Answer:
A harvest sown and reaped on the same day in an unplowed field. Which increases without growing, remains whole though it is eaten within and without. Is useless and yet the staple of nations.
What turns everything around but does not move?
You can tumble in it, roll in it, burn it, animal eat it. Used to cover floors, still used beyond stall doors. Freshens whatever it is placed on. Absorbs whatever is poured into it.
He stands beside the road. In a purple cap at tattered green cloak. Those who touch him, curse him.
You can hold it without using your hands or your arms. What is it?
Long and slinky like a trout, never sings till it's guts come out.