Aluminum in soil

Plants may be affected by indirect modifications of the environment. Soil acidification, for example, can cause the leaching of nutrients, and the release of toxic aluminum. These effects may operate together to produce nutrient deficiencies or imbalances to plants. High soil concentrations of aluminum may prevent uptake and utilization of nutrients by plants.Increased availability of aluminum in soils has been implicated as a cause of forest declines in both Europe and the United States, possibly through the toxic effects on small feeder roots 14),... 

Both ratio of base cations to aluminum, and the aluminum concentrations, are used as indicators for steady-state geochemical and biogeochemical processes. By assigning established critical loads to these indicators (for example, the concentrations of aluminum in soil solution should not exceed 0.2 meq/L and the base cations to aluminum ratio should not be less than 1), it is possible to compute the allowable acidification for each ecosystem. An extensive overview of critical values for the ratio of base cations to aluminum for a large variety of plants and trees can be found in Prof. Sverdrup s papers (for example, Sverdrup et al., 1995 Warfvinge et al., 1992, 1993). 

But Smith s research had relatively little impact on the scientihc community over the next seven decades. During this time, acid deposition continued to be of some minor interest to scientists in parts of Europe. For example, the Swedish biologist J. R. Erichsen-Jones reported in the late 1930s that acid from rainwater dissolved aluminum in soil and that that dissolved aluminum was toxic to certain types of aquatic organisms. 

Z.M. Xie, Z.H. Ye, M.H. Wong, Distribution characteristics offluoride and aluminum in soil profiles of an abandoned tea plantation and their uptake by six woody species. Environ. Int. 26 (2001) 341-346. 

CS028 Lancaster, L. A. and B. Rajadurai. An automated procedure for the determination of aluminum in soil and plant digest. J Sci Food Agr 1974 25 381. 

Aluminum levels in soil also vary with different vegetation types. For example, aluminum levels in the soils of coniferous forests are often higher than in soils of beech forests since coniferous forests tend to have more acid soils (Brusewitz 1984). Alternate views of the data are that the acidic soil produced by conifers can preferentially mobilize aluminum from deeper layers toward surface soil, or that conifers over beech preferentially grow in soils rich in aluminum and it is their metabolic processes which produce more acidic soil. An analysis of aluminum in soils by depth could improve the understanding of this process. 

Femandez-Sanjurjo MJ, Alvarez E, Garcia-Rodeja E. 1998. Speciation and solubility control of aluminum in soils developed from slates of the river Sor watershed (Galicia, NW Spain). Water Air Soil Pollut 103 35-53. 

Kloppel H, Fliedner A, Kordel W. 1997. Behaviour and ecotoxicology of aluminum in soil and water-Review of the scientific literature. Chemosphere 35 353-363. 

Miller EK, Huntington TG, Johnson AH, et al. 1992. Plant and environment interactions-aluminum in soil solutions from a subalpine spruce-fir forest at Whiteface Mountain, New York. J Environ Qual... 

Fuller CC, Davis JA, Coston JA, Dixon E (1996) Characterization of metal adsorption variability in a sand and gravel aquifer. Cape Cod, Massachusetts, USA. J Contamin Hydrol 22 165-187 Furer G (1993) New aspects on the chemistry of aluminum in soils. Aquatic Sci 55 281-290 Ganapathi SK, Owen DM, Chokshi AH (1991) The kinetics of grain growth in nanocrystalhne copper. Scr Metall Mater 25 2699-2704... 

H. Cui, L. Meng, and Z. Zhu, Automatic Flow Injection Colorimetric Determination of Available Aluminum in Soils [in Chinese]. Fenxi Huaxue, 12 (1984) 754. 

Jones and Lowe (1969) applied the described procedure for the estimation of the anodic Tafel eonstant for samples of steel exposed in soil, while Schwerdtfeger (1958, 1961) did so for steel and aluminum in soil and sea water. However, satisfactory conformity between calculations and experimental measurements was not obtained in all cases. The applicability of the described method is in accordance with assumptions limited to corrosion systems with activation control showing a distinct Tafel slope over the range of cathodic polarization. The presence of concentration and ohmic polarization renders determination of the correct value difficult or impossible, and therefore the method did not find wider application in practice, especially in cathodic protection technology where it was to be applied. 

The oitedon for cathodic protection of aluminum in soils and waters has been published by the National Association of Corrosion Engineers (Ref 14). The suggested practice is to shift the potential at least -0.15 V but not beyond the value of -120 V as measured against a saturated copper sulfiite (C11/CUSO4) reference electrode. In some soils, potentials as low as -1.4 V have been encountered without appreciable cathodic corrosion (Ref 15). Essentially the same criterion is followed in eastern Europe (Ref 16). 

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