Web alarm clock for 8:47 a.m.
Before handing the rice-drying watch to someone else at 8:47 am, tell them exactly when to spread the grains and what signs of rain to watch for. Setting the alarm for 9:00 am gives the next person a clear checkpoint to inspect the rice, turn any damp patches, and keep the drying on track before the usual midday shower.
Because you are changing shifts, leave the alarm running on a phone or computer that will stay awake until it sounds. If that device sleeps first, the rice may remain unattended past the planned check, and a browser alarm cannot alert the person taking over once its page has been closed. Keep the page visible, raise the volume enough for the work area, and mention the alarm during the handover so its sound is expected.
As the rice is laid out, listen to how the morning surroundings change near 9:00 am: passing tricycles, neighbours starting chores, and voices around the yard can easily cover a soft alert. Place the device away from sacks and machinery, choose a level that carries across the drying area, and ask the incoming person to stay within hearing distance until the check is done.