Effect of deep loosening of soil on weed infestation of winter wheat cultivated in few crop rotations

Deep loosening of soil was carried out every years since 1989. The effect was studied in the years 1990-1993. Winter wheat was grown in 5 crop rotations. The weed infestation values were: number of weeds in spring, surface of coverage by weeds in the full vegetation and the total weight of weeds before harvest. Deep loosening resulted in lessening of the weed infestation of winter wheat. The weed infestation of the winter wheat decreased in each consecutive year of deep loosening. In the fourth year of deep loosening the number of seedlings of weed in spring decreased by 21% and total weight at harvest decreased by 36% in comparison with conventional cultivation.