Variations in soil bacterial communities and putative functions in a sugarcane soil following five years of chemical fertilization

Abstract

ABSTRACT Chemical fertilizers are often applied to increase soil nutrient contents and improve crop yields. However, the impact of chemical fertilizers on abiotic and biotic characteristics of soil is unclear. Here, we investigated the variations in soil chemical properties and bacterial communities of sugarcane soil after a five-year chemical fertilization period with five different regimes, namely, Control (no fertilizer), PK (phosphorus plus potassium fertilizer), NK (nitrogen plus potassium fertilizer), NP (nitrogen plus potassium fertilizer), and NPK (combined nitrogen, phosphorus plus potassium fertilizer). We found that N-addition fertilizer treatments resulted in lower bacterial biodiversity as estimated by Chao1 and Shannon’s indexes. Proteobacteria, Acidobacteria, Chloroflexi, and Actinobacteria were the predominant phyla in all of the fertilizer treatments. The concentrations of different N forms (TN, NH4 +-N, and NO3 –N) were the most important factors in shaping bacterial community structure. Functional groups involved in carbon, nitrogen, and sulfur cycling significantly increased or decreased with chemical N-related fertilizer treatments (NK, NP, and NPK). The community composition and functions related to element cycling of soil bacteria were strongly affected by N-containing fertilizer treatments. The results suggest that bacterial communities in sugarcane soil may have been phylogenetically and functionally altered in response to chemical fertilization.