In total nitrogen (TN), nitrate-N contributed around 88%,ammonia-N (TAN) 11% and nitrite-N < 1%. Regardless of the
treatments, the overall average TN, nitrate-N and TAN increased markedly until wk 2, slightly wk 2 to 3 and leveled off wk 3 to 4, showing their accumulation had lessened. The overall average nitrite-N reached its peak in wk 3, 0.9 mg L1 and decreased to 0.6 mg L1 in wk 4.