Media fertility is a critical factor in the successful production of container grown plants. Fertility treatments including fertigation and slow-release fertilizers (topdressed and incorporated) were compared. Fertility treatments were studied over a two-year period on a variety of deciduous and evergreen plant materials. Plant growth was quantified based on height, volume, branching, and quality. Soil fertility levels based on leachates were followed during the study. Nutrient release for incorporated fertilizers tested was variable although less so than when the same fertilizers were topdressed. Fertility treatment effects were species-dependent. Several incorporated, slow-release fertilizers, especially those high in nitrogen (Sierra 17-6-10, Sierra High N 24-4-6, Woodace Briquettes 23-2-0, Woodace 21-4-10), show promise for use in two-year container production systems.
Bert T. Swanson, James B. Calkins, Daniel G. Krueger, and Theresa L. Stockdale
Paula Stonerod and Bernadine Strik
All life stages of grape phylloxera [Daktulosphaira vitifoliae (Fitch) (Homoptera: Phylloxeridae)] were eradicated with a hot-water treatment (dip) of 5 minutes at 43 °C (110 °F) to warm roots, followed by a 5-minute dip at 52 °C (125 °F). Neither grafted nor nongrafted dormant grape plants were damaged by the hot-water treatment.
James B. Calkins, Bert T. Swanson, Daniel G. Krueger, and Karin R. Lundquist
A study was designed to ascertain the efficacy, water use efficiency, runoff potential, and cost effectiveness of four container irrigation systems: overhead sprinkler irrigation, in-line trickle irrigation, capillary mat with leaky hose, and sub-irrigation. Results were species dependent. Plant growth was best under capillary mat and trickle irrigation treatments, however, differences in plant growth and performance between irrigation treatments were minimal. Differences in water use, however, were quite significant. Overhead irrigation was inefficient regarding water use while capillary mat and trickle systems used much lower volumes of water. Conservative irrigation systems which maintain acceptable plant growth using less water and reduce runoff from container production areas can clearly benefit growers by reducing production and environmental costs.
Laurie Robinson-Hipple, Faye Propsam, James B. Calkins, and Bert T. Swanson
Media fertility, plant nutrient availability, and subsequent plant nutrition are critical factors in the production of quality landscape plant materials. The method of mixing slow-release fertilizers into the media prior to planting is becoming more widespread. This study evaluates different controlled-release fertilizers, their rates of release, and three methods of irrigation regarding water-use efficiency and effects on plant growth performance. The combined effects of fertility and irrigation practices on nutrient loss to the environment are also being monitored. Although the ranking of fertility treatments, based on plant quality, varied among species, Woodace 21–4–10, Sierra 17–6–10, Sierra High N (24–4–6, Scotts 20–7–10, (270–26.67 lb/yd3), Woodace 20–5–10, Polyon 25–4–12, Nutricote 18–6–8 (270–30 lb/yd3), and Nutricote 18–6–8 (270–20 lb/yd3) produced high-quality plants for most of the species evaluated. The control and Nutri-Pak 18–6–12 treatments resulted in relatively poor-quality plants across the board. The effects of irrigation techniques on leachate analysis are being completed.
D.E. Deyton, C.E. Sams, J.C. Cummins, R.E. Myers, and M.A. Halcomb
Hand-defoliation of field-grown `Golden Delicious' apple and `Bradford' pear nursery trees before autumn digging is a major production cost. One-year-old field-grown trees were sprayed to runoff on 18 Oct. 1994 with; 1) 1% FeEDTA, 2) 1% CuEDTA, 3) 1% ZnEDTA, 4) 100 ppm Harvade, 5) 50 ppm Dropp, 6) 500 ppm Folex, or 7) 2.5% EDTA or 8) leaves were removed by hand or 9) leaves left on trees (control). Treatments were arranged in a randomized complete-block design, with three trees/plot and four replications. Leaves on each tree were counted before treatment and 7, 14, 21, 28, and 35 days after treatment (DAT). One tree per plot was dug, stored until February and grown the following summer. Nontreated apple and pear trees had 13% and 38% defoliation, respectively, 35 DAT. CuEDTA treated apple trees had 62% and 93% defoliation 7 and 14 DAT, respectively. Pear trees treated with Cu had 18% and 100% defoliation 7 and 14 DAT, respectively. Treatment with FeEDTA resulted in 96% defoliation of pear within 7 DAT but only 57% defoliation of apple 35 DAT. ZnEDTA, Harvade, Folex, or Dropp did not significantly promote defoliation. Copper-treated apple trees had less budbreak than nontreated trees but similar budbreak as hand-defoliated trees. None of the treatments influenced budbreak of pear. None of the treatments affected the cumulative dry weight of trees at the end of the next growing season.
Norman Pellett and David Heleba
Chopped newspaper at 3.5 and 7.0 kg.m-2 enclosed in white polyethylene sheeting or enclosed in nylon netting at 3.5 kg.m-2 was compared with two layers of 0.64-cm microfoam as winter covering of four taxa of container-grown nursery plants. White polyethylene-enclosed newspaper moderated winter temperatures more than net-enclosed newspaper or two layers of microfoam under white polyethylene. All coverings provided protection against winter injury, as evidenced by container temperature, but net-enclosed newspaper at 3.5 kg.m-2 resulted in a minimal percentage of Daphne burkwoodii `Carol Mackie' plants with three or more shoots longer than 2 cm in the spring. Gaillardia grandiflora, covered by newspaper during winter, had less spring growth than plants covered by microfoam, but all coverings provided protection for Juniperus horizontalis `Prince of Wales' and Physostegia virginiana.
Houchang Khatamian and Alan Stevens
During the Spring of 1992 a survey of over 2000 respondants was conducted as personal interviews at Flower/Garden Shows in Atlanta, Kansas City, Los Angeles, Philadelphia and