Interrelationships between Defoliation Systems, Morphological Characteristics, and Growth of ‘Coastal’ Bermudagrass 1

DURING the past several years Coastal bermudagrass (Cynodon dactylon [L.] Pers.) has increased in importance as a forage for the southeastern United States. Many studies have been conducted to determine the growth characteristics and produc t ion of Coastal bermudagrass under systems of hay utilization; however, information is lacking concerning its performance under varying grazingutilization management systems. In recent investigations in Georgia (4), Coastal bermudagrass was studied under harvesting systems which varied from 3-week to 24-week intervals. Total dry matter production was less on the 3-week or the 24-week interval than the other intervals; little difference in crude protein production was obtained between the 3-, 4-. 5-, and 6-week intervals. Most workers have found that very close and frequent defoliations of bunch-type grasses have the general effect of reducing the total yield. However, with sod-forming grasses of different morphological -characteristics, some studies have shown that close, frequent defoliation resulted in increased production. Results of this nature have been reported, for example, from sod-forming grasses, such as Kentucky bluegrass (Poo. pratensis L.) Graber (5) and Mortimer and Ahlgren (6). Recent studies (1) relating different management systems and the Leaf Area Index (LAI) of Coastal bermudagrass to growth gave LAI's ranging from 1 to 20 depending upon the system of management. Investigators working with other forages have suggested that an LAI of approxi-