Impact on the soil bacterial communities by the herbicides used by the Lotus tenuis pormotion

NIEVA, AMIRA SUSANA; BAILLERES, MATÍAS ANDRES; LLAMES, MARÍA EUGENIA; MENENDEZ, ANA B.; RUIZ, OSCAR A.

Mar del Plata, Buenos Aires

Congreso; 51st Annual Meeting Argentine Society of Biochemistry and Molecular Biology; 2015

Promoting the forage Lotus tenuis is an important alternative for cattle-forage production in the Flooding Pampa, Argentina. This agricultural practice requires the application of herbicides to remove plant species competing. The use of them, in addition to the removal of native vegetation, may affect the diversity of bacterial communities. To evaluate this, we analyzed three different rangeland sites of the Flooding Pampa region. At each site, two paddocks were compared: one managed to promote de forage legume L. tenuis, and the second covered by natural grasses. To asses bacterial diversity we used 454-FLX pyrosequencing technology of the V4 region of the 16S rRNA gene, on genomic DNA isolated from soil samples. From the 18 soil samples studied, we obtained 135.918 sequences, representing 3187 Operational Taxonomic Units (OTUs). The main identified components of the bacterial community were Acidobacteria, Verrucomicrobia, Planctomycetes and Chloroflexi. NMDS ordination in two dimensions based on Bray-Curtis distances and PERMANOVA test did not show differences in bacterial community composition between paddocks promoted or not with L. tenuis, although differences among sites were detected. Our results suggest that 5-6 years of land use with L. tenuis promotion using herbicides, does not produce enough impact on the microbial community structure in this ecosystem.