Evaluation of Biochar for On-Farm Soil Management in California

Sanjai J. Parikh1, Associate Professor of Soil Chemistry, William R. Horwath1, Prof. Soil Biogeochemistry, Daniel Geisseler1, Assistant Cooperative Extension Specialist, Milt McGiffen2, Veg. Crops Spec. & Vice Chair for Coop. Ex,  Michelle Leinfelder-Miles3, Coop. Ex. Farm Adv,  Toby A. O’Geen1, Soil Resource Specialist, Kate M. Scow1, Professor of Soil Microbiology, Danielle Gelardi1, PhD Student in Soils and Biogeochemistry,

1Department of Land, Air and Water Resources, University of California, Davis, One Shields Avenue, Davis, CA 95618. 2Deptartment of Botany and Plant Science, University of California, Riverside, 4101 Batchelor Hall, Riverside, CA 92521 3Cooperative Extension San Joaquin County, 2101 East Earhart Ave., Stockton, CA 95206

Project Summary: This project evaluates the potential for biochar to be used in California agriculture as a strategy to enhance soil-crop nutrient use efficiency, improve soil-water-crop relations, and increase soil carbon storage. It is hypothesized that biochar amendment in conjunction with appropriate fertilization rates will lead to increased nutrient retention and use efficiency with potential impacts on soil aggregation and soil health.

The overarching objective is to provide baseline data and information specific to CA regarding the potential for biochar to provide benefits as a soil amendment for increasing nutrient retention and C sequestration in CA’s Central Valley. Specific project objectives are to: 1) characterize biochars produced from locally available biomass; 2) evaluate the impact of biochar amendments on soil water and nutrient availability and loss (e.g., NO3-, NH4+, PO43-), carbon stocks, and soil aggregation; 3) evaluate soil conditions and biochar parameters, including biochar and fertilization application rates, which are most likely to lead to beneficial outcomes from biochar amendment; and 4) create the California Biochar Initiative as a central point for objective information regarding biochar use in CA agriculture.

The proposed project will utilize a series of field, greenhouse, and lab studies to examine a variety of soil, biochar types, and application rates under management conditions, which represent mixed agricultural systems. Field plots will be established at the UC Davis Campbell Tract (Yolo County) and UC Kearney Research and Extension Center (Fresno County) and biochar will be incorporated in combination with synthetic N-P-K fertilizer. Additionally, a robust set of greenhouse trials are being conducted at UC Davis to examine impacts on crop growth, nutrient retention/leaching, and water relations. As biochar feedstock and production parameters will have a significant impact on its performance and outcome as a soil amendment, full characterization and evaluation of the biochars, with different soils, will be conducted. Fertilizer rates are based on soil sample analysis and both normal- and high-end of the recommended application rates will be used to evaluate biochar impact on nutrient use efficiency. Biochars feedstocks include pine wood, cedar wood (± inoculation*), almond shells, and coconut shells.

*This study includes the use of BioCharUnlimited inoculated char, made from KarrChar (Cedar Wood 550 °C)