Weed management of peppermint (Mentha piperita) using narrow leaf cover crops and their effect on yield

Today, cover crops are an effective tool in non-chemical weed management in sustainable agriculture (Ateh and Doll, 1996). This experiment was conducted to investigate the effect of cover crops on weed management and the yield of peppermint (Mentha piperita). In order to evaluate the effect of cover crops on weed management and yield of peppermint (Mentha piperita), a factorial experiment was conducted with a randomized complete block design with three replications at the Agricultural Research Field of the University of Mohaghegh Ardabili, Iran, in 2012. The first factor included: spring wheat, spring barley, winter rye, winter wheat, winter barley, mixed winter rye + winter barley. Cover crop management methods included: undercutting mulch, heading living mulch, and cover crops killed with herbicide as a second factor. Two controls were also included in the experiments: no cover crop with weeding and no cover crop without weeding. To investigate the effect of cover crops on density and weed biomass, three stages of weed sampling were performed, 30, 60, and 90 days after the peppermint (Mentha piperita) planting (except for weed control plots and no weeding) in a plot of 0.5 × 0.5 square meters. Also recorded were number of branches, stem length, leaf fresh weight, leaf dry weight, and fresh yield. The results showed that the main effect of the cover crop was significant on the number of branches and the main effect of cover crop management had a significant effect on peppermint properties and the dry weight and density of weeds. Most of the trait impact was positive in all the methods of cover crop management of weed control. The results showed that peppermint traits were most affected with undercutting management and heading living mulch. The second most effective was cover crops killed with herbicide. Comparison of interaction effects showed that by using heading living mulch winter wheat, undercut spring barley and winter rye had the highest fresh yield. The main effect of cover crop type on the first sampling on dry weight of redroot pigweed (Amaranthus retroflexus L.) was significant for weed density of bindweed (Convolvulus arvensis L.) in the third sampling and the cover crop management for all weeds in all three samplings. On average in the three stages of sampling, the dry weight and density of the control weed of redroot pigweed, common lambsquarters (Chenopodium album) and bindweed in undercutting mulch, heading living mulch, killed cover crops with herbicide were 66%, 73%, 38% and 59%, 70% and 44%, respectively. The results of this study showed that cover crops are effective strategies for weed control. In this experiment, cereal crop plants with rapid growth and high biomass, reduced the density and dry weight of annual and perennial weeds (Blanco-Canqui et al., 2013 Jahanzad et al., 2013 Jahanzad et al., 2014) and had a good effect on the fresh leaf yield of peppermint. In general, to achieve more effective control of weeds and healthy production, the treatment of heading living mulch winter wheat was appropriate.