No abstract

No abstract

No abstract

Tropical signalgrass is one of the dominant weeds in the Florida turfgrass industry and is potentially troublesome for the southeastern turfgrass industry. Tropical signalgrass is especially problematic for St. Augustinegrass sod producers because of lack of control options. The objectives of our research were to determine the effect of light, pH, temperature, water potential, and planting depth on tropical signalgrass germination and emergence. Tropical signalgrass germination does not require light and is optimum at pH 5 to 6, temperature 25 C, and water potentials greater than − 0.4 MPa. Tropical signalgrass shoots emerged from depths of 0 to 7 cm, with maximum germination when placed on the soil surface. Tropical signalgrass seedlings emerged in the field during the second week of March in Ft. Lonesome, FL. Weekly mean soil and ambient air temperatures at the time of emergence were 20 C. Tropical signalgrass emergence was first observed at 118 and 73 growing degree-days (GDD) (13 C base temperature), with a peak emergence period at 222 and 156 GDD for 2001 and 2002, respectively.

Double‐ring infiltrometers are routinely used by turfgrass specialists, soil scientists, and other professionals to measure the infiltration rate of field sites. Measurement of infiltration rate is important in proper golf course design development and other scenarios that require estimates of runoff. This study compared several commonly performed double‐ring infiltration methods as follows: 30‐ (inner) and 60‐cm (outer) diameter rings with a constant water depth (head), 15‐ (inner) and 30‐cm (outer) diameter rings with a constant head, and 15‐ (inner) and 30‐cm (outer) diameter rings with a falling inner head. In addition, a Mariotte siphon device was fabricated to maintain a constant inner head for the 15‐cm diameter rings. The 15‐ and 30‐cm rings with the constant head resulted in significantly higher infiltration rates compared to 30‐ and 60‐cm diameter rings with a constant head and 15‐ and 30‐cm rings with a falling head. This was due to variation in the 30‐ and 60‐cm test inner ring water level that had to be maintained manually and because of the non‐constant water level in the 15‐ and 30‐cm falling head test. Thus, we concluded that the constant head 15‐ and 30‐cm double‐ring test was adequate to represent the infiltration rate in the sandy soils tested. The Mariotte siphon device made it easy for one person to conduct a test while maintaining a constant inner head under infiltration rates ranging from 22 to 225 mm/h.

No abstract

No abstract

No abstract