All tax assessors, in assessing for public taxes any tract of land lying partly within the limits of a drainage district or drainage and levee district and partly outside of the limits of such district, shall assess that part of the tract lying within the limits of such district as one (1) independent tract, and that part of any such tract lying outside of the limits of such district as an independent tract, to the end that it may be definitely known what is the amount of the state and county taxes, and any special school district taxes, assessed against the part of the land within the limits of such district.