Comparison of Iron Analyses and Iron Chlorosis in Kentucky Bluegrass Cultivars

Abstract Iron chlorosis is a common problem for Kentucky bluegrass (Poa pratensis L.) grown on calcareous soils. Iron concentrations are commonly used to assess cultivar differences to chlorosis. Iron concentrations in leaf clippings determined by x‐ray, O‐phenanthroline, and ferrozine were used to evaluate visual Fe chlorosis ratings of 12 Kentucky bluegrass cultivars over two years. Cultivar differences for Fe concentration were greater for total Fe (x‐ray and o‐phenanthroline) than for ferrous Fe (ferrozine). Total Fe concentrations determined by o‐phenanthroline were higher than by x‐ray; ferrous Fe concentrations were relatively low. Leaf Fe concentrations determined by each method did not correlate with cultivar leaf Fe chlorosis ratings. From visual chlorosis ratings, the cultivars Sydsport, Victa, and Glade were fairly tolerant and Park, Wabash, and Delta were fairly susceptible to Fe chlorosis when grown on a calcareous soil in the field.