SOME EFFECTS OF pH ON THE GROWTH OF CITRUS IN SAND AND SOLUTION CULTURES

Abstract

An investigation was undertaken to study the effects of pH on the growth of citrus, with special reference to the direct effects as contrasted with the well-recognized indirect effects. Three separate culture expts. are reported: 2 in sand and 1 in soln., under conditions which ranged from pH 2 to 11. At these extremes, citrus plants were killed in a few days. At pH 2.5 and 3, plant life persisted for months, but little or no growth occurred. Good growth was obtained between pH 4 and pH 9.7, though difficulties due to indirect effects were encountered and the actual limits at which H and OH ions begin to exert direct deleterious effects were consequently not established. Despite these complications, the results warrant the conclusion that H- and OH-ion concs. corresponding to pH values ranging from slightly below pH 4 to somewhat above pH 9 exert no appreciable direct ill effect on the growth of sweet-orange plants.