pH-Änderungen in der Rhizosphäre von Mais- und Erdnußwurzeln

pH changes in the rhizosphere of peanut and maize roots pH changes in soil near growing peanuts and maize seedlings were measured using antimony microelectrodes. The roots of each plant actively altered pH, both at the root tip and root hair zone (maize) and immediately behind the root elongation zone (peanut). Along the root elongation zone and at distances greater than 10-15 cm from the root tip, pH moved towards the value in the soil outside of the rhizosphere. Peanut seedlings grown in unfertilized and NO₃-fertilized soil (initial pH 5.5) lowered soil pH by 1.5 and by 0.7 units, respectively; whereas maize seedlings caused pH increases of 1.0 and 1.5 units, respectively. In NH₄-fertilized soil, both seedlings caused soil pH to fall by 2-3 units. In an acid soil, pH changes occurred at distances of up to approximately 2.5 mm from root surfaces.