Figure 7

Effect of fertilizer treatments on dry weight of biomass (a) and grain yield (b) of Brassica napus. CK: untreated soil; B: soil treated with biochar; B + U: soil treated with biochar and urea; Urea: soil treated with only urea as nitrogen fertilizer; BCRNF: soil treated with BCRNF as nitrogen fertilizer. Different small letters indicate significant differences between different treatments (p < 0.05).