Ciclagem de nutrientes e qualidade do solo em veredas do sudeste brasileiro

Abstract

Palm swamps are Cerrado vegetations type that have peat soils saturated with water for much of the year. The monitoring of litter production and decomposition can assist in understanding the productivity and nutrient cycling of the ecosystem. Additionally, the physical, chemical and microbiological properties of the soil reflect the quality of the soil. In this sense, the objective of this study was to evaluate litter deposition and decomposition, as well as soil quality through chemical, physical and microbiological attributes, in two palm swamps at different stages of conservation. The study was carried out in Amescla (preserved) and in Peruaçu (degraded). We evaluated litter deposition using collectors and decomposition with litter bags. Soil granulometry, carbon and nutrient contents and soil microbial biomass were also evaluated up to 20 cm in depth. The data obtained were submitted to generalized linear models, followed by ANOVA. The litter production was higher in the Peruaçu, with the leaf fraction corresponding to more than 70% of the total in both areas. The decomposition constant (kc) was higher in the Almescla. The concentration of nutrients in decreasing order was Ca> N> K> Mg> S> P for both. The clay, P availble and Ca amount was higher in Peruaçu. Microbial carbon, total organic carbon, microbial quotient and carbon stock were higher in Almescla, while the metabolic quotient was higher in Peruaçu. We can conclude that the degraded palm swamp showed the highest litter deposition, due to a higher number of pioneer species, less decomposition constant due to unfavorable conditions for the decomposing microorganisms, in addition to presenting a higher metabolic quotient and less carbon stock, which may indicate a stress of the edaphic microbiota.