Iron fertilization of kentucky bluegrass

Abstract

Iron applications are sometimes used to enhance the color (darker green) of turfgrass stands even when iron is not deficient. A study was conducted to determine the feasibility of replacing a portion of the total yearly N applied to Kentucky bluegrass (Poa pratensis L.) with iron. Turfgrass response to iron chelate (Sequestrene 330) applications at 2.2 kg Fe ha^‐1 in combination with three liquid‐applied N sources (urea, Formolene, and FLUF) at 25 kg N ha^‐1 was compared to turf response from applications of the N sources at 49 kg N ha^‐l. Iron was substituted for part of the N in either the first and second, second and third, or third application in a four application per year program. The study was conducted for three years, and the fertilized turf was rated for color weekly during the growing season. Depending on N source and frequency of Fe application, turf treated with N received higher color ratings compared to turf receiving Fe + N on 13 (Formolene + Fe in third application) to 36% (Fluf + Fe in first and second application) of the rating dates. Turf color was judged acceptable on 78 to 85% of the rating dates for turf treated with N and 62 to 85% of the rating dates for turf treated with Fe + N. The results indicate that it is feasible to substitute iron for a portion of the N in a urea or Formolene fertilization program but that caution should be used when replacing N from FLUF with iron.