'Stubble' in the Bible

“Will You cause a windblown leaf to tremble?Will You pursue the chaff of the dry stubble?

“Are they like straw before the wind,And like chaff that the storm steals and carries away?

“The arrow cannot make him flee;Slingstones are treated as stubble by him.

“Clubs [also] are regarded as stubble;He laughs at the rushing and the rattling of the javelin.