Can I use automatically programmed sprinklers?
Yes, but not if using automatic timers on a schedule for lawn grass, which needs water more frequently. Your bulbs do not require irrigation if the ground is damp more than two or three inches below the surface. Always check the amount of moisture in the soil before turning on sprinklers or you risk over watering. If your lower leaves turn yellow and drop suddenly, you need to cut back on irrigation. If Mother Nature is doing the watering, please move your lily bulbs to a dryer location for the next season or they may be lost during a cold and/or wet winter. Daylilies (Hemerocallis) can do very well with over watering, which would rot lily bulbs, and can adjust to the lower moisture requirements of Lilium Hybrids.
Soaker hoses are convenient and can also be used, but keep hose from resting directly above bulbs or you'll experience over watering symptoms and basal plate rot. If using "flood irrigation", plant on the high edge of ridges allowing only roots in water.