Abstract

St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] has been grown on organic soils in south Florida since the 1930's.  However, this grass has not produced or persisted well on mineral soils, even though it is extensively grown as a turfgrass.  The purpose of this paper is to report dry forage mass, nutritive quality, persistence, and total non-structural carbohydrates (TNC) of three St. Augustinegrasses managed at four mob-grazing frequencies.  The experimental design was a split plot with three randomized complete blocks of 2-, 4-, 6-, and 8-wk grazing frequencies (GF) as whole plots and grass entries ('Floralawn', 'Roselawn', and FX-33) as subplots.  Annual fertilization was 168-23-86 kg ha^-1 N-P-K with N splits in March, July, and September.  Grazing frequency had little influence on dry forage mass, persistence, and TNC, but affected (P ><0.05) forage quality.  St. Augustinegrass entries influenced (P<0.05) forage mass, grass persistence, forage quality, and TNC.  Generally, crude protein (CP) and in vitro organic matter digestion (IVOMD) decreased (P > 0.05) as GF was delayed from 4 to 6 wk.  Roselawn produced 24% and 39% more forage than other entries during the warm and cool seasons, respectively.  Entry FX-33 was the least persistent under grazing, averaging 43% infestation by common bermudagrass (Cynodon dactylon (L) Pers. var. dactylon) after 3 yr of grazing.  This entry generally was lower (P <0.05) in IVOMD (530 g kg^-1) compared with the average for Roselawn and Floralawn (580 g kg^-1) during the warm season.  These data indicate St. Augustinegrass is not a desirable species for forage on a mineral soil.