Browsing by Subject "Soil Amendment"

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    Biochar And Ecosystem Recovery: Evaluating Artificial Regeneration Outcomes And Understory Plant Community Dynamics In Response To Top-Dress Amendments In Northern Minnesota
    (2024-05) Ackerman, Sophie
    Recurring and severe droughts present significant obstacles to successful forest regeneration. Biochar soil amendments have emerged as a promising possible solution, providing the dual benefit of mitigating climate change through carbon sequestration while enhancing forest soil health in areas facing regeneration challenges. These amendments improve seedling drought resilience through enhanced cation exchange capacity, water retention, and nutrient availability. However, existing research in forested systems is limited, and primarily focuses on short-term impacts of the amendment on soil nutrients, physical properties, and microbial communities. Researchers have identified a need for long-term, site-specific research regarding how biochar affects forests' growth and stand dynamics. Over a five-year period, we investigated the effects of two different doses of top-dressed biochar soil amendments on tree growth across four different species. Our study did not reveal significant positive effects of biochar on seedling growth or survival over this period. However, it also did not indicate any negative influence on seedling survival or growth. Notably, each species exhibited distinct response patterns, suggesting potential trends deserving further investigation and emphasizing the importance of temporal scale in such studies. Additionally, our analysis of vegetative community composition and structure in response to the biochar amendments revealed distinct species-community responses, indicating complex underlying mechanisms warranting further investigation. In summary, this study contributes to a deeper understanding of biochar’s role in post-disturbance vegetation recovery and sheds light on the variability in seedling response patterns influenced by biochar soil amendment. Emphasizing the significance of species-specific responses, as well as the potential ecosystem-wide cascading effects, our findings highlight the complexity of biochar applications and their interactions with both tree species and understory vegetation over time. This research adds to the growing body of knowledge on biochar applications in forestry, underscoring its potential benefits in reforestation and carbon sequestration efforts. Furthermore, it enhances our understanding of the potential long-term effects of biochar soil amendments on forest health, stand dynamics, and sustainable forest management practices in a changing climate.
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    Re-examining the Amazonian Dark Earth Phenomenon: Biochar
    (2017-08) Colosky, Edward
    This thesis presents three linked research projects. The first and second research chapters (Ch. 2 & 3) exhibit results from studies examining biochar material properties. The third and final research chapter (Ch. 4) provide two unique findings; 1) that there are mineralogical differences between Amazonian Dark Earth and Brazilian Oxisol soil profiles, and 2) that iron mineralogy does affect soil microbial respiration rates. These chapters are associated with each other through hypotheses surrounding Amazonian Dark Earth (ADE) pedogenesis. Biochar (a subset of black carbon materials) is often cited as the key factor for explaining the observed enhanced fertility of ADE soils when compared to natural occurring surrounding Brazilian Oxisol soils. Biochar is often researched to understand how the effects observed in ADE soils may be applied elsewhere. Data presented in chapters 2 & 3 of this thesis, however, raise questions regarding its soil enhancing properties. Data presented in chapter 4 provide evidence for how a previously overlooked factor in Amazonian Dark Earth soils, iron mineralogy, could potentially affect additional soil properties including soil microbial respiration rates. Differing soil microbial rates with time will alter carbon sequestration rates and soil fertility. The fundamental conclusion of this thesis is that the data collected here supports the suggestion that ADE soils should be reexamined, with a focus on the iron mineralogical differences found between ADE and Brazilian Oxisol soils.