3.3. Changes in soil properties
RG and RR rotations significantly increased soil pH under most fertilization treatments, while RW rotation had no significant influences on soil pH (Fig. S1a). In general, RG rotation increased soil pH more than RR rotation (Fig. 4a). Crop rotation, fertilization, and their interaction had significant effects on the changes in soil pH (Table S6). Three rotation treatments significantly increased SOC and TN under most fertilization treatments (Fig. S1b, c). The application of BBU could facilitate the increase of SOC under RG and RW rotations (Fig. 4b) and TN under RG and RR rotations (Fig. 4c) compared with CU. Both crop rotation, fertilization, and their interaction had no significant effects on the changes in SOC and TN (Table S6). RG-CB1, RR-CU, RW-WN, RW-CU, and RW-CB1 significantly altered the soil POXC contents (Fig. S1d). The N treatments weakened the increase of POXC in comparison to WN under RG rotation, while it facilitated the increase of POXC under RR and RW rotations (Fig. 4d). Only the interaction between crop rotation and fertilization showed a significant effect on the change in POXC (Table S6). Soil AK and available Al, Fe, Cu, Zn were increased, while soil available Ca, Mg, and Mn were decreased after crop rotation and fertilization (Fig. S2). Soil AP had no significant change in most of the treatments (Fig. S2). Crop rotation had significant effects on the changes in soil AK and available Ca, Mg, Al, Mn, Zn. Fertilization had significant effects on the changes in soil AP and available Ca, Mg, Al, Mn, Fe, Cu. Interaction between crop rotation and fertilization had significant effects on the changes in soil AP, AK, and available Mg, Al, Mn, Fe, Cu (Table S6).