Ilex × `Nellie R. Stevens' holly, Rhododendron sp. `Hinodegeri' azalea and Pyracantha coccinea, scarlet firethorn rooted cuttings were potted in • 3.81 containers. Irrigation was applied by Dram rings daily, or every 2,4,or 6 days. Approximately 1000 ml of water were applied at each irrigation. Three container media, including pine bark, and pine bark amended with either Terra-Sorb AG synthetic moisture extender incorporated at 1.2 kg/m3 or Aqua-Gro G wetting agent incorporated at 0.9 kg/m3 plus monthly drenches of 700 ml of 2500 ppm Aqua-Gro L were compared for physical and chemical properties and plant growth responses. Decreasing irrigation decreased pH, increased nutrient leachate levels, and increased foliar tissue levels of N,P,K,Ca,and Fe in holly and azalea. Pyracantha top and root dry weight was reduced at 4 and 6 day irrigation intervals, holly top growth was reduced by 6 day and azalea had greatest shoot growth at 2 day irrigation and was reduced by other irrigation frequencies. Top growth of all 3 species and root growth of pyracantha was reduced in the pine bark treatment.
Gary R. Bachman and Ted Whitwell
Demand for commercially grown Uniola paniculata L. (southern seaoats) is increasing for use in restoring beaches damaged by tropical storms. Fresh seeds harvested from the Jekyll Island, Ga area (with permission of the Jekyll Island Authority), were planted in 50 peat: 50 perlite and treated with 100 or 500 ppm GA4 for 24 h. Germination was higher for 100 compared to 500 ppm GA4. Liners grown from seed and planted with the crowns even with the surface of the pine bark-sand media, compared to deep planting to simulate burial conditions of beach planting, had the highest shoot and root weights after 100 days. Uniola paniculata liners with the crowns buried had reduced weights due to higher moisture conditions in the bottom of the containers. Uniola paniculata grown without supplemental fertilization had shoot weights similar to those of plants receiving 1.5 lb N/yd3 (0.89 kg N/m3) from both quick or slow release fertilizers. Increasing N to 3 lb/yd3 (1.78 kg N/m3) and/or supplying micronutrients only, reduced shoot weight. Nursery production of Uniola paniculata in pine bark-sand is one way to increase the supply of this important dune plant.
Timothy L. Grey, Mark Czarnota, Thomas Potter, and B. Todd Bunnell
applied as a granular formulation will provide residual activity to plant roots over an extended period of time. However, with high percolation rates for pine bark media ( Simmons and Derr, 2007 ) leading to rapid water loss and low water retention
Elio Jovicich, Daniel J. Cantliffe, Peter J. Stoffella, and Dorota Z. Haman
frequency and with perlite and pine bark (media with lower water-holding capacity than peat mix; ( Figs. 6 , 7 , and 9 ). Blossom-end rot developed in small green fruit (diameter, 3–4 cm) on upper plant nodes and was removed from plants during the last two
P.R. Knight, J.R. Harris, and J.K. Fanelli
Year-old seedlings of Acer rubrum L. and Crataegus phaenopyrum (L.f.) Medic. were grown for 1 year in a Groseclose silty clay loam. Seventy-two plant per species were harvested on 15 Dec. 1995 and weighed. Plants were stored at 4°C for 0, 1, 3, 5, 10, or 15 weeks. At the end of each storage period, 12 plants were weighed to determine water loss. Six plants were then sacrificed to determine percent embolism, and six plants were planted in a pine bark media and grown in a glasshouse for 15 weeks to determine the influence of storage on post-transplant growth and embolism recovery. Length of storage had no influence on embolism of Crataegus. Embolism of Acer increased linearly with increasing length of storage. Embolism was greater for Crataegus compared to Acer at each harvest. Water loss for both species increased linearly as time of storage increased.
P.R. Knight, J.R. Harris, and J.K. Fanelli
Two-year-old, bareroot, Corylus colurna seedlings were grown in 7.5-L containers from 15 Mar. to 23 June 1995. Plants were grown in a glasshouse using pine bark media. Temperatures were maintained at 30/20°C. Plants received no fertilization or Osmocote 18–6–12 top-dressed at 14 or 28 g/container. Additionally, plants were pruned to remove 0%, 25%, or 50% of the root system based on root length. Height, diameter, branch number, leaf area, and root and shoot dry weight increased linearly as rate of fertilization increased. Percent embolism was not influenced by rate of fertilization. Plant height, branch number, leaf area, and root and shoot dry weight were not influenced by rate of root pruning. Plant diameter increased linearly as rate of root pruning decreased. Percent embolism increased linearly as rate of root pruning increased.
