ACCUMULATION OF NUTRIENTS AT THE SURFACE OF ROOTS OF BLIGHT-AFFECTED ORANGE TREES

Soil pH and the levels of potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) in the soil at the root surf ace and the surrounding soil were compared under healthy and citrus bl ight-affected orange trees at two locations. The feeder roots were als o analyzed for these elements. Potassium, Ca, and Mg were highest in t he rhizosphere of blighted trees, with some, but lower accumulation ar ound healthy roots. Potassium was higher and Fe, Mn, and Zn were lower in feeder roots of blighted than of healthy trees.