Effects of Mulching Types and Nitrogen Rates on the Performance of Garlic (Allium sativum L.) in Igboora

Abstract

Garlic is an important vegetable and medicinal crop, but its yield in Nigeria is low due to poor soil moisture, high weed pressure, and improper nutrient management. In Igboora, Oyo State, farmers often cultivate garlic without appropriate cultural practices such as nitrogen fertiliser application and mulching, which reduces nutrient-use efficiency, bulb yield and quality. This study therefore assessed the influence of mulching materials and nitrogen rates on the growth and bulb yield of garlic under field and screenhouse pot conditions. The experiment was conducted at the Teaching and Research Farm, Oyo State College of Agriculture and Technology, Igboora. The treatments involved four mulching materials: black polythene, dry grass, sawdust, and no mulch, and five nitrogen fertiliser rates: 0, 50, 100, 150, and 200 kg N ha⁻¹. A 4 × 5 factorial experiment was laid out in a completely randomised design for the screenhouse pot experiment and a randomised complete block design for the field trial; each was replicated three times. Data were collected on plant height, number of leaves, bulb yield, bulb diameter, and bulb length. Data were analysed using analysis of variance, and means were separated at the 5% probability level using Duncan’s Multiple Range Test. Results showed that mulching and nitrogen fertiliser rates significantly influenced garlic performance. Black polythene and dry grass mulches outperformed sawdust and no mulch in terms of higher growth parameters, bulb yield and nutritional quality. Bulb yield increased as the nitrogen rate increased from 0 to 150 kg N ha⁻¹, but declined at 200 kg N ha⁻¹. Black polythene and dry grass produced optimal bulb yield with N application at 150 kg N ha⁻¹. In conclusion, mulching and nitrogen application rates significantly influenced plant height, number of leaves and bulb yield. Black polythene and dry grass mulches combined with 100–150 kg N ha⁻¹ gave the highest garlic performance and can therefore be recommended for garlic production in this agro-ecological zone.