Seyyed Mahdi Hoseyni^1,, Hossein Najafi²

In order to study the effect of different combinations of cover crops and time of their removal on weeds population in sugar beet fields, an experiment was conducted at the Iranian Research Institute of Plant Protection, . The study was based on two factorial experiments with randomized complete blocks design with four replications. Treatments in first experiment were type of cover crop including: 1) X Triticosecale wittmack, 2) Hordeum vulgare, 3) Trifolium alexandrium), 4) Raphanus sativus and removal times including: 1) at four-leaf sugar beet stage, 2) at eight-leaf stage of sugar beet. In the second experiment, different combinations of cover crops were evaluated. Treatments were cover crop combination including: 1) Hordeum vulgare & Raphanus sativus, 2) X Triticosecale wittmack & Raphanus sativus, 3)Hordeum vulgare & Trifolium alexandrium, 4) X Triticosecale wittmack & Trifolium alexandrium and removal time of cover crops (as the same of the first experiment). The results showed significant effects of different cover crops and their removal times on weeds dry weight and population. Between treatments, combination of X Triticosecale wittmack & Trifolium alexandrium had the lowest weed dry weight and population when removed at four-leaf stage of sugar beet.

non-chemical control, weed control, cover cro