Long-Term N Fertilization Decreased Diversity and Altered the Composition of Soil Bacterial Communities

BEHNKE, GEVAN; SUN, RENPENG; ZHANG, PAN; RIGGINS, CHANCE W.; ZABALOY, MARÍA CELINA; RODRIGUEZ ZAS, SANDRA; VILLAMIL, MARÍA BONITA

Baltimore

Congreso; 2018 ASA and CSSA Annual Meeting, Nov. 4-7, Baltimore, MD; 2018

American Society of Agronomy; Crop Science Society of America

Soil microbial communities are an essential component of agroecosystems due to their influence on the soil environment and the cycling of nutrients that affect crop production. Ecological studies have shown that N gradients resulting from deposition significantly alter the soil microbiome in natural settings. Yet research on this area is currently scarce in agricultural settings. Our goal was to characterize the microbial community structure following 34 years of N fertilization treatments in continuous corn production in highly fertile soils. Three N fertilization rates (0, 200, and 270 kgN/ha) were arranged in a randomized complete block design with three replications on an Aquic Argiudoll. Using 16S rRNA gene-based pyrosequencing analysis of the V4 region using Illumina HiSeq2500 technology, we characterized the structure, composition of the bacterial communities involved. Downstream bioinformatics processing and analysis were conducted with QIIME 2.0. The V4 region of 16S rDNA gene sequences were clustered into operational taxonomic units (OTUs)and the bacterial community composition and diversity were analyzed based on the OTUs extracted. Principal component analyses and canonical discriminant analysis of our major bacterial phyla indicated that high N fertilization level decreased the diversity of soil bacterial community and altered the relative abundance of the major bacterial phyla. Changes in relative abundance of Proteobacteria, Acidobacteria, Bacteroidetes, Gemmatimonadetes, Actinobacteria, Verrucomicrobia, Cloroflexi, and Planctomycetes, indicated that these phylla were the most sensitive at differentiating among N levels in this long-term experiment. A better understanding of N fertilization effects on soil health will contribute to safeguard agroecosystem sustainability.