Australian Acid Soil Amendment Using Coal Fly Ash

Australia, a main coal exporter for Hokkaido Electric Power Co., Inc. (HEPCO), curently promotes a national forestaion policy. However, the potential sites for forestation include large areas, particularly in East and Southwest areas of Australia, where tree growth is difficult due to the acidic soils. Fly ash, the main by-product from coal-fired power stations, usually contains some alkalinity, and so has the potential to be a useful amendment for acidic soils. If fly ash proves to be a useful soil amendment, it will expand the range of applications in which it can be used, and furthermore, contribute to the reduction of a green house-gas (CO2) by promoting forestation.

HEPCO have formed a collaboration with the University of Queensland, Australia, from FY 2006, in order to assess a Fly ash-derived Fertilizer (FF) as an acidic soil amendment in Australia. The pot-scale trials for the preriminary evaluation of the FF were completed in 2006. The field-scale plantation trials were commenced in 2008 using two Australian sites which have acidic soils; a podsol and a ferrosol.

In order to compare the effect of FF with lime, a common acidic soil amendment, we applied the FF and lime at various rates at the field sites (figure 2). After application of these amendments, common Australian plantation species of eucalyptus and pine seedling trees were planted on the ferrosol and podsol sites, respectively, in April-May 2008.

At this time, there is no difference in the tree growth between each treatment (figure 1), but we have planned to continue to monitor the tree growth and the changes in soil environmental conditions a number of times in the future.