Table 4: Effects of tillage, N application and different seasons on Δ13C values (%) of wheat grain*.

Year Conventional till (CT) No-till (NT) Year mean
No N added (N0) 75 kg N ha-1 (N75) No N added (N0) 75 kg N ha-1 (N75)
1992 14.08 13.72 14.70 14.36 14.22
1993 nd nd nd nd nd
1994 14.97 13.78 15.00 13.95 14.43
1995 14.15 13.80 14.27 14.03 14.06
1996 14.90 14.82 15.25 15.01 15.00
Mean 14.53 14.03 14.81 14.34 14.43

*Treatment effects: least significant difference at P < 0.05; year, 0.23; tillage, 0.16; N, 0.16; year × N, 0.32. Year × tillage, tillage × N and year × tillage × N interactions were not significant.