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Lambrecht, Freya

University of British Columbia

Conventional agricultural practices contribute to soil degradation and soil organic carbon (SOC) losses. To address the climate crisis and improve soil quality, increasing the soil carbon pool through alternative agricultural practices is of global interest. Biochar shows promise in positively influencing SOC and soil quality. However, the strength of these benefits varies, especially on dissolved organic carbon (DOC), a labile form of carbon. Additionally, studies examining DOC concentrations past the growing season are limited. The chemical characteristics of the DOC quality are important indicators impacts on soil microbes, soil carbon stabilization and aquatic systems. Understanding biochar’s impact on DOC concentrations, flux and chemical characteristics is crucial for comprehending its role in SOC and carbon sequestration. This thesis examines the effects of biochar and manure-activated biochar amendments applied to experimental plots at Totem Field Plant Science Station on DOC concentrations, characteristics, and flux from August 2022 to March 2023. Results indicate that seasonal DOC concentrations are correlated with soil temperature. The activated biochar increased the average DOC concentrations and flux in the topsoil, while the pristine biochar decreased DOC concentrations in the fall and decreased the flux from the topsoil. Spectral analysis of the soil solution suggested that the biochar likely decreased the DOC concentrations and flux due to its capacity to retain the high-weight humic-like components in the DOM. Notably, treatment effects were predominantly limited to the topsoil, suggesting that the DOC became stabilized in the subsoil, whereas the pristine biochar stabilized DOC levels in the topsoil. This research highlights that biochar effects on DOC are affected by biochar properties as well as soil and climate characteristics. Understanding the effects of these amendments on carbon losses and storage at depth is crucial for decisions on biochar’s role in sustainable soil management practices.

Text

2023-08-25

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/85640

Resources, Environment and Sustainability

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/