Sulfur Fertilization of Cool Season Grasses and Effect on Utilization of Minerals, Nitrogen, and Fiber by Steers

Abstract

Two studies were to ascertain effects of sulfur fertilization on intake and nutrient utilization of Kenhy tall fescue and orchardgrass hay by steers. Hay was harvested in vegetative stage in mid-July from paddocks that had been fertilized with 0 or 132kg sulfur/ha as gypsum. Forage sulfur was increased by sulfur fertilization from .33 to .40% in tall fescue and from .29 to .37% in orchardgrass. The increased forage sulfur resulted from an increase of nonprotein sulfur. Hay intake was not affected by sulfur fertilization during 28-day intake. Sulfur fertilization of orchardgrass increased apparent digestibility of dry matter, neutral detergent fiber, acid detergent fiber, and permanganate lignin by 5.1, 12.9, 11.9, and 67.2% but decreased protein digestibility by 5.7%. Dry matter and fiber digestibility of tall fescue were not affected by sulfur fertilization, but protein digestibility was increased. Apparent absorption of sulfur and urinary sulfur excretion were increased by sulfur fertilization of both grasses. Increasing sulfur in orchardgrass through fertilization reduced apparent absorption of calcium and magnesium. Sulfur fertilization of tall fescue tended to decrease apparent absorption of magnesium and calcium but increased forage potassium and absorption and retention of potassium by steers.