Ciclagem de nutrientes em cerrados sobre Neossolos calcário e arenítico

Abstract

We investigated whether the nutrient cycling in a cerrado sensu stricto on Calcareous Neosol indicates a more efficient nutrient cycling than the same cerrado physiognomy on sandy soil. We installed three transects for distribution of 60 plots in each cerrado. Among these, 20 were randomly selected, where we evaluated soil chemical properties, quantified litter litter collectors in the year of study and estimated decomposition through litter bags. We chemically analyzed leaf litter from both collectors and litter bags each month. We tested correlations between loss of dry mass and release of nutrients. The macronutrient contents of the calcareous Neosol were higher than in of sandstone Neosol, being characterized, respectively, as eutrophic and dystrophic. In the first, acidity and Al were lower than in the second. The production of litter and all its components was higher in the cerrado calcareous. The litter and leaf production was significantly higher in several months of the year in the calcareous cerrado, when compared to that of the arenitic cerrado. The decomposition in the calcareous cerrado was significantly faster than that of the arenitic cerrado. The nutrient production was significantly higher in different months in the cerrado, except S and N. In general, loss of dry mass did not correlate with the release of nutrients. This is the first study of nutrient cycling in areas of cerrado sensu stricto on two types of neosols in the same spatio-temporal scale. The calcareous cerrado, with its high levels of macronutrients in the soil (eutrophic) without extractable soil Al and mainly with limestone rock outcrop, represents a cerrado sensu stricto with its own characteristics and intermediate levels of soil fertility between cerrado sensu stricto on Latosols and deciduous forests on Neosols of Brazil. Such a differentiated nutritional condition also reflects in the leaf litter. Thus, we indicate the importance of more researches that characterize Cerrado savanna physiognomies on Neosols in the Triângulo Mineiro region, especially in those with calcareous influence, subsidizing their conservation.