Aluminium and acid soils

Abstract

The addition of aluminium salts to culture solutions and to soils will bring about certain changes; these may be summed up as follows:1. A change in the hydrogen ion concentration, which will vary in amount with the original buffer properties of the solution or the soil.2. A change in the buffer properties of the solution or the soil; the hydrogen in concentration of a culture solution containing an aluminium salt will tend to remain more constant than that of a normal culture solution during the period of growth of the plant, when both start at the samepH value.3. Precipitation of soluble phosphate as aluminium phosphate except in solutions or soils more acid thanpH 3·5 to 4·0; this might lead to phosphate starvation in water cultures but would have little or no effect in a soil, where the particles would remain accessible to the plant roots.