warmXtrophic plant-soil interaction greenhouse experiment, Kellogg Biological Station, Hickory Corners, MI, 2021

Climate warming influences plant communities through both direct effects, such as changes in temperature, and indirect pathways mediated by changes in soil microbial communities. These microbe-mediated indirect effects may alter plant traits and ecosystem dynamics in ways that are often overlooked in studies focused solely on the direct impacts of warming. To test these microbe-mediated indirect effects, we used field-conditioned soil from a 7-year (2015-2021) warming experiment (warmXtrophic) in an early successional plant community in Hickory Corners, Michigan, USA at Michigan State University's Kellogg Biological Station Long-Term Ecological Research site. In a greenhouse during 2021, we assessed how warmed versus ambient soil inocula influenced plant growth and traits of two species: Trifolium pratense (red clover) and Phleum pratense (Timothy grass). We measured above, below, and total biomass, height, number of leaves, timing of germination, leaf % carbon and nitrogen, C:N ratio, specific leaf area (SLA), and greenness (a proxy for chlorophyll content). We also measured the timing of emergence of the cotyledon and first leaf for Trifolium pratense.

气候变暖可通过两类途径影响植物群落：一是直接作用（如温度变化），二是由土壤微生物群落变化介导的间接通路。这类微生物介导的间接效应可能会改变植物性状与生态系统动态，而此类变化在仅聚焦气候变暖直接影响的研究中常被忽视。
为验证这类微生物介导的间接效应，我们采集了美国密歇根州希科里科纳斯密歇根州立大学凯洛格生物站长期生态研究站点一处早期演替植物群落中，为期7年（2015-2021年）的增温实验（warmXtrophic）的田间驯化土壤。
2021年于温室中，我们评估了增温土壤接种剂与对照土壤接种剂对两种植物生长及性状的影响：红三叶（Trifolium pratense，Red Clover）与梯牧草（Phleum pratense，Timothy Grass）。
我们测定了多项指标，包括地上生物量、地下生物量、总生物量、株高、叶片数、萌发时间、叶片碳氮百分比、碳氮比（C:N ratio）、比叶面积（specific leaf area, SLA）以及可作为叶绿素含量替代指标的绿度值。
此外，我们还测定了红三叶的子叶与第一片真叶的出土时间。