Publication Date: February 2019
Small onions, a staple in daily cooking, are widely cultivated in Tamil Nadu.
Varieties
The Tamil Nadu Agricultural University has released several varieties such as Co.1, Co.2, Co.3, Co.4, Co.5, and YDU.1. Among these, Co.5 is notable for yielding 7.2 tons per acre and has a maturity period of 90 days. The bulbs are red and suitable for cultivation throughout Tamil Nadu.
Season
The optimal planting periods are April, May, October, and November, avoiding the rainy season. An acre requires 400 kg of onion sets with dense bulbs. For seed planting, 3.25 kg per acre is sufficient.
Soil Selection
Small onions grow well in red soil with good drainage. Avoid heavy clay soils as waterlogging can hinder germination and growth. The soil pH should be between 6-7. Plow the field 4-5 times and create ridges and furrows 1.5 feet apart. Plant the sets 10-12 cm apart on the sides of the ridges.
Irrigation
Irrigate immediately after planting the sets or seeds. Subsequent irrigation is needed on the third day and then weekly. Stop irrigation 10 days before harvesting.
Fertilization
Based on soil analysis, apply 10 tons of farmyard manure per acre. Additionally, mix 4 packets each of Azospirillum and Phosphobacteria with 20 kg of farmyard manure and 40 kg of neem cake, and apply before planting. Use 30 kg of nitrogen, 60 kg of phosphorus, and 30 kg of potash per acre as a basal application. Apply 30 kg of nitrogen as top dressing 30 days after planting.
Crop Protection
To control leaf miner and thrips, spray 1.2 ml of quinalphos per liter of water or 7 ml of dimethoate per 10 liters of water. Use 5 yellow sticky traps per acre to monitor pests. Place 5 pheromone traps per acre to attract and capture male insects. To manage leaf spot disease, spray 2 ml of mancozeb per liter of water.
For controlling basal rot, spray 4 g of Trichoderma viride per liter of water or apply 1 kg of Pseudomonas fluorescens per acre to the soil before planting. Surround the field with two rows of maize as a barrier crop.
Perform seed treatment and spray a solution of 10 g of Pseudomonas fluorescens and 5 g of Beauveria bassiana per liter of water 30 days after planting. At 40 days, spray a solution of 2 ml of azadirachtin per liter of water.
Harvesting
To prevent sprouting and extend the storage life, spray Cycocel at 200 ppm and carbendazim at 1000 ppm 30 days before harvest.
Dr. V. Danushkodi, Dr. S. Eswaran, Dr. K. Amuthaselvi, Dr. Noorjahan A.K.A. Hanif, Agricultural Science Center, Sirugamani-639115, Trichy District.
