Effects of solarization on critical period of weed control in sesame (Sesamum indicum L.)

In order to determine the critical period of weed control in sesame, field studies were conducted during the 2014 and 2015 growing seasons in Estahban, Iran. The experiments were conducted based on factorial arrangement which involved a randomized complete block design with three replications. The first factor was conducted in two weed-infested and weed-free series until different phonological stages of sesame growth. These stages included a third pair true leaf initiation, first bud emergence, 50% opened flowers, and minor plants stop flowering, and the second factor was related to solarization which was achieved using light and dark polyethylene plastics and control. The results showed that the critical period of weed control was influenced by solarization so that solarization using light polyethylene plastic could severely shorten the critical period. Weed dry weight also gradually reduced, with increase in weed control, and the formation of first flower buds decreased significantly. Solarization did not have a great effect on the number of Convolvulus arvensis L. among the weeds, but its effect on one-year-old weeds was evident. Thus, weed infestation until the third pair true leaf initiation did not reduce sesame yield.