Studies on the optimisation of seedling age, nitrogen dose and split application for lowland rice established by the seedling throwing method

摘要

In a field experiment in Coimbatore, Tamil Nadu, India, with rice cv. ADT38 (medium duration ) and ADT36 (short duration) in the wet and dry seasons, respectively, seedlings were thrown or planted in rows or randomly. In the wet season, seedlings were 20, 30 or 40 days old and were given 150 or 187.5 kg N/ha in 3 or 4 splits; in the dry season, seedlings were 25 or 35 days old and were given 120, 150 or 180 kg N/ha in 4 or 5 splits. In the dry season, the highest yield was achieved with the seedling throwing method, while in the wet season, there was no significant difference between the seedling throwing method and row planting. The seedling throwing method resulted in a higher benefit:cost ratio (BCR) than row planting. In the wet season, N ratehad no significant effect on yield, while yields and BCR were higher with 5 than 4 splits and with 30- and 40- than 20-day old seedlings. In the dry season, yields and BCR increased with increasing seedling age, N rate and number of splits.