A 3‐yr field study was conducted to determine the influence of N level (98 and 196 kg ha−1 yr−1), mowing height (3.2,5.5, and 8.8 cm), and three herbicides on weed encroachment and overall quality of tall fescue Festuca arundinacea Schreb. cv. Rebel II. The major objective of this study was to identify cultural methods of excluding weed development in tall fescue. Dithiopyr [3,5‐pyridinedicarbothioic acid, 2‐(difluoromethyl)‐4‐(2‐metbylpropyl)‐6‐(trifluoromethyl)‐S,S‐dimethylester] and pendimethalin [N‐(l‐ethylpropyl)‐3, 4‐dimethyl‐2,6‐dinitrobenzenamine] were applied preemergence for smooth crabgrass [Digitaria ischaemum (Schreber) Schreber ex Muhlenb.] control, and fenoxaprop [(±)‐2‐[4‐[(6‐chloro‐2‐benzoxazolyl)oxy]‐ phenoxylpropanoic acid] was applied postemergence for crabgrass control. Rates of dithiopyr and pendimethalin were reduced or eliminated on selected plots in the last 2 yr of the study to determine if reduced herbicide inputs would continue to provide effective crabgrass control. Tall fescue mowed at 8.8 cm resisted smooth crabgrass invasion, exhibited best visual summer turf quality in 1990 and 1991, had poorest winter turf quality, and had highest white clover (Trifotium repens L.) populations. Other environmental factors and lower mowing height (3.2 or 5.5 cm) reduced summer turf quality in 1990 and 1991. High N improved fall and winter turf quality, but not summer quality. Nonherbicide‐treated plots receiving high N had less smooth crabgrass than low N plots, but high N provided no additional crabgrass reduction in herbicide‐treated plots. High mowing (8.8 cm) was the best cultural management strategy for reducing smooth crabgrass encroachment and maintaining tall fescue cover. Results indicated that smooth crabgrass control with label use rates of herbicides was warranted when mowing tall fescue at 3.2 or 5.5 cm.

While Festuca spp. are suited to low management,there is little information regarding their performance with little or no inputs of irrigation, fertilizer, or herbicides. In this 3‐yr field study, the quality of ‘Bighorn’ blue fescue [Festuca ovina L. spp. glauca (Lam.)W.D.J. Koch], ‘Aurora’ hard rescue (F. longifolia Thuill.), and ‘Silverado’ and ‘Rebel II’ tall rescue (F. arundinacea Schreber) were compared under three mowing regimes. Turf received no supplemental irrigation or fertilizer following seedling emergence. The three mowing regimes were mowing as needed to a height of $.5 cm (Regime I); monthly mowing to a height of 8.0 cm (Regime H); and monthly mowing initiated following seedhead senescence to a height of 8.0 cm (Regime HI). Initially, both tall rescue (TF) cultivars exhibited very good quality. Within I yr of seeding, however, Bighorn and Aurora quality surpassed that of both TF cultivars. Both TF cultivars were more rapidly and extensively invaded by smooth crabgrass [Digitaria ischaemum (Schreber) Schreber ex Muhlenb.] and white clover (Trifolium repens L.) than either Bighorn or Aurora following a spring drought in the second year of study. By the second summer and thereafter, Bighorng enerally received the highest quality ratings followed by Aurora. Turf maintained in Regime I was generally of higher quality, but seasonal quality ratings during the latter 2 yr of the study were similar for Regimes I and II. Lowest turf quality was most often associated with Regime III, particularly during spring and summer. Herbicide use in the final study year was important in improving the quality and cover of the TF cultivars but only slightly improved Bighorn or Aurora quality. Hence, in a 3‐yr absence of irrigation or fertilizer inputs, Bighorn and Aurora maintained better quality and better resisted weed invasion compared with the TF cultivars evaluated.

Man‐made erosion control materials are increasingly being used at construction sites. The performance of these materials in comparison to natural materials is largely unknown. A rainfall simulation study was designed in which four man‐made materials (wood excelsior, jute fabric, coconut fiber blanket, and coconut strand mat) and two natural materials (straw and turfgrass sod) were evaluated. The erosion control materials were evaluated on a Sassafras loamy sand (fine loamy, mixed mesic Typic Hapludult) having a 8% slope and on a Sassafras sandy clay loam (fine, silty, mixed mesic Typic Hapludult) having a 14 to 21% slope. Disturbed soil surface areas (0.76 m2 each) were covered with each material and subjected to a 96 mm hr−1 simulated rainstorm. Runoff and sediment loss rates were determined every 5 rain for 35 min after recording the time required for runoff initiation. Sod was the only material that extended the time required for runoff initiation. Runoff from all materials was less than bare soil for the first 5 rain of runoff; however, only straw, jute, and sod reduced runoff over the entire storm event. The total amount of runoff, compared with bare soil, was decreased by 61% for sod, 25% for straw, and 16% for jute. Erosion control materials reduced bare soil erosion by 80 to 99%. Of the man‐made rosion control materials, only jute reduced runoff and sediment losses at both locations. Therefore, of the materials tested, only sod, straw, and jute would be expected to effectively reduce both runoff and sediment losses

No abstract

Smooth crabgrass [Digitaria ischaemum (Schreber) Schreber ex Muhlenb.] is an invasive weed of cool-season turfgrasses. Previous research has demonstrated that quinclorac is an effective postemergence herbicide for crabgrass control, but performance has been erratic in some regions. Furthermore, quinclorac may elicit objectionable levels of discoloration in creeping bentgrass (Agrostis stolonifera L.). The objectives of this 3-year field study were to determine optimum rates and timings of quinclorac applications that provide consistent levels of effective crabgrass control and to assess creeping bentgrass quality responses to quinclorac. To evaluate crabgrass control, quinclorac was applied in early-, mid- and late-postemergence timings at various rates to a perennial ryegrass (Lolium perenne L.) turf. Similar treatments were applied to creeping bentgrass to determine if application timing and rate influenced the level and duration of discoloration. Quinclorac was applied alone or was tank-mixed with either urea (N at 6.1 kg·ha-1) or chelated iron (Fe)+nitrogen (N) (FeSO4 at 1.1 kg·ha-1+N at 2.2 kg·ha-1) to determine if they would mask discoloration. Crabgrass control generally was more effective in the early- and midpostemergence application timings. A single application of quinclorac (0.84 kg·ha-1) was effective where crabgrass levels were moderate, but sequential (i.e. multiple) applications were required where crabgrass levels were severe. The most consistent level of crabgrass control where weed pressure was severe occurred with three, sequential quinclorac (0.37 or 0.42 kg·ha-1) applications. Creeping bentgrass exhibited 2 to 11 weeks of unacceptable discoloration in response to sequential quinclorac applications. Chelated Fe+N was more effective than urea in masking discoloration. In general, chelated Fe+N tank-mixed with quinclorac masked discoloration and turf had quality equivalent to untreated bentgrass on most, but not all rating dates. Chemical names used: 3,7,-dichloro-8-quinolinecarboxylic acid (quinclorac).