Agricultural use of wood ash as a fertilizer and liming material

Wood-derived boiler ash was mixed with two acid soils at rates equivalent to 0, 2.24, 4.5, 9.0, 17.9, and 35.9 metric tons/ha to evaluate changes in extractable nutrients and soil pH. Concentrations of extractable P, K, and Ca increased linearly with application rate. Soil pH increased linearly with the logarithm of the application rate. The ash was compared with commercial potash fertilizer and agricultural limestone. The equivalent neutralizing value was about half of that for agricultural limestone. 4 references.