Abstract

In the Tanjore delta which has nearly a million acres unuer irrigated rice, the rice growers are in the habit of applying ammonium sulphate to their rice crop without the addition of any organic matter. This was particularly so during the post war boom period of 1919-1929, when paddy was selling at Rs 3 to Rs. 3-12-0 a kalam of 64 lb. Later on there were complaints that the yields of rice crop declined in fields that received ammonium sulphate. Invariably such statements were made by persons who applied a bag (80 lb.) of ammonium sulphate to one crop and stopped applying it to the following crop. It might be that the reduction in yield was the result of discontinuance of manuring. There was also no experimental evidence to declare that continued application of an artificial manure like ammonium sulphate really brought down the yield of rice. With a view to find out the effect of continued applications of ammonium. sulphate on the rice crop, the following experiment was designed and con- ducted at the Agricultural Research Station, Aduturai in the Tanjore district for a period of five years from 1935-36 to 1940-41.

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