Sufficient number of healthy seedlings
KEY CHECK 4:
Sufficient number
of healthy seedlings
Healthy seedlings have short leaf sheaths, long and dense roots, and even height. They grow uniformly and have no pest damage.
With uniform growth, healthy seedlings produce a good canopy and every plant can avail of sufficient sunlight and soil nutrients. They can also easily recover from transplanting shock, and have higher survival rate. They produce productive tillers that translate to increased potential for higher yield.
KEY CHECK 3: Practiced synchronous planting after a rest period.
ASSESSMENT OF KEY CHECK
For Transplanted Rice (TPR):
- Followed the recommended seeding rate of 20-40kg/ha high-quality rice seeds.
- Ensured hill density of 25 hills/m2 if manually transplanted, or 21 hills/m2 if mechanically transplanted.
- Ensured one healthy seedling per hill.
How to assess hill density and health status of TPR:
1. At 10 DAT, randomly select three sampling locations at least 1m from the dike and in a diagonal line across the field.
2. Count the hills from each location using a 1m x 1m quadrat for manual transplanting. For mechanical transplanting, measure a 1.1m x 0.9m quadrat.
3. Add the counts and divide the total by three to get the average number of hills/m2.
4. In every parcel, randomly select 10 hills. Each hill should have at least one healthy seedling.
Manual | at least 25 hills/m2 with at least one healthy seedling per hill |
Mechanical | at least 21 hills/m2 with at least one healthy seedling per hill |
For Direct Wet-Seeded Rice (DWSR):
- Followed the recommended seeding rate of 40-60kg/ha for row seeding and 60-80kg/ha for broadcast seeding.
- Ensured plant density of at least 150 plants/m2 if row seeding or at least 225 plants/m2 at 60kg/ha seeding rate if broadcast seeding.
- Plants in each quadrat have no pest damage and are uniform in leaf color and plant height.
How to assess plant density and health status of DWSR:
1. At 15-18 DAS, randomly select three sampling sites at least 1m from the dike and in a diagonal line across the field.
2. Use a 0.5m x 0.5m quadrat. Count the plants in each quadrat, compute the average number of plants per quadrat, then multiply by four to determine the average number of plants/m2.
3. In every quadrat, visually inspect plants for uniformity in leaf color and plant height, and for pest damage.
RECOMMENDATIONS TO ACHIEVE KEY CHECK
For TPR:
1. Follow these recommendations
Method | Seeding rate | Seedbed area | **Age of seedlings (days) | No. of seedlings per hill | Planting distance (cmxcm) |
---|---|---|---|---|---|
Manual | 20 or 40 kg/ha | 400m² | 18-21 | 2-3 | 20×20 (WS) 20×15 (DS) |
Mechanical (tray method) | 70-160 g/tray*(20-40kg/ha) | 250-300 trays | 14-18** | 3-6 | 30×15 (WS/DS) |
Mechanical (Modified wet dapog method) | 420-960g/m² (20-40kg/ha) | 50m² | 14-18 | 3-6 | 30×15 (WS/DS) |
*Size of tray: 28cm x 58cm | **Can use 12-day-old seedlings if height is not less than 15cm | Lower seeding rate in mechanical transplanting is recommended for hybrid commercial rice production because of high price of seeds.
- Sowing the right amount of seeds results in strong and healthy seedlings.
- A 20m x 1m seedbed provides enough space for seedlings to grow.
- Apply organic materials or carbonized rice hull before leveling the seedbed. This helps loosen the soil, making pulling of seedlings easier with less root damage.
Type of soil Rate of application Fine-textured 3-4 bags commercial organic fertilizer Medium-textured no need to apply organic materials - Young seedlings are susceptible to invasive apple snails, also known as golden apple snails (GAS). Seedlings older than 25 days will have difficulty recovering from transplanting stress and will produce less tillers.
- Close spacing results in mutual shading and less tillers. Tall plants are susceptible to lodging.
- Do not cut the leaves of seedlings before transplanting. The cut area can be an entry point for disease-causing organisms.
2. Replant missing hills within 7 DAT. Use seedlings from the same seedbed to avoid uneven maturity.
For DWSR:
1. Follow the recommended seeding rate of 40-60kg/ha for row seeding and 60-80kg/ha for broadcast seeding.
2. Prepare the field for seeding by following the land preparation and levelling recommendations outlined in Key Check 2.
3. Protect pre-germinated seeds from birds, rats, snails, and weeds by following the recommended pest management practices.
4. Use drumseeder or broadcast pre-germinated seeds evenly onto the field.
5. Sow extra 1kg pre-germinated seeds on the side of the field for replanting. Replant bald areas with a radius of more than 10cm within 7-10 DAS to ensure even maturity.
MATERIALS
Handouts
Learning Modules
Audio Clips