Evaluating the effect of cover crops and cultivation system on weed management in vineyards of Miandoab city

The purpose of this study was to investigate the effect of cover crops and their residues and mechanical and chemical methods on weed density and biomass in the Miandoab vineyards.

To achieve the research goal, a factorial experiment was conducted in the form of completely random blocks with 4 replications and 2 factors in the spring of 2015 and 2016 in the Sogli Tappeh (altitude 1300 meters, latitude 46 degrees and 2 minutes and longitude 36 degrees and 93 minutes) and Nasir Kandi villages (altitude 1300 meters, latitude 46 degrees and 7 minutes and longitude 36 degrees and 91 minutes). The first factor includes planting Vicia peregrina cover crop (after plowing), planting Vicia peregrina cover crop (without plowing), planting Ajowan cover crop (after plowing), planting Ajowan cover crop (without plowing), the application of glyphosate herbicide after growing (3 liters per hectare), manual weeding, weed-free control, and the second factor includes the standing and traditional systems.

The predominant weeds in the studied vineyards include Johnson grass, Binweed and Licorice. Nonplowed Vicia peregrina in the standing system (132 g.m-2 ) and Ajowan after conventional plowing in the standing system (95 g.m-2 ) had the highest and lowest biomass production of cover crops. In both Vicia peregrina and Ajowan plants, cover biomass production was the same in traditional and standing systems. Application of herbicide, similar to weed-free control, reduced weed density by more than 90%, and the highest length and weight of grape were obtained in this treatment. But Vicia peregrina and Ajowan without plowing in both horticultural systems reduced the weed density by 47% and 32%, respectively, compared to the weedinfected control. Regardless of plowing type in both horticultural systems, the weight and length of grape in planting cover crops such as Vicia peregrina and Ajowan increased significantly compared to weed-infected conditions (no weeding). Also, the amount of soluble solids varied from 10.8% in weed-infected control to 15.16% in glyphosate herbicide usage.

Since among the cover crops, non-plowed Vicia peregrina had the highest reduction in weed growth with comparing the weed density averages, it can be introduced as the best management strategy for weed control in vineyards. In general, planting cover crops in both garden systems with any type of plowing can reduce weed density and increase the quantitative and qualitative of grapes, although herbicides and weedfree control are superior to cover crops.