J.C. Rodriguez, D.J. Cantliffe, N.L. Shaw, and Z. Karchi
In the spring of 2001 and 2002, different combinations of media (coarse perlite, medium perlite, and pine bark) and containers (polyethylene bags and plastic pots) were used for hydroponic production of `Galia' muskmelons (Cucumis melo L.) to determine their effect on fruit yield and quality, and their influence on costs of production. Marketable yields obtained for `Gal-152' in the spring 2001 and 2002 were 25.5 kg·m–2 and 39.0 kg·m–2 respectively. When data were combined for 2001 and 2002, fruit yield and fruit quality were unaffected by any combination of media and container. Average soluble solids content was generally greater than 10° Brix. It was determined that the use of pine bark media and plastic pots instead of perlite and bags would save $18,200 per year (two crops)—a feasible option for reducing costs of producing `Galia' muskmelons in greenhouses using soilless culture without loss of yield and fruit quality.
Russell S. Harris*, Edward W. Bush*, and Ronald J. Ward
Bifenthrin and fipronil are important pesticides used in the nursery industry for the control of imported fire ants. Our research measured the influence of irrigation frequency and time on the degradation of bifenthrin and fipronil in pine bark nursery medium. Pine bark media leachates were collected over a 180-d period. Levels of bifenthrin, fipronil, and metabolites of fipronil (MB 46513, MB 45950, MB 46136) were measured using gas chromatography and mass spectrophotometery. Bifenthrin leachate concentrations decreased from 60 ppb on day 1 to ≈1 ppb after 120 d. Fipronil leachate concentrations decreased from 40 ppb on day one to a low of 15 ppb after 120 d. In contrast, metabolites MB 45950 and MB 46136 gradually increased over the 180-d period. Metabolite MB 46513 was not detected during the experiment. Pine bark medium leachate concentrations of bifenthrin and fipronil were greater than previously reported levels in pure water. We theorize that organic compounds present in pine bark may have increased the solubility of these chemicals.
Jeff S. Kuehny, Blanca Morales, and Patricia Branch
Irrigation water quality is an important factor in ornamental plant production; however, there is little information in this area. Saline (NaCl) and alkaline (NaHCO3) water have been shown to cause general chlorosis, tip burn, and defoliation of plants. The growing medium used in crop production may be an important factor when irrigating with saline and alkaline water. Our objectives were to determine the effects of increasing concentrations of NaCl: CaCl2 and NaHCO3 in irrigation water on growth and development of spring and fall bedding plants grown in peat, peat/pine bark, and pine bark media. Plant dry weight, height, and width were significantly lower at 300 and 400 ppm NaCl: CaCl2 and NaHCO3 levels. Early visible symptoms were necrosis of leaf tips, some leaf discoloration and finally plant death in the NaCl: CaCl2 experiment. The leaves of plants in the NaHCO3 experiment became water soaked and chlorotic, and some leaf abscission occurred. The best plant growth in the NaHCO3 experiment occurred in peat and the best plant growth in the NaCl: CaCl2 experiment occurred in pine bark. Decreased uptake of K+, Ca++, and Mg++ occurred when high levels of sodium were present.
A. Abu El-Kashab, A.F. El-Sammak, A.A. Elaidy, M.l. Salama, and M. Rieger
We studied the effect of a 200-mg·liter–1 foliar application of paclobutrazol (PBZ) on growth and physiological responses of Prunus persica `Nemaguard' (salt-sensitive) and Olea europea `Manzanillo' (salt-tolerant) to salt stress. One-year-old trees were grown in 3 sand: 3 field soil: 4 pine bark media in 20-cm pots in a greenhouse and were irrigated with nutrient solutions adjusted with 0, 9, 18, or 36 mmol NaCl for peach and 0, 36, 72, 108 mmol NaCI for olive. Dry weight, photosynthesis, and leaf conductance decreased with increasing salinity for both species. However, leaf expansion rate was unaffected by NaCl. PBZ reduced dry weight for peach only, but PBZ increased photosynthesis and reduced leaf expansion rate for both species. Relative water content was decreased by salt but increased by PBZ. PBZ reduced the foliar Na and Cl content in peach but not olive. Olive had less Na in leaves than peach at 36 mmol NaCI, accumulated less C in leaves in all salt treatments, and had higher foliar Na without symptom expression. PBZ may reduce salt stress in sensitive species like peach by reducing foliar Na and Cl accumulation but has less influence on the salinity response of the more salt-tolerant olive.