Soil aluminium extraction methods in relation to plant aluminium and yield on Austrian and Brazilian soils

Abstract

A pot experiment with soils from Austria (Mollisol and Alfisol) and Brazil (two Oxisols), quite different in pH values and organic carbon contents, was carried out. Several soil tests for aluminum (Al) were evaluated and compared for their ability in predicting plant growth reductions and plant Al concentrations. Concerning the efficacy of the extradants in solubilizing soil Al, the amount of Al extracted decreased in the following order: 0.03M LaCl₃> 1M KCl > 1M NH₄Cl > 0.01 M CaCl₂. Only AlCaCl₂ and Al saturation correlated significantly with shoot yield of Poa pratensis (r = 0.76*** for CaCl₂; r = 0.84 *** for Al saturation) and Phaseolus vulgaris (r = 0.65** for CaCl₂; r = 0.83** for Al saturation). The results indicated that soil organic matter and the nutrient status of the soil had an important effect as diminishing Al uptake and improving growth of both Poa pratensis and Phaseolus vulgaris. Interactions between Al and magnesium (Mg) were also observed.