Search Results
Abstract
Field studies were conducted for 3 years on putting green turf to determine the influence of the plant growth regulators (PGR) pronamide (PRON), ethephon (ETHR), mefluidide (MEFL), and maleic hydrazide (MH) on the transition from overseeded perennial ryegrass (Lolium perenne L. ‘Yorktown II’) turf to hybrid bermudagrass [Cynodon dactylon (L.) pers. × C. transvaalensis Burtt-Davy ‘Tifgreen’] in the spring. All PGR treatments were effective in increasing bermudagrass coverage over untreated grass; however, all reduced turf quality to some degree, with the exception of ETHR. The high PGR rates generally had lower turfgrass quality than the low rates. The March and early April application had the greatest bermudagrass coverage in 1982 and 1985, whereas the early March treatment generally had lower turfgrass quality than later applications. PRON at 0.28 kg·ha−1 applied as a single application in 1985 had higher initial bermudagrass coverage than when applied as split application, but split application maintained higher turfgrass quality than the single application. The split application of MEFL at 0.56 kg·ha−1 provided greater bermudagrass coverage than the single application when applied 6 Mar. or 3 Apr.; however, the split application resulted in lower quality than obtained from a single application applied on 6 Mar. in 1985. PRON at 0.28 kg·ha−1 and higher rates reduced growth and corresponding mowing requirements. Chemical names used: 1,2-dihydro-3,6-pyridazinedione (maleic hydrazide); N-(2,4-dimethyl-5-[([trifluoromethyl]-suIfonyl)amino]phenyl) acetamide (mefluidide); 2-chloroethyIphosphonic acid (ethephon); and 3,5-dichloro-(N-1,1-dimethyl-2-propynyI) benzamide (pronamide).
Research was conducted to determine the influence of the rate of seeding perennial ryegrass (Lolium perenne L.) over bermudagrass [Cynodon dactylon (L.) Pers × C. transvaalensis Burtt-Davy] on both the establishment of the ryegrass and the quality of bermudagrass golf greens. Increasing seeding rate from 90 to 180 g·m–2 resulted in more rapid establishment and a linear increase in turf quality. Turf density, as measured by leaf number, displayed linear and quadratic responses to seeding rates, with higher rates producing the greatest leaf numbers. Leaf width declined linearly with seeding rate, suggesting higher putting quality, as did tillers per plant. Spring transition to bermudagrass was slowed at high (150–180 g·m–2) seeding rates, with significantly more ryegrass present in late May. Emergence and growth of bermudagrass were suppressed longer at the higher overseeding rates. We conclude that the choice of seeding rate for ryegrass is a compromise between rapid development of, and maintenance of, quality turf vs. early smooth transition to bermudagrass in the spring.
Abstract
Rooted cuttings of ‘Annette Hegg Lady’ poinsettia (Euphorbia pulcherrima Willd.) were planted in growing media of equal volumes clay loam and sand or ash with 30 or 60% (by volume) pine bark, sphagnum moss peat, perlite, or rubber. Media physical measurements revealed better drainage with 60% perlite during maximum vegetative growth resulted in plants of highest quality: greater aerial fresh weight, increased height, greater inflorescence diameter, and higher grade.
Abstract
Field studies were conducted for 4 years on putting green turf to determine the influence of cultivation practices on the transition from overseeded perennial ryegrass (Lolium perenne L. ‘Yorktown II’) turf to hybrid burmudagrass [Cynodon dactylon (L.)Pers. × C. transvaalensis Burtt-Davies] in the spring. The cultivation practices of core aeration, vertical mowing, and topdressing were shown to have no positive influence of increasing the rate of bermudagrass coverage during the spring on bermudagrass greens overseeded with perennial ryegrass. The verticut treatment resulted in decreased bermudagrass coverage as well as a reduction in turf quality. All cultivation practices resulted in some quality loss at various times during the spring transition period compared to the control.
Abstract
Mineralization of nitrogen fertilizers was determined in an organic medium composed of 6 pine bark : 3 sand : 1 soil (by volume). Nitrification was evident by day 7 following treatment with urea and isobutylidene diurea (IBDU) and increased rapidly after day 14. Nitrification was not evident until day 56 in medium treated with urea + nitrapyrin (NI). Medium treated with urea or IBDU were depleted of NH4 + within 1 month, which corresponded to a peak in NO2 – + NO3 – accumulation. Only a small amount of NH4 + was not accounted for by nitrification and was assumed to be adsorbed by bark particles. Chemical names used: 2-chloro-6-(trichloromethyl)pyridine (nitrapyrin), 1,1-diureido isobutane (IBDU).
Abstract
Extensive losses in N applied to container-grown woody ornamental plants prompted this investigation to determine a) leaching of N from urea (U) and isobutylidene diurea (IBDU); b) influence of nitrapyrin (NI), a nitrification inhibitor, on N leaching losses from U; and c) to evaluate influences of these materials on growth, quality, and N uptake by Rhododendron obtusum Lindl. cv. Hinodegiri. In root medium composed of 60 pine bark : 30 sand : 10 soil (by volume), 48.8% of applied N from U was leached after 87 days, whereas leachate losses of N from IBDU and U + NI were 42.3% and 37.2%, respectively. All plants attained marketable quality by the end of the study. Azaleas fertilized with IBDU were of significantly higher quality on days 70 and 77 than those treated with U + NI and higher quality on days 77, 84, and 87 than those treated with U. No differences were found in shoot dry weight or N content in shoot tissues.
Abstract
Physical properties of various hardwood bark-soil mixes for containers were compared to a soil-peat-perlite mix. Bark-soil mixes containing a wide range of bark particle sizes were found to possess superior physical properties initially and remained satisfactory after a 13-month incubation period. However, bark-soil mixes were much less stable and deteriorated to a significantly greater extent. For golf greens, physical properties of hardwood bark or peat and soil and sand mixes were studied following compaction at 40 cm moisture tension. Initially, the bark mixes were superior and this was postulated to be due to a more uniform distribution of bark within the mixes. Based on the deterioration that occurred in bark-soil mixes for containers, it is concluded that use of hardwood bark in golf green mixes does not appear feasible.