Blow

onizoWhat does each verse mean

Those are lines, not verses. They mean just what they say; I see no idioms.

onizo how blow off and blow away could differ here?

It is merely the way or direction in which the poet visualizes the wind acting on the plain, the sunshine, and the rain.

onizo Little Wind, blow up the sunshine, Little wind, blow off the rain.

So, here wind is not blowing the sunshine up as in blowing the sunshine up your bottom, and
blow off the rain isn't blowing the rain away as in blowing balloons away(if you have this expression), in which balloons is a direct object?

onizoblow up the sunshine

cause sunrise or a sunny day

onizoblow off the rain.

cause the rain to disappear and have a sunny day

Thank you.