Nature of Cementing Materials in Ortstein Horizons of Selected Florida Spodosols: II. Soil Properties and Chemical Form(s) of Aluminum

Abstract

Possible differences in soil characteristics between ortstein and nonortstein Spodosols were studied. Organic C, fine particles (silt plus clay), and extractable Al by dithionite‐citrate, pyrophosphate, acid NH4 oxalate, and NaOH were all higher in Bh than other horizons, except silt plus clay contents in Btg horizons of the St. Lucie County soils. While dithionite‐citrate‐extractable Si was higher at the surface, larger amounts of Fe seemed to occur in lower horizons. Both contents were much lower than extractable Al with the exception of Si in the A and E horizons. Quartz, gibbsite, kaolinite, and hydroxy‐Al interlayered vermiculite were dominant clay‐size minerals. In general, no consistent differences were found in soil properties between the paired ortstein and nonortstein Spodosols except that the ortstein horizons contained more clay and more extractable Al. The cementing materials were shown to dissolve in reagents commonly used for Al and Fe extractions. The dithionite‐citrate reagent was the most effective extractant. The amounts of extractable Al and Fe by dithionite‐citrate, acidic oxalate, and NaOH were small after the ortstein samples were treated with pyrophosphate. These findings suggested that Al in the cementing materials was likely in organic complex form. Ratios of pyrophosphate‐extractable Al to oxalate‐extractable Al and the percentage of maximum Al‐organic complexes supported this assumption. Higher fulvic‐C contents and higher fulvic‐C to humic‐C ratios in ortstein than in nonortstein spodic horizons indicated the complex probably was an Al‐fulvate form.

Pyrite and other sulphur minerals in giant aquic spodosols, Western Australia

“…These soils have developed spodic horizons containing illuvial mineral and organic materials; they are consequently classified as Aquods (Soil Survey Staff, 2006). The cementing agent between the coarse sand grains is composed of Fe and/or Al compounds and organic compounds (Lee et al, 1988;McHardy and Robertson, 1983;McSweeney and FitzPatrick, 1990). These spodosols contain authigenic pyrite and are therefore potential acid sulphate soils.…”

Fracionamento do alumínio por técnicas de dissoluções seletivas em espodossolos da planície costeira do Estado de São Paulo

“…No entanto, a figura 2 mostra que a reta da equação de regressão entre Al n e Al o ajusta-se próxima à da linha 1:1 e que os pontos que mais se afastam da reta situam-se abaixo da linha de regressão, sugerindo que formas minerais de Al também ocorrem em determinados horizontes e perfis estudados, o que será discutido posteriormente. Lee et al (1988), estudando Espodossolos da Flórida, constataram que NaOH dissolveu os maiores conteúdos de Al, enquanto pirofosfato extraiu o menor, com valores intermediários para Al o . Esses autores atribuíram esses resultados ao fato de que NaOH pode dissolver gibbsita e outros constituintes minerais pouco cristalinos, enquanto pirofosfato é assumido ser específico para complexos organometálicos.…”

“…Nos solos estudados, o NaOH 0,5 mol L -1 geralmente extraiu mais Al que os outros extratores, como constatado por Lee et al (1988). Observa-se que Al n aumenta com o aumento das diferenças entre A figura 4 mostra a correlação e a equação de regressão entre os conteúdos de Al extraídos por pirofosfato e aqueles extraídos com oxalato e DC de todos os horizontes e solos aqui estudados.…”

Distribution and Genesis of Ortstein and Placic Horizons in Soils of the USA: A Review

“…In the USA, ottstein has been studied in soils in the "flatwoods" of Flotida (Lee et al, 1988a(Lee et al, , 1988b, on sandy drift in New England and New York (Freeland and Evans, 1993), on outwash in northern Michigan (Mokma et al, 1990;Mokma, 1997;Battett, 1997), and on uplifted matine terraces in Oregon (OR; Bockheim et al, 1991Bockheim et al, , 1996. Soils with ortstein have been tepotted throughout the world, including eastetn and western Canada (Lavkulich et al, 1971;Lapen and Wang, 1999), Finland (Yli-Halla et al, 2006), Great Britain, Getmany and Poland (Kaczorek et al, 2004), Russia (Katavayeva, 1968), and in tropical regions such as northern Queensland, Australia (Farmer et al, 1983) and the People's Republic of Congo (Schwattz, 1988).…”