Fine and coarse straw-, husk- and bran-char were thoroughly homogenized with the contaminated soils (5% biochar by weight), flooded with deionized water and incubated for two weeks. An addition of 5% was chosen because it is a typical addition based on previous work on biochar. Pore water was collected with a soil moisture sampler (Rhizosphere Research Products, Netherlands) inserted into each pot prior to transplanting rice seedlings. Basal fertilizers were added to the soil as 200 mg N (as Ca(NO3)2·4H2O), 180 mg P (as KH2PO4) and 60 mg Mg (as MgSO4·7H2O) kg−1 (based on air-dry weight). Soils without biochar addition (0%) were designated as the control. There were seven treatments and each treatment was replicated four times containing 400 g soil and 2 seedlings per pot. Plants were harvested after 4-weeks growth. Shoots were cut at the soil surface, washed with deionized water, dried at 70 °C for 48 h, and then weighed. Roots were taken from soils by gentle sieving for further measurements.