Question

which activity of the farmer can promote growth of earthworms and microbes in the field

Answer 1

for that
farmer should keep the places cool for growing earth worms
they should not use hard pests
add natural pests
and manure
so that they will not harm earthworms
don't stump the soil
if you stump earth worms will be harmed
hope it helps
thank you

Answer 2

they can use organic manures and proper water which is favourable conditions for a earthworm...
actually earthworms are also called farmers friends because they help in increasing yield by helping in nitrogen fixation..

thus they play an important role in both economically and environmentally profiet....

and using organic manures does not harm our environment

i hope it will help you