SULFATE SORPTION BY TWO OXISOLS AND AN ALFISOL OF THE TROPICS1
SULFATE SORPTION BY TWO OXISOLS AND AN ALFISOL OF THE TROPICS1
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热带地区的两种氧化物和阿菲溶胶对硫酸盐的吸附1
DOI：
10.1097/00010694-197902000-00008
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
D. Bouldin
中科院分区：
文献类型：
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作者：
W. Couto;D. J. Lathwell;D. Bouldin
热带土壤中硫酸盐的有效性变化很大，影响其在土壤剖面中吸附的因素尚不完全清楚。使用代表巴西圣保罗的两种 Oxisol 和一种 Alfisol 的土壤样品，通过平衡程序研究了 pH 值和 SO4 浓度对 SO4= 吸附量和土壤负电荷的影响。这些实验表明，底土 (B2) 样品中 SO4= 吸附量显着。在 pH 值约为 4.0 时，一个样品中的吸附量达到 2 me/100 g 土壤以上，相对于这些高度风化的热带土壤的低阳离子保留能力而言，这一吸附量很高。硫酸盐吸附明显取决于平衡溶液的 pH 值；随着每种土壤 pH 值的增加，吸附量减少。在有机质含量较高的地表层位，SO4=吸附能力较小，pH效应不太明显。当 SO4= 吸附发生时，平衡溶液的 pH 值增加，可能至少部分是 SO4= 取代氧化物表面上的 OH− 的结果。吸附的 SO4= 在某些土壤样品中仅部分解吸，而在其他土壤样品中，SO4= 解吸的量比实际吸附的量大，表明天然 SO4= 的释放。解吸的钾被认为是衡量阳离子交换能力的指标，表明由于吸附 SO4= 水平的增加，阳离子保留位点增加。
Sulfate availability in tropical soils is highly variable, and factors influencing its sorption in the soil profile are incompletely understood. The influence of pH and SO4 - concentration on the amount of SO4= sorbed and on negative charges of the soil was investigated through equilibration procedures using soil samples representing two Oxisols and one Alfisol of Säo Paulo, Brazil. These experiments revealed that the amount of SO4= sorbed was significant in subsoil (B2) samples. At a pH of about 4.0, the amount sorbed reached more than 2 me/100 g of soil in one sample, an amount that is high in relation to the low cation retention capacity of these highly weathered tropical soils. Sulfate sorption was clearly dependent on the pH of the equilibrium solution; the amount sorbed decreased as the pH increased with each soil. In the surface horizons with relatively high organic matter content, the SO4= sorption capacity was smaller, and the pH effect was less evident. When SO4= sorption occurred, the pH of the equilibrium solution increased, probably in part at least a result of SO4= substitution for OH− on the surface of oxides. Sorbed SO4= was desorbed only partially in some soil samples, while in others SO4= was desorbed in larger amounts than were actually sorbed, indicating a release of native SO4=. Potassium desorbed, considered as a measure of cation exchange capacity, suggested an increase in cation retention sites as a result of increasing levels of sorbed SO4=.