Analysis of functional microorganisms and their relationship with physicochemical parameters of soil in a reserved forest

Abstract

This study addresses the need to understand the presence of functional microorganisms in tropical soils, providing valuable information for conservation and sustainable management. The main objective is to analyze the variability of functional microorganisms at different soil depths and their correlations with physicochemical parameters. To this end, soil samples were collected from 15 random points in a reserved forest and analyzed for physicochemical and microbiological properties at two depths (10 and 20 cm). The following functional microorganisms were quantified: viable aerobes, lactobacilli, actinomycetes, fungi, and nitrogen-fixing bacteria using specific protocols. The non-parametric Wilcoxon test was used to determine differences between depths, and the Pearson correlation coefficient (|ρ| ≥ 0.8) was used to analyze correlations between physicochemical parameters and microorganisms. The results suggest that the abundance of viable aerobic microorganisms, Lactobacillus, Actinomycetes, and Fungi decreases with soil depth, while nitrogen-fixing bacteria show no significant differences. The decrease in abundance is related to factors such as nutrient and oxygen availability and microenvironmental conditions. There is a strong positive correlation between the amount of viable aerobic microorganisms and Lactobacillus with phosphorus content, and a negative correlation between Actinomycetes and clay content. Actinomycetes prefer sandy soils, while Fungi thrive in soils rich in organic matter. The negative correlation between Fungi and Actinomycetes suggests competition for limited resources and possible chemical interactions, such as the production of antibiotic compounds by Actinomycetes. This study demonstrates that a detailed understanding of soil microbiota can offer new opportunities to improve agricultural practices, especially in terms of soil fertility management and environmental sustainability.