3.1 Effect of amendments on soil physicochemical
properties
Amended treatments and incubation time had significant effects on
physicochemical properties, and with significant interactions between
the two factors (P <0.001).
During the entire incubation
period, soil pH was significantly lower after addition of N fertilizer
than CK treatment; a significant increase in SOC, TN, AN, AP, AK
contents in all amended treatments than CK treatment (Table 2).
Specifically, pH decreased more in N3 level, ordered by C-M2-N3, C-M1-N3
and C-N3. SOC with higher contents in M2 level, in which C-M2-N0
treatment supported the highest value, followed by C-M2-N2, C-M2-N1,
C-M2-N3. TN and AN contents had higher contents in N3 level, ordered by
C-N3, C-M2-N3, C-M1-N3 and C-M2-N3, C-M1-N3 C-N3, respectively. N2 level
had higher AP and AK contents, in which both C-M2-N2 treatment supported
the highest value, followed by C-M1-N2 (Fig. 2). With the increasing
incubation time (Fig.2), pH increased up to day 12 and then decreased
during the remaining incubation time (day 12 to 90) in all amended
treatments. AN, AP and AK increased significantly in all amended
treatments up to day 45, and then decreased during the remaining
incubation time (day 45 to 90). In addition, there was an increase in
SOC and TN contents over the entire incubation time in all amended
treatments.