Crop–weed interactions are affected by environmental alterations resulting from a crop’s presence, such as modifications in temperature, light quality and quantity, and moisture conditions that could modify weed performance. The objectives of this work were to study (1) how soybean [Glycine max (L.) Merr.] crop structure modifies the environment under the canopy and large crabgrass [Digitaria sanguinalis (L.) Scop.] plant structure, biomass, and seed production and dormancy; and (2) the relative importance of these environmental changes on the weed’s characteristics. A field experiment in a completely randomized block design with five replicates was performed to evaluate narrow and wide interrow spacing and soybean maturity groups 3 and 4. Measured variables were intercepted solar radiation (RAD); red–far red (R-FR) ratio; humidity; minimum, maximum, and alternating temperatures; and weed biomass, tillers per plant, height, and seed dormancy. Crop canopy reduced solar radiation, R-FR ratio, and daily average maximum and alternating temperatures. Soybean presence reduced the weed biomass, tillers and seeds per plant, and seed dormancy. High solar radiation intercepted by the crop during the reproductive phase was the main environmental variable related to reductions in weed biomass, tillers per plant, and fecundity. The combination of low temperature and solar radiation received by developing seeds was more related to seed dormancy than the rest of the variables. Crop management decisions focused on the fact that keeping the crop canopy alive for a longer time at the end of the season would not only reduce the weed growth but also seed dormancy.

中文翻译：

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大豆作物结构对大马唐（Digitaria sanguinalis）生长和种子休眠的影响

作物与杂草的相互作用会受到因作物存在而导致的环境变化的影响，例如温度、光照质量和数量的变化以及可能改变杂草性能的湿度条件。这项工作的目的是研究 (1) 大豆 [最大甘氨酸(L.) Merr.] 作物结构改变了树冠和大马唐草下的环境 [血楹(L.) Scop.] 植物结构、生物量、种子生产和休眠；(2) 这些环境变化对杂草特性的相对重要性。进行了具有五个重复的完全随机区组设计的田间试验，以评估窄和宽的行间距以及大豆成熟度组 3 和 4。测量变量是截获的太阳辐射 (RAD)；红-远红 (R-FR) 比率；湿度; 最低、最高和交变温度；和杂草生物量、每株分蘖、高度和种子休眠。作物冠层减少了太阳辐射、R-FR 比以及日平均最高温度和交变温度。大豆的存在减少了杂草生物量、每株植物的分蘖和种子以及种子休眠。作物在生殖阶段截获的高太阳辐射是与杂草生物量、每株植物分蘖和繁殖力减少有关的主要环境变量。与其他变量相比，发育中的种子接受的低温和太阳辐射的组合与种子休眠的关系更大。作物管理决策的重点是在季节结束时让作物冠层保持更长的生命，这不仅会减少杂草生长，还会减少种子休眠。