Marine calcium application on 'Palmer' mango production/Aplicacao de calcio marinho na producao da mangueira 'Palmer'

HIGHLIGHTS: Application of calcium from Lithothamnium increases the yield of 'Palmer' mango. Application of calcium until the first 30 days after flowering is crucial in increasing mango production. Application of calcium increases fruit production up to a dose of 10 L [plant.sup.-1]. Considering the growing demand for mango to meet the national and international market and the competitiveness among the producing markets, the use of new products and management techniques that improve the potential production in the irrigated areas of the Brazilian northeast can be an important tool for the sustainability of its cultivation. In this context, the objective of the present study was to evaluate the effect of doses and periods of application of calcium from Lithothamnium seaweed via fertigation, in two production cycles of 'Palmer' mango in the Brazilian semiarid region. The experiment was conducted at the Saude farm, located in the Projeto Senador Nilo Coelho N-09, in the city of Petrolina, PE, Brazil. The experimental design was randomized blocks, in a 5 x 4 x 2 factorial scheme, corresponding to five doses of Lithothamnium via fertigation (0, 5, 10, 15 and 20 L [ha.sup.-1]), four periods of application (30, 60, 90 and 120 days afer flowering) and two production cycles, with three blocks, totaling 120 plots. The variables evaluated were: number of marketable fruits and parthenocarpic fruits per plant, average weight of marketable fruits and parthenocarpic fruits, and marketable fruit production. Application of 12 L per plant of calcium from Lithothamnium promotes a 20% increase in 'Palmer' mango yield in the Sub-middle Sao Francisco Valley. Calcium from Lithothamnium should be applied from the beginning up to 30 days afer flowering of 'Palmer' mango in the Sub-middle Sao Francisco Valley. The effect of the application of calcium from Lithothamnium seaweed on 'Palmer' mango production varies according to doses and production cycles. Key words: Mangifera indica L., fertigation, Lithothamnium Considerando a crescente demanda pela manga para atender ao mercado nacional e internacional e a competitividade entre os mercados produtores, o uso de novos produtos e tecnicas de manejo que melhore o potencial produtivo nas areas irrigadas do nordeste brasileiro pode ser uma importante ferramenta para sustentabilidade do cultivo da mesma. Neste contexto, o objetivo do presente estudo foi avaliar o efeito de doses e periodos de aplicacao de calcio proveniente das algas mar