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).