Biochar Effects on Mycorrhizal Fungi in Sagebrush Roots

Non-native annual grasses such as cheatgrass (Bromus tectorum) are fueling more extensive and frequent fires in sagebrush-steppe ecosystems. These disturbances have changed soil biological properties inhibiting native sagebrush (Artemisia tridentata) reestablishment. Sagebrush depends on symbiotic soil fungi (AMF) to enhance nutrient uptake. Biochar, a plant-based charcoal used as an ameliorant for soil health, can positively impact AMF colonization in some plants. We hypothesized that adding soil from an intact sagebrush stand, which harbors AMF, in combination with biochar would increase root colonization by AMF in sagebrush seedlings grown in post-fire soil. We grew sagebrush seedlings in post-fire soil in the greenhouse for three months. We added an inoculum of sagebrush soil that had not burned, and half of the pots received a biochar treatment (dose). Upon harvest, we measured the percent of fungal colonization in roots via the line intercept method. Our preliminary findings show no significant increase in root colonization by AMF with biochar added to post-fire field soil. Similar studies conducted in other fires showed contradictory results, suggesting an interaction between biochar and soil microbial communities that vary among ecosystems. Further research into soil amendments and their influence on AMF could greatly benefit post-fire sagebrush restoration efforts