Effects of Strip Width on Inter-Row Heterogeneity in Light Interception and Utilization of Intercropped Soybeans

Strip intercropping improves productivity through enhanced light interception. In this study, we quantified the effects of strip width on light interception of soybean across six strip widths (2.2 m, 2.5 m, 2.8 m, 3.1 m, 3.4 m, 3.7 m) when intercropped with maize. Results showed that photosynthetically active radiation (PAR) in western rows of intercropped soybeans peaked at 11:30 a.m., whereas in eastern rows, it occurred at 1:00 p.m. Across 2.2 m to 3.7 m, PAR in the western rows of intercropped soybeans was 6.1% higher than that of the eastern rows for the whole growth period. During the R5 stage, compared to eastern rows, radiation use efficiency (RUE), dry matter accumulation, and leaf area of soybean in western rows increased by 4.0%, 7.4%, and 6.7%, respectively. Compared to the 2.2 m strip width, grain yields in eastern rows of 2.5-3.7 m strip widths were 8.5%, 54.7%, 56.5%, 63.4%, and 69.0% higher than those of the 2.2 m strip width, respectively. PAR had the strongest influence on dry matter and leaf area at a 3.7 m strip width, while RUE had the strongest influence at 3.1 m strip widths. These findings advance our understanding of light partitioning in strip intercropping and support future climate-adaptive intercropping systems' modeling.