Herbicide-mediated promotion of Lotus tenuis (Waldst. & Kit. ex Wild.) did not influence soil bacterial communities, in soils of the Flooding Pampa, Argentina

NIEVAS, S; BAILLERES, M; M.E. LLAMES; MJ CORRIALE; A. B. MENENDEZ; RUIZ O

APPLIED SOIL ECOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015

0929-1393

Promoting the forage Lotus tenuis is an appealing alternative to meet the needs for cattleproduction in the Flooding Pampa region, Argentina. This agricultural practice requires herbicidesapplication to remove plant species competing with L. tenuis. The use of chemical compounds, inaddition to the removal of native vegetation, eventually may change the diversity of other ecosystemcomponents such as bacterial communities. The underlying hypothesis of this work was that L. tenuispromotion with herbicides impacts on soil bacterial communities. Here we studied three differentrangeland sites of the Flooding Pampa region. At each site, two paddocks were compared, onemanaged to promote the forage legume L. tenuis, and the other lacking of management history andhence, covered by natural grasses. To asses bacterial diversity we used 454-FLX pyrosequencingtechnology of the V4 region of the 16S rRNA gene, on genomic DNA extracted from soil samples. Weobtained 135.918 sequences, representing 3187 Operational Taxonomic Units (OTUs) distributed in 12phyla and 45 classes. Overall, the main identified components of the bacterial community at thePhylum level were Acidobacteria, followed by Verrucomicrobia, Planctomycetes and Chloroflexi. Ourresults suggest that 5-6 years of land use with L. tenuis promotion does not affect the microbialcommunity structure in this ecosystem. NMDS ordination in two dimensions based on Bray-Curtisdistances and PERMANOVA test did not show differences in bacterial community composition betweenpaddocks promoted or not with L. tenuis, although differences among sites were detected. In parallel,Pearson´s correlation analysis suggested that L. tenuis promotion would indirectly affect members ofclasses Acidobacteria and Anaerolineae, through altering water-related soil properties.