The relative drought resistance of turf-type tall fescue (Festuca arundinacea Schreb.) cultivars compared to forage-type cultivars has not been well-documented. Greenhouse and field studies were conducted between 1991 and 1994 to determine rooting potential and drought response of a slow-growing, turf-type tall fescue (`MlC18'), a turf-type cultivar with a moderate growth rate (`Mustang'), and a forage-type cultivar (`Kentucky-31'). In the greenhouse, rooting was determined in sand or calcined clay using clear, polyethylene root tubes 4 cm in diameter by 122 cm deep. Root length density (RLD) was measured for 0- to 30-, 30- to 60-, 60- to 90-, and 90- to 120-cm depths. No differences were observed in RLD at the 0- to 30-cm depth. At other depths, RLD of `Mustang” was generally superior to that of `K-31' and `MlC18'. During a 3-week dry-down in the field in 1994, `MlC18' exhibited greater drought stress and a higher canopy minus air temperature than other cultivars. Advantages afforded by reduced mowing of slow-growing tall fescue cultivars may be negated by reduced drought resistance.
Field studies were conducted in Kansas and Maryland to compare the safety and efficacy of halosulfuron-methyl (HM) and bentazon for topkill of yellow nutsedge (Cyperus esculentus L.). Kentucky bluegrass (Poa pratensis L.) and creeping bentgrass (Agrostis palustris Huds.) treated with single (in Kansas) or sequential (in Maryland) HM (35 to 140 g·ha–1) or bentazon (1120 or 1680 g·ha–1) applications exhibited little injury, and treated turf had acceptable quality in all studies. Bentazon caused an unacceptable reduction in perennial ryegrass (Lolium perenne L.) quality at ≥5 weeks after treatment in four of five tests. Perennial ryegrass quality declined linearly with increasing HM rates (between 35 and 140 g·ha–1). In Maryland, HM (≥70 g·ha–1) elicited unacceptable perennial ryegrass quality for 2 or 3 weeks; however, in Kansas, quality was unacceptable for ≈1 week. In Kansas, yellow nutsedge topkill by HM (70 kg·ha–1) ranged from 52% to 97%. A single HM application (35, 70, or 140 kg·ha–1) provided > 97% topkill in Maryland. Yellow nutsedge topkill by bentazon (1680 g·ha–1) generally was inferior to that by HM (70 g·ha–1). Chemical names used: 3-(1-methylethyl)-1H-2,1,3-benzothiadiazin-4 (3H)-one 2,2-dioxide (bentazon), methyl 3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyrazole-4-carboxylate (halosulfuron-methyl).