Nitrogen in litterfall and precipitation and its release during litter decomposition in the Chilean piedmont matorral

Abstract

Parts of the nitrogen cycle involving two dominants (Lithraea caustica and Quillaja saponaria) in the Chilean piedmont matorral have been studied over a 15-month period. Analyses showed that 8.2 kg N ha - 1 yr - 1 entered the system in rainfall and dry deposition, though impaction of N-containing compounds on vegetation (not measured) may elevate this value. 1. caustica, by virtue of its greater percent cover, contributed more leaf litter than did Q. saponaria to the system (1089, vs 737 kg dry matter ha -I yr- I, respectively), although on an individual basis Q. saponaria produced more litter (640, vs 350 g dry leaflitter m - 2 yr- 1 r 1. caustica). This plus the greater nitrogen release of 1. causlica leaf litter during decomposition (2.61, vs 0.60g N kg dry litter-I yr- I for Q. saponaria) and Q. saponaria's higher N-content of dropped leaves (0.54, vs 0.37% N for 1. caustica) may indicate a more external cycling of nitrogen in Q. saponaria relative to that in 1. caustica. These two species may therefore represent two different strategies of individual nitrogen cycling, external and internal.