Abstract: A laboratory incubation study was carried out to elucidate the
dynamic response of insecticide (triazophos) on a paddy field soil health under
controlled moisture (flooded soil) and temperature (25ºC).The insecticide
was applied at five levels that were 0.0 (control),0.5 field rate (FR),1.0
FR,5.0 FR,and 10.0 FR,where FR was 1500 ml/hm²,and the parameters were
studied at 1,4,7,14,and 21days after treatments' addition.The electron
transport system (ETS)/dehydrogenase activity exhibited a negative correlation
with insecticide concentrations,and the activity affected adversely as the
concentration increased.The higher doses of 5 and 10 field rates significantly
reduced the ETS activity,while lower rates failed to produce any significant
inhibiting effect against the control.The toxicity of insecticide decreased
towards decreasing the ETS activity with the advancement of incubation
period.The insecticide caused an improvement in the soil phenol content and it
increased with increasing concentration of insecticide.The insecticide
incorporation applied at various concentrations did not produce any significant
change in soil protein content and it remained stable throughout the incubation
period of 21 - days.The response of biomass phospholipid content was nearly
similar to ETS activity.The phospholipid content was decreased with the
addition of insecticide and the toxicity was in the order:10 FR (field rate)
> 5 FR> 1.0 FR > 0.5 FR > control and it also decreased with
incubation period.
Keywords: electron transport system (ETS) activity, phenol, phospholipids, protein, insecticide, anoxic conditions
