IMPACT ON THE SOIL BACTERIAL COMMUNITIES BY THE HERBICIDES USED BY THE Lotus tenuis PROMOTION

NIEVA, A.S.; BAILLERES M.; LLAMES M.E.; MENENDEZ A.B.; RUIZ O.A.

MAR DEL PLATA

Congreso; CONGRESO 2015 SAIB; 2015

Sociedad Argentina de Bioquímica y Biología Molecular

Promoting the forage Lotus tenuis is an importantalternative for cattle-forage production in the Flooding Pampa, Argentina. Thisagricultural practice requires the application of herbicides to remove plantspecies competing. The use of them, in addition to the removal of nativevegetation, may affect the diversity of bacterial communities.  To evaluate this, we analyzed three differentrangeland sites of the Flooding Pampa region. At each site, two paddocks werecompared: one managed to promote de forage legume L. tenuis, and thesecond covered by natural grasses. To asses bacterial diversity we used 454-FLXpyrosequencing technology of the V4 region of the 16S rRNA gene, on genomic DNAisolated from soil samples. From the 18 soil samples studied, we obtained135.918 sequences, representing 3187 Operational Taxonomic Units (OTUs).  The main identified components of thebacterial community were Acidobacteria, Verrucomicrobia, Planctomycetes andChloroflexi.  NMDS ordination in twodimensions based on Bray-Curtis distances and PERMANOVA test did not show differencesin bacterial community composition between paddocks promoted or not with L.tenuis, although differences among sites were detected. Our results suggestthat 5-6 years of land use with L. tenuis promotion using herbicides, doesnot produce enough impact on the microbial community structure in thisecosystem.