Abstract

Litterfall transfers nutrients to soil; roots (and mycorrhizas) absorb nutrient but also die and decompose. A long-term litter manipulation experiment established in 2003 in lowland tropical forest in Panama investigates the effects of changing nutrient input in litterfall. A general prediction is that root mass should increase in the infertile condition, but first measurements of roots after 18 months of manipulation (Sayer et al., 2006) showed the opposite – less root biomass in litter removal plots. Therefore my study aims to investigate the general idea of root-nutrient relationships and fine root dynamics specifically in lowland tropical forest using various methods including sequential coring, ingrowth cores and root windows. After a long-term of manipulation (10 years) the results from sequential coring showed that fine root biomass in top soil layer (0-5 cm) was significantly lower in litter removals than the controls during wet season (ANOVA, F1,88 = 4.1, p < 0.05), which is the opposite of the general prediction. Thus although across site those with less fertile soils have higher root biomass and root/shoot ratio, when a site is impoverished by removing nutrients root biomass and litter production decrease.”