4 The Commodity Board is authorized, in relation to the powers granted to it by section 3 with respect to the marketing of potatoes in interprovincial and export trade, to make orders fixing, imposing and collecting levies or charges from persons situated in the Province of New Brunswick who are engaged in the production or marketing of potatoes, and for such purposes classifying such persons into groups and fixing the levies or charges payable by the members of the different groups in different amounts, and the Commodity Board may use such levies or charges for its purposes, including the creation of reserves, the payment of expenses and losses resulting from the sale or disposal of potatoes and the equalization or adjustment among producers of potatoes, of moneys realized from the sale thereof during such period or periods of time as it may determine.