Chemical Weathering of Biotite by Organic Acids

Soil carbon, nitrogen, and base cation cycling 17 years after whole-tree harvesting in a low-elevation red spruce (Picea rubens)-balsam fir (Abies balsamea) forested watershed in central Maine, USA

“…The nearly four-fold higher CO 2 /H 2 CO 3 concentration, coupled with the higher concentration of low molecular-weight (LMW) organic acids in the regenerating relative to the reference watershed could have increased mineral weathering rates in the regenerating watershed, releasing higher amounts of Ca 2+ and Mg 2+ than in the reference watershed. Carbonic acid formed from CO 2 and H 2 O interactions in both acidic and calcareous forest soils and LMW organic acids have been shown to play important roles in mineral weathering (Henderson and Duff, 1963;Johnson et al, 1968;Boyle and Voigt, 1973;Boyle et al, 1974;Schnitzer and Kodama, 1977;Adams and Boyle, 1979).…”

Effect of pH and organic acids on nitrogen transformations and metal dissolution in soils

“…The relative effective ness of different organic acids in mineral weathering has been demonstrated by several soil scientists (Boyle et al, 1974;Kwong and Huang, 1979;Manley and Evans, 1985;Pohlman and McColl, 1985). The result of biotite weathering by organic acids showed that the relative amounts of various cations ex tracted varies with the acid used.…”

“…The organic acids ex tracted greater percentage of cations than HCl of approxi mately the same pH. Citric acid with higher stability of metal complexes than malonic acid removed more Fe, Mg, and A1 at the same pH (Boyle et al, 1974). Dissolution of feld spars by low-molecular-weight aliphatic and aromatic acids 31 revealed, however, that the total amounts of elements and of A1 released is correlated with the pH of their 10"^ M solu tions (Manley and Evans, 1986).…”

“…Even though the concen tration of these organic acids may be low, there is abundant evidence indicating their profound roles in various chemical and biological processes in soils. Numerous studies in the past have been conducted to elucidate the role of organic acids in mineral weathering (Huang and Keller, 1972;Boyle et al, 1974;Manley and Evans, 1986;Song and Huang, 1988), in inhibiting seedling or root plant development (Takijima, 1964;Tang and Waiss, 1978;Wallace and Whitehead, 1980;Krogmeier, 1988), and in soil genesis as well as in soil fertility (Stevenson, 1967;Vance et al, 1986). However, to my knowledge, no information is available on the effect of field, 1953Tabatabai, 1977, 1978;Abdelmagid, 1980;Chae and Tabatabai, 1986).…”

“…The weathering of soil silicate minerals such as feldspar and biotite by organic acids has been demonstrated by various scientists (Huang and Keller, 1972;Boyle et al, 1974;Manley and Evans, 1986). The susceptibility of minerals to decomposition by organic acids varies depending on the con centration and chemical reactivity of acids.…”