engleski

The effects of herbicides on the growth of S. meliloti strains

Biological nitrogen fixation has an important role in sustainable agriculture. In order to increase the utilization of biological nitrogen fixation, the inoculation of alfalfa seeds with efficient Sinorhizobium meliloti strains is recommended. For successful production of commercial inoculum it is necessary to use highly efficient rhizobial strains which are, among other things, herbicide tolerant. In this study, the effects of herbicides imazamox, thifensulfuron-methyl and fomesafen on growth of ten S. meliloti strains was analysed in order to improve alfalfa pre-sowing seed inoculation. The filter-disc method and four different herbicide concentration (10 ppm, 100 ppm, 1000 ppm, 10 000 ppm) was used in this study.The results showed negative effects on growth of some rhizobia, but only when the highest herbicide concentration were used (10 000 ppm). Thifensulfuron-methyl inhibited growth of strains S. meliloti C 16 and S. meliloti S 26 and herbicide fomesafen inhibited the growth of S. meliloti strains 2001 and Os 5. The highest herbicide concentrations used in this study were multiple increased than the herbicide rates used in agriculture practice. The application of highest concentration of herbicide fomesafen resulted in decreasing and very slow growth of stranis S. meliloti Z 21, Os 6 and 9930, as well as herbicide thifensulfuron-methyl decreased the growth of strain S. meliloti 9930.Imazamox application in all four herbicide concentration, resulted in increasing the bacterial growth of all tested S. meliloti strains. The results of this study revealed that strains of nitrogen-fixing bacteria differently tolerate herbicides application, so for future work it is necessary to test the growth and symbiotic efficiency of rhizobial strains after herbicides treatment in field conditions.

biological nitrogen fixation; pre-sowing seed inoculation; Sinorhizobium meliloti strains; herbicide treatment

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