01839nam a2200277 a 450000100080000000500110000800800410001910000170006024501560007726000460023330000100027950000200028952010770030965000140138665000120140065000140141265000200142665000130144665000100145965000200146965000140148965000140150365000120151765300110152965300210154015595902000-02-14       1981    bl uuuu  m   00u1 u    #d1 aPAVAN, M. A.  aToxicity of Al (III) to coffee (Coffea arabica, L.) in nutrient solution culture and in Oxisols and Ultisols amended with CaCO3, MgCO3, and CaSO4 2H2O.  aRiverside: University of Californiac1981  a214p.  aTese Doutorado.  aGrowth and development of coffee plants on acid soil are restricted by high concentrations of soluble Al and low base saturation. Solution culture and soil experiments were conducted to study the effect of Al and Ca nutrition on coffee seedlings and a soil experiment was conducted to measure the neutralization of subsoil acidity by the application of carbonate and sulfate materials to the surface horizon. Specifically, the solution culture experiments were designed to show the influence of (1) low to excessive concentrations of Al, (2) low to high Ca concentrations on the toxicity of Al, and (3) ionic strength of nutrient solution on Al toxicity. Aluminum toxicity was associated with reduced uptake of Ca, Mg, and P; increased uptake of K and Al, and reduced shoot and root growth. Increasing the Ca concentration did not offset the toxicity of the Al treatments. Aluminum toxicity was found to be correlated with the activity of Al 3+ rather than the total Al or Al3+ concentrations. The critical aAl 3+ concentrations. The critical aAl 3+ value was 0.65 x 10-5.  anutrients  aOxisols  aseedlings  asoil amendments  atoxicity  aCafé  aCoffea Arábica  aNutriente  aPlântula  aToxidez  aCoffee  aCorrecao do solo