Strength and direction of plant-soil feedback (PSF), the reciprocal interactions between plants and soil, can change over time and have distinct effects on different life stages. PSF and its temporal development can also be modified by external biotic and abiotic factors such as competition and resource availability, yet most PSF research is conducted in simple experimental settings without considering temporal changes. Here I have studied the effect of different competitive settings (intraspecific, interspecific, and no competition) and nutrient addition on the magnitude and direction of biomass-based PSF (performance in conspecific relative to heterospecific inoculum) across 46 grassland species, estimated at the 4th, 10th, and 13th month of the response phase. I also examined whether conspecific inoculum had a long-term effect on plant survival at the 36th month, and whether biomass-based PSF may predict survival-based PSF effects. PSF pooled across all treatments and time points was negative, but a significant overall temporal trend or differences among competitive settings were missing. PSF developed unimodally for interspecific competition across the three time points, whereas it declined gradually in case of intraspecific and no competition. Nutrient addition attenuated negative biomass-based PSF and eliminated negative effects of conspecific inoculum on survival. Interspecific differences in biomass-based PSF were related to survival-based PSF, but only after nutrient addition. This study demonstrates that PSF is dynamic and modulated by external abiotic and biotic factors. PSF research should consider the temporal dynamics of focal communities to properly estimate how PSF contributes to community changes, preferably directly in the field.

植物-土壤反馈（PSF）的强度和方向（植物与土壤之间的相互作用）会随时间变化，并对不同的生命阶段产生不同的影响。PSF及其时间发展也可以通过外部生物和非生物因素（例如竞争和资源可利用性）进行修改，但是大多数PSF研究是在简单的实验环境中进行的，没有考虑时间变化。在这里，我研究了46种草地物种在第四种情况下估计的不同竞争环境（种内，种间和无竞争）和养分添加对46种草地物种基于生物质的PSF（相对于异种接种物的同种性能）的大小和方向的影响。 ，响应阶段的第10个月和第13个月。我还检查了同种接种物在第36个月是否对植物存活有长期影响，以及基于生物质的PSF是否可以预测基于存活的PSF的影响。所有治疗合并的PSF和时间点均为阴性，但缺少明显的总体时间趋势或竞争环境之间的差异。PSF在三个时间点以单峰方式发展为种间竞争，而在种内竞争且无竞争的情况下，PSF逐渐下降。添加营养可减轻基于生物质的负PSF，并消除同种接种物对存活的不利影响。基于生物质的PSF的种间差异与基于生存的PSF有关，但仅在添加营养物之后。这项研究表明，PSF是动态的，并受到外部非生物和生物因素的调节。