<b>Sweet potato yield and starch substance in roots according to the levels of P₂O₅</b> - DOI: 10.4025/actasciagron.v27i4.1342

Abstract

Aiming to evaluate the influence of the phosphate fertilization on the sweet potato (Rainha Branca) yield and its starch substance, a trial was carried out from February to July 2003 in a Quartz psamment soil, at the Universidade Federal da Paraíba, Areia, state of Paraíba, Brazil. The experimental design was randomized blocks with five treatments with doses of P₂O₅ (0, 100, 200, 300 and 400 kg ha^-1), in four replications. The highest sweet potato roots yields, total and commercial, due to the levels of P₂O₅, were 23.5 and 18.9 t ha^-1, and they were reached with 259 and 231 kg ha^-1 of P₂O₅, respectively, while the economical level to the commercial roots yield was 194 kg ha^-1 of P₂O₅. The economical level included more than 80% of the highest yield and its occurrence indicates the economical viability of phosphorus application on the sweet potato cultivation. The P₂O₅ level which promoted the maximum commercial roots yield and economical yield is correlated, respectively, with 23 and 20 mg dm^-3 of available P by Melich 1 extractor. The level of 293 kg ha-1 of P₂O₅ brought about the maximum starch substance (15.7%) in the commercial roots of sweet potato.