Figure 4

The effect of biochar, USAS (un-stabilized ammonium sulphate) and SAS (stabilized ammonium sulphate with DMPP) on the concentration of NO₃⁻–N (mg L⁻¹) in soil solution. NoAS No ammonium sulphate, CON control, 1%BC 1% biochar, 2%BC 2% biochar, DAS day after sowing.