Acúmulo, exportação e restituição de nutrientes pelas bananeiras "Prata Anã" e "Grand Naine"

The knowledge about the content of nutrients in the harvested part of plants is important to assess the quality of product and the removal of the nutrients from the cultivated area. This research was carried out to evaluate the nutrients exported (rachis of the inflorescence + fruits), and restituted to the soil, in a banana plantation. The study was conducted during the period of June, 2004 to May, 2005, in an Inceptisol, in the municipality of Limoeiro do Norte, Ceara, where two blocks of samplings were planted with 'Grand Naine' and 'Prata Ana' cultivars. Starting from the 30 days after planting, at 45 days interval, plant samples were collected, harvesting four clumps in full competition, chosen at random for analysis. The sequence of nutrients exported by the bunch in case of 'Prata Ana' was K>N>Ca>P>Mg while in Grand Naine cultivar the sequence was of K>Ca>N>P>Mg. At harvest time, in the clumps of cv. Prata Ana were accumulated on an average 2.2 times more nutrients in comparison to mother plant while in the plants of Grand Naine such relation was 1.2 times. Independent of cultivar, the order of the amount of nutrients returned to the soil after the crop removal was K>Ca>N>Mg>P.