(a) Share up to 50 percent of the cost with participants of installing eligible practices specified in the conservation plan for which CCC determines that cost sharing is appropriate and in the public interest, and at the levels and rates of cost-sharing determined in accordance with the provisions of this part; and

(b) Pay to eligible participants for a period of years not in excess of the contract period an annual rental payment, including applicable and available incentive payments, in such amounts as may be specified in the CRP contract.