Qualidade do solo e fluxo de CO₂ edáfico como indicadores da sustentabilidade de sistemas agrícolas

Abstract

Land use and management practices cause physical, chemical, and biological changes that affect the environmental and economic sustainability of agricultural activities. This study aimed to evaluate microbial activity in five land use and management systems in the Brejo Microregion of Paraíba, Brazil. The study was conducted in five land use systems: a forest area, an agroforestry system (AFS), an organic vegetable production area (mandala), a forage cactus monoculture, and a degraded area, all located at the Federal University of Paraíba (UFPB), Center for Human, Social and Agricultural Sciences, Campus III, Bananeiras, Paraíba, Brazil. Microbial activity was estimated by quantifying carbon dioxide (CO₂) released during the soil respiration process and captured using a KOH solution. Soil CO₂ emissions were significantly higher during the daytime than during the nighttime in all evaluated land use systems. No statistically significant differences were observed among the treatments during the nighttime period. The agroforestry system (AFS) showed the highest CO₂ emission, followed by the mandala system, degraded area, forage cactus monoculture, and forest, respectively, with a 57.79% difference between the highest and lowest values. Climatic factors, such as precipitation and temperature, influenced the decomposition dynamics and the CO₂ emissions released by soil microorganisms.