For nutritional diagnosis of the banana it is necessary to standardize the tissue sampling to be used, since the mineral composition changes with the plant age, sampled leaf, among the several parts of the leaf, besides ecological conditions, variety differences and seasonal fluctuations of the elements. Therefore, the possibility of mistake in the interpretation is considerable. The Method of International Sampling of Reference (MEIR) for banana recommends to collect the third leaf of plants with bunches that present all of the visible hands and no more than three hands of open masculine flowers, leaving the internal half of a central grade of the limbus, without the central rib. There is some difficulty in following such recommendation for banana tree 'Prata-Anã' cultivated in the North of Minas Gerais, because it possesses high load and very dense foliar rosette that confuses the location of the sampled leaf. Moreover, usually the samples are removed with width different from the recommended 10 cm. Due to the sampling difficulties of the 'Prata-Anã' banana and the fact that this cultivar, under irrigation, to be little studied when compared to those of the subgroup Cavendish, the present work aimed to determine the effect of the sampled leaf and the sample width on the mineral contents of the 'Prata-Anã' banana tree cultivated under irrigation in the North of Minas Gerais. In spite of the statistical variations, the foliar contents maintained themselves inside of the sufficiency grade, regardless of the sampled leaf position - 2nd, 3rd or 4th leaf - or of the sample size - 10, 20 or 30 cm of width. This suggests that the leaf collection in the position above (second) or below (fourth) of the third recommended leaf, in a foliar width from 10 to 30 cm, does not alter a lot the foliar contents in relation to the indication by the MEIR, thus being tolerated as a possible sample variation for the tested position and foliar width.
nutritional diagnosis; foliar analysis; diagnostic-leaf
