BIOGEOCHEMICAL PROCESSES INFLUENCING FORMATION AND STABILIZATION OF SOIL ORGANIC MATTER AND SOIL STRUCTURE
Location: Soil, Water, and Air Resources Research Unit
Title: Impact of Biochar Amendments on Soil Quality for a Typical Midwestern Agricultural Soil
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 25, 2009
Publication Date: August 12, 2009
Citation: Laird, D.A., Fleming, P.D., Wang, B., Karlen, D.L. 2009. Impact of Biochar Amendments on Soil Quality for a Typical Midwestern Agricultural Soil. North Amer. Biochar Conf. 2009, Aug. 9-12, 2009, Boulder, CO. 28:50-38:11.
The harvesting and processing of biomass via pyrolysis with soil applications of the biochar co-product has attracted much attention because of the potential to simultaneously produce large amounts of renewable energy, permanently sequester large amounts of carbon, enhance water quality, and enhance soil quality. However, little is known about the impact of biochar applications on the quality of highly productive Midwestern agricultural soils, the subject of this investigation. We incubated repacked soil columns amended with 0, 5, 10, and 20 g-biochar kg-1 soil for 500 days at 25 °C and 80% relative humidity. On week 12 of the incubation, 5 g of dried and ground swine manure were incorporated into the upper 3 cm of soil for half of the columns. Once each week during the incubation, all columns were leached with 200 mL of 0.005 M CaCl2. By day 54 and thereafter soil bulk density was significantly lower for biochar amended soils relative to the unamended soils. Cation exchange capacity increased from 18.1 to 21.7 cmol kg-1 and pH increased by up to 1 pH unit as a result of the biochar amendments. The biochar amendments increased total N by 7% and organic C by up to 69%. Using mass balance analysis, we observed no detectable loss of the biochar C during the incubations but recovered less than 20% of the manure C. The biochar amendments significantly increased Mehlich III extractable P, K, Mg, and Ca but had no effect on Mehlich III extractable S, Cu, and Zn. The biochar treatments significantly reduced leaching losses of NO3-N, total P, K, and other nutrients. The results indicate that biochar amendments have the potential to substantially improve the quality and fertility status of Midwestern agricultural soils.