Therefore, the intercropping systems received a relatively lower total N than corresponding sole maize, taking into consideration the N available in the pea strips after the pea harvest. All plots received P fertilizer at 150 kg P ha−1 as a base fertilizer; then, for the plots without N fertilizer, calcium superphosphate (0–16-0 of N-P2O5-K2O) was used, while for the plots with N fertilizer, diammonium phosphate (18–46-0 of N-P2O5-K2O) was used. For the topdressing of N fertilizer in the maize strip, a 3-cm diameter hole (10-cm deep) was made 4–5 cm away from the maize stem, the fertilizer was applied in the hole, and the hole was compacted with soil.