Biochar is a form of stable organic carbon whose application to soils has the potential to sequester large amounts of atmospheric CO2 while improving the physical, chemical and biological properties of soil. However, the optimal rates and methods of biochar application are unknown for many situations. Three experiments were performed to test methods of biochar application to soils as a stand-alone amendment, in combination with biosolids as a complementary amendment and in-situ through controlled landscape burning. The first was a greenhouse pot study, which involved combining biochar with spoil from an Appalachian surface coal mine to grow trees. Biochar combined with mine soil produced a much higher growth rate for trees, and pure biochar helped tree root growth, suggesting that it might be useful as a broadcasted amendment, as a nursery growing medium or as a backfill in tree planting holes. The second experiment explored methods to combine biochar and biosolids materials to form a granular product. Combining biochar and biosolids before applications reduced windborne losses of biochar as well as the nutrient leachate produced by the biosolids. Drum rolling was found to work best for producing aggregate granules. Wetting pure biochar to 100% gravimetric water content before applications reduced windborne losses from over 50% to under 5% as compared to when it was applied as a dry product. A series of controlled burns were conducted in the third experiment to determine the ideal range of meteorological conditions to produce the highest possible biochar yields in-situ. Relative humidity, forest litter moisture and ambient temperature were found to be the governing factors over the tonnage of biochar produced. Up to 3.0 Mg Ha-1 of biochar were produced under ideal conditions by controlled burning. Repeated high-yielding burns have the potential accumulate large amounts of biochar in the soil to improve soil properties. / Ph. D. / Biochar is charcoal added to soils to improve their fertility and to store carbon in the ground to help reduce greenhouse gases in the air. Three experiments were performed to test ways of applying biochar to soils. Rocky material from a reclaimed coal mine was combined with biochar to grow trees. Biochar produced a much higher growth rate for trees and would be useful as a nursery growing medium or as a fill material in tree planting holes. Biochar was also combined with biosolids materials to form a granular product. The granular product produced less dust, nutrient runoff and greenhouse gases than either biochar or biosolids applied alone. Controlled burns were conducted in a pine forest in the third experiment to produce biochar from the litter on the ground. Relative humidity and forest litter moisture were found to determine the amount of biochar produced. Up to three tons of biochar per hectare were produced through controlled burns. Repeating controlled burns for many years may accumulate biochar in the soil, helping to improve soil fertility and to sequester greenhouse gases.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/83401 |
| Date | 01 December 2016 |
| Creators | Fields-Johnson, Christopher Warren |
| Contributors | Crop and Soil Environmental Sciences, Fike, John H., Galbraith, John M., Day, Susan D., Zedaker, Shepard M., Maguire, Rory O. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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