Annual bluegrass (Poa annua L.) is an invasive weed producing copious amounts of viable seed that compete with seedling turfgrasses during renovation. These field studies were conducted to determine the effectiveness of dazomet (tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione), a granular soil sterilant that breaks down in soil to release methyl isothiocyanate (MITC), for controlling the soil seed bank of annual bluegrass during turfgrass renovation. Field trials in Urbana, Ill., and West Lafayette, Ind., in Spring and Fall 2000 and 2001 evaluated dazomet rate from 0 to 504 kg·ha-1 and soil preparation techniques to determine the most effective practices to reduce annual bluegrass reestablishment into a creeping bentgrass (Agrostis stolonifera L.) seeding. The interval, in days, between dazomet application and creeping bentgrass planting was also examined to determine the optimal seeding time as measured by the level of annual bluegrass reestablishment. Spring trials generally gave poor results that were attributed to windy conditions resulting in rapid loss of MITC. The annual bluegrass soil seed bank was reduced 46% in spring trials compared to 78% in fall trials. Increasing dazomet rates reduced the absolute number of viable annual bluegrass seeds remaining in the soil. However, significant quantities of viable seed remained, regardless of dazomet rate. Annual bluegrass infested the renovated turf in all trials to varying degrees. Dazomet rates of 420 or 504 kg·ha-1 yielded the lowest rates of annual bluegrass reestablishment. Trials conducted in the fall at these rates resulted in annual bluegrass cover of 1% to 20% in the resulting turf. Creeping bentgrass planted at 1 day after dazomet application had significantly less annual bluegrass than when seeded at 7 or 9 days after dazomet application. Dazomet is a tool that can help reestablish a new turf with lower levels of annual bluegrass. However, eradication of annual bluegrass with dazomet is not likely and environmental conditions will dramatically affect the success of the sterilization.
Bruce E. Branham, Glenn A. Hardebeck, Joseph W. Meyer and Zachary J. Reicher
Matthew D. Jeffries, Travis W. Gannon, W. Casey Reynolds, Fred H. Yelverton and Charles A. Silcox
-scale turfgrass renovations and can be problematic on certain topographies (e.g., steep slopes). In addition, dazomet soil incorporation via cultivation alone may provide unacceptable control. Unruh et al. (2002) reported dazomet (392 kg·ha −1 ) provided 98
Peter J. Landschoot, Bradley S. Park, Andrew S. McNitt and Michael A. Fidanza
Fumigation of annual bluegrass (Poa annua L.)-infested putting greens before seeding creeping bentgrass (Agrostis stolonifera L.) prevents stand contamination due to annual bluegrass seedling emergence. Dazomet is a soil fumigant labeled for use in putting green renovation; however, limited data are available on efficacy of dazomet controlling annual bluegrass seedling emergence following surface-applications. The objectives of this study were to determine the influence of rate and plastic covering of surface-applied dazomet on annual bluegrass seedling emergence in putting green turf; and safe creeping bentgrass seeding intervals following applications of dazomet to putting green surfaces. Treatments were applied in late summer to the surface of a 20-year-old stand of turf maintained as a putting green and plots were watered immediately after application and throughout each test period. Plastic-covered dazomet treatments had fewer annual bluegrass seedlings than noncovered dazomet treatments. Three plastic-covered dazomet treatments (291, 340, and 388 kg·ha-1) provided complete control of annual bluegrass seedlings during 2000 and 2001. None of the noncovered dazomet treatments provided complete control of annual bluegrass seedling emergence. Results of the seeding interval experiment revealed that creeping bentgrass seedling development was not inhibited in both plastic-covered and noncovered dazomet treatments, when seeded 8, 10, 13, and 16 d after dazomet was applied to the turf surface. Results of this study demonstrate that dazomet, applied at rates ≥291 kg·ha-1 to the surface of a putting green in summer and covered with plastic for 7 d, can control annual bluegrass seedling emergence. Chemical name used: tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione (dazomet).
