Abstract

Sulfur fertilization of bahiagrass (Paspalum notatum Flugge ‘Pensacola’) has not been a common practice on northern Florida Spodosols. A 6-yr study was begun in 1978 on an established sward of bahiagrass on Myakka fine sand (sandy, siliceous, hyperthermic Aeric Haplaquod) to determine if an S response could be obtained by intensive management of bahiagass and to evaluate N and S rates for this forage crop. Herbage yield, N and S uptake, the stolon-root mass, and soil S were measured and evaluated at two rates of N fertilization (200 and 400 kg ha⁻¹) and four rates of S fertilization (0, 10, 20, and 40 kg ha⁻¹) as gypsum (CaSO₄·2H₂O). Splitting S into four applications had no effect on yield, S uptake, or N uptake over a single annual application. At the low N rate, a dry matter yield response did not occur until the fourth year of the study, with maximum yields thereafter predicted at an average annual S application between 27 and 33 kg ha⁻¹. At the high N rate, a dry matter yield response occurred the second year with 10 kg S ha⁻¹ applied, and by the fifth and sixth years, maximum dry matter herbage yield was predicted at an annual S application between 40 and 51 kg ha⁻¹. The stolon-root system accumulated N and S, but S treatments had no effect on extractable or total soil S. Sulfur removed in the herbage exceeded that applied at all but the highest S rate. Sulfur fertilization also enhanced N recovery. A critical S concentration of 1.61 g kg⁻¹ was identified for bahiagrass herbage.

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