Browsing by Subject "Biochar"

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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.
Biochar as a Soil Amendment in Minnesota: Findings from Literature and Interviews
(2023-05) Hunt, Samantha
The Sustainable Farming Association of Minnesota (SFA) Central Chapter initiated an effort to research biochar production as an alternative to burning wood waste, and to understand the potential benefits of utilizing biochar as a soil amendment to improve soil function and sequester carbon. With support from the University of Minnesota Extension Sustainable Development Partnerships, a graduate student was hired to review the research literature on biochar and interview subject matter experts. In partnership with representatives from the Minnesota Composting Council, Pope/Douglas Solid Waste Management, United States Department of Agriculture, the University of Minnesota Extension Sustainable Development Partnerships, and SFA Central Chapter, U of M graduate student Samantha Hunt produced this report. Biochar, a stable carbon created via pyrolysis (heating without the presence of oxygen), can be produced from the massive amounts of woody debris generated by tree removal and trimming, brush removal, woodlands management, and storm damage. Biomass that is currently burned or left to decompose releases most of the carbon back into the atmosphere. Conversion of woody biomass into biochar could provide an alternative to burning and therefore reduce greenhouse gas emissions. Biochar is also a valuable soil amendment that can improve soil health and productivity. There is a high interest from local produce growers and regenerative farmers in Central Minnesota to utilize biochar as a soil amendment.
Biochar as a sorbent for naturally occurring and synthetic agricultural chemicals
(2018-06) Hall, Kathleen
The idea of adding biochar to soil to sequester carbon and improve fertility has soared in popularity over the past few decades; however, a strong scientific understanding of this material and its environmental effects is still lacking. This body of work explores biochar's interactions with chemicals, both naturally occurring (i.e., allelochemicals) and anthropogenically applied (i.e., herbicides), and sheds light on the mechanisms involved and our ability to predict and optimize its sorptive behavior. The first chapter investigates how the feedstock material from which a biochar is produced impacts its sorptive behavior toward allelochemicals. Mixing different feedstocks, such as pine chips and poultry litter, is thought to be a way to create “designer biochars” that combine the beneficial properties of each feedstock. However, results from this study revealed that mixing feedstock materials did not have predictable effects on organic compound sorption. The second chapter begins to evaluate biochar-chemical interactions in soil to better understand realistic applications of biochar as a sorbent. Here, the leaching potentials of six different herbicides were assessed in vulnerable Hawaiian soils, and biochar was tested as a tool to reduce the transport of the most mobile herbicide, aminocyclopyrachlor. It was found that none of the four biochar amendments tested significantly altered the leaching potential of aminocyclopyrachlor in these soils based on fate and transport models. In the third chapter, the focus shifts more towards understanding the mechanisms of biochar-herbicide interactions. Here we specifically looked at glyphosate, the world’s most widely used herbicide, and found that biochar macroporosity and specific surface functionality influenced glyphosate sorption. Additionally, pre-pyrolysis addition of Fe and Cu had no significant effect on sorption. Results from this work also demonstrated the reversibility of glyphosate sorption on biochar in the presence of phosphate, suggesting similar binding mechanisms and potential interferences from phosphate fertilizers. The fourth chapter continues to investigate the sorption mechanisms responsible for the observed biochar-herbicide interactions and simultaneously assesses our ability to optimize biochars for sorption through activation treatments. It was found that activation of a low-temperature biochar by hydrogen peroxide can improve the removal of organic acid herbicides from aqueous solution, but was of little value in optimizing the removal of non-ionizable herbicides. The improved removal efficiency was attributed to pH effects and charge-based interactions with biochar. Collectively, the research presented in this dissertation highlights the variability of biochar's sorptive behavior and illustrates the challenges in predicting this behavior, particularly when feedstocks are combined. While the sorptive applications in soil initially appear limited, there is potential to improve the sorption capacity of these materials through activation, and more targeted improvements will be possible once sorption mechanisms are better understood.
Biochar Metal Sorption and Effect on Microbial Sulfate Reduction
(2016-11) Sande, Kipp
Biochar is a stabilized, recalcitrant carbon compound, created when biomass is heated to temperatures between 300-1000°C, under low oxygen concentrations. It can be produced from a variety of biomass feedstock, such as agricultural residues, wood chips, and manure. Recently, biochars have found several applications in environmental remediation. This study evaluated the effect of biochar on microbial sulfate reduction in cell suspension assays and batch growth experiments, as well as the potential of biochar to remove heavy metals from aqueous solution. Irrespective of dosage (0.5 – 10 g/L), biochar increased the extent of sulfate reduction by Desulfovibrio alaskensis G20 up to 4-fold in suspension assays. Batch growth experiments demonstrated that biochar concentrations up to 10 g/L have no inhibitory effects on microbial sulfate reduction and cell growth. We further compared the sorptive properties of different biochars for copper and nickel. Biochars were pyrolyzed in the presence of magnesium hydroxide (Mg(OH)2) or magnesium chloride (MgCl2) and sorption isotherms for copper and nickel were compared to unmodified biochar. Copper and nickel sorption capacities were greatly improved for the magnesium-enhanced biochars, indicating that biochar mineral supplementation can increase the efficiency of metal adsorption and removal from solution. Ongoing research under this theme aims at the development of a biochar-mineral composite material that promotes biological sulfate reduction and heavy metal adsorption in order to provide an efficient, low-cost, environmentally-friendly absorbent material that can be used for mine water treatment in bioreactors and/or permeable reactive barriers.
