Rice is regarded as the first important staple crop of Nepal in case of production and consumption. In 2076/77 the area under cultivation was 1458915 hectares with a productivity of 3804 kg/ha. Nepalese rice productivity – an average of 3 tons/ha is very low compared with leading rice-producing countries and lower than in most South Asian countries (IRRI 2006). While rice cultivation is very important for Nepal’s farmers and its economy, high production costs together with continuing low productivity have made rice farming less profitable and less attractive in recent decades. Despite rapid population growth and considerable unemployment, in many rural areas, labor shortages present an additional constraint for expanding agricultural production. So, it’s crucial to discuss some new methodologies in techniques of rice cultivation to increase the yield in the coming season.
Crop yield is dependent upon the quality of seedlings produced. Those prepared with proper guidelines seem to meet the targeted yield as per scientific recommendation. The major goals of seedbed preparation are to retain the maximum amount of soil moisture, control competing vegetation, improve seed to soil contact, and allow for the proper seeding depth, germination, and emergence of the species to be seeded in the conservation planting.
Various methods of seedbed preparation.
1.Dry bed method: Prepare the nursery in dry soil conditions. Ensure that the site is free of shade and has access to irrigation facilities. Allot 1/10 of the field for the seedbed area, and prepare 60−80 kg of seed to transplant 1 ha of land. Its steps are:
• Prepare beds at 1 m wide by convenient length. Raise the soil to 5−10 cm in height.
• Distribute a layer of half-burned paddy husk on the nursery bed to facilitate uprooting.
• Prevent moisture stress by irrigation. Without appropriate moisture, roots may be damaged during pulling.
• If nutrient supply is low, apply basal fertilizer mixture and incorporate it between rows.
• Transplant seedlings at 15−21 days old.
• Seedlings raised in dry-bed are short, strong, and have a longer root system than those raised in wet beds.
2: Wet bed method: Use this method in areas with sufficient water supply. Allot 1/10 of the field for the seedbed area, and prepare 40 kg of seed to transplant 1 ha of land.
• Prepare beds at 1 m wide by convenient length. Raise the soil to 5−10 cm height.
• Broadcast pre-germinated seeds in thoroughly puddled and leveled soil.
• Construct drainage canals for proper water removal.
• Add organic manure (decompose) and a small amount of inorganic fertilizer as basal dressing. This increases seed vigor and allows easier uprooting for transplanting.
• Transplant seedlings at 15−21 days old.
3: Dapog method: Dapog or mat method is most appropriate for growing short-duration varieties, as seedlings experience less transplanting shock. Compared to other methods, this requires less labor and has minimal root damage. Prepare dapog nurseries where a flat firm surface is available and the water supply is very reliable. Allot 100 m2/ha or 1% of the field for the seedbed, and prepare 40−50 kg of seed per ha. Its steps are:
• Mark out 1 m wide and 10−20 m long plots.
• Cover the surface with banana leaves, plastic sheets, or any flexible material from penetrating the bottom layer of the soil. Cemented floors may also be used as a base. Form the boundary with bamboo splits or banana sheath.
• Cover the seedbed with about 1 cm of burned paddy husk or compost.
• Sow pre-germinated seeds on the seedbed. Maintain a thickness of 5−6 seeds (1 kg per 1.5 m2).
• Sprinkle water to the seeds after sowing, and then press down by hand or with a wooden flat board.
• Prevent water stress by irrigation.
• Transplant seedlings at 9−14 days old.
4: Modified mat nursery: The modified mat nursery uses less land and requires fewer seeds and inputs (i.e., fertilizer and water). Allot 100 m2/ha for the seedbed, and prepare 18−25 kg of good quality seeds.
• Cover the surface of 4 cm layer soil mix with banana leaves, plastic sheets, or any flexible material from penetrating the bottom layer of the soil.
• Sow pre-germinated seeds on the seedbed, then sprinkle with water. Maintain a thickness of 2−3 seeds.
• Water the nursery 2 times a day for 5 days.
• Transplant seedlings at 15−21 days old, when seedlings reach the four-leaf stage.
4: Bubble tray nursery: The bubble tray nursery follows the modified mat system to develop seedlings with root balls. Seedlings raised on bubble trays experience less transplanting shock. At 12−15 days old, seedlings are broadcast in the field. It can be done as follows
• Prepare 750 trays per hectare of paddy.
• Raise seedlings on plastic trays of 59 cm x 34 cm with 434 embedded holes.
Seed Selection:
• Seed should be of quality in terms of physical purity, germination percentage, moisture content, and health.
• Seed should be bought from an authorized dealer with a tag or label attached to a bag or packet.
• Treat the seed as per necessity with chemicals like Ceresan wet
• 5% @ 0.6 g/kg seed or Bavistin @ 2 g/kg seed
• If the farmer uses his own seed, select healthy seed as necessary.
Floatation method of seed selection:
It is necessary to use high-quality paddy seed for the increment of quality seed production. The un-matured, light, and pest-infected seeds have many bacterial diseases, which can be reduced by removing those seeds with saltwater treatment. Its process is:
• Mix around 2 kg salt or 3 kg ammonium sulfate in 10 liters of water in a bucket for making a specific density of water 1.14. Now, put the paddy seed into the water.
• Remove the floated seed from the bucket. Floated seeds are mostly those seeds that are un-matured, damaged, and pest infested.
• Collect the well-matured and healthy seeds, which are settled on the bottom of the bucket, and should be washed 2-3 times with clean water.
Seed Incubation:
Submerge seeds in water for 12−24 hrs. or until small shoots appear at the end of the seed. In colder weather, seeds may need to be soaked for 36−48 hrs. Drain and dry the seed in a bag for 24 hrs. in a shady area where air can circulate around the bags. If bag temperatures exceed 42°C, some seeds will be damaged. Broadcast or drum seed before the roots exceed 5 mm in length. When calculating the planting rate, allow for expansion of 10-30% in seed weight.
Sowing:
• Broadcast seed uniformly throughout the bed and cover it with thin layer of soil in case of dry bed
• Inline sowing maintain row distance of 10 cm
Seed rate:
Nutrient management:
Soil with good organic matter content or application of organic manure during tillage operations helps in healthy seedling production
• In case, organic manure is not applied, use chemical fertilizer
• Apply 500g urea or 1000 g ammonium sulfate per 10 m2 as basal dose
• If nitrogen deficiency symptoms occur top-dress another 500g urea
• In case of Zn deficiency spray Zinc @ 5 kg/ha
Irrigation:
• In case of moisture deficiency, irrigate water in the canal between the seedbeds.
• At an early stage, water shouldn’t be flooded over the bed.
• Gradually, saturate the seedbed with water.
Uprooting:
• Seedlings are ready for uprooting at about 20-25 DAS for early varieties and 30-35 DAS for long-duration
• Irrigate bed 3-5 days before uprooting, which will lose the soil, makes it easier for uprooting, and reduces damage to roots.
Conclusion:
The number of tillers per plant varied significantly due to different methods of raising the seedlings for transplanting. The increment in the average number of tillers per plant was remarkably higher in the newly developed single seedling tray treatment than the conventional practice. Under the present-day constraints of lower production of rice crops, this study depicted that using the newly developed single seedling nursery tray is one of the options to increase the number of tillers in SRI farming in order to increase the number of effective tillers, number of panicles, straw yield and grain yield of rice plants. The results from the experiment clearly revealed that younger seedlings raised by the newly developed single seedling tray method resulted in a significantly higher number of tillers than in the conventional practice. Thus, the above SRI technique can be extended to the farmers to maximize the total production of rice, ultimately contributing to food security.
