Equal amounts of N, P, K were applied in each plot in the experiment except the control. Chemical N, P and K fertilizers as urea, calcium superphosphate, and KCl were used, respectively. All of the fertilizers including manure were applied in the cultivation layer as basal fertilizer one day before transplanting. Plot area was 5m×5m, and concrete wall with 6 cm width and 50 cm height was used to separate each plot to avoid the overflow of floodwater.