The Effects of Biochar, Weed Control, and Irrigation on the Growth and Survival of Jack Pine Seedlings and Native Plant Communities in Northern Minnesota, USA
(2019-05) Kelso, Sara
Climate change is predicted to result in more frequent and more severe droughts in the northern Midwest region of the United States. This has and will continue to impact forests of the region, especially in regards to establishing regeneration during periods of drought stress. This is leading researchers and land managers to explore adaptive silviculture strategies to promote resilience in their forests. One option hypothesized to improve regeneration success in forest systems is the application of biochar to the soil to increase seedling resistance and resilience to drought conditions Biochar is a bio-based soil amendment created through pyrolysis that has been used for centuries in tropical environments to increase productivity. Since then, biochar has been widely used in agriculture, as it has proven to be effective in increasing nutrient cycling, cation exchange capacity, and water holding capacity of the soil. Additionally, biochar has recalcitrant properties, meaning that it is very slow to degrade and thus is a viable option for sequestering carbon in the soil as a way of off-setting atmospheric emissions. However, there are very few field studies exploring the potential of biochar use in forestry in the Lake States (Minnesota, Wisconsin, and Michigan), USA. Chapter 1 aims to examine the effect that biochar and/or compost has on the growth and survival of jack pine (Pinus banksiana Lamb.) seedlings in northern Minnesota through a series of field experiments. This was done by conducting three field based experiments: 1) quantifying the influence of soil amendment and weed control treatments on survival and growth of jack pine seedlings; 2) quantifying the influence of soil amendments and irrigation when competition was controlled on survival and growth of jack pine seedlings; 3) quantifying the differences in planting stock – bareroot and containerized jack pine seedlings – and soil amendment in relation to jack pine survival and growth. Chapter 2 explores a topdress application treatment of biochar to a recently-harvested pine site. Biochar was spread at two different rates, with two different levels of torrefaction. This was done to learn more about what effects topdressing could have on native plant communities over time. These studies have the potential to help landowners make informed decisions about how to promote drought resilience in their forests, as well as provide a basis for long-term research projects looking into biochar use in the region’s forestry.
Field-scale evaluation of MN-sourced biochar for comprehensive contaminant removal from parking lot runoff
(2023-03) Weelborg, Karina
The performance of catchment-scale filters containing sand and red-pine biochar, produced at 550oC, were monitored for 2 years. Six events from the 2022 field season showed relative flow equalization between the sand and biochar filters and were used for detailed performance analysis. Both filters provided removal of E. coli, total phosphorus, metals, total organic carbon, and total suspended solids. The sand and biochar filters provided inconsistent removal of orthophosphate. Both filters exported nitrate, though the biochar filter to a lesser degree. The addition of biochar provided greater concentration decreases for zinc and total suspended solids though no statistically significant difference between the sand and biochar was found for any filter performance. Results from this study highlight the importance of adjusting biochar production conditions for development of characteristics needed for contaminant removal and the importance of validating laboratory results in the field.
Impact of management practices on Minnesota's specialty crop production: from biochar to tillage practices
(2014-09) Nooker, Eric
Climate fluctuations have always been a risk to our ability to provide adequate food for the increasing global population. To reduce crop production uncertainties in this variable climate, two management practices were examined: biochar application and conservation ridge tillage. Different biochars, application rates, and soil types were evaluated for their effect on seedling emergence and plant growth of specialty crops. Increases and decreases were observed in seed emergence and plant growth rates from biochar amended soil in a greenhouse study. A slow pyrolysis corn cob biochar (5% w/w) improved seed emergence performance the greatest across five specialty crops in the 4 soil types, with increases in emergence ranging from 2 to 67%. Biochar weathering from previous trials also influenced plant growth responses, and eliminated initial negative growth effects. Yield from field plot studies were not significantly different between biochar and control treatments. No universal relationship between biochar and its impact on specialty crop growth were observed across different soil types. However, there was good correlation between the suppression in plant growth with lower availability of nitrate and higher amounts of sorbed organic compounds on the biochar. Biochar additions had the greatest positive plant impacts on sandy textured soils with low initial soil fertility, which increased growth and soil moisture retention.Secondly, the impacts of ridge and conventional tillage on the yield and quality of three sweet corn varieties, Overland, Protégé, and Ambrosia were investigated. Protégé had greater marketable yields when grown under ridge tillage compared to conventional tillage. During 2012, there were no significant differences noted between ridge and conventional tillage treatments. However, in 2013, ridge till increased cut corn yield and ear marketability compared to the conventional tilled plots, suggesting additional benefits that were not adequately captured in this 2 year study. This study suggests that increasing the soil moisture holding capacity (with biochar or other amendments) as well as utilizing ridge tillage offers a potential tool for agricultural production to buffer future climate uncertainties.
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.
University of Minnesota Extension Master Gardener CenUSA Biochar Demonstration Gardens 2012-2015
(2017) Davenport-Hagen, Lynne; Weisenhorn, Julie; Meyer, Mary H.; Sui, Luna Xiaoye
Soil serves as the foundation of all gardens, and thus incorporating beneficial amendments before planting is of the utmost importance to a healthy, roductive crop. Increased interest and research in biomass and biofuels has promoted the use of biochar, a coproduct of the pyrolysis process, as one amendment to improve soil health. Urban soils, the site of many home and community gardens, can be carbon-poor, so we wondered if biochar would benefit home gardeners and grow more productive plants. Soils at four demonstration sites in Minnesota were amended with hardwood biochar. With the help of Extension Master Gardener volunteers, we grew, harvested and measured common garden crops over four years to see if those grown in biochar-amended soils were more productive. Variables in weather, crops and volunteer interpretation of data did not provide conclusive results. However, the poorer soils amended with biochar showed some increase in soil pH and percent organic matter, and clay loam soils were less compacted. Most crop yields showed improvement over the four years; however, we believe these increased yields were likely affected by a combination of factors (rainfall, air temperatures) and cannot be directly attributed to the addition of biochar.

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