Abstract:
In order to find out the long term effect of continuous application of organic and
inorganic fertilizers on soil fertility and yield of rice, permanent manurial trial was started
at the Rice Research Station, Kayamkulam since 1964. Data for seven years from 1978-79
to 1985-86 revealed that highest yield was recorded by treatments that received either full
the quantity of N (80 kg/ha) as cattle manure or three-fourth the nitrogen requirement (60
kg/ha) as cattle manure and one-fourth (20 kg/ha) as ammonium sulphate along with 40
kg/ha each of phosphorus and potassium as superphosphate and muriate of potash,
respectively. This emphasises the need of application of organic matter in this sandy loam
tracts of Onattukara. The inferior yield recorded by treatments that did not receive either
one or more of the three major nutrients again reveals the importance of phosphorus and
potassium nutrition and shows that there is no scope for skipping P or K if long term soil
fertility is to be maintained.
