Estudio comparativo de la movilización de bioelementos por los subsistemas arbóreo y herbáceo del ecosistema de Dehesa

The quantity of various elements such as N, P, K, Ca, Mg, Na, Fe, Cu, Mn and Zn, mobilized annually by the two phytocoenotic components of the «dehesa» ecosystem has been evaluated from the data collected over two consecutive years. For this purpose, zones dominated by Oaks (Quer- cus rotundifolia Lam. and Q. pyrenaica Willd.) were selected, and, based on the annual nutrient input of the soil throug leaf litter and other re- sidues, the quantity of minerals removed was estimated. In the same lo< cations, nutrients removed from pastures were also estimated in áreas with and without tree cover. From the results obtained, comparisons have been made between the two phytocoenotic components of the «dehesa». Conclusions have been formulated regarding the recycling tendencie exhibited by each nutrient element, based on the results obtained from internutrient comparisons. The role of tree cover in regulating the rate of nutrient cycling and conservation of nutrient reserves in the ecosystem, has also been eva- luated. 20