Effects of large-spike type maize on interspecific competition and intercropping advantage in maize–peanut intercropping system

Maize–peanut intercropping (maize||peanut) has a significant advantage in terms of yield. However, interspecific competition between maize and peanut in the later period of coexistence limits further yields increasing. Investigating the coordination effects of large-spike maize on interspecific competition and intercropping advantages in maize||peanut systems can provide a theoretical basis for high yield and efficiency. The experiment was conducted at the experimental farm of Henan University of Science and Technology from 2020 to 2021, with medium-spik maize cultivar ‘Zhengdan 958’ intercropping with peanut (M_ZD||P) as the control. The effects of large-spike maize cultivar ‘MC4520’ intercropping with peanut (M_MC||P) on crop dry matter accumulation and distribution, leaf area index, interspecific competitiveness index, photosynthetic characteristics, yield, and intercropping advantages were studied in a two-year field experiment. The results showed that compared with M_ZD||P, M_MC||P significantly increased the dry matter weight per plant of maize and peanut by 7.55%–9.68% and 16.07%–26.77% (P<0.05), respectively. M_MC||P improved dry matter accumulation of maize grains and peanut pods at the harvest stage, which was significantly increased by 9.74%–10.84% and 34.56%–38.33% (P<0.05), respectively. M_MC||P promoted the distribution of dry matter to maize grain and peanut pod, in particular for peanut, significantly increased by 9.12%–15.93%. M_MC||P increased the leaf area index of peanuts by 5.78%–29.58%, and the interspecific competitiveness index of peanuts relative to maize by 24.44%–65.12% (P<0.05). M_MC||P significantly increased the net photosynthetic rate of maize and peanut by 8.18%–15.74% and 3.15%–18.05% (P<0.05), respectively. In addition, the stomatal conductance and transpiration rate of maize and peanuts increased, whereas the intercellular CO₂ concentration of peanuts decreased. The yield of peanuts in M_MC||P significantly increased by 26.39%–51.61%, and the intercropping advantage and land equivalent ratio improved by 22.21%–24.08% and 13.26%–15.27%, respectively (P<0.05). In conclusion, in maize||peanut systems, large-spike type maize intercropping with peanuts can effectively coordinate interspecific competition at a later period of coexistence, which enhances the interspecific competitiveness of peanuts and improves the yield of peanuts, thus improving the yield and land equivalent ratio of intercropping systems and further enhancing the intercropping advantages.