mat nursery rice mechanical transplanter tray soil seed rate
6 Answers
For a mechanical transplanter you need a mat-type nursery where seedlings grow on a thin soil layer that lifts off as a mat. Lay polythene sheet on a level surface or use trays, spread a 2 to 2.5 cm layer of fine sieved soil mixed with well rotted FYM, sow pre-sprouted seed densely, cover lightly with soil and keep it just moist. You need roughly 1 to 1.5 kg seed per tray equivalent and about 20 to 25 trays or mats to plant one acre, raising seedlings for only 15 to 20 days till they are 10 to 15 cm tall. Keep the mat thickness even so the transplanter picks seedlings uniformly. Harden seedlings by reducing water 1 to 2 days before transplanting. Match the variety and tray count to your machine.
Younger 18 day mat seedlings transplant cleaner than older ones. Even soil thickness is the main trick for the machine.
In Andhra I sieve the soil twice and remove every stone and root piece, because even a small stone tears the mat when the machine fingers pick it up. Clean fine soil reduced my missing hills a lot.
One caution: water the mats gently with a rose can or sprinkler, never a strong jet, or you wash out the seed and get bare patches. I also keep the trays shaded for the first two days for even germination.
In Punjab I raise the mats on a raised bed with a polythene base so excess water drains and the roots mat together nicely without rotting. A slightly raised, well-drained spot gave me stronger mats than flat ground that stayed soggy.
One tip from my fields in Odisha: pre-sprout the seed only to a tiny white tip, not long sprouts, because long sprouts break when you spread them and germination goes uneven. A short chit gave me a cleaner, even stand on the mat.