Abstract

Twelve 45-d-old seedlings of rice cv. Jaya were transplanted into pots containing 20 kg soil and given urea, superphosphate and muriate of potash to supply 0, 45 or 90 kg/ha each of N, P2O5 and K2O. Organic matter (OM) was added in the form of dried and ground leaves of Gliricidia sepium at a rate of 0, 2, 4, 8 and 10 percent of soil weight. Grain and straw yields increased (non-significantly) with increasing levels of OM alone. This grain yield increase was attributed to overall improvements in soil properties such as water and nutrient retention. Straw yield increased with rate of NPK up to the highest rate. Maximum grain yield was recorded at 45-45-45 NPK and 10 OM. Since it is difficult to maintain 10 OM, it is suggested that applying 90-90-90 NPK and maintaining 2 percent soil OM is the best compromise