Relationship Between Cultivable Bacterial Abundance and Soil C, N, And P Contents Across A Land Use Gradient in The Brazilian Cerrado

Abstract

Purpose: The aim of this study was to investigate how soil bacterial abundance relates to soil C, N and P contents along land use change gradient in the Cerrado landscape.   Method/design/approach: Land use categories were classified according to the succession stage of natural vegetation and agricultural activity. Soil physicochemical analyzes and plate counts of cellulolytic, amylolytic, free-living diazotrophic, phosphate solubilizing and actinobacteria were carried out. Linear regression analysis was used to investigate the interaction between the abundance of bacterial cultivable groups and soil C, N and P contents. Redundancy analysis (RDA) was used to determine the influence of environmental variables. Land use change affected how bacterial cultivable abundance interacts to soil C, N and P dynamics.   Results and conclusion: The regression analysis revealed 27 significant interactions between bacterial cultivable abundance (BCA) and soil C, N and P contents. In general, the increase of BCA is related to higher soil C, N and P rates. The influence of BCA in soil nutrient cycling seems to be more expressive in stressful environments such as intermediate succession area and agricultural lands. Nitrogen was the most affected nutrient and actinobacteria are the microbial group that can most enhance soil fertility. RDA showed that K, Mg and Ca contents were the main environmental factors acting on bacterial abundance.   Research implications: Conservation of natural resources and maintenance of biodiversity.   Originality/value: Soil bacterial functional groups and actinobacteria are directly involved in biogeochemical cycling being key factors for ecosystem conservation.