Abstract
SUMMARY: Controlling weeds until 6 weeks after crop emergence gave a yield of soyabeans only 85 per cent that of the clean-weeded control treatment. Delaying weeding until 3 or 6 weeks after emergence gave yields 89 per cent and 69 per cent respectively of the control. Narrow crop rows (30.5 cm.) gave higher yields than wide rows (61 cm.). Defoliation of soyabeans reduced pod number, seed size and yields more with late and severe defoliation, and with lower plant populations. Delayed harvesting during the dry season led to seed shedding and yield was at the maximum for only about one week.