There is a drive to improve the sustainability of agricultural systems including the biodiversity component. Cultivar mixtures offer yield benefits from the same land area, but the mechanisms behind this overyielding have not been completely worked out. One potential mechanism is improved competition with weeds. We use an experimental approach of varying barley (Hordeum vulgare L.) genotypic and phenotypic diversity to test the hypothesis that increases in diversity have an impact on weed growth strategies and community assembly, or if responses are driven by barley performance. There was no effect of increasing barley mixture diversity on weed traits, either in terms of species means or the community‐weighted mean. However, Functional Richness of the weed community decreased with increasing barley mixture diversity mainly as a result of reduced specific leaf area Functional Richness. This pattern was driven by a reduction in species richness of the weed community rather than by reduced variation within species. Whilst barley phenotype had different impacts on weed traits, there were no specific mixtures of phenotypes or genotypes that had consistent effects on community assembly or weed species responses. The competitive exclusion of weed species could have agronomic and environmental benefits, through better targeting or less frequent use of herbicides. Growing crop mixtures is one of many strategies available to improve agricultural sustainability and resilience, and one that has clear benefits.

中文翻译：

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作物多样性的增加减少了杂草可用的功能空间

推动包括生物多样性组成部分在内的农业系统的可持续性得到改善。栽培品种混合物提供相同土地面积的产量收益，但这种超产背后的机制尚未完全弄清楚。一种潜在的机制是改善与杂草的竞争。我们使用不同大麦 (Hordeum vulgare L.) 基因型和表型多样性的实验方法来测试多样性增加对杂草生长策略和群落组装有影响的假设，或者响应是否由大麦性能驱动。无论是在物种平均值还是群落加权平均值方面，增加大麦混合物多样性对杂草性状都没有影响。然而，杂草群落的功能丰富度随着大麦混合物多样性的增加而降低，这主要是由于比叶面积功能丰富度的降低。这种模式是由杂草群落物种丰富度的减少而不是物种内变异的减少所驱动的。虽然大麦表型对杂草性状有不同的影响，但没有特定的表型或基因型混合物对群落组装或杂草物种反应有一致的影响。通过更好地定位或减少除草剂的使用频率，对杂草物种的竞争性排除可能具有农艺和环境效益。种植混合作物是提高农业可持续性和复原力的众多策略之一，而且具有明显的好处。这种模式是由杂草群落物种丰富度的减少而不是物种内变异的减少所驱动的。虽然大麦表型对杂草性状有不同的影响，但没有特定的表型或基因型混合物对群落组装或杂草物种反应有一致的影响。通过更好地定位或减少除草剂的使用频率，对杂草物种的竞争性排除可能具有农艺和环境效益。种植混合作物是提高农业可持续性和复原力的众多策略之一，而且具有明显的好处。这种模式是由杂草群落物种丰富度的减少而不是物种内变异的减少所驱动的。虽然大麦表型对杂草性状有不同的影响，但没有特定的表型或基因型混合物对群落组装或杂草物种反应有一致的影响。通过更好地定位或减少除草剂的使用频率，对杂草物种的竞争性排除可能具有农艺和环境效益。种植混合作物是提高农业可持续性和复原力的众多策略之一，而且具有明显的好处。没有表型或基因型的特定混合物对群落组装或杂草物种反应具有一致的影响。通过更好地定位或减少除草剂的使用频率，对杂草物种的竞争性排除可能具有农艺和环境效益。种植混合作物是提高农业可持续性和复原力的众多策略之一，而且具有明显的好处。没有表型或基因型的特定混合物对群落组装或杂草物种反应具有一致的影响。通过更好地定位或减少除草剂的使用频率，对杂草物种的竞争性排除可能具有农艺和环境效益。种植混合作物是提高农业可持续性和复原力的众多策略之一，而且具有明显的好处。