Optimum Dosage of Hyper-Thermophilic Aerobic Compost (HTAC) Produced from Sewage Sludge for Rice Yield

Hyper-thermophilic bacteria can shorten the duration of composting process. This study aimed to elucidate the applicability and the optimum fertilization amount of hyper-thermophilic aerobic compost (HTAC) for rice growth and yield. The stem height, tillers number and rice yields in the treatments with HTAC significantly increased with increasing fertilization amount. But the ripening rate of grain was found to be lower at higher fertilization amount (250 and 500 kg N/ha). The rice yield in 180 kg N/ha HTAC treatment was 5.38 t/ha, which is similar with that using recommended amount of chemical fertilizer. The N and P concentrations in surface water of 180 kg N/ha HTAC treatment before midsummer drainage were lower than 1 mg/L and 0.1 mg/L, reaching the environmental quality standard. Thus, the optimal fertilization amount of HTAC was deemed as 180 kg N/ha when considering the plant quality and environmental friendliness.