Abstract

CHAVES-BEDOYA, Giovanni; ORTIZ-MORENO, Martha Lucia  and  ORTIZ-ROJAS, Luz Yineth. Effect of agrochemicals on soil microorganisms of a rice culture. Acta Agron. [online]. 2013, vol.62, n.1, pp.66-72. ISSN 0120-2812.

This paper show an analysis of the effect of agrochemicals used in a rice crop on the abundance of Oxisol soil microorganisms in the region of the Eastern Plains of Colombia, under field conditions. Evaluated Agrochemicals were Glyphosate, Bispiribac, Azoxystrobin and Malathion, applied in commercial dosages, in a block design with repeated measures. For the enumeration of microorganisms, soil samples were taken from rhizospheric soil using the transects methodology. From the samples, microbial counts were carried out using the method of dilution in plate and the data were analyzed using the Minitab 14 software using analysis of variance and test for multiple comparisons. In the counts bacteria Gram (+), Gram (-), actinomycetes, and functional groups: nitrogen fixers, and phosphorus solubilizing, together with the fungus, Trichoderma spp., Fusarium spp., and Penicillium spp. were found. In general, fungi, actinomycetes and the phosphorus solubilizing microorganisms were more affected by the agrochemicals with reductions in their abundance. Bacteria presented varying behaviors depending on the agrochemical and the nitrogen fixers were stimulated by the treatments. These results indicate that the chemicals may impact in different ways to the microorganisms that are responsible for the decomposition of organic matter.

Keywords : Agrochemicals; microorganisms; soil; Xenobiotics.

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