RECOVERY OF RICE PLANTS WITH LEAF TANNING SYMPTOMS

Abstract

The effect of zinc sulfate spraying on zinc deficient rice plants, at different stages of development was studied. The experiment was carried out on soil under “cerrado”, and the experimental design was randomized blocks with 5 treatments and 4 replications. The cultivar IAC - 12/46 was used. In the treatments receiving only one spraying, plants were sprayed at the ages of 20, 40 and 60 days, and in that one receiving two sprayings, these were executed at 20 and 50 days after sowing. The symptoms intensity of zinc deficiency was computed when the plants were 80 days old. Results showed that it is possible to recuperate rice plants with evident symptoms of zinc deficiency by spraying with a zinc sulfate solution at 0.2%. Although there are not significant differences among treatments sprayed once at 20, 40 and 60 days after sowing, it seems that late applications of this micronutrient are 1ess efficient in reducing symptoms occurrence. Best results were obtained with two sprayings. It was concluded that spraying with zinc sulfate is a viable way to minimize losses in those rice plants showing clear symptoms of zinc deficiency. It was suggested that, in such cases the rice grower should spray once with zinc sulfate solution at 0.2% between 20 and 40 days after sowing.