Productivity 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. A 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. Intercropping 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 and 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, photosynthetically active radiation, and root morphology in cotton compared to other treatments. Within the distance of 100–150 mm from the soybean, cottons were more competitive than soybeans, indicating subtle interspecific competition between the two species. By 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.

中文翻译：

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通过选择棉豆间作系统中的大豆品种和播种日期来管理种间竞争以提高生产力


间作系统的生产力和效益受到物种之间重叠时期和竞争动态的影响，这取决于品种选择和种植计划。然而，通过调整播种日期以实现最小株高差异的组合来提高间作系统生产力的研究有限。进行了为期两年的田间试验，采用四行棉花和五行大豆的条带间作。对具有不同株高和类型以及早播期和晚播期的三个大豆品种（杞黄 34、吉豆 12 和吉豆 17）进行了检查。棉花和大豆间作比单作产量更高，其中吉豆12号被认为是最适合与棉花间作的品种。棉豆间作系统的土地当量比（LER）在两年内平均在 1.04 至 1.15 之间。值得注意的是，与早播相比，间作晚播杞黄 34、吉豆 12 和吉豆 17 的 LER 分别提高了 4%、5% 和 3%。这表明调整大豆播期可以调节棉花和大豆之间的竞争动态，减轻种间竞争。此外，与其他处理相比，晚播吉豆12间作棉花在棉花干物质、冠层光合作用、光合有效辐射和根系形态方面表现出优异的性能。在距离大豆 100-150 毫米的范围内，棉花比大豆更具竞争力，这表明两个物种之间存在微妙的种间竞争。 通过精心选择大豆品种和调整播期，可以实现时间互补和空间生态位分化，缓解种间竞争，提高棉豆间作系统的生产力。