Any local improvement district heretofore duly organized may avail itself of and be subject to any of the provisions of this chapter increasing the number of annual installments, not to exceed fifty, after the directors of the irrigation district duly adopt a resolution to that effect, and it shall be the duty of the board of directors to adopt such resolution whenever in the judgment of the board the best interests of the local improvement district will be served thereby, and the interests of the irrigation district will not be jeopardized.