“…This has been demonstrated for wheat with Ca, Mg, K, and Na (Camargo, 1985 and1987;Kinraide and Parker, 1987), for soybean with Ca (Alva et al, 1986a), and for corn with silicon (Si) ( Barcel6 et al, 1993). Such protection has been interpreted as a result of competition for absorption sites, or in the latter case, on the basis of removal of Al from the solution due to the formation of precipitates.…”