DIFFERENT AMOUNTS OF NITROGEN, PHOSPHORUS AND POTASH AND AGRONOMIC TRAITS OF POTATO ON 2 PH LEVELS

This experiment was carried out in order to evaluate the effects of di fferent amounts of fertilizer at planting day and the influence of the soil pH on agronomic traits of potato, as well as to compare the kind of fertilization used by potato growers of Santa Catarina State, Braz il, with the one recommended by the official research (ROLAS) in this region. The pH levels tested were 5,5 and 6,0. The amounts of fertiliz er employed were 0, 1, 2, 3 and 4 ton/ha of the formulation 5-20-10(N- P2O5-K2O). The increase of the soil pH from 5,5 to 6,0 did not affect tuber yield and components, but promoved greater incidence of Streptom yces scabies symptons in the harvest tubers. The higher tuber yields w ere achieved with 2,8 and 3,9 ton of 5-20-10 per hectare, for potato s eed and potato consumption, respectively. The tuber yield obtained wit h the application of the fertilizer dosage suggested by the official r esearch was similar to those verified with the fertilization used by p otato seed growers of Santa Catarina.