74 d)淹水培养过程中铁锰元素在土壤溶液/矿物相中的分布形态演变。结果表明:在淹水培养初期,葡萄糖的添加可以促进铁锰离子的还原溶出,同时土壤中可交换态和酸可提取态铁、以及可交换态锰的含量也会随之增加;而腐殖酸的添加则会促进土壤中可氧化态铁/锰含量的升高。随着培养时间的增加,铁锰离子浓度及各个土壤提取形态的铁锰含量大多呈现降低趋势,铁锰元素逐渐转化成提取性更低的矿物形态。因此,淹水环境中铁锰还原溶出-分布形态演变受到土壤中有机物质种类和含量的显著影响,呈现出不同的金属移动性和生物有效性。 相似文献
13.
水稻土的氧化还原过程及其与水稻生长的关系 总被引：1，自引：0，他引：1
水稻土的主要特点是在一年之中有季节性的淹水和落干,而各种水稻土的干湿程度和时间都有不同,因而影响土壤性质发生复杂的变化。在这些性质中,氧化还原状况是变化最剧烈而指示最明显的性质,并且直接或间接影响水稻的生长。为此,作者等从1954年起,开始了这方面的研究工作,下面是关于几个主要简题的筒单概括。 相似文献
14.
岩溶区植烟土壤pH、有效铁锰和交换性钙的空间异质性——以重庆市酉阳县为例 总被引：1，自引：0，他引：1
本研究通过野外调查,结合经典统计学和地统计学方法,分析了重庆市酉阳植烟区土壤表层pH、有效Fe、有效 Mn 和交换性 Ca 的空间异质性及相关性特征,以为岩溶区植烟土壤改良和平衡施肥以及特色优质烟叶开发提供理论依据。结果表明：酉阳植烟区土壤总体呈酸性,有效Fe、有效Mn和交换性Ca含量丰富;pH、有效Fe、有效Mn和交换性Ca变异系数为12.10%~47.86%,属于中等变异性,在土壤中比较稳定,块金效应在5.690%~7.338%,具有很强的空间相关性;pH和交换性Ca的空间分布为西高东低,有效Fe空间分布为东高西低,中部往西南方向含量最丰富,有效Mn的空间分布大致为中间低、四周高的趋势;pH与有效Fe、有效Mn存在显著的负相关性,pH与交换性Ca存在显著的正相关性。总之,研究区营养元素空间变异性中等,空间相关性强。 相似文献
15.
Robert Brinkman 《Geoderma》1977,17(2):111-144
Extensive areas of periodically wet, acid soils in Bangladesh have a seasonally fluctuating pH of the surface horizon and evidence for net clay loss. Morphological, chemical, mineralogical and other data mainly on a typical profile of these surface-water gley soils indicate a clay loss of some 1.5 kg/dm' ; alteration of smectite to a soil chlorite, interlayered material with trapped ferrous iron; the consequent drop in C.E.C. of the clay fraction; and the presence of amorphous silica. The data were used to reconstruct a sequence of three soil forming processes: Vertisol formation, then argilluviation, followed by ferrolysis.Ferrolysis involves, in the wet season: reduction producing ferrous iron, which displaces part of the exchangeable basic cations and aluminium; leaching of bases and part of the aluminium; and interlayer formation by the remaining aluminium while some exchangeable ferrous iron is trapped in the interlayers. In the dry season, oxidation of exchangeable ferrous iron produces exchangeable hydrogen, part of which attacks the clay minerals and is neutralized by liberation of Al, Mg and other ions from the clay structure. Part of the silica remaining from the clay structure is leached out in the next wet season, part accumulates in amorphous form. In soils long used for paddy cultivation, man has concentrated the ferrolysis process in the ploughed layer by the formation of a slowly permeable ploughpan causing strong reduction only in the surface horizon.The hydromorphic albic horizon over more clayey material is indicative of the dominant process in surface-water gley soils. This sequum could usefully have a more important place in soil classification than it has at present, e.g. at great group level. 相似文献
16.
对河北省中南部棉区36个地块土壤钠形态和含量进行了测定。结果表明,冀中南棉田土壤020cm全钠含量为10.7～24.6g.kg;交换性钠含量为48～10250mg.kg,水溶性钠含量为21.5～10400.5mg.kg。土壤全钠含量与交换性钠含量、水溶性钠含量之间及土壤交换性钠含量与水溶性钠含量之间均呈正相关关系;土壤全钠含量与土壤有机质含量、土壤阳离子交换量之间呈负相关关系;土壤交换性钠含量、水溶性钠含量与土壤阳离子交换量之间呈负相关关系;水浇地棉田土壤全钠含量与水溶性钠含量之间呈负相关关系。从供试土壤全钠含量为14.1～17.6g.kg,交换性钠含量为39.0～189.0mg.kg,水溶性钠含量为19.5～114.0mg.kg条件下的盆栽试验结果看出,棉花苗期干物质积累量与土壤交换性钠含量、土壤水溶性钠含量之间以及棉花苗期钠吸收量与土壤交换性钠含量、水溶性钠含量之间均呈曲线相关关系。 相似文献
17.
18.
《Communications in Soil Science and Plant Analysis》2012,43(19):2318-2329
An experiment was conducted to evaluate the effect of zinc (Zn) rates and vermicompost levels on distribution of Zn forms of a calcareous soil. After incubation periods, soil samples were air dried, and a sequential extraction scheme was used to fractionate Zn into soluble and exchangeable, bound to carbonate, organically bound, bound to manganese (Mn) oxide, bound to amorphous iron (Fe) oxide, bound to crystalline Fe oxide, and residual forms. In untreated soil, Zn was mainly in the residual fraction. Increasing rates of applied Zn significantly increased all forms of Zn. Carbonate and residual forms showed the greatest increase. Application of vermicompost significantly increased all fractions except Mn-oxide form. This increase was more pronounced for organically bound, soluble, and exchangeable forms, indicating an increase in bioavailability of soil Zn. Incubation time significantly decreased soluble, exchangeable, and organically bound forms but increased other forms of Zn, meaning a significant reduction in Zn phytoavailability in soil with time. 相似文献
19.
《Communications in Soil Science and Plant Analysis》2012,43(9):1038-1049
Information on soil zinc (Zn) distribution is essential for understanding its chemical reactions and bioavailability. An experiment was conducted to evaluate the effect of wheat straw, cow manure, and vermicompost applied with Zn rates on Zn distribution in a calcareous soil. A sequential extraction scheme was used to fractionate Zn into soluble and exchangeable, bound to carbonate, organically bound, bound to manganese (Mn) oxide, bound to amorphous iron (Fe) oxide, bound to crystalline Fe oxide, and residual forms. In untreated soil, Zn was mainly in the residual fraction. Increasing rates of applied Zn increased all forms of Zn. Carbonate and residual forms showed the greatest increase. Organic materials application increased all fractions, except Mn-oxide form, and this increase was more pronounced for the organically bound form. Concentration of soluble, exchangeable, and organically bound forms was greatest in cow manure–amended samples as compared to other organic materials, suggesting that cow manure contained more bioavailable Zn than other organic materials. 相似文献