Levantamento dos elementos minerais em plantas forrageiras de áreas delimitadas do Estado de São Paulo. II - Sódio e potássio

Abstract

Determinations of the cations content — sodium and potassium— in Guinea grass (Panicum maximum), Jaraguá (Hyparrhenia rufa (Nees) Stapf) and Molasses grass (Melinis minutiflora), were carried out. The herbage samples were collected in limited area of the São Paulo State' hinterland, according with the types of soils, and two different seasons. In order to make an analysis of the results contained in table I and figure I we can see that the sodium levels were similar in the three grasses studied (table I). However, the statistical analysis showed that there were significant differences of sodium content — highest values in dry season — in the three forages plants; the low concentrations of this element suggest an inadequate supply in the soil to permit deposition in the plant. On the other hand, the distribution of potassium in the three herbage samples was dissimilar as well as there was difference between the dry seasons. Whereas the sodium concentration decreased in rainy season, the potassium levels increased in this same season (table II).