Productivity of potato tubers in function of the doses and time of nitrogen and potassium application

With the purpose of assessing the effect of doses and application times of mineral fertilizers on the production and quality of tubercle potato, this experiment was carried out in the south center of Bahia and at the Universidade Estadual do Sudoeste da Bahia-UESB. Five application times were used (100% upon planting; 1/3 upon planting and 2/3 upon tuberization; 50% upon planting and 50% upon tuberization; 1/3 upon planting, 1/3 upon tuberization and 1/3 25 days after tuberization; 1/4 upon planting, 1/4 upon tuberization, 1/4 25 days after tuberization and 1/4 50 days after tuberization) and 3 doses of N and K (75% of the recommended dose; recommended dose according to soil analysis; 125% of the recommended dose; recommended dose according to soil analysis). The experimental outline was the factorial one (5 x 3), with plots arranged in randomized blocks with four repetitions. Tubercle productivity was assessed, as well as tubercle average weight, great tubercles productivity, great tubercles average weight, firmness, soluble solids, total titulable acidity and reducing sugars. The split application of N and K fertilization (50% upon planting and 50% upon tuberization) favored higher tubercles productivity in relation to the total fertilizer application. The application time and the doses of N and K did not promote significant responses in the dry mass, total titulable acidity, soluble solids and content of reducing sugars in the tubercles potato Vivaldi.