Strong evidence suggests that amending soils with charcoal increases soil fertility, improves soil drainage, and helps manage nitrogen and phosphorus nutrient pollution. Adding charcoal to soils also sequesters carbon when this charcoal is made from biomass (biochar) that would otherwise rapidly decompose to CO2. In collaboration with researchers at Rice, Becca is investigating the fate of this biochar in soils — does it increase DOC export? if so is the DOC from increased biomass production or the biochar itself? How do biochar additions change the movement of water through soils? These questions and others will help us understand the ecological impact of using biochar as a carbon sequestration method. Carrie Masiello & I both contributed to this Nature perspective piece on biochar.
1. Biochar and soil hydrology: Biochar alteration of the hydrologic cycle may be its single-most important driver of plant productivity. We are characterizing the impact of biochar amendment on soil hydrophobicity, water-holding capacity, and permeability. Check out our PLOS One paper.
2. Biochar effects on plant-mycorrhizal symbiosis: biochar alters the rhizosphere through processes that are poorly understood. We use greenhouse experiments to understand the effects of biochar soil amendment on plant above- and below-ground NPP, degree of plant fungal colonization, and fungal hyphae length. We follow these experiments up with XPS analyses of the biochar to understand how plant-fungal interactions alter the surface chemistry of biochar.
3. Biochar and dissolved organic matter: Biochar releases DOM abundantly into the environment and may be a major source of dissolved humic substances in global soils and watersheds. We are characterizing the amount and chemical composition of dissolved carbon and nitrogen released by biochars made from a range of feedstocks under a range of pyrolysis conditions.
Collaborators: Carrie Masiello, Brandon Dugan, Zuolin Liu (Rice), Morgan Gallagher (Duke) , William Hockaday (Baylor), Jenn Rudgers (University of New Mexico). This research is funded by NSF and The Shell Center for Sustainability
Fire and Black Carbon
Black carbon is a combustion product and therefore if we can measure black carbon in the soils, stream sediments and stream organic matter we can trace the effects of fire on carbon stocks and transport. Currently I am working with CC students in fire impacted watersheds in Colorado to try and quantify the recovery and resilience of carbon stocks in forest ecosystems. We are comparing soils from several 2002 burn scars (and nearby reference sites). There were over 35 named fires in Colorado and 2002 due to high temperatures combined with a small snowpack and early snowmelt. Over the last two summers (2015 and 2016) we have sampled watersheds within the Hayman (Ponderosa, montane), Schoonover (Ponderosa, montane), Missionary Ridge (Gamble Oak, montane), Skinny Fish (Spruce-Fir, subalpine), Hinman (Lodgepole-Spruce, subalpine) fires, in addition to three montane and 2 subalpine reference sites. These sites represent almost the entire range of precipitation totals within the mountain environments (i.e. excluding the Pinyon Juniper and plain ecosystems in the lower elevations of the state). By comparing and characterizing soil quality and carbon stocks across ecosystem and disturbance gradients we are starting to understand how ecosystem type & climate variability affect forest C stock recovery post-fire.
During Summer 2016, in conjunction with Lynne Gratz, we started taking additional deeper soil cores (up to 100 cm, to saprolite) to understand the depth profile of C and Hg in the soils. This information will help us understand the fate of C and Hg post fire.