POTASSIUM-BORON AND CALCIUM-BORON RELATIONSHIPS IN PLANT NUTRITION

Abstract

It is evident from sand-culture studies, that injury resulting from an inadequate supply of B, and the destructive effects due to excessive B, are definitely associated with the available supply of K and of Ca in the growth medium. Both K and Ca, particularly at the higher concs., aggravate the injury resulting from B deficiency. At the other extreme, external symptoms of B toxicity at high B levels, like deficiency symptoms at low B levels, are progressively accentuated with increasing K conc. in the growth medium. Ca, however, tends to check or prevent injury to the plants caused by too much borax. Quantitative analyses show that B accumulation in the plant tissues is associated with the amt. of K supplied to the plants, low K in the growth medium corresponding to low B in the tissues, and high K corresponding to high B in the plant. Ca, when added to the growth medium in increasing quantities, retards the accumulation of B in the tissues. This explains its inhibitory influence upon B toxicity. In this respect the influence of Ca is opposite to the accentuating effect of K on the injury resulting from too much B in the growth medium.