Optimization of planting spacing and bed types for different garlic (Allium sativum L.) cultivars under prolonged drought stress conditions

Planting spacing and bed types are critical factors that influence crop growth and yield. This three-factor experiment looked at the effect of planting spacing (15 cm x 15 cm, 10 cm x 15 cm, 10 cm x 10 cm) and bed types (sunken, raised, flat) on garlic growth (measured by leaf length and plant height), yield (determined by weight), and soil moisture (determined by gravimetric method) under drought stress in three garlic cultivars. The 10 cm x 15 cm spacing gave the overall highest bulb yield of 38.35% (although 10 cm x 10 cm slightly surpassed it on Mozambique local), while 15 cm x 15 cm gave the lowest yield of 25.52%, albeit producing the best results vegetatively. Sunken beds worked best in all cultivars and in all conditions by retaining soil moisture longer. Among the cultivars, the Elephant cultivar had the highest water consumption capacity, and consequently died after 10 days of drought. Conversely, Mozambique and Malawi local cultivars survived; Mozambique local had the highest yield with the widest and heaviest bulbs under drought. The findings of the present study suggest that Mozambique cultivar is a relatively drought-tolerant cultivar, producing higher yields at a spacing of 10 cm x 15 cm. Furthermore, sunken beds have demonstrated efficiency in enhancing growth and yield, producing larger bulbs under both well-watered and drought-stressed conditions. These findings highlight the importance of bed configuration, spacing, and cultivar selection in enhancing garlic growth and yield under water-limited conditions.