RESPONSE OF ONION (Allium cepa L.) ON GROWTH, YIELD AND WEEDSUPPRESSION AS INFLUENCED BY SEEDLING AGE ANDSOLARIZATION

Nigeria’s onion production has increased in recent years, driven by the crop’s nutritional, culinary, and medicinal value. To improve yield and suppress weeds sustainably, farmers are adopting practices such as adjusting seedling age and using soil solarization. In this context, field trials were conducted at two locations in the Sudan savanna agro-ecological zone during the 2019/2020 dry season. The trials were carried out at the Teaching and Research Farm of the Faculty of Agriculture, Bayero University, Kano (BUK) and at the Kadawa Irrigation Scheme, Bunkure. The experiment was a 4 × 3 factorial combination involving four seedling ages (4, 6, 8, and 10 weeks old) and three levels of solarization (control, white polythene, and dark polythene), arranged in a Randomized Complete Block Design (RCBD) with three replications. Data were collected on weed parameters (weed cover score, weed density, and weed dry matter) and growth and yield characters (stand count, bulb diameter, bulb fresh weight, and bulb yield). These data were analyzed using analysis of variance (ANOVA) in GenStat (17th edition), and means were separated using Student–Newman–Keuls (SNK) test at the 5% probability level. Results indicated that both seedling age and solarization had significant effects on plant height, stand count, bulb size, and yield. Older seedlings (6, 8, and 10 weeks) consistently outperformed younger seedlings (4 weeks) across all measured parameters. Dark polythene solarization was the most effective in suppressing weeds and enhancing soil health, leading to the highest bulb yields at both sites 8,470 kg ha⁻¹ at BUK and 5,369 kg ha⁻¹ at Kadawa. The combination of older seedlings with dark polythene solarization produced the best outcomes for growth, yield, and weed control. These findings demonstrate that optimizing seedling age and employing effective solarization practices can significantly boost onion production in semi-arid regions.