Effect of Planting Spaces and Weed Control Treatments on Onion Seed Yield and Associated Weeds

A field experiment was conducted at the Gemmeiza Agricultural Research Station, Agricultural Research Center in Egypt, during the winter seasons of 2022/2023 and 2023/2024. The objective was to determine the optimal planting spaces and the most efficient combination of different herbicides for weed control in onion seed yield. Three replicates were used in the split plot experiment in randomized complete block design (RCBD). Three planting spaces- 20 cm (3.990 ton bulbs/fed), 25 cm (3.192 ton bulbs/fed) and 30 cm (2.659 ton bulbs/fed) were utilized in the main plots. Six different weed control treatments were distributed at random across the experiments sub plots as follows: T1: Stomp-extra +Hand hoeing once, T2: Omega +Hand hoeing once, T3: Goal 4F + Giako, T4: Flora + Fuzeiled forty, T5: Hand hoeing (twice) and T6: Weedy check. Results indicated that lowest both fresh and dry weight of total weeds resulted from low onion planting spaces 20 cm or 25 cm under weed control treatment control T1: Stomp-extra + hand hoeing once, T2: Omega +Hand hoeing once, and T5: Hand hoeing (twice) over two seasons. Also, these treatments produced higher the umbel diameter, number of scapes/plant, 1000 seed weight and seed yield (g/plant). Interaction between planting spaces and weed control treatments (25 cm with T1: Stomp-extra + Hand hoeing once treatment) gave the highest seed yield kg/fed, % germination, net income/fed and benefit cost ratio compared with the other planting spaces and other weed control treatments.