Forage and Nitrogen Contributions of Arrowleaf and Subterranean Clovers Overseeded on Bermudagrass and Bahiagrass1

Tropical perennial grasses are the foundation of the pasture systems in the southeastern USA. However, they are low quality and require N fertilizer. Forage production and distribution and N accumulation of clover‐grass mixtures were compared to that of the grass alone receiving various rates of N fertilizer on a Crowley soil (fine, mortmorillonitic, thermic Typic Albaqualf). ‘Coastal’ bermudagrass [Cynodon dactylon(L.) Pers.] and ‘Pensacola’ bahiagrass (Paspalum notutumFlugge) sods were (i) overseeded with ‘Yuchi’ arrowleaf (Trifolium vesiculosumSavi) or ‘Mt. Barker’ subterranean clovers (Trifolium subterraneumL.), (ii) fertilized with 0, 84, 168, 252, or 336 kg N ha−1, or (iii) overseeded with arrowleaf or subterranean clover plus 112 kg N ha−1. Dry matter production of clover‐Coastal bermudagrass and clover‐bahiagrass mixtures was not significantly different from the grass alone at the 168 and the 252 kg N ha−1rate, respectively. Overseeding clovers improved seasonal forage distribution by providing forage one to two months earlier and reduced the May–June forage peak exhibited by the N fertilizer‐grass treatment. Average annual N accumulations of clover‐grass mixtures ranged from 177 to 217 kg N ha−1, which equaled or exceeded the 336 kg N rate except for the arrowleaf–bermudagrass mixture. The amount of N fertilizer required by the grass to replace the clover dry matter contribution was 127, 211, 160, and 254 kg N ha−1for the arrowleaf‐bermudagrass, arrowleaf‐bahiagrass, subterranean‐bermudagrass, and subterranean‐bahiagrass mixtures, respectively. Applying 112 kg N ha−1to clover‐grass mixtures did not improve total yield, forage distribution, or N accumulation, but did decrease percentage clover in the stand 5 to 33%.