Amaranthus hybridus is a noxious weed in Ontario, with demonstrated allelopathic properties that can lead to decreased agricultural production. We tested the germination and growth of five cover crop species exposed to A. hybridus extracts, and to dried or fresh materials in soil. A germination index was calculated, and the dry weight of plant organs were measured to quantify responses to treatments. All species had reduced germination (≤29%) in 100% extract. Trifolium pratense had significant root weight reductions in extract (52%) and dried (72%) treatments, whereas shoot weight only decreased (48%) in dried treatment. Medicago sativa shoot weight decreased (52%) in 20g fresh treatment, while root weight decreased (62%) in dried treatment. Shoot weight of Raphanus sativus increased (32%) at mid-extract concentrations, while root weight increased (33%) only with dried treatment; however, both its shoot and root weight decreased (>40%) in fresh treatment. Only the shoot weight of Lolium multiflorum increased (41% in 75% extract and 55% in dried treatment). Both Cichorium intybus shoot and root weights decreased (~50%) in fresh treatment. Crop responses to A. hybridus are complex, and material and species-dependant. Further testing in the field may provide a more comprehensive understanding of how to improve the management of A. hybridus.

中文翻译：

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安大略南部光滑杂草（Amaranthus hybridus）对覆盖作物的影响

mar菜（Amaranthus hybridus）是安大略省的一种有害杂草，具有证明其化感作用，可导致农业产量下降。我们测试了五种覆盖农作物种子的萌发和生长情况，这些农作物暴露于杂种曲霉提取物以及土壤中的干燥或新鲜材料。计算发芽指数，并测量植物器官的干重以量化对处理的反应。所有物种在100％提取物中的发芽率均降低（≤29％）。fo藜在提取物和干燥处理中的根重显着减少（52％），而在干燥处理中则仅降低（48％）。紫花苜蓿在20g新鲜处理中，枝条重量减少（52％），而在干燥处理中，根重减少（62％）。在提取液中浓度下，萝卜的芽重增加（32％），而根重仅在干燥处理下增加（33％）。然而，在新鲜处理中其枝条和根重均下降（> 40％）。多花黑麦草的芽重仅增加（75％提取物中41％，干燥处理中55％）。既菊苣枝条和根重在新鲜的处理降低（〜50％）。作物对杂种曲霉的反应是复杂的，并且取决于物质和物种。在该领域的进一步测试可以提供更加全面的了解如何改善杂交曲霉的管理。