Response of the Florida legume Galactia elliottii to shade

Abstract

The need for shade tolerant forage species for forested grazing lands of the Southeastern United States has been recognized for some time. Introduced grasses and temperate legumes have been evaluated for this use with some success. Sparse stands of native legumes occur throughout these woodlands. The potential value of these native legumes has received little attention. Seedlings of Galactia elliottii Nuttall, a widely occurring native legume in the pine flatwoods (Spodosols), were established in pots and subsequently evaluated for growth response to shade levels of 0, 25, 55, 75, and 92% under vinyl shade cloth. Maximum herbage yield and maximum nitrogen yield after a 60-day growth period were obtained under 25% shade. Responses of herbage yield, percent nitrogen, and nitrogen yield to shade were described by quadratic equations with initial increases followed by decreases as shade increased. A second experiment involving small plots of G. elliottii in dense bahiagrass (Paspalum notatum Flugge) sod produced negative linear relationships between shade and yield of each forage species. However, G. elliottii yield declined at a slower rate than bahiagrass. These results indicate that G. elliottii is adapted to shaded flatwoods environments and suggest that further efforts to evaluate local woodland legumes for forage potential could provide productive species for reseeding shaded woodland sites in the Southeastern United States.