ESTABLISHMENT OF TIFTON-9 BAHIAGRASS IN RESPONSE TO PLANTING DATE ANDSEED COAT REMOVAL

Stands of 'Tifton 9', like those of other bahiagrasses (Paspalum notat um Flugge var. saurae Parodi), develop slowly. Our objectives were to determine seedling emergence and stand establishment responses to plan ting date and mechanical seed coat removal using greenhouse and field plantings. Seed dehulled by acceleration in an airstream to hit a meta l plate (7.8 kg ha(-1)) or whole seed (11.2 kg ha(-1)) was planted at equivalent rates in five blocks of a randomized complete block design on seven biweekly planting dates from 9 March through 1 June in 1994 a nd 1995 at both a droughty upland site (Dothan loamy sand: fine-loamy, siliceous, thermic Plinthic Kandiudults) and a lowland site (Alapaha sand: loamy, siliceous, thermic Arenic Plinthic Paleaquults) near Tift on, GA (31 degrees 26' N, 83 degrees 35' W), to observe emergence and establishment. Spring and fall plant counts and final stand ratings of percent bahiagrass occurrence were used to evaluate emergence and est ablishment. Emergence 7 d after greenhouse planting of dehulled seed ( 18.3%) was greater (P < 0.01) than whole seed (0.7%), Emergence at 28 d after planting was not different (36.2%) between seed treatments, Me an surface (0 to 50 mm) soil moisture content at the lowland site (58 g kg(-1)) was higher than the upland site (28 g kg(-1)). Seedling heig hts, measured in June 1994, spring seedling number in both years, and 1995 fall plant numbers were often higher with earlier planting date. No differences in final stand (% occurrence) could be attributed to pl anting date. Final stand ratings were greater (P < 0.05) at the lowlan d (84%) than at the upland site (79%), and greater (P < 0.05) for whol e than for dehulled seed in 1994, but no differences were observed in 1995. Development of Tifton 9 bahiagrass stands at these Coastal Plain sites was slow, but relatively insensitive to differences in spring o r early summer planting date. Dehulled seed emerged more rapidly, but this provided no sustained advantage in stand establishment in these e nvironments.