A field experiment was conducted in China to investigate the effect of different root partition patterns on wheat/maize competitiveness under intercropping system and how it affects yield. Two root partition patterns (plastic film and nylon mesh partition patterns) were used. Results showed that wheat/maize competitiveness in intercropping system steadily increased from sowing to flowering stage of wheat and then decreased the competitive advantage of wheat over maize under intercropping decreases by root partitioning. Intercropping system without root partition increased the competitive advantage of wheat by 20.5 and 4.9% respectively, compared to those with plastic film and nylon mesh partitions. The land equivalent ratios of intercropping systems without root partition, with plastic film partition and nylon mesh partition were 1.46, 1.20 and 1.39, respectively. Yield for the intercropping system was quadratically correlated with wheat competitiveness to maize. Improving wheat/maize competitiveness in intercropping systems increased yield. The stage of wheat flowering was critical for optimizing wheat competitiveness.
