Fig. 2From: Residual effects of corncob biochar on tropical degraded soil in central UgandaResidual Effect of biochar, farmyard manure compost and/or NPK on the collard plant leaf length. The same letter on the bars are not significantly different at p ≤ 0.0 5 using Tukey HSD; Control (CTRL), 10 t/ha compost only (CM), 200 kg NPK (NPK), 10t/ha Biochar only (BC1), 20 t/ha Biochar only (BC2), 5 t/ha Biochar + 5 t/ha compost (BC1+CM), 10 t/ha Biochar + 5 t/ha compost (BC2+CM), 5t/ha Biochar + 100 kg/ha NPK (BC1+NPK), 10 t/ha Biochar + 100 kg/ha NPK (BC2+NPK); Error bars represent standard deviation of the meansBack to article page