LAUSR

Abstract Intercropping has been widely adopted by farmers for higher yield compared to monoculture, and the border effect was responsible for the yield advantage in irrigated areas. However, few studies have investigated the border effect based on photosynthesis, especially under rainfed conditions. Here, we evaluated the yield in rainfed wheat/maize strip relay intercropping, and explored the associated differences in yield components and physiological process compared to sole crops. A two-year field experiments was conducted including three treatments (sole wheat, sole maize and wheat/maize intercropping) in Yangling, located in the semi-humid region of northwest China. Grain yield, yield components, chlorophyll relative content (SPAD) and photosynthetic parameters in different rows were measured for wheat and maize. Results showed that wheat/maize intercropping increased the land use efficiency and total yield of wheat and maize under rainfed conditions. The yield of intercropped wheat was significantly (p   0.05) decreased (6%), mainly attributed to the border rows (19% lower than in sole maize), in which the kernel number per cob and thousand kernel weight were 14% and 8% (p