Through litter and root inputs, plants modulate soil properties and the soil microbial communities around them. In turn, these changes in soil properties and microbial community composition can impact plant performance (i.e., plant-soil feedbacks). Many studies have focused on how plant-soil feedbacks affect plant performance and successional patterns, but studies on the impact of plant-soil feedbacks on ecosystem processes are rare. Our research focused on the potential of species-specific plant-soil feedbacks to affect rates of soil organic matter (SOM) decomposition. We conducted a “home vs. away” plant-soil feedback greenhouse experiment using two C₃ grass species (Bromus inermis and Pascopyrum smithii) grown in C₄ tallgrass prairie soil. We used a closed-circuit CO₂ trapping method and isotopic analysis to differentiate between root-derived and SOM-derived CO₂ production. Contrary to our predictions, plant-soil feedbacks on plant biomass were independent of the effects of plant-soil interactions on SOM-derived CO₂ production, but we did detect a significant legacy of conditioning by B. inermis on subsequent total belowground respiration (i.e., total belowground respiration was higher in soils originally conditioned by B. inermis regardless of which plant species was currently growing in those soils). We attribute these results to the differential effects of these plant species on soil chemistry and soil microbes during the original conditioning phase. This is supported by the observation that differences in soil chemistry and bacterial community composition persisted in soils conditioned by different plant species throughout the entire experiment. Together these results suggest that plant-soil history is important for soil respiration and that differences in soil microbial communities induced by conditioning with different plant species may have lasting effects on ecosystem processes.

通过凋落物和根系输入，植物调节土壤特性及其周围的土壤微生物群落。反过来，土壤特性和微生物群落组成的这些变化会影响植物性能（即植物-土壤反馈）。许多研究都集中在植物-土壤反馈如何影响植物性能和演替模式上，但关于植物-土壤反馈对生态系统过程影响的研究很少。我们的研究侧重于物种特异性植物-土壤反馈影响土壤有机质 (SOM) 分解速率的潜力。我们使用生长在 C _{4 中的}两种 C ₃草种（无刺雀麦草和Pascopyrum smithii）进行了“家与外”植物-土壤反馈温室实验高草草原土。我们使用闭路 CO ₂捕集方法和同位素分析来区分根源性和 SOM 源性 CO ₂生产。与我们的预测相反，植物 - 土壤对植物生物量的反馈与植物 - 土壤相互作用对 SOM 衍生的 CO ₂产量的影响无关，但我们确实检测到B. inermis对随后的总地下呼吸（即, 总地下呼吸在最初由B. inermis调节的土壤中更高无论目前在这些土壤中生长的是哪种植物）。我们将这些结果归因于这些植物物种在原始调节阶段对土壤化学和土壤微生物的不同影响。这得到了观察结果的支持，即在整个实验过程中，土壤化学和细菌群落组成的差异在由不同植物物种调节的土壤中持续存在。这些结果共同表明，植物-土壤历史对土壤呼吸很重要，并且由不同植物物种调节引起的土壤微生物群落差异可能对生态系统过程产生持久影响。