|
|
Regulace plevelů v porostu mrkve obecné pěstované na semeno
Coufal, Václav
The aim of this bachelor thesis was the elaboration of a literature review on weed control in carrot (Daucus carota) for seed production and to conduct laboratory experiment focused on testing selectivity and efficacy of herbicides in carrot using the chlorophyll fluorescence imaging technique. The aim of this experiment was to evaluate the efficacy of selected herbicides on common lambsquarters (Chenopodium album) and their phytotoxicity on carrot plants under pre-emergence and post-emergence applications. In addition, preemergence applications were performed in two variants simulating contrast soil conditions. The first was an organic substrate and the other quartz sand. Altogether, 8 herbicide active ingredients were used, some of which are registered in carrots, and some were previously tested abroad, thus providing the potential for improving the system of chemical weed control in carrots. These were carfentrazone-ethyl, clomazone, diflufenican, linuron, mesotrione, metribuzin, pendimethalin and S-metolachlor. Under preemergence application in the organic substrate, the best results were achieved with linuron and pendimethalin, both exhibiting high efficacy against common lambsquarters and low phytotoxicity to carrot plants. Preemergence application of herbicides in quartz sand showed a clear increase of phytotoxicity of preemergence herbicides. Increased phytotoxicity was evident in almost all herbicides, but mostlyin linuron. On the other hand, a decrease in phytotoxicity was found in diflufenican. The lowest phytotoxicity rate was observed for pendimethalin. In early post-emergence applications, the efficacy of all selected herbicides ranged above 90%. The lowest level of phytotoxicity was observed for pendimethalin, linuron, clomazone and mesotrione. Chlorophyll fluorescence imaging represents a very good tool for early assessment of the physiological herbicide effect, however, the evaluation by chlorophyll fluorescence in herbicides affecting directly photosynthesis led to overestimation the effects in comparison with other herbicides.
|
guest ::
RSS feed.