Equidistant plant arrangements have shown positive impacts, in the United States over the last century, on soybean (Glycine max L.) yield and seed quality by reducing intraspecific plant competition and enhancing early canopy cover. This study aims to (i) assess the effects of equidistant versus non‐equidistant plant arrangements on soybean yield and seed quality across different regions in the United States; (ii) explore the effect of modified soybean plant canopy resulting from different plant arrangements on yield and seed quality. In 2021 and 2022, 13 trials were conducted in Kansas, Mississippi, and South Dakota. The treatments consisted of three equidistant plant arrangements of 13 cm × 13 cm, 15 cm × 15 cm, and 20 cm × 20 cm (620,000, 430,000, 242,363 seeds ha−1, respectively), and a non‐equidistant with 38 cm of row space (321,236 seeds ha−1). Soybean yield and yield components were collected, and canopy coverage (%) was monitored throughout the growing season. Overall, there is no evidence of any advantage of equidistant over non‐equidistant arrangements in soybeans. Yield differences related to spatial arrangement were observed in only three trials: the non‐equidistant increased yield compared to the 20 cm × 20 cm equidistant arrangement (lowest density) in two trials, while the 13 × 13 and 15 × 15 patterns (highest density) showed higher yield compared to the 20 cm × 20 cm arrangement in one trial. Furthermore, seed quality remained constant across spatial arrangements in the 13 trials. In contrast to prior research, our study found no correlation between canopy coverage development and yield improvement. The tested equidistant arrangement while promising did not provide substantial evidence of yield improvement relative to the non‐equidistant.

中文翻译：

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不同密度下等距与非等距种植的大豆产量和种子质量


上个世纪，在美国，等距植物排列通过减少种内植物竞争和增强早期冠层覆盖，对大豆 (Glycine max L.) 产量和种子质量产生了积极影响。本研究旨在 (i) 评估等距与非等距植物排列对美国不同地区大豆产量和种子质量的影响； (ii) 探索不同植物排列产生的改良大豆植物冠层对产量和种子质量的影响。 2021 年和 2022 年，堪萨斯州、密西西比州和南达科他州进行了 13 项试验。处理包括三种等距植物排列，分别为 13 cm × 13 cm、15 cm × 15 cm 和 20 cm × 20 cm（分别为 620,000、430,000、242,363 个种子 ha−1），以及 38 cm 的非等距植物排列。行空间（321,236 个种子 ha−1）。收集大豆产量和产量组成部分，并在整个生长季节监测冠层覆盖度（%）。总体而言，没有证据表明大豆等距排列比非等距排列有任何优势。仅在三项试验中观察到与空间排列相关的产量差异：在两项试验中，与 20 cm × 20 cm 等距排列（最低密度）相比，非等距增加了产量，而 13 × 13 和 15 × 15 模式（最高密度） ）在一项试验中，与 20 cm × 20 cm 排列相比，显示出更高的产量。此外，在 13 次试验中，种子质量在空间布局上保持不变。与之前的研究相比，我们的研究发现冠层覆盖度发展与产量提高之间没有相关性。测试的等距排列虽然有希望，但并没有提供相对于非等距排列提高产量的实质性证据。