Effect of cover crops and metribuzin herbicide on weed seed bank of potato (Solanum tuberosum L.) in conservation and convention tillage systems

To investigate the effects of cover crop and metribuzin herbicide on weed seed bank of potato in different tillage systems, the experiment was carried out as a split- split plot based on a randomized complete block design with three replications at the Research Station of Agricultural Faculty of Bu-Ali Sina University, 2013. The treatments included tillage systems at two levels (conventional tillage and minimum tillage) as main plots, three levels of cover crop (Vetch (vica villosa roth), barley (Hordeum vulgare L.) and without cover crops) as subplot, and two levels of metribuzin herbicide (with herbicide and no herbicide) as sub-sub plots. The results showed that the application of metribuzin herbicide reduced seed bank density of weeds. Seed bank density of weeds reduced with application of metribuzin herbicide was about 33.62 percent, compared to no herbicide. Application of cover crops in the minimum and conventional tillage reduced seed bank density of weeds 44.43 and 54.88 percent, respectively, compared to no cover crops. The use of barley and vetch cover cover decreased the richness index of seed bank of weeds. Metribuzin herbicide in the minimum and conventional tillage in comparison to control treatment decreased 23.22 and 71.51 percent the richness index of the weed species. Cover crops decreased by 24.60 and 23.13 percent in conventional tillage and minimum indices of Shannon-Weiner weeds. The decrease in the Shannon-Weiner index with application of herbicides and cover crop in the conventional and minimum tillage was 85.17 and 32.66 percent, respectively, compared to no cover crops.