Can High-Carbon Char Improve Soil Properties?.

Can High-Carbon Char Improve Soil Properties? Carbon-enriched soil amendments could help improve soil properties and crop productivity, especially in low C soils. Char, a high-C by-product of the sugar beet industry, could be used to restore soil C. While char contains many plant essential macro and micro-nutrients, there is limited research on the use of char as a soil amendment. The objective of this research was to determine the impact of char produced by the Western Sugar Cooperative (Nebraska) on soil physical and chemical properties. Char was applied to a degraded and non-degraded sandy loam soil near Sidney, NE at six rates (0, 11, 22, 34, 45, and 67 Mg ha-1) in quadruplicate. Char was applied in April of 2016 and rototilled into the top 15 cm of soil and soil was sampled in spring 2017 to 0-10 cm depth. Penetration resistance and shear strength were determined for the 0-10 cm depth, and soil samples were analyzed for bulk density, cation exchange capacity (CEC), total C, organic C, and nutrients. Char application did not affect bulk density, shear strength, or soil fertility. However, char applied to the non-degraded soil tended to reduce penetration resistance. Char did have a significant impact on total C and organic C. For the degraded soil at Sidney, total C content increased by 90% with 34 Mg ha-1 and 149% with 67 Mg ha-1 of char application. Organic C content increased by 23% with 11 Mg ha-1and by 128% with 67 Mg ha-1 of char application. This increase in soil C with char use could benefit low C soils. Our study reports first year results, and char may require more time to improve soil properties. The findings suggest that char could be used as a possible soil amendment, but more long-term studies are needed.