Table 1: Effect of biochar concentration and biochar feedstock on soil pHwater and cation exchange capacity (CEC; cmol Kg−1 soil) of Kettering and Cameroon soils. Data are mean ± SEM ( ) and values are derived from one-way ANOVA with biochar concentration as the factor. Mean values within each soil and biochar type combination sharing the same letter are not significantly different ( ).

Biochar conc. (mg g−1)pHCEC
Kettering soilCameroon soilKettering soilCameroon soil

Pine wood biochar
 07.3 ± 0.25.4 ± 0.114.9 ± 0.38.4 ± 0.2b
 157.5 ± 0.15.4 ± 0.114.9 ± 0.89.3 ± 0.3ab
 307.4 ± 0.25.5 ± 0.114.5 ± 0.28.7 ± 0.7b
 1507.5 ± 0.35.4 ± 0.115.4 ± 0.610.1 ± 0.6a
value0.540.560.250.015
Straw biochar
 07.3 ± 0.2c5.4 ± 0.1d14.9 ± 0.3b8.4 ± 0.2c
 158.4 ± 0.2b6.6 ± 0.2c15.6 ± 0.3ab8.1 ± 0.8c
 308.5 ± 0.5b7.4 ± 0.3b16.1 ± 0.7a9.6 ± 0.4b
 1509.6 ± 0.1a8.5 ± 0.4a14.8 ± 0.5b11.7 ± 0.3a
value<0.001<0.0010.02<0.001