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Potential Benefits of Biochar and Mycorrhizal Fungi on Shortleaf Pine (Pinus echinata) Restoration in Northcentral Alabama
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  • Casey Iwamoto,
  • Courtney Siegert,
  • Joshua Granger,
  • Krishna Poudel,
  • Adam Polinko
Casey Iwamoto
Mississippi State University

Corresponding Author:ci175@msstate.edu

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Courtney Siegert
Mississippi State University
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Joshua Granger
Mississippi State University
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Krishna Poudel
Mississippi State University
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Adam Polinko
Mississippi State University
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Abstract

Coal strip mining has left degraded soils throughout the southeastern United States. These soils tend to have low pH, high bulk density, impacted hydraulic processes, and an accumulation of heavy metals that limit revegetation and reforestation efforts. Shortleaf pine (Pinus echinata) has the adaptability to grow on post-mined sites due to being able to tolerate soils with a low pH. It also has the largest native range of pines in the southeastern United States, making it an ideal species for such restoration efforts. Furthermore, soil restoration using a combination of biochar and mycorrhizal amendments can provide many benefits for degraded soils ranging from increasing carbon sequestration, reducing erosion, promoting plant growth, and immobilizing heavy metals. However, limited empirical field trials have been conducted on the success of these soil amendments on both soil health and tree productivity. To provide restoration recommendations to land managers and landowners, we established a field trial in Winston County, Alabama at a reclaimed mining site. In Spring 2021 we planted Shortleaf pine in a complete randomized block design with 30.5x30.5 m spacing with two treatments: biochar and microbial inoculation in four replicates. We measured soil bulk density, pH, heavy metal content, electrical conductivity, carbon content, and nitrogen content both before and after planting every three months. We will also monitor shortleaf pine survival and growth. Our preliminary results for pH, bulk density, and electrical conductivity are within the expected range for shortleaf pine to do well on this post-mined site. Prior to soil treatments and planting, soil pH was 5.55 ± 0.54 pH, dry bulk density was 1.46 ± 0.14 g/cm3, wet bulk density was 1.74 ± 0.12 g/cm3, and electrical conductivity was 273.19 ± 141.33 µS. Soil nitrogen content was 0.15 ± 0.04% and soil carbon content was 2.31 ± 0.76%. The average C:N ratio was 15.8:1. Survival of planted seedlings after three months was 98%. Changes in soil physical and chemical conditions relative to restoration treatments are pending. This study will help support our understanding of biochar’s interaction with mycorrhizal fungi inoculation, role in restoration, and use in southeastern United States soils.