Monitoramento contínuo do potencial redox e de variáveis complementares em ambiente hipersazonal no Pantanal Norte

Abstract

The analysis of redox potential and other associated soil variables may be useful for understanding the dynamics of hydromorphic soils throughout the water cycle of the Pantanal. This study investigated the redox potential and soil variables (CO2, O2, temperature, moisture and matric potential) by continuous and uninterrupted monitoring. Measurements were made at 10 and 30 cm depth in a Haplic alitic gleisolic Planossol soil with Cerrado sensu stricto vegetation, in the municipality of Barão do Melgaço in the northeastern Pantanal. Redox potential values ranged from 636 mV (rising water period) to -341 mV (flooded period), characterizing an anaerobic environment when flooded and an oxidized environment in the other seasons of the hydrological cycle. This confirmed the redox potential as a versatile indicator to understand the oxidative-reductive reactions in the hydromorphic soils of the Pantanal wetlands, since the redox values decreased when soil moisture was high. The study also showed that continuous and uninterrupted monitoring of additional variables can be important for further analyses of the hyperseasonal nature of these soils. Soil matrix potential and soil moisture were the variables that explained most variation in the data of the hydrological cycle, indicating that these physical parameters are crucial for biological processes in this tropical soil with hydric hyperseasonality.