EFFECT OF WEED PERSISTENCE ON GROWTH OF SUGAR BEET (BETA VULGARIS)

摘要

Two field experiments were carried out at Sharkia Governorate, Egypt during 1989/1990 and 1990/1991 seasons to study the response of growth sugar beet Raspoly cv. to persistence of weed and some weed control treatments. The study included 14 treatments; 4 treatments as hand weeding for 6, 9, 12 and 15 weeks from sowing sugar beet, 4 treatments as hand weeding after sowing with 6, 9, 12 and 15 weeks till harvesting, one treatment as hand weeding during all the growing season, two chemical weed control treatments by using pyramin + TCA as a mixture and Goltix, one treatment as hand hoeing, intercroping fenu-greek plants with sugar beet and the unweeded treatment. At 140 days from sowing, the experimental survey showed that sugar beet plants were infested by Beta vulgaris (wild chard), Rumex dentatus; L., Polypogon monspeliensis; L; Sonchus aleracens; L, Lepidium sativum; L, Cynodon dactylon; L and Melilotus indica; L. The number of chard plants were the highest species infested sugar beet plants. The reduction in number of broad and narrow leaved weeds, total number of weeds, fresh and dry weight of weeds as a result of applying hand weeding for 6, 9, 12 and 15 weeks from sowing or after 6, 9, 12 and 15 weeks till harvesting, hand weeding for all growing season and hand hoeing was more efficient than using the herbicides pyramin + TCA or Goltix. Intercropping fenugreek plants with sugar beet plants resulted in significant reduction in weed characters than using herbicides but less reduction than of hand weeding and hand hoeing treatments. The vegetative growth characters of sugar beet plants were measured at 150 days from planting. Number of leaves, fresh weight of leaves increased consistently as the period of keeping sugar beet plants free from weeds. Application of pyramin + TCA or Goltix was not efficient concerning the effect on vegetative growth characters of sugar beet plants.