Contributions of Forest Opal and Associated Crystalline Phases to Fine Silt and Clay Fractions of Soils

Abstract

AND AbstractThe scanning electron microscope (SEM') is useful in the identification of biogenic opal 9 Opaline spheres, cups, and scrolled or convoluted sheets were identified in both soil and vegetative isolates. X-ray diffraction analysis indicates that both alpha quartz and cristobalite were co-associated with the amorphous opaline phase synthesized during life metabolism of deciduous tree leaves. Such crystalline phases were most abundant in the 2-5/zm fraction and many consist of anitsotropic rods with parallel extinction or equidimensional bodies with aggregate e~tinction. Between 2/3 and 3/4 of the total opal isolate from deciduous tree leaves was solubilized when digested for 2.5-min ir~ boiling 0.5 N NaOH. Rate of dissolution was a function of particle-size and tree species. Biogenic opal of forest origin was about 10-15 times more soluble than grass opal, which probably reflects the higher specific surface of the former.

Tracing the origin of dissolved silicon transferred from various soil-plant systems towards rivers: a review

“…The storage of BSi in grasslands ecosystem ranges from 4 to 16 kg Si ha −1 yr −1 (Blecker et al, 2006). Wilding and Drees (1974) have shown that forest BSi is about 10-15 times more soluble than grass BSi, owing to its greater specific surface area.…”

Tree species impact the terrestrial cycle of silicon through various uptakes

“…Thus, we can expect various dissolution rates of BSi particles in forest floor. Wilding and Drees (1974) have shown that phytoliths dissolution rates are a function of the phytoliths morphology: forest BSi is about 10-15 times more soluble than grass BSi, due to the higher specific surface area of the former.…”

Phytolith taphonomy: a comparison of dry ashing and acid extraction on the breakdown of conjoined phytoliths formed in Triticum durum

“…Wilding and Drees (1974) conducted experiments to measure the dissolution rates of phytoliths in heated sodium hydroxide and found that the rate of dissolution was dependent on taxa and was ten to fifteen times greater in phytoliths from trees than in those from grasses (Wilding and Drees 1974).…”