Decomposition of leaf litter in the Brazilian savanna on limestone and sandstone Neosols

Abstract

Litter decomposition in the soil is an important stage of the nutrient cycling process that interferes with functioning of terrestrial ecosystems. Soil fertility and litter nutritional quality are fundamental factors that affect decomposition effi ciency of plant residues. We evaluated decomposition in two areas of 'cerrado sensu stricto', each with a type of Neosol -limestone (eutrophic) and sandstone (dystrophic). In a rural area located in the municipality of Ituiutaba (MG, Brazil), 10 plots were randomly selected to install litter bags with 10 g of mixture of dry leaves that were used to estimate rate and time of leaf-litter decomposition from October/2015 to January/2016. Decomposition rate in the limestone cerrado was signifi cantly higher than in the sandstone cerrado. This difference mustn't be explained by the edaphic texture between areas, since it was similar between them. But may be explained through aluminum absence and higher soil fertility in the limestone cerrado, especially phosphorus that is highly limiting in dystrophic cerrados like the sandstone cerrados, in which decay of decomposing leaflitter was directly proportional to the levels of phosphorus. Limestone presence reduces aluminum toxicity and circumvent phosphorus limitation in the cerrado, favoring decomposition. Such infl uence is probably an important feature for limestone cerrados.