A Thesis submitted in the partial fulfilment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 1989

This study examined the effect of duck diet, bedding material and manure storage on nutrient release characteristics of duck manure in water. A second experiment examined the effect of those factors on the suitability of duck manure for improving yields of Nil e tilapia (Oreochromis niloticus ) . The first experiment was fresh manure of low and high grade diet with and without rice husk; the second one was four week old manure of the same low grade diet as used in the first experiment, except manure was stored under two different conditions; and the third was four week old manure of high grade diet stored as in the second experiment. The accumulative ammonia-N released from manure in the first experiment varied from a minimum 6 . 5 mg / g dry matter (DM) t o a maximum 9 . 2 mg / g DM a nd soluble reactive phosphorus (SRP ) release varied f rom 1 . 7 mg / g DM to 2 . 0 mg / g DM . In second experiment , the accumulative ammonia - N release from manure varied f rom 7 . 0 t o 8 . 8 mg/g DM a nd SRP release varied from 2.2 mg / g DM to 2.6. mg / g DM . In third experiment the release of ammonia-N range from 7.lto 9. 1 mg / g DM a nd t h e SRP release varied from from 3 . 5 to 4.1 mg/g DM. Nearly all soluble nitrogen and phosphorus were released on the fourth day of manure application . The release was in creased by the improved diet management of manure. Use of bedding material of the amount of nutrient release on a per unit rate of nutrient manure and proper ca used a reduction weight basis. The improved manure obtained from high grade diet in creased the fish yield but the use of bedding materiel did not effect the fish yield significantly.