Plant soil feedback (PSF) occurs when a plant modifies soil biotic properties and those changes in turn influence plant growth, survival or reproduction. These feedback effects are not well understood as mechanisms for invasive plant species. Eragrostis lehmanniana is an invasive species that has extensively colonized the southwest US. To address how PSFs may affect E. lehmanniana invasion and native Bouteloua gracilis growth, soil inoculant from four sites of known invasion age at the Appleton-Whittell Audubon Research Ranch in Sonoita, AZ were used in a PSF greenhouse study, incorporating a replacement series design. The purpose of this research was to evaluate PSF conspecific and heterospecific effects and competition outcomes between the invasive E. lehmanniana and a native forage grass, Bouteloua gracilis. Eragrostis lehmannianaPSFs were beneficial to B. gracilis if developed in previously invaded soil. Plant-soil feedback contributed to competitive suppression of B. gracilis only in the highest ratio of E. lehmanniana to B. gracilis. Plant-soil feedback did not provide an advantage to E. lehmanniana in competitive interactions with B. gracilis at low competition levels but were advantageous to E. lehmanniana at the highest competition ratio, indicating a possible density-dependent effect. Despite being beneficial to B. gracilis under many conditions, E. lehmanniana was the superior competitor.

中文翻译：

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入侵性植物通过植物土壤的反馈使本地植物受益，但仍是竞争者

当植物改变土壤生物特性时，就会发生植物土壤反馈（PSF），而这些变化又会影响植物的生长，存活或繁殖。这些反馈效应尚未很好地理解为入侵植物物种的机制。Eragrostis lehmanniana是一种入侵物种，已在美国西南部广泛殖民。为了解决PSF如何影响雷曼氏大肠杆菌的入侵和原生Bouteloua gracilis生长的问题，在PSF温室研究中，使用了位于亚利桑那州Sonoita的Appleton-Whittell Audubon研究牧场的四个已知入侵年龄的土壤接种物，并采用了替代系列设计。这项研究的目的是评估PSF同种异体效应和异种效应以及入侵性E.lehmanniana与本地牧草Bouteloua gracilis之间的竞争结果。如果在先前入侵的土壤中发育，Eragrostis lehmannianaPSFs对纤毛芽孢杆菌是有益的。植物-土壤反馈仅以雷曼氏梭菌与细小芽孢杆菌的最高比率有助于抑制细小芽孢杆菌。在低竞争水平下，植物土壤反馈在与细纹芽孢杆菌的竞争性交互作用中没有提供优势，但在最高竞争率下却有利于Lehmanniana，表明可能存在密度依赖性效应。尽管在许多情况下对细纹芽孢杆菌都有益，但雷曼氏大肠杆菌还是竞争者。lehmanniana在低竞争水平下与纤细芽孢杆菌发生竞争性相互作用，但在最高竞争率下对E. lehmanniana有利，表明可能存在密度依赖性效应。尽管在许多情况下对细纹芽孢杆菌都有益，但雷曼氏大肠杆菌还是竞争者。lehmanniana在低竞争水平下与纤细芽孢杆菌发生竞争性相互作用，但在最高竞争率下对E. lehmanniana有利，表明可能存在密度依赖性效应。尽管在许多情况下对细纹芽孢杆菌都有益，但雷曼氏大肠杆菌还是竞争者。