Relación entre la producción de hojarasca y las condiciones edáficas en bosques pluviales tropicales del Chocó Biogeográfico, Colombia

Abstract

Litter production (NPPlitterfall) is one of the main components of net primary productivity (NPP) in forest ecosystems. Such NPPlitterfall is determined considerably by the soil conditions in tropical rainforests. To evaluate this hypothesis five 1-ha permanent plots were established in two forests of Chocó (Opogodó and Pacurita) where NPPlitterfall was measured in 125 collectors, monthly-monitored for a year. In addition, basic soil-fertility parameters were measured and related to the NPPlitterfall. It was observed that both forests exhibited nutrient-poor soils, but with higher sand content, total N and organic matter (OM) in Opogodó. The NPPlitterfall was similar in both forests (7.82 t ha-1 yr-1 in Opogodó, and 7.35 t ha-1 yr-1 in Pacurita). Also, the litter-fall components with greatest contribution were leaves (> 60%), stems (19%) and miscellaneous (14%). Total NPPlitterfall showed a weak negative correlation with the percentage of silt. Leaf litter production was positively associated with sand content, pH, O.M. and total nitrogen; whereas, it was negatively correlated with aluminum (Al), effective cation exchange capacity (ECEC) and silt. In general, correlations between NPPlitterfall and soil parameters were weak, apparently due to the small variation in soil fertility and low availability of some nutrients (phosphorus and calcium). Therefore, these results partially confirmed the hypothesis of soil-fertility limitation upon NPP in the forests of Chocó.