Manganese deficiency in cassava in Sergipe State, Brazil

Abstract

This work was carried out in the field to study the relationship among the appearence of intervein chlorosis of the cassava (Manihot esculenta Crantz) leaves, the nutritive state of the plants, and the soil conditions. Samples of leaves taken from chlorotic and non-chlorotic plants, as well as, samples from the soil around them, were collected and analyzed. The manganese was the chemical element identified as the cause of cassava's leaf chlorosis. The symptoms of manganese deficiency appeared on the cassava leaves, when this nutrient reached levels bellow 20 ppm in the leaves. Low contents of Mn in the leaves and appearence of symptoms of its deficiency occurred in cassava when pH values were superior to 5.8 and the quantities of Ca⁺⁺ and Ca⁺⁺ + Mg⁺⁺ in soil were above 3.8 e.mg/100 g and 5.2 e.mg/100 g respectively.