Investigating the Influence of Biochar On the Soil N‐Cycle, C Sequestration, and Stabilization with Soil.

Investigating the Influence of Biochar on the Soil N‐Cycle, C Sequestration, and

Stabilization with Soil

Since the discovery of the Terra Preta de Indio (Indian Black Earth) soils in the Amazon, the use of biochar amendments to agricultural soils is receiving increased attention as a method for reducing N leakage and decrease N₂O emissions while sequestering carbon (stabilize soil organic C and decrease CH₄ emissions), improving soil fertility (increase cation retention), and increasing water retention in soil. Biochar research is still in its infancy with fundamental questions such as how and why biochar amendments might confer their proposed beneficial properties to soils. The objective of our research is to better understand the role of the physical and chemical characteristics of biochar originating from various organic residues on soil processes. Laboratory incubations are ongoing (1 d to 1 yr) in which we measure CO₂ and N₂O emissions from a soil amended with walnut shell and wood feedstock biochars at an application rate of 10 tons/ha to determine the effect of biochar on soil C sequestration and N-cycling. Molecular-level interactions involved in the stabilization of biochar by soil are also being investigated using a suite of analytical tools including FT-IR, XRD, SEM-EDX, and NMR. Initial results show considerable differences in the biochar physical and chemical properties as a function of the source material and pyrolysis temperature, these differences are evident in the amended soil’s pH, water retention and cation exchange capacity. Preliminary gas emission data show the biochar to have an effect on the fluxes of the green house gases.

Fungai N. D. Mukome¹, Emma Suddick², Johan Six² and Sanjai J. Parikh¹

¹Land, Air and Water Resources, University of California Davis, Davis, CA 95616

²Department of Plant Sciences, University of California Davis, Davis, CA 95616

Email: fmukome@ucdavis.edu; ecsuddick@ucdavis.edu; sjparikh@ucdavis.edu; jwsix@ucdavis.edu