Root traits and soil legacies drive species competition outcomes

Plant competition can be affected by plant functional traits but also by differences in fitness mediated by soil microbes. Climatic conditions such as drought further influence plant competition. Yet little is known about how soil microbes and drought interact with species with distinct root traits differences and how this influences plant competition outcomes. We grew three plant species that co-occur in temperate grasslands in China (Stipa krylovii, Artemisia frigida, Agropyron cristatum) in monocultures and mixtures and subjected the plant combinations to five soil inocula (root-associated soil of S.krylovii, A.frigida, A.cristatum, an equal mixture of the three root zone soils, and sterilized soil) as well as to a drought treatment. The relative change in plant biomass was used to determine plant competition outcomes. The three species exhibited clear differences in competitive abilities with A.cristatum > S.krylovii > A.frigida, and soil inocula or the drought treatment did n..., , , # Root traits and soil legacies drive species competition outcomes

**Experimental Procedures:**

1. **Experimental Design:**
* **Objective:** To evaluate how soil microbes and drought impact the competition between three plant species
* **Plant Species:** *Stipa krylovii,* *Artemisia frigida*, and *Agropyron cristatum*.
* **Treatment Groups:**
* Plant arrangement: monoculture and mixture
* Soil inocula: root zone soil of S.krylovii (SK), A.frigida (AF), *A.cristatum* (AC), the mixed root zone soil of the three species  and sterilized  MIX inocula
* Drought treatment: wet and dry
* **Replications:** Each treatment had 4 replicates.
2. **Methods:**
* **Soil Preparation:** Soil was inoculated and water treatment with high and low amounts were added according to the treatment plan.
* **Planting:** Seeds of *Stipa krylovii,* *Artemisia frigida*, and *Agropyron cristatum* were sown in pots with treated soil.
* **Growth Conditions:** Plants were grown in a ...