RESUMO O objetivo deste estudo foi avaliar o enraizamento e crescimento de mudas de batata-doce em bandejas em reposta à suplementação do substrato com cálcio (Ca) e fósforo (P). Foram conduzidos dois experimentos em casa de vegetação no delineamento de blocos casualizados em esquema de parcelas subdivididas com oito repetições. No experimento com Ca as parcelas foram as doses de 0, 100 e 200 mg kg-1 de Ca e no experimento com P as doses de 0, 150 e 300 mg kg-1 de P. Em ambos experimentos as subparcelas corresponderam às épocas de amostragem das mudas (15, 30, 45, 60 e 75 dias após o plantio). O Ca presente no substrato foi suficiente para promover o adequado enraizamento e crescimento das mudas de batata-doce nas bandejas. O fornecimento de Ca em excesso (200 mg kg-1) afetou negativamente o crescimento de mudas que permanecem na bandeja por mais de 60 dias. Apesar das mudas adubadas com P apresentarem maior taxa de crescimento radicular após os 45 dias, o P inicialmente disponível no substrato foi suficiente para promover o crescimento adequado das mudas nas bandejas até os 60 dias.

ABSTRACT The objective of this study was to evaluate the rooting and growth of sweet potato seedlings in trays in response to substrate supplementation with calcium (Ca) and phosphorus (P). Two greenhouse experiments were conducted in a randomized block design with a split plot scheme and eight repetitions. In the Ca experiment, the plots were the doses of 0, 100 and 200 mg kg-1 of Ca, and in the P experiment, by the doses of 0, 150 and 300 mg kg-1 of P. In both experiments, the subplots corresponded to the sampling time of seedlings (15, 30, 45, 60 and 75 days after planting). The Ca present in the substrate was sufficient to promote the proper rooting and growth of sweet potato seedlings in the trays. The Ca supply in excess (200 mg kg-1) adversely affected the growth of seedlings that remained in the tray for more than 60 days. Although the seedlings supplied with P showed higher root growth rate after 45 days, the initial P available in the substrate was sufficient to promote the adequate growth of the seedlings in the trays until 60 days.