Effect of Stale Seedbed on the Reduction of Hordeum spontaneum Population in Wheat

Hordeum spontaneum C.Koch. is known as a significant factor in decreasing wheat yield. Its control by stale seedbed is a step toward achieving sustainable agriculture in wheat. For this purpose, field experiments were performed during 2007-2008 and 2008-2009 in the experimental fields of the Iranian Institute of Plant Protection, Varamin, Iran. In order to contaminate the field with the weed, wheat was planted in association with H. spontaneum, during the first year. After harvesting wheat in the summer, an experiment was conducted with 9 treatments. Treatments included: 1) field plowing after wheat harvesting and corn (Cultivar SC704) planting, irrigating weekly up to corn harvesting, 2) field plowing no corn cultivation, but irriatted up to corn harvesting in treatment 1. Treatments 3, 4, 5, 6, 7, 8, and 9 were not plowed but irrigated only once, each at an indicated date (July 4th, July 19th, August 1st, August 18th, September 10th, September 23th, and October 8th). Results revealed that stale seedbed from the middle of August favored H. spontaneum emergence. Thus its density reduced in wheat up to two thirds and wheat grain yield increased two times. Field plowing after wheat harvesting increased H. spontaneum burial depth and reduced its density in corn and wheat.