Soil conditioning affects interactions between native and invasive exotic perennials of semi-natural grasslands

1. Semi–natural perennial grasslands are of increasing importance as components of multifunctional agroecosystems, combining biomass production with provision of other ecosystem services. Soil legacies from previous land use or exotic species can hinder their establishment, but might be overcome through a multi–stage successional strategy, whereby certain species are used to facilitate native grassland species establishment. We tested this strategy via a feedback experiment examining soil conditioning effects on interference interactions between native and exotic species. 2. Soils in a former maize–soybean production field in Minnesota, USA, were conditioned for three years with native or invasive exotic perennials or a maize–soybean crop rotation. Nitrogen (N) fertilisation was an additional treatment in field plots. In a greenhouse, native and invasive exotic perennial grassland seedlings were grown on these soils, in monoculture and in native–exotic species pairs, with and without ...1. 半自然多年生草地（Semi–natural perennial grasslands）作为多功能农业生态系统（multifunctional agroecosystems）的组成部分，其重要性与日俱增——这类系统可兼顾生物质生产与其他生态系统服务的供给。既往土地利用或外来物种（exotic species）带来的土壤遗留效应（soil legacies）会阻碍其建植，但可通过多阶段演替策略（multi–stage successional strategy）加以克服：即利用特定物种促进本土草地物种的定植。我们通过一项反馈实验（feedback experiment）验证了该策略，该实验旨在探究土壤驯化效应（soil conditioning effects）对本土与外来物种间干扰互作（interference interactions）的影响。 2. 实验场地位于美国明尼苏达州一处曾开展玉米-大豆轮作的农田，研究人员分别采用本土多年生植物、入侵性外来多年生植物，以及玉米-大豆轮作（maize–soybean crop rotation）模式对土壤进行了为期三年的驯化处理，并在田间样地中增设氮肥（Nitrogen, N）施肥作为附加处理。在温室（greenhouse）环境中，研究人员将本土与入侵性外来多年生草地幼苗分别以单栽种植（monoculture）以及本土-外来物种种对（native–exotic species pairs）的形式种植于上述驯化后的土壤中，设置有/无……（原文未完整给出后续内容）。