Ashley Leavell

Biochar Impacts on Soil and Sagebrush Seedling Establishment in the Sagebrush Steppe

Abstract

Increased fire frequency in the sagebrush steppe has altered plant-soil feedbacks, which complicates restoration efforts. Altered plant-soil feedbacks are the result of increased soil nitrate (NO3–) concentrations following fire, which catalyzes growth of invasive species. Further, fire-induced loss of soil carbon and organic matter reduces soil water retention. Finally, fire disrupts soil symbiont-plant interactions that are essential to sagebrush establishment. Biochar, created from pyrolyzed plant biomass, is a soil amendment that may be used to reduce soil NO3–, improve soil water retention, and increase colonization with arbuscular mycorrhizal fungi (AMF) an essential soil symbiont for sagebrush.  However, its impact on restoration in the sagebrush steppe is uncertain. With this study I ask: (1) How does the application of biochar affect soil biogeochemical properties and sagebrush seedling survival? (2) How does the physicochemical composition of biochar impact soil properties and sagebrush establishment? (3) How does post-fire recovery mediate the impact of biochar on soil properties and sagebrush establishment? To address these questions, I installed a manipulative field experiment in an area that burned in 1983 located in the sagebrush steppe approximately 17 miles south of Boise. I established the following treatments: three biochar types that vary in particle size and chemical composition and a control (i.e. no biochar added). All treatments were established across two post-fire recovery zones. I will analyze sagebrush seedling survival, seedling Net primary productivity, drought stress, soil organic matter, soil C, soil NO3-, soil microbial community composition, and AMF root colonization. This study will increase our understanding of biochar as a restoration technique and improve post-fire restoration in the sagebrush steppe.