Two grow-out experiments were conducted to evaluate the functional role of chicken manure for Nile tilapia, Oreochromis niloticus (L.). production in central Thailand. Experiment 1 examined the relationship between chicken manure input and net fish yield (NFY). Experiment 2 determined the value of chicken manure in providing tilapia paniculate organic carbon, and/or dissolved inorganic carbon (DlC) for stimulating algal productivity. In both experiments supplemental urea and triple superphosphate (TSP) gave all treatments total nitrogen (N) and phosphorus (P) inputs of 28-Okg/ha/week and 7-Okg/ha/week, respectively.Addition of chicken manure to inorganic fertilization did not enhance production of Nile tilapia. NFY in experiment 1 increased with decreasing manure loading, which corresponded to increasing TSP input. Regression analysis suggested that chicken manure-? was about 10% effective as TSP-P at increasing NFY. NFY was linearly correlated to net primary productivity {r= = 0-62, P < 0001), which was linearly correlated to total alkalinity (r = 0-77. P < 0-001). Treatment differences in alkalinity, community respiration or dissolved oxygen concentrations at dawn were not related to manure input. Simple economic comparisons discourage the purchase of chicken manure as a source of soluble N and P for increasing algal productivity in Thailand.

No abstract

No abstract

No abstract

No abstract

No abstract

ABSTRACT

No abstract