PH24 Environmental Assessment, Environmental Toxicology
Exhibit Hall
8:00 AM - Thursday
(PH259) Glyphosate impact on C and N microbial functional groups in a soyabean rhizosphere.
Avanzi, M1, Matsumoto, L1, Martines, A1, Albino, U1, Brasil, C1, Rampazo, L1, Edwards, S2, Andrade, G1, 1 Universidade Estadual de Londrina, Londrina, PR, Brazil2 Harper Adams University College, Newport, Shropshire, England
ABSTRACT- The no-tillage system requires a higher use of herbicides, increasing the concern as to the effect that such products might have on the environment. However, there are few studies reporting the influence of glyphosate on soil microorganisms. The aim of this work was to evaluate the effect of two formulations of glyphosate on functional groups of microorganisms in a soybean rhizosphere. The experiment was performed in a greenhouse and the treatments were the isopropylamine salt and the ammonium salt of glyphosate at the maximum and twice the maximum permitted dose. The control treatment had no application. The populations of bacteria, fungi, actinomycetes, fluorescent pseudomonas, cellulolytics, amylolytics, proteolytics and free-living N-fixing were determined by plate counts on selective media. Plant root dry weight, shoot dry weight and the number and dry weight of nodules was determined. The application of herbicides had little effect on the populations of microorganisms as well as on plant growth. Nevertheless, the interactions among some populations of microorganisms and between these and the plant were influenced by the formulation of glyphosate applied.
Key words: interaction, glyphosate, rhizosphere, soybean