The cropping system was double rice cropping, with thefirst
rice transplanted around 20th April and harvested around 20th
July and the second rice transplanted around 25th July and
harvested around 1st November. Rice seedlings were manually
transplanted at the same density in each plot. In all the treatments
studied, fertilizers were applied at rates of 180 kg-N ha
1
, 90 kgPha
1
and 165 kg-K ha
1
. Urea and potassium chloride were
applied, 50% and 30% as basal fertilizer, 25% and 30% as tillering
fertilizer, and 25% and 40% as panicle fertilizer, respectively.
Superphosphate was applied 100% as basal fertilizer. Thefields
wereflooded to 50–80 mm above the ground three to four days
before transplanting and lasted till the establishment of seedlings,
followed by one week free drainage, re-flooded till the peak
tillering stage, followed by another one week free drainage, and reflooded during theflowering stage, followed by free drainage after
thefilling stage. In total, there were three times of free drainage
during a rice growth period.