XVI International Botanical Congess
The prairie covers more than 95% of the Uruguayan territory. Grazing exclusions have allowed to generate some hypotheses over the behavior of the prairie, in order to know its evolution and the relationships between botanic composition and soil type. It is accepted that the vegetal succession is accompanied by environment modifications. It involves a regulation of the limitant elements by part of the grasses' communities. This was expressed in variations correlated with the changes in the management. P, K, Na, ICP, bases saturation, total bases and organic matter as employed like indicators.