Effects of Strip Configurations on Canopy Photosynthetic Performance and Resource Use Efficiency of Winter-Seeded Spring Wheat Relay Intercropped with Sunflower in the Hetao Irrigation District

Le résumé fourni par la source

The traditional spring wheat–sunflower relay intercropping system in the Hetao Irrigation District of Inner Mongolia is constrained by restrictions on sowing time, relatively low resource use efficiency, and suboptimal strip configurations. Based on the winter-seeding technique for spring wheat, this study established an annual double-cropping system of winter-seeded spring wheat relay intercropped with sunflower. The objectives were to evaluate crop photosynthetic performance, grain yield, resource use efficiency, and economic benefits under different strip configurations and to identify a suitable strip arrangement. A two-year fixed-site field experiment was conducted from 2023 to 2025. Four winter-seeded spring wheat/sunflower relay-intercropping treatments (W9S2, W9S4, W18S2, and W18S4) were compared with sole-cropped winter-seeded spring wheat and sole-cropped sunflower. Relay intercropping increased leaf area index, SPAD values, and the net photosynthetic rate of both crops at key growth stages and also improved grain yield and resource use efficiency. Among the strip configurations, W18S2 showed the best overall performance. Its two-year average grain yields of wheat and sunflower were 13.2% and 32.2% higher, respectively, than those of the corresponding sole-cropping treatments. The land equivalent ratio and nitrogen uptake equivalent ratio of all relay-intercropping treatments were greater than 1, with the highest values observed under W18S2. In addition, W18S2 had higher light use efficiency, water use efficiency, and nitrogen partial factor productivity than the sole-cropping treatments and the other relay-intercropping configurations. The two-year average net profit of W18S2 was 46.8% and 8.0% higher than that of sole-cropped wheat and sole-cropped sunflower, respectively. Overall, the superior performance of W18S2 was associated with a more favorable canopy structure and photosynthetic performance, greater dry matter accumulation, and coordinated improvements in grain yield, resource use efficiency, and economic benefits. These findings provide a reference for the high-yield and resource-efficient cultivation of winter-seeded spring wheat relay intercropped with sunflower in the Hetao Irrigation District.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.