3.1 Soil physical-chemical properties changes with biochar amendment
Overall, the trend of the results illustrated that BW, SWC, and TN decreased with biochar addition, while pH, TP, SOC, and DOC contents showed a noticeable or small increas. There was a steady increase, about 46%, for TP from 0.24g/kg in CK to 0.35g/kg in T10. A significant drop of TN contents, about 10%, was observed with biochar addition. A small change was observed when SOC contents increased from 12.06g/kg in CK to 13.60g/kg in T10. Despite the small change of DOC contents between CK and LK, it increased rapidly in HK treatment, and was about 25% and 67% in T5 and T10 more than that in CK, respectively. As expected, an increment in soil pH was observed but within a small range, from 8.22 in CK to 8.44 in T10 treatment (Table 2).