52    EFFECTS OF PAPERMILL WOOD ASH ON CHEMICAL
PROPERTIES OF SOIL
Lewis M. Naylor, Senior Research Associate
Department of Agricultural Engineering
Cornell University
Ithaca, New York 14853
Eric J. Schmidt, Senior Environmental Engineer
Georgia-Pacific Corporation
Atlanta, Georgia 30348
INTRODUCTION
The pulp and paper industry has used wood waste as fuel on a wide scale since the 1960's and has
recognized that wood can be an economical and readily available source of energy. However, the ash
residual from such commercial wood burning facilities can also be a valuable source of crop nutrients
and lime for agricultural uses. This report discusses results and provides recommendations for the use
of wood ash in agriculture.
Pulp and paper industries utilize enormous quantities of timber resources annually for production
of paper products. Since a portion of the tree is unusable in production operations, these residuals
such as the bark from production operations must be managed through other methods. Burning such
residues known as hog fuel in wood fired boilers for production of steam and electricity is economical, environmentally sound, and energy conserving. However, ash is generated from burning the hog
fuel. Agricultural use of this ash along with the fly ash from air pollution control can represent the
final step in this resource recovery program.
Wood ash has been known to be an important source of potash and lime for many years [1,2],
although a recent comprehensive reference makes little reference to it [3]. In the 1938 Yearbook of
Agriculture [2], wood ash was suggested to "rate as a potash material with a comparatively high lime
content, some phosphoric acid and magnesium, and small amounts of other elements." Unleached
hardwood ashes were suggested to contain upward of 6% potash in the form of carbonate, 2°7o
phosphoric acid and 30% lime. Thus, with the increasing use of wood as a fuel and the subsequent
need to dispose of the ash, it is important to reconsider the use of wood ash for agricultural purposes
and to put such use on a quantitative basis.
The overall objective of this research was to quantify through laboratory and field studies the
agronomic value of paper mill wood-derived ash as a fertilizer and an alternative liming material.
Specific objectives of this research were to: 1) examine the characteristics of the wood ash in terms of
macronutrient content (N, P, K, Ca, Mg) and trace mineral content; 2) assess the availability of these
crop nutrients in the soil where the wood ash is incorporated; and 3) quantify the liming value of the
wood ash when incorporated into soil.
MATERIALS AND METHODS
The experimental lime equivalences of the wood ash and the effects on the extractable nutrient
content of soil were investigated initially in soil incubation studies.
Wood ash samples used in the research were supplied by the Lyons Falls Paper Company (formerly
a Georgia-Pacific Corp. facility), Lyons Falls, NY. The limestones used as controls were Limecrest
Pulverized Limestone (Limestone Products Corp., Sparta, NJ) and Modern Rotary Kiln Hydratcd
lime (Millard Lime and Stone, Annville, PA), and potash (Muriate of Potash, Agwav). The soils used
in the incubation studies were Mardin silt loam (coarse, loamy, mixed mesic Typic Fragiocrcpt) and
Burdett silt loam (fine, loamy, mixed, mesic Aerie Ochraqualfs).
The experimental design was two soils by three liming/fertilizer treatments by six application rates
with three replications for a total of 108 pots. The entire quantity of soil to be used in each experiment
437