EFFECT OF CROP ROTATION ON THE CONTROL OF WILD OAT IN WHEAT IN UPPER EGYPT

Long term study in Shandaweel Station during the period from 1991 to 1995 on the role of four-year crop rotation for wild oat control in wheat fields with four crop sequences and four weed control methods was carried out in naturally heavy infested soil with oat seeds (average of 624 wild oat seedlings/m2 in 1991/92 winter season). Striking find­ings were obtained indicating that crop sequences including herseem with wheat or berseem in three years sequence followed with wheat were less favorable for wil oat growth and exhaust wild oat seed bank accompanied with high wheat yield and yield components with less con­taminated wheat grains with weed seed than in the case of non rotated wheat. Thus, the present study recommended to use crop sequence of berseem/wheat/bersem followed by handweeding or using herbicides for controlling wild oat for preventing renewal of wild oat contamination from other sources. Such system exhaust the reserve of wild oat seeds in soil and maintain wheat productivity with cutting herbicide use.