Variación de la composición mineral de la hierba de una pradera semiagostante con su estado de madurez

In this paper seasonal advance and maturity effects on the contents of ten bioeiements (N, P, Na, K, Ca, Mg, Fe, Mn, Cu and Zn) in a grass community from a Salamanca área pasture, are studied. N, P, K, Fe, and Mn levéis show a high decreasing tendency with maturity while those of Na and Ca tend to increase. Influence by the plamt stage is very little: Cu, Mg, and Zn show no effect at all. Seasonal advance largely affects to K, Mn, Fe, Ca, and Na: causing a decrease in the contents of the first three and showing a tendency to increase in those of the 'last two. This influence slightly appeared in P and Mg, while N and Cu are not affected. Data of dried sustance production and each element productions along the chosen period for this study are included. June reaches the highest yieids with the exception of Cu and Mg whose máximum productions are found during the first fortnight of July. PASTOS