The Role of Forest Conversion and Agroecological Practices in Enhancing Ecosystem Services in Tropical Oxisols of the Amazon Basin

This study evaluates the effectiveness of agroecological practices—organic fertilization and biofertilization—in enhancing ecosystem services in agroforestry and pasture systems. A field experiment was conducted over three years, comparing these practices to a control treatment and a natural ecosystem as a reference. Soil chemical, physical, and biological parameters were assessed, including soil organic carbon (SOC), microbial respiration, root density, and gene abundances of key microbial groups (Archaea, Bacteria, and Fungi). Organic fertilization resulted in a significant increase in SOC, phosphorus, microbial biomass, and root density, indicating improved soil structure and fertility. Biofertilization showed selective effects, promoting archaeal abundance but reducing bacterial and fungal diversity. Seasonal variation influenced nutrient cycling, with organic fertilization buffering against dry-season declines in microbial activity and nutrient availability. Aboveground dry biomass and litter deposition were highest in the natural ecosystem, followed by organic fertilization treatments in agroforestry and pasture systems. Despite improvements under agroecological management, the natural ecosystem consistently maintained superior soil quality and biological resilience. The findings highlight that organic inputs and diversified cropping systems enhance soil health but do not fully replicate the ecological benefits of undisturbed forests. In conclusion, agroecological practices provide viable alternatives to mitigate soil degradation and sustain ecosystem services in tropical Oxisols. Organic fertilization emerges as the most effective strategy, fostering long-term improvements in soil fertility and microbial dynamics. However, continued research is needed to optimize these practices for greater resilience and sustainability in Amazonian agroecosystems.