Quantification of Slow‐Release Fertilizer on Year‐Round Forage Production

Overseeding annual ryegrass [Lolium perenne L. ssp. multiflorum (Lam.)] into warm-season grass pasture is a common practice producing almost year-round forage for cow-calf operations in the southern United States. Such an approach requires continuous soil nutrient availability throughout the season for consistent forage production. Coated fertilizers marketed as "slow-release" may be an efficient and continuous plant nutrient source. Therefore, a study was conducted to investigate the impact of fertilization options targeting sustainable nutrient release on year-round dry matter (DM) production. Research was conducted to determine fertilization effects of split application of uncoated inorganic fertilizer, slow-release coated fertilizer, broiler litter, and zero-fertilizer on forage production and nutritive value of annual ryegrass overseeded bahiagrass (Paspalum notatum Fluegge) pasture. The slow-release coated fertilizer produced more total forage mass (30 Mg ha(-1)), which was of higher crude protein during spring (>= 200 g dry matter [DM] kg(-1)), than the other treatments (<23 Mg ha(-1) and 173 g DM kg(-1), P < .05). The broiler litter and split application of uncoated inorganic fertilizer produced similar amounts of forage DM. The N uptake from the slow-release coated fertilizer was higher than the other treatments until mid-summer. Although early spring-applied slow-release fertilizer can enhance total forage production and quality indicators, high cost limits revenue above variable cost of this slow-release fertilizer to levels similar to that of split-applied uncoated inorganic N, with broiler litter providing the more economic supply of N to pastures with long growing seasons.