All contracts for the sale of any such lands included within any irrigation district, in addition to the purchase price to be paid, shall provide that such purchaser, on or before March 1 in each year, until he has secured a patent for such lands, shall pay to the register of the state board of land commissioners an amount to equal the district assessments so levied upon such lands for the year in which such payment is to be made, and such moneys when so received by said register shall be turned in to the state treasurer and kept in a separate fund for the payment of such assessments.L. 09: p. 431, § 7. C.L. § 2032. CSA: C. 90, § 494. CRS 53: § 149-3-17. C.R.S. 1963: § 150-3-17.