The department is hereby authorized, empowered and directed to formulate and submit to the Secretary of Agriculture, in conformity with the provisions of said Soil Conservation and Domestic Allotment Act , a state plan for each year. It shall be the purpose of each such plan and each such plan shall be designed to promote such utilization of land and such farming practices as the department finds will tend, in conjunction with the operation of such other plans as may be approved for other states by the Secretary of Agriculture, to preserve and improve soil fertility and soil health; to promote adaptation to changes in climate and environment; to promote the economic use and conservation of land; to diminish exploitation and wasteful and unscientific use of natural soil resources; to protect rivers and waterways against the results of soil erosion and aid in flood control; and to reestablish and maintain the ratio between the purchasing power of the net income per person on farms and that of the income per person not on farms, as defined in subsection (a) of section 7 of the Soil Conservation and Domestic Allotment Act. Each such plan shall provide for adjustments in utilization of land, and in farming practices through agreements with producers or through other voluntary methods, and for benefit payments in connection therewith, and for such methods of administration not in conflict with any law of the state, and for such reports as the Secretary of Agriculture finds necessary for the effective administration of the plan, and for ascertaining whether the plan is being carried out according to its terms.