Centipedegrass Response to Foliar Application of Iron and Nitrogen
- R. N. Carrow ,
- B. J. Johnson and
- G. W. Landry
The lawn-care industry has interest in the use of foliar iron (Fe) to enhance the color of common centipedegrass [Eremochloa ophiuroides (Munro.) Hack.] without using excessive N. We evaluated different Fe carriers, Fe rates, and N rates in three different studies conducted on centipedegrass grown on a Cecil sandy loam (clayey, kaolinitic, thermic Typic Hapludult). Minor differences occurred with respect to phytotoxicity but not visual quality or color from ferrous sulfate, ferrous ammonium sulfate, and Sequestrene 330 chelate. When visual quality and color ratings were made at 2 wk or more after application, the highest Fe and N rates always provided the best response. However, initial phytotoxicity [within 1 to 6 d after treatment (DAT)] from Fe and N dictated the use of much lower rates. If applied on a moderately warm day (21–33 °C), the maximum acceptable Fe rate was 2.0 kg ha−1 in combination with 0 or 9.8 kg N ha−1. Centipedegrass could receive up to 39.0 kg N ha−1 without any Fe before N burn was objectionable. On a very hot day (28–37.5 °C), only 0.73 kg Fe ha−1 could be applied with 12.2 kg N ha−1 without objectionable phytotoxicity. The maximum N rate that could be applied alone under these conditions was 24.2 kg N ha−1 before N-induced phytotoxicity occurred. The 2.0 kg Fe ha−1 rate provided positive visual quality and color responses for up to 35 DAT, while 0.73 kg Fe ha−1 improved color for only 22 DAT. Results show that Fe can improve centipedegrass color, but that centipedegrass is very sensitive to phytotoxicity from Fe. Addition of N further reduces centipedegrass tolerance to Fe.
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