The Secretary of Agriculture is authorized to make payments to agricultural producers who carry out emergency measures to control wind erosion on farmlands or to rehabilitate farmlands damaged by wind erosion, floods, hurricanes, or other natural disasters when, as a result of the foregoing, new conservation problems have been created that (1) if not treated, will impair or endanger the land, (2) materially affect the productive capacity of the land, (3) represent damage that is unusual in character and, except for wind erosion, is not the type that would recur frequently in the same area, and (4) will be so costly to rehabilitate that Federal assistance is or will be required to return the land to productive agricultural use.