La humificación en diversos ecosistemas forestales representativos de la provincia de Toledo (España)

Abstract

The humus of several representative forest ecosystems in the Toledo province was characterized. It is demostrated how the evolution of the organic matter on granite in the Pinus pinea L., Juniperus oxycedrus L. subsp, oxycedrus, Quercus rotundifolia Lam., Q. pyrenaica Willd, and Castanea sativa Miller woodlands, ends in the formation of forest mutl and mull-moder humus, but generally with scarce transformation of soluble forerunners, what ¡s showed by the abundance of the fulvic acids, and the predominance of the slight polimerizated humic acids on the very polimerizated humic acids. Only the humus of the Castanea sativa Miller wood establishes an exception and its ratio Af/Ah=0,52, and its rate of inmovile humic acids (lightly higher than the mover humic acids), indicates the favourable conditions for the humification of this arboreal species. The Quercus coccifera L. brushwoods developed on "arcosic clays" promotes the formation ofmesotrophicforest mull, which shows scarce polimerization of the humic acids. The evolution of the organic matter in Quercus rotundifolia Lam. and Q. pyrenaica Willd, woodlands developed on the siliceous standstones is more favourable because the greater rate of clay induces an humification which ends in an adjusted proportion of the fulvic acids, and a predominance of the humic acids more polimerizated fractions. The humus of the Quercus rotundifolia Lam., woodlands on gypsum marls and limestones, is a calcic-mull butlittle evolved by the early insolubilization of the fulvic acids by the calcic carbonate.