Batch‐Determined Elements Release from Wood Ash Mixed with an Acidic Forest Soil Sample

Abstract

A serial batch leaching experiment was carried out to evaluate the release of elements from wood ash mixed with a strongly acidic forest soil sample. Wood ash application resulted in increased leachate pH, dissolved organic carbon (DOC), and electrical conductivity (EC). Increasing application of wood ash increased cumulative release of inorganic carbon (IC), chloride (Cl), nitrate (NO₃), sulfate (SO₄), potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), manganese (Mn), phosphorus (P), and copper (Cu). Release of NO₃, P, iron (Fe), aluminum (Al), Cu, and lead (Pb) continued. Large amounts of DOC, K, Ca, and SO₄ were mobilized. Inorganic C, Fe, and Mg were released in moderate quantities. Manganese, Na, Al, Cl, and NO₃ were released in limited amounts. Amounts of leached P, Pb, and Cu were lower. The mixed order equation adequately described the release of elements in the soil‐ash mixture. Accumulation of elevated amounts of trace elements does not appear to be a problem when higher wood ash rates are avoided. Wood ash should be applied in split application to avoid short‐term concentrated alkaline and salty conditions that could interfere with plant growth.

Keywords:

• Element release
• macroelements
• microelements
• wood ash
• acidic forest soil
• kinetics modeling

Acknowledgments

This work was conducted within Alexander von Humboldt research fellowship programme and was carried out at Institut für Bodenkunde of Universität Bonn in Germany. We thank the Alexander von Humboldt Foundation and the Institut für Bodenkunde for their support and assistance to this study.