Land preparation for main field
Prior to transplanting, field should be ploughed and disked properly to eliminate debris and soil clods. Organic manures equivalent to 75 kg N/ha (approximately FYM 15 t/ha or poultry manure 7.5 t/ha or vermicompost 7.5 t/ha) should be incorporated at the time of last ploughing and beds with appropriate size should be prepared after leveling. Mostly, flat beds of the size 1.5-2.0 m width and 4-6 m length is formed. However, flat bed should be avoided to prevent water logging during Kharif or rainy season. Water logging favours Anthracnose disease which is most devastating during Kharif season. Broad bed furrows (BBF) of 15 cm height and 120 cm top width with 45 cm furrow are formed to achieve proper spacing and population density. It is suitable for drip and sprinkler irrigation as well. BBF is the best method for Kharif onion production because the excess water can be drained out through the furrow. This improves the aeration and helps in reducing the incidence of Anthracnose disease.