CEDAR RAPIDS — Critics of a proposed Cargill rail yard in the Rompot neighborhood have been closely watching as the assessed value of the 28 acres of vacant city-owned land designated a pollinator zone had jumped to more than $1.1 million and then corrected to $68,800 in recent months — neither of which match Cargill’s offer of $83,200.Beginning in mid-2018, Iowa assessors were required to assess non-taxable property such as this one, which previously had not been given a value since the land doesn’t generate taxes.The initial rate assigned was $40,000 an acre or $1.1 million overall.