Intercropping with functionally diverse crops can reduce the availability of resources that could otherwise be used by weeds. An experiment was conducted across 6 site-years in New York and Maryland in 2013 and 2014 to examine the effects of functional diversity and crop species richness on weed suppression. We compared four annual crop species that differed in stature and nitrogen acquisition traits: (1) pearl millet, (2) sorghum sudangrass, (3) cowpea, and (4) sunn hemp. Crops were seeded in monoculture and in threeand four-species mixtures using a replacement design in which monoculture seeding rates were divided by the number of species in the intercrop. Crop and weed biomass were sampled at ~ 45 and 90 d after planting. At the first sampling date, intercrops produced more crop biomass than monocultures in all but 1 site-year; however, weed biomass in intercrops was lower than monocultures in only 1 site-year. By the second sampling date, crop biomass was consistently greater in the intercrops than in the monocultures, and weed biomass was lower in the intercrops than in monocultures in 2 site-years. Although we observed several negative relationships between crop species richness and weed biomass, crop biomass was a more important factor than species richness for suppressing weeds. Despite the weak weed suppression from the two legumes compared with the two grasses, legume crops can provide other benefits, including increased forage quality, soil nitrogen for subsequent crops, and resources for pollinators if allowed to flower. On the other hand, if weed suppression is the top priority, our results suggest that monocultures of high biomass–producing grasses will provide more effective suppression at a lower seed cost than functionally diverse intercrops that include low biomass– producing legumes in warm-season intercrops. Nomenclature: Cowpea, Vigna unguiculata (L.) Walp; pearl millet, Pennisetum glaucum (L.) R. Br.; sorghum sudangrass, Sorghum bicolor (L.) Moench × S. sudanense (Piper) Stapf; sunn hemp Crotalaria juncea L.

中文翻译：

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作物生物质而非物种丰富度推动了东北部暖季一年生草 - 豆科间作作物的杂草抑制 – 勘误表

与功能多样的作物间作会减少可被杂草利用的资源。2013 年和 2014 年在纽约和马里兰州进行了为期 6 年的实验，以检查功能多样性和作物物种丰富度对杂草抑制的影响。我们比较了四种在身高和氮获取性状方面不同的一年生作物物种：(1) 珍珠粟、(2) 高粱苏丹草、(3) 豇豆和 (4) 晒麻。使用替代设计在单一栽培和三和四物种混合物中播种作物，其中单一栽培播种率除以间作物种数。在种植后约 45 天和 90 天对作物和杂草生物量进行采样。在第一个采样日期，除 1 个地点年外，间作比单一栽培产生更多的作物生物量；然而，间作杂草生物量仅在 1 个地点年低于单一栽培。到第二个采样日期，间作作物生物量始终高于单一栽培，而间作作物的杂草生物量在 2 个地点年低于单一栽培。尽管我们观察到作物物种丰富度和杂草生物量之间存在几种负相关关系，但作物生物量是比物种丰富度更重要的抑制杂草的因素。尽管与两种草相比，这两种豆科植物对杂草的抑制作用较弱，但豆科作物可以提供其他好处，包括提高草料质量、为后续作物提供土壤氮，如果允许开花，则可为传粉媒介提供资源。另一方面，如果杂草抑制是重中之重，我们的结果表明，与功能多样的间作（包括暖季间作中的低生物量豆类）相比，高生物量产生草的单一栽培将以更低的种子成本提供更有效的抑制。命名：豇豆、豇豆 (L.) Walp；珍珠粟，Pennisetum glaucum (L.) R. Br.；Sorghum sudangrass, Sorghum bicolor (L.) Moench × S. sudanense (Piper) Stapf; sunn 大麻 Crotalaria juncea L.