Abstract
Carbon sequestration by large-scale afforestation in arid regions is expected to be a countermeasure against global warming. In much of arid areas in Western Australia, there is a water-impermeable layer near the ground surface which is known as hardpan and inhibits tree growth. For successful afforestation in such arid areas, the soil structure must be modified to enable tree growth. Although it was demonstrated that blasting with explosives is effective in breaking the hardpan, the amounts of explosives used must be reduced and the blasting method must be optimized to reduce the carbon emission and carbon fixation cost involved in the afforestation process. We therefore conducted a hardpan blasting experiment with different patterns of packing explosives in an arid area in Western Australia.
ANFO prills or ANFO prills diluted with polystyrene beads were packed in vertical holes 3.6 m deep and 96 mm in diameter drilled into the hardpan. Explosives were packed at varying depths. A soil zone necessary for tree growth was able to be created by hardpan blasting using half as much explosive as that used in the previous experiment. Furthermore, the results suggested that the amount could be reduced to less than one half.
