Two methods Transplanting – requires preplanting &nursery Direct Seeding
Comparison transplanting vs direct sowing Transplanting High labour Longer to establish More uniform crop Less weed problem Direct seeding Low labour Fast to establish Less uniform crop More weed problem
Nursery preparation Soil must be level, can be dry or wet
Types of rice nursery There are 4 nursery systems for transplanting: The wet-bed nursery The dry-bed nursery The dapog or mat nursery Seedling boxes for mechanical transplanting
The wet bed type Pre-germinated seeds are broadcasted on a soil that is thoroughly puddled and levelled. Drainage canals for proper removal of water must be constructed. Addition of organic manure (decomposed) and small amount of inorganic fertilizer as basal dressing will increase easiness of uprooting of seedlings and improve seedling vigour. Total seed bed area is about 1/10 of the area to be transplanted and about 40 kg of seed are required to transplant 1 hectare. The best seedling age for transplanting is about 15-21 days.
The wet bed type..cont.. Seed required Preparing nursery area Pre germinated seeds Fertilizer top dressing Irrigating the seedbed Sowing Pulling the seedling
The dry-bed type The nursery is prepared in dry soil conditions. Raised seed beds of about 5-10 cm. A layer of half burned paddy husk could be distributed on the nursery bed to facilitate uprooting.
The dry-bed type...cont The site should be free of shade and with adequate irrigation facilities. About 40 kg of seed are required to transplant 1 ha (if germination is lower can increase the quantity to 80 kg). Uprooting of seedlings should be done between 15 - 21 days after germination. Nursery should be maintained without any moisture stress. A basal fertilizer mixture can be applied and incorporated between rows if the soil nutrient supply is low.
The dry-bed type... cont The advantage of the dry-bed method is that seedlings are short and strong, with a longer root system compared with the wet-bed method. A disadvantage is however that roots may get damaged during pulling. Seedlings are more prone to pests such as rodents etc.
The dapog or mat nursery Dapog nurseries can be located anywhere on a flat firm surface but water supply/control should be very reliable. The area needed is about 100 m 2 /ha or 1% of the transplantable land which is much smaller than conventional nurseries.
The dapog type ….. cont Uprooting of seedling is minimal. Very young seedlings (12-15days) from dapog nurseries suffer less transplanting shock compared with other nurseries, thus the seedlings are more suitable for short duration varieties. Irrigation is obligatory to prevent water stress.
Transplanting Transplanting seedlings that are grown in nurseries first. Transplanting of rice seedlings into puddle fields is widely practiced in Asia, primarily to better control of weeds. Transplanting requires less seed but much more labour, and the crop takes longer to mature because of the transplanting shock.
Transplanting ……cont Before being transplanted, seedlings are grown for different lengths of time in the nursery: Traditional varieties: 40 to 80 days old seedlings; Improved varieties: 15 to 20 days old seedlings; Machine transplanted seedlings: 15 days old seedlings.
Transplanting …..cont How to plant seedlings A.Manually 1-3 days after soil preparation.
Transplanting …..cont i.Random method Seedlings are transplanted without a definite distance or space between plants.
Transplanting …..cont ii.Straight row Follows a uniform spacing between plants. The seedlings are transplanted in straight rows. About 20-25 cm between rows.
Transplanting …..cont Plants spacing Proper plant spacing can increase grain yield by 25-40%. So, what is the optimum spacing? Three factors determine plant spacing during transplanting.
Transplanting …..cont i.Variety Tall, leafy, heavy tillering and susceptible to lodging at wider spacing (compare to short and lodging resistant variety). Tall variety = wider spacing Short variety = closer spacing.
Transplanting …..cont ii.Season Rainy or wet season at wider spacing relative to dry season. Wet season = wider spacing Dry season = closer spacing.