Bohan Liu and Peter J. Landschoot
Phosphorus (P)-containing starter fertilizers are often recommended for establishing new turf, regardless of P levels indicated by the soil test. However, few field studies have been conducted to determine the effects of P in starter fertilizer on the rate of turf establishment. The primary objective of this study was to determine if P in starter fertilizer enhances tall fescue groundcover and growth during establishment on silt loam soil. This 2-year field study was conducted on silt loam soil tilled with a rototiller or core-aerated and vertically sliced. Mehlich-3 P levels ranged from 38 to 270 mg·kg−1. Experiments were conducted during late summer and fall, and all tests were seeded with ‘Bullseye’ tall fescue (Festuca arundinacea Schreb.). Treatments included 49 and 73.5 kg·ha−1 of nitrogen (N) without P, 49 kg·ha−1 of N plus three different rates of P (24.5, 49, and 73.5 kg·ha−1), and a nonfertilized control. Comparisons between groups that received treatment with 49 kg·ha−1 of N without P and treatments with 49 kg·ha−1 N with P revealed few significant groundcover responses to the addition of P. Of 12 groundcover assessments performed during four experiments, contrasts revealed only one instance of a higher percentage of groundcover in response to the addition of P. This occurred during an experiment having a pretreatment Mehlich-3 P level of 38 mg·kg−1. Comparisons indicated greater clipping yields in response to the addition of P in one of the four experiments. This occurred in soil that was core-aerated and sliced with an initial Mehlich-3 P level of 66 mg·kg−1. In most cases, Mehlich-3 P levels at the end of each experiment increased as the P application rates increased. The only instance in which comparisons between treatment with 49 kg·ha−1 N without P and treatments with 49 kg·ha−1 N with P demonstrated a significant leaf tissue response to P during the experiment with soil that was core-aerated and sliced with a pretreatment Mehlich-3 P level of 66 mg·kg−1. When individual treatments were compared, the 73.5 kg·ha−1 N treatment without P produced similar or higher groundcover and clipping yields than all other treatments during all four experiments. This study revealed few groundcover and variable tall fescue clipping yield responses to P additions when applied at rates used for starter fertilizer applications on silt loam soil during late summer and fall. Groundcover and growth responses due to P in starter fertilizers do not appear to be solely related to soil test P levels, and other factors such as the method of establishment (tilling soil vs. core-aerating and slicing the soil surface), environmental conditions, and the N content of soil may be involved.
Jacob S. Bravo, Thomas Okada Green, James R. Crum, John N. Rogers III, Sasha Kravchenko and Charles A. Silcox
.A. Meyer, J.W. Reicher, Z.J. 2004 Turfgrass renovation using dazomet to control the annual bluegrass L. soil seed bank HortScience 39 1763 1767 Brecke, B.J. Unruh, J.B. Stephenson, D.O. IV 2005 Dazomet blended with rootzone mix for fumigation Intl
Marco Schiavon, Brent D. Barnes, David A. Shaw, J. Michael Henry and James H. Baird
residual activity of herbicides used in turfgrass renovation. 1977 Mtg. Weed Sci. Soc. Amer. p. 50. (Abstr.) Jellicorse, W.R. Richardson, M.D. McCalla, J.H. Karcher, D.E. Patton, A.J. Boyd, J.W. 2012 Seeded bermudagrass establishment in an overseeded
Jared A. Hoyle, J. Scott McElroy and Elizabeth A. Guertal
during turfgrass renovation practices because deep tillage can redistribute weed seeds present deeper in the profile to the soil surface and may cause an increase emergence. Across all weed species, soil texture influenced emergence, suggesting soil
Thomas O. Green, Alexandra Kravchenko, John N. Rogers III and Joseph M. Vargas Jr.
successful management program Golf Course Mgt. 59 9 438 442 Branham, B.E. Hardbeck, G.A. Meyer, J.W. Reicher, Z.J. 2004 Turfgrass renovation using Dazomet to control the Poa annua L. soil seed bank HortScience 39 1763 1767 Calhoun, R.N. 2010 Growing degree