Seedling Kentucky Bluegrass Growth Responses to Chelated Iron and Biostimulator Materials
- J. M. Goatley * and
- R. E. Schmidt
Enhanced growth of seedling turfgrasses with biostimulator materials or chelated Fe could accelerate the rate of establishment. Field experiments in the spring and fall of 1987 and in the greenhouse in the winter of 1988 were designed to measure seedling Kentucky bluegrass (Poa pratensis L.) growth responses to foliar applications of benzyladenine (BA, 6-benzylaminopurine), propiconazole [l-( [ 2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-y~methyl]-l-(1H-1,2,4-triazole], triadimefon [l-(4-chlorophenoxy)-3,3-dimethyl-l-(lH-1,2,4-triazol-l-yl)-2-butanone], or a fortified seaweed extract (SWE, containing 500 µg L−1 of glycol kinetin and 500 pg L−1 gibberellins) applied alone or in combination with chelated Fe (8% Fephosphate citrate). The seaweed extract (0.03 mL product m−2)significantly increased root and shoot growth 6 wk after treatment (WAT) in the spring experiment, and 4 and 6 WAT in the winter greenhouse experiment. The SWE also increased the gross CO2 exchange rate (CER) on a land area basis 4 and 6 WAT in the winter experiment. Propiconazole (42 mg m−2) significantly increased seedling leaf number 6 WAT in the fall experiment. Triadimefon (150 mg m−2)or BA (6 mg m−2)ap plications generally were not as effective in increasing seedling growth as were the SWE or propiconazole. Foliar Fe applications (112 mg m−2)e,it her alone or in combination with biostimulators, significantly increased root and shoot growth and gross CER on a land area basis 4 and 6 WAT in the winter greenhouse experiment. Applications of Fe increased root dry weight 6 WAT in the spring field experiment. Growth responses to individual biostimulator and Fe combinations were highly variable among experiments, suggesting possible interactions between the growth response mechanisms of the treatments.
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