Sufficient number of healthy seedlings
Sufficient number of healthy seedlings leads to a good canopy that maximizes photosynthesis and enables better competition against weeds. Healthy seedlings have better root growth that improves nutrient uptake and nutrient use efficiency.
To obtain this:
- sow the right amount of high quality seeds;
- transplant the right amount of seedlings; and
- provide the right kind and amount of nutrients at the right time.
- Seed rate: 20 to 40kg/ha for inbred; 15 to 20 kg/ha for hybr
- Replant missing hills within 7 days after transplanting (DAT)
- Assess health status of seedlings at 10 DAT
- Randomly select 3 sampling sites in a diagonal line across the field. The sampling sites should be at least 1 m from the edge of the field.
- Count the number of hills/m2 using a 1 m x 1 m quadrat. Add the number of hills and divide the total by 3 to get the average number of hills/m2.
For direct wet-seeded rice (DSWR):
- Fifteen days after seeding pre-germinated seeds, plant density should be at least 150 plants per meter square, for a rate of 40kg seeds/ha,
- For a seed rate of 80kg/ha, plant density should be at least 300 plants per meter square.
- To asses plant density, use 1 m x 1 m quadrant.
- Randomly select 3 sampling sites in a diagonal line across the field. Each sampling site should be at least 1 m from the edge of the field
In every parcel for TPR and DWSR, randomly select 10 hills. Each hill should have at least one healthy seedling. A healthy seedling is:
- with good growth; and
- free from pest and disease.
Resulting seedlings have higher survival rate and easily recover from transplanting shock. Sowing a higher amount of seeds results in thinand weak seedlings. Proper spacing enables the crop to develop a goodground cover and helps control weeds.
- For transplanted rice, establish seedbed near a water source and protect it from pests, particularly birds and rats. It should have a good drainage. Proper water and pest management are important at this stage. If thegerminated seeds are covered too deeply with water, this will result inweak seedlings with poor root growth because of lack of air in thesoil. Birds and rats feed on seeds directly and pull up germinatingseeds and so it is important to guard the seedbed against these pests.
- Apply the organic materials before leveling the seedbed. For fine-textured soil, incorporate 10-15 bags organic material or 3-4 bags commercialorganic fertilizer in a 400 m2 seedbed before sowing the seeds. Organic materials help loosen the soil. Thus, it makes pulling ofseedlings easier and minimizes root damage. Use compost or any fullydecomposed organic materials such as dried animal manure, carbonized rice hull, or rice straw.
- For medium-textured soil, you may not apply organic materials.
- For direct wet-seeded rice,the field is ready for seeding after land preparation and leveling asdescribed in the recommendation for Key Check 2. Pre-germinatedseeds/seedlings should be protected from birds, rats, snails and weedsfollowing the standard practices described in the pest managementsection. Broadcast pre-germinated seeds evenly onto the leveled field.
- Sow extra pre-germinated seeds (1 kg) on the side of the field for replanting. Replant bare patches 7-10 DAS.
|Variety||Seeding Rate (kg/ha)||Minimum Seedbed Area m2||Age of Seedlings (days)||No. of Seedlings (per hill)||Planting Distance (cm x cm)|
|INBRED||20-40||400-600||20-25||1-3||20 x 20|
|HYBRID||15-20||400-600||20-25||1-2||20 x 20|