Wild barley (Hordeum spontaneum C. Koch) response to weed management approaches in wheat-chickpea-wheat rotation

Wild barley (Hordeum spontaneumC. Koch) population dynamic in a wheat-chickpea-wheat rotation was investigated in a randomized complete block design by split-factorial arrangement with three replications in Great region of Khorramabad, Iran, 2009-2011. Wild barley picking to prevent current year seed rain in wheat and chickpea sowing time in the next season were main plots and weed management treatments in chickpea were sub-plots. In spring 2009, a Wheat field with relatively uniform wild barley infestation to was chosen. The experiment included three factors: (a) wild barley weed seed rain in wheat at two levels: 1- without seed rain, 2- seed rain; (b) chickpea sowing time at two levels: 1- early planting, 2- late planting; and (c) 5 levels of weed management in chickpea: 1- hand weeding, 2- post-emergence application of clethodim, 3- pre-emergence application of metribuzine, 4- pre-emergence application of imazethapyr, and 5- weedy check. In autumn 2010, wheat was planted in experimental plots. In the spring of 2011, wild barley spikes were counted in wheat. Prevention of wild barley seed rain in wheat 71% reduced density and biomass of this weed in the cultivation of chickpeas in the following year. Average wild barley spike numbers in wheat in third year of rotation was declined 71.9% due to no seed rain treatment in wheat in the first year of rotation. Delay in chickpea sowing time increased 68.7% wild barley spike numbers in wheat at the next year. Hand weeding in chickpea in no seed rain, and seed shedding of wild barley in wheat at initial year of the rotation, reduced 94.6% and 88.3% wild barley spike numbers in wheat in third year of rotation, respectively. It seems that the correct strategy for wild barley management in wheat crop could be find in agronomic strategies like crop rotation.