The closed landfill investment fund is established in the state treasury. The fund consists of money credited to the fund, and interest and other earnings on money in the fund. Beginning July 1, 2003, funds must be deposited as described in section 115B.445. The fund shall be managed to maximize long-term gain through the State Board of Investment. Money in the fund may be spent by the commissioner after fiscal year 2020 in accordance with sections 115B.39 to 115B.444.