Abstract

                                To maintain the food supply for an ever-increasing population, every endeavour will have to be made for conserving soil fertility. The productive power of soils is steadily reduced when successive crops are grown and no adequate manuring is made. The chief food crop in Madras, paddy, (occupying nearly 11 million acres in the State) removes from an acre of soil, 48 lb. of Nitrogen, 23 lb. of Phosphoric acid and 41 lb. of Potash. Nitrogen and Phosphoric acid are the two important elements that are required for paddy, as our soils are sufficiently rich in Potash. The main sources of manure for agricultural purpose is farm. yard manure, compost, green manures, "Patti mannu", and oil cakes. The availability of these manures to the area cropped is insufficient. To meet our immediate needs, the only way is to go in for chemical mannres -ammonium sulphate and superphophate - which supply the two main elements required for the paddy crop.

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