Figure 7

Effects of combined application of biochar and NF on soil enzyme activities. The error bars indicate SE. Treatments: B0, B8, B16, and B24 corresponding to the application of 0, 8, 16, and 24 t/ha of biochar, respectively. N0, N150, and N300 corresponding to the application of 0, 150, and 300 kg/ha of NF. **, *and NS indicate an extremely significant difference, a significant difference and no significant difference among treatments (P = 0.05, Tukey’s HSD test).