On-line version ISSN 1678-4499
SOUZA, Derly Machado de and HIROCE, Rúter. Diagnosis and prevention treatment, of zinc defficiency in upland rice, cultivated in soils with pH below 7, in São Paulo State, Brazil. Bragantia [online]. 1970, vol.29, n.unico, pp. 91-103. ISSN 1678-4499. http://dx.doi.org/10.1590/S0006-87051970000100009.
An abnormality in rice plants was recently noticed in Miguelopolis, Leme and Campinas counties (São Paulo State, Brazil) in soils with pH below 7. It affected the plants soon after germination, killing most of them. The surviving plants had their normal development delayed. Affected plants had their older leaves with brown color, except along the rim and the main vein which continued green. In some cases, leaves split along its length. Younger leaves, however, appeared normal. The cause of these symptoms was attributed to zinc deficiency. Chemical analyses of the whole plant indicated that symptoms appear on rice plants when zinc content was below 15 ppm in dry matter. Application of 5 kg/ha of zinc sulfate in the soil, at the planting time, was enough to avoid manifestation of defficiency signs.