Photosynthetic mechanism of high yield under an improved wide-narrow row planting pattern in maize.

Wide-narrow row maize planting patterns are a popular way to enhance maize yield via improving canopy PAR. To further optimize canopy PAR, we designed an improved wide-narrow row planting pattern (R2) based on the principle of the shortest projection length and the longest illumination of objects on the ground. Compared to the traditional wide-narrow row planting pattern (R1), maize yield increased by about 10% in R2. R2 maize had higher PAR, leaf area index, chlorophyll content, and photosynthetic rates than maize grown in R1. Moreover, compared to maize leaves in R1, the carbon assimilation enzymatic activities were also significantly higher in R2. The higher carbon assimilation enzymatic activity in R2 could account for the increased photosynthetic rate. Thus, the improved wide-narrow row planting pattern could improve photosynthetic performance by enhancing the PAR of the plant canopy, which further promotes the ear number and yield in northeast China.