Sulfate Retention by an Acid BE Horizon of an Ultisol1
Sulfate Retention by an Acid BE Horizon of an Ultisol1
复制标题
DOI：
10.2136/sssaj1985.03615995004900050025x
复制
发表时间：
1985-09
影响因子：
2.9
通讯作者：
N. Hue;F. Adams;C. Evans
中科院分区：
文献类型：
--
作者：
N. Hue;F. Adams;C. Evans
许多关于土壤中硫酸盐（SO3~）滞留的明显相互矛盾的报告表明，单一的、包容性的机制可能不足以解释SO3~-土壤反应，需要对不同的土壤进行额外的实验。酸性Benndale（典型古成人）BE层，主要是粘土部分中的高岭石和三水石，最初用五种石灰率或五种石膏率处理。在田间容量培养14天后，用石膏对先前石灰化的土壤进行修正，并对先前石膏处理过的土壤进行石灰化。所有样品再次潮湿孵育14 d，之后置换土壤溶液并测定其化学成分。Ca(OH)2和CaSO4的添加顺序不影响so5.6)电解质的吸附作用。随着土壤pH值的增加，OH~增益与SOI保留的比值也随之降低。硫酸盐的保留也伴随着总交换阳离子的增加。然而，阳离子的增加随pH和SOJ~速率的变化而变化。OH和交换阳离子的联合增加，特别是在低pH和高SO3~速率下，是目前SOJ -土壤反应模型无法解释的。附加指标词：电解质吸附，特定阴离子吸附，沉淀，多机理，土壤溶液，可交换阳离子。顺化，n.v.， F.亚当斯和C.E.埃文斯1985。硫酸根在优度溶胶的酸性BE层的滞留。土壤科学。Soc。点。j . 49:11961200。酸性土壤的硫潴留已被证明随着(i) pH值的降低而增加（Elkins和Ensminger, 1971； Kojentajer等人，1983），（ii）溶液SO4~的增加(Kamprath等人，1956；Couto等人，1阿拉巴马州农业和土壤部的贡献。Exp Stn。奥本大学，加州36849。经阿拉巴马州农业局局长批准出版。Exp Stn。作为期刊第3 - 84721。1984年11月20日收到。1985年1月28日核准。2名研究助理和教授。（iii）高岭石、氧化铁或氧化铝增加（Chao et Al ., 1964; Harward and Reisenauer, 1966; Aylmore et Al ., 1967）， （iv）有机物减少（Couto et Al ., 1979）。然而，Johnson和Todd（1983）最近报道，森林土壤的酸性（<pH 5）层与土壤pH、粘土含量或可提取的Al组分之间的SO4~保留表现出弱相关性或无相关性。他们还发现SO4~保留率与有机质含量之间存在很强的负相关关系。他们的结果表明，诸如带正电的铁和铝氧化物等表面吸附模型（Parfitt和Smart, 1978; Rajan, 1978）可能过于僵化，无法完全解释土壤对SOI的保留。Pavan等人（1984）最近对Oxisol进行的浸出研究发现，添加CaSO4既不会改变土壤pH值，也不会改变CEC，这一观察结果与大多数吸附模型相矛盾。他们还报告说，CaSO4的加入导致可交换性Al的减少（pH不变），这表明在CaSO4存在的情况下，Al要么转化为一种较难溶的矿物，要么从柱中浸出。在对A12O3SO4-H2O体系的回顾中，Nordstrom（1982）提出了一个强有力的论点，即在低土壤pH值下，在Al存在的情况下，通过沉淀反应保留SO4~，这是Adams和Rawajfih（1977）首先提出的建议。尽管Rajan（1978）将扩散双层中的SO4~与被认为与固相A12O3形成共价键的SO4~分离，Johnson和Todd（1983）将SO4~分离为水可萃取和磷酸盐可萃取两部分，但大多数关于土壤保留SO4~的报告并未考虑多种机制。显然，自然土壤的SO4~滞留不能用单一的、包罗万象的机制来解释，需要对不同的土壤进行额外的实验。本研究的第一个目的是确定在Ultisol的BE层中土壤材料的SO4~保留率与pH和SO4~速率的关系。第二个目的是确定石膏-石灰添加顺序是否会影响SO4~的保留。然而，SO4~的保留具有色相等特征：硫酸盐被酸保留的程度是ULTISOL的水平[197]<表1。石灰和硫酸钙对硫酸盐保留率和羟基增益的影响。0 2。4 6 8 10 12添加强音强度x10图1。Benndale BE层土壤pH值随CaClj溶液离子强度的增加而降低。Lg、LI、Lj、L3、L4曲线的初始ph值分别为4.55、4.71、5.18、5.70、6.35；ApH分别应用于每条曲线。通常在悬浮液中测量，本研究将处理过的土壤平衡在大约田间容量的水分含量。材料与方法
Many apparently conflicting reports on sulfate (SO3~) retention by soils suggest that a single, inclusive mechanism may not be adequate in explaining SO3~-soil reactions and that additional experimentation is needed for different soils. An acid Benndale (Typic Paleudults) BE horizon, predominantly kaolinite and gibbsite in the clay fraction, was initially treated with either five lime rates or five gypsum rates. After 14-d of incubation at field capacity, previously limed soils were amended with gypsum, and previously gypsumtreated soils were limed. All samples were again incubated moist for 14 d, after which soil solutions were displaced and their chemical compositions determined. The sequence of Ca(OH)2 and CaSO4 additions did not affect SO 5.6) electrolyte adsorption was dominant. This was further supported by the decrease in the ratio of OH~ gain to SOI' retention as soil pH increased. Sulfate retention was also accompanied by an increase in total exchangeable cations. Cation increases, however, varied with pH and SOJ~ rates. The combined increases in OH and exchangeable cations, particularly at low pH and high SO3~ rates, are inexplicable with current SOJ'-soil reaction models. Additional Index Words: electrolyte adsorption, specific anion adsorption, precipitation, multiple mechanisms, soil solution, exchangeable cations. Hue, N.V., F. Adams, and C.E. Evans. 1985. Sulfate retention by an acid BE horizon of an Ultisol. Soil Sci. Soc. Am. J. 49:11961200. S RETENTION by acid soils has been shown to increase as (i) pH decreases (Elkins and Ensminger, 1971; Kojentajer et al., 1983), (ii) solution SO4~ increases (Kamprath et al., 1956; Couto et al., 1 Contribution from the Dep. of Agronomy and Soils, Alabama Agric. Exp. Stn., Auburn Univ., AL 36849. Published with the approval of the Director of the Alabama Agric. Exp. Stn. as Journal Series no. 3-84721. Received 20 Nov. 1984. Approved 28 Jan. 1985. 2 Research Associate, and Professors, respectively. 1979), (iii) kaolinite, Fe oxide, or Al oxide increases (Chao et al., 1964; Harward and Reisenauer, 1966; Aylmore et al., 1967), and (iv) organic matter decreases (Couto et al., 1979). Johnson and Todd (1983), however, recently reported that acid (<pH 5) horizons of forest soils exhibited either weak or no correlation between SO4~ retention and soil pH, clay content, or extractable Al fraction. They also found a strong negative correlation between SO4~ retention and organic matter content. Their results suggest that such surface adsorption models as the positively charged Fe and Al oxides (Parfitt and Smart, 1978; Rajan, 1978) may be too rigid to explain fully SOI" retention by soils. A recent leaching study of an Oxisol by Pavan et al. (1984) found CaSO4 additions altered neither soil pH nor CEC, an observation that contradicts most adsorption models. They also reported that CaSO4 additions caused a decrease in exchangeable Al (unchanged pH), which suggests that Al was either transformed to a less soluble mineral or leached out of the column in the presence of CaSO4. In a review of A12O3SO4-H2O systems, Nordstrom (1982) presents a strong argument for SO4~ retention via precipitation reactions in the presence of Al at low soil pH, a suggestion first made by Adams and Rawajfih (1977). Most reports on SO4~ retention by soils have not considered multiple mechanisms, although Rajan (1978) separated SO4~ in the diffuse double layer from that which was believed to form covalent bonds with solid-phase A12O3, and Johnson and Todd (1983) separated SO4~ into water-extractable and phosphate-extractable fractions. It seems clear that SO4~ retention by natural soils cannot be explained by a single, inclusive mechanism and that additional experimentation is needed for different soils. The first objective of this study was to determine SO4~ retention as a function of pH and SO4~ rate for soil material from a BE horizon of an Ultisol. A second objective was to determine if the gypsum-lime addition sequence would affect SO4~ retention. Whereas SO4~ retention has HUE ET AL.: SULFATE RETENTION BY AN ACID BE HORIZON OF AN ULTISOL 1197 < Table 1. Sulfate retention and hydroxyl gain as a function of lime and CaSO< addition. 0 2 . 4 6 8 10 12 Added tonic strength x10 Fig. 1. Soil pH decrease of a Benndale BE horizon as a function of added ionic strength from CaClj solutions. Initial pHs of Lg, LI, Lj, L3, and L4 curves were 4.55, 4.71, 5.18, 5.70, and 6.35, respectively; ApH applies to each curve separately. generally been measured in suspensions, this study equilibrated treated soil at approximately field-capacity moisture content. MATERIALS AND METHODS