Relation between nitrogen fertilization and brown spot of rice in Cerrado soils

Abstract

The influence of nitrogen fertilization on the incidence
of brown spot (Helminthosporium oryzae Breda de Hann) on leaves
of rice cultivar IAC 47 was studied under upland conditions. The
experimental area was fertilized with 60 kg/ha P₂O₅, 30 kg/ha
K₂O and 0, 15, 30, 45 and 60 kg/ha of N, in the form of ammonium
sulfate. Increase in nitrogen levels from 0 to 45 kg/ha decreased the
number of lesions per leaf. A further increase to 60 kg/hA of N
increased the lesion number.