Abstract

In recent years, chemical fertilizers such as urea, Ammonium sulphate nitrate, Calcium ammonium nitrate etc. are being used for better crop production and there is no crop which has not responded for the application of nitrogen. When once it is decided what type if fertilizer is to be used for a particular crop the important problem arises for determining when and how they are to be applied in order to get maximum benefit. Hence it becomes necessary to evolve or fix by experi- mentation the right time and the right way of utilising the fertilizers. Mariakulandi (1957) has reported from trials conducted at Aduthurai during 1953-56 that there was no significant difference between single and split application; however, ammonium sulphate showed encouraging responses when applied at planting. No differences was noticed between ammonium sulphate and urea as they gave equal responses at 20 and 40 lb. nitrogen level in cultivators' fields. Manamohan Lal and Surendranath Naidu (1963) have stated that better yields are possible if ammonium sulphate is applied in two equal doses, one half at planting and the other 30 or 60 days after planting for kuruvai and thaladi crops respectively.

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