At lower levels (up to twenty per cent), if applied to the
agricultural soils, fly ash may enhance the micronutrient avail-
ability and microbial activity and results in better crop growth,
while higher dose of fly ash led to accumulation of toxic metals in
soil and suppressed the microbial growth and activity. Application
of fly ash up to 40 per cent in heavy texture soil does not interfere
in the N mineralization process due to enhanced aeration. How-
ever, FA dose optimization need extensive field trials and will vary
based on soil type and source of fly ash. Bioavailability of
accumulated toxic metals and their entry into food chain should
be thoroughly studied. Besides, studies should be conducted to
examine the long term impact of FA application on soil quality