ACCUMULATION OF SALTS IN SUB-IRRIGATION OF POT PLANTS

The distribution of nutrient salts in plastic pots on different types of subirrigation benches has been studied. Moderate amounts of nitrogen and potassium in the water supply led to a considerable accumulation of salts over a relatively short period of time. This accumulation was largely concentrated in the upper layers of the pots. A marked accumulation also occurred on benches with free drainage of the substrate. Increasing amounts of supplied nitrogen and potassium caused increasing amounts of calcium and magnesium in the water extracts, while the concentrations of exchangeable calcium and magnesium showed a slight decrease. Thus a distinct increase of concentrations of nutrient salts other than those introduced was also found in the surface layers. The Ca/K and Mg/K ratios in the water extracts increased with distance from the water channels. Nitrogen and potassium fertilization led to some reduction in the pH. © 1969 Martinus Nijhoff.