MANEJO DA ADUBAÇÃO NITROGENADA PARA A BA TATA-DOCE: FONTES E PARCELAMENT O DE APLICAÇÃO Management of nitrogen fertilization for sweet potato: sources and application parceling

摘要: For the purpose of evaluating yield sweet potato [Ipomoea batatas (L.) Lam.], variety “Rainha Branca”, subjected to sources and parceling nitrogen, an experiment was carried out in soil classified as typical “Inceptisol Regolitico Psamitico” at Universidade Federal da Paraiba, Areia county, from April August 2007. The experimental design used one randomized blocks, with a factorial scheme 2 x 7, using two nitrogen fertilizer (urea ammonium sulfate) eight application times (100% planting; 100% 30 days after planting (DAP); 60 DAP; 50% 33% planting, DAP), four replicates. following variables were evaluated: average weight commercial roots plan t-1 , total, commercial, noncommercial productivities roots. highest obtained urea DAP, (293.75 g).. Parceling 30, DAP responsible for per plant. lowest plant obtained in same source (26.48 g). number roots, total productivities, sulfate parceled provided values (1.50 30. 28.4 t ha -1 respectively.