NITROGEN AND PHOSPHORUS LEACHING FROM THE FOREST FLOOR OF A MATURE PINUS-RADIATA STAND

In a mature Pinus radiata plantation we studied the amounts and forms of nitrogen and phosphorus leached from the forest floor paying specia l attention to seasonal changes. Forest floor leachates were collected using zero-tension lysimeters placed underneath the Oa horizon. A lar ge amount of the N and P leached throughout the year leached during sh ort periods of time (61% of the P and 51% of the N in two months). The amount of litter and its quality (C, N and P concentration and the C: N, C:P and N:P ratios) were not related to spatial variability in litt er leachates. The seasonal pattern of inorganic P concentration and le aching suggested that peaks could be attributed to increases in throug hfall that were not completely retained by organic layers. Organic for ms accounted for a high proportion of the N and P leached, especially for the former.