a
Seven treatments were laid out: (1) a single basal application with compost at 1000 mg N kg1 (C4) or (2) with urea at 500 mg N kg1 (U2), (3) a basal
application of urea at 250 mg N kg1 followed by an additional application of compost at 500 mg N kg1 (U1/C2) or (4) an additional application of urea
at 250 mg N kg1 (U1/U1), (5) a basal application of compost at 500 mg N kg1 followed by an additional application of compost at 500 mg N kg1 (C2/
C2) or (6) an additional application of urea at 250 mg N kg1 (C2/U1), and (7) no N fertilization (control). Additional applications were applied at 40
DAT. Values are the means of triplicates. b
At 60 DAT, the d15N of the inorganic-N [(NH4
++NO3
)–N] were measured, because the quantities of NH4
+ and NO3
were too low to allow the d15N
to be measured separately.