The Effects of Maize Varietal Traits and Maize Planting Density on Soybean-Maize Relay Strip Intercropping

Abstract

As a major consumer of soybean, the growth in China’s annual soybean production is crucial to its national food security. Both maize and soybean are upland crops with overlapping growth periods, leading to trade-offs in production when either crop is cultivated as a sole crop. However, the soybean-maize strip intercropping system enables the production of an additional soybean harvest with only a slight reduction or no loss in maize yield, thereby making a highly significant contribution to the expansion of total grain output. This study explored the effects of maize varietal traits and maize density on the production indicators of the two crops under this intercropping model by designing different maize varieties and maize planting densities. The results showed that maize lodging extent had an extremely significant negative correlation with maize yield and gross income. Maize plant height had a significant negative correlation with maize 100-grain weight, soybean SPAD values, and soybean grains per plant. Within a certain range, as maize density increased, maize yield first increased and then decreased, while soybean yield showed a continuous downward trend. Based on this regularity, a quadratic function mathematical model was constructed, with maize planting density as the independent variable and production benefit per unit area as the dependent variable. This model can be used to determine the optimal maize planting density for soybean-maize relay strip intercropping. This study identifies suitable maize varieties and optimal planting density, thereby providing references for local production practices.