Hairy vetch is a widely adopted cover crop in the United States. However, hairy vetch can become weedy in subsequent crops as seeds germinate after the cover crop growing season, which is largely attributed to seed dormancy. We conducted two field experiments to determine seed germination, viability and seed production phenology of two common hairy vetch cultivars in Blacksburg and Blackstone, Virginia, US. ‘Groff’ and ‘Purple Bounty’ seed were sown in October 2015 and May 2016 and germination was tracked until June 2017. Subsequently, ungerminated seeds were tested for viability. Both cultivars had <2% germination after the initial germination period, and <1% of seed recovered was still viable at the end of the experiments. We also conducted experiments to determine when these cultivars produce viable seed. Hairy vetch seeds were counted and tested for germination in the spring. Both cultivars produced seed beginning in late‐May, but most seed were not viable until mid‐June in Virginia. Our results indicate that seed dormancy is not the primary cause of hairy vetch weediness in subsequent crops as nearly all germination, 99% of the total germinated seed, occurred during the cover crop growing season. Also, if complete termination occurs before mid‐June in Virginia, it is unlikely viable seed will be added to the seed bank. To better utilise this cover crop species, cultivar selection and proper termination are important to prevent weediness.

中文翻译：

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紫云英种子发芽和成熟对随后农作物杂草的影响

有毛。子在美国被广泛采用。但是，由于在覆盖作物生长季节之后种子发芽，所以在随后的作物中多毛紫v可能会变得杂草，这在很大程度上归因于种子的休眠。我们进行了两个田间试验，以确定在美国弗吉尼亚州布莱克斯堡和黑石市的两个常见毛v子品种的种子发芽，活力和种子生产物候。“ Groff”和“ Purple Bounty”种子分别于2015年10月和2016年5月播种，发芽一直持续到2017年6月。随后，对未发芽的种子进行了可行性测试。在初始发芽期后，两个品种的发芽率均<2％，并且在实验结束时仍可回收<1％的种子。我们还进行了实验，以确定这些品种何时产生可行的种子。春季计数有毛v子种子并测试发芽率。两个品种都在5月下旬开始播种，但是大多数种子直到6月中旬才在弗吉尼亚州存活。我们的结果表明，种子休眠不是随后作物中多虫紫菜杂草的主要原因，因为几乎所有萌发（占发芽种子总数的99％）都发生在覆盖作物生长季节。另外，如果在弗吉尼亚州6月中旬之前发生完全终止，则不太可能将可行的种子添加到种子库中。为了更好地利用这种覆盖作物物种，品种选择和适当终止对于防止杂草很重要。我们的结果表明，种子休眠不是随后作物中多虫紫菜杂草的主要原因，因为几乎所有萌发（占发芽种子总数的99％）都发生在覆盖作物生长季节。另外，如果在弗吉尼亚州6月中旬之前发生完全终止，则不太可能将可行的种子添加到种子库中。为了更好地利用这种覆盖作物物种，品种选择和适当终止对于防止杂草很重要。我们的结果表明，种子休眠不是随后作物中多虫紫菜杂草的主要原因，因为几乎所有萌发（占发芽种子总数的99％）都发生在覆盖作物生长季节。另外，如果在弗吉尼亚州6月中旬之前发生完全终止，则不太可能将可行的种子添加到种子库中。为了更好地利用这种覆盖作物物种，品种选择和适当终止对于防止杂草很重要。