ContextProductivity and benefits in intercropping systems are influenced by the overlapping period and competitive dynamics between species, which are contingent upon variety selection and planting schedules. However, there is limited research on improving the productivity of intercropping systems by adjusting sowing dates for combinations with minimal plant height differences. MethodsA two-year field experiment utilizing a strip intercropping with four rows of cotton and five rows of soybeans was conducted. Three soybean varieties (Qihuang 34, Jidou 12, and Jidou 17) with varying plant heights and types, along with early and late sowing dates, were examined. ResultsIntercropping cotton and soybeans resulted in higher yields than monoculture, with Jidou 12 identified as the most suitable variety for intercropping with cotton. The land equivalent ratio (LER) for the cotton-soybean intercropping system averaged between 1.04 to 1.15 over two years. Notably, intercropping cotton with late-sown Qihuang 34, Jidou 12, and Jidou 17 demonstrated increased LER by 4%, 5%, and 3% respectively, compared to early-sown. This demonstrates that adjusting the soybean sowing date can modulate the competition dynamics between cotton and soybean, mitigating interspecific competition. Furthermore, intercropping cotton with late-sown Jidou 12 exhibited superior performance in terms of dry matter, canopy photosynthesis, border photosynthetically active radiation, and root morphology in cotton compared to other treatments. Within the distance of 100-150mm from the soybean, cottons were more competitive than soybeans, indicating subtle interspecific competition between the two species. ConclusionsBy carefully selecting soybean varieties and adjusting sowing dates, temporal complementarity and spatial niche differentiation can be achieved, alleviating interspecific competition and enhancing the productivity of cotton-soybean intercropping systems.