Multivariate analysis of chemical and microbial properties in histosols as influenced by land-use types

The histosols of the Everglades agricultural area in South Florida, USA, were drained in early 1900s and converted from wetlands to agricultural use, which subsequently increased soil oxidation and altered soil properties. The objectives of this study were to determine land-use effects on integrated soil chemical properties and how their discriminations regulate microbial community composition and function using multivariate analytical methods. Soil was collected from sugarcane, cypress, and uncultivated sites. Cluster analysis (CA) and discriminant analysis (DA) were applied to determine differences in soil chemistry and microbial community structure and function, while principal components analysis (PCA) was used to reduce variables. Canonical correlation analysis (CCA) evaluated dependent relationships between soil chemical and microbial parameters. Soils under different land-uses were perfectly clustered into their own groups, which was distinguished by labile inorganic P and total P. Discriminations on integrated soil microbial characteristics were significant. Microbial biomass C and N, community-level physiological profile components, and potentially mineralizable N contributed most to such differentiations. Canonical correlations between soil chemical and microbial indexes were significant on both canonical variates (R1 = 0.91, p = 0.0006; R2 = 0.65, p = 0.03). Cumulatively, 63% of the variances in microbial indices were explained by chemical canonical variates. Agricultural management, especially historic P fertilization, altered soil nutrient availability and consequently modified the microbial community composition and function. Future land-use changes and management should consider the role of labile P on the functioning of microbial communities and their control of nutrient cycling since this parameter had the most influence on changing soil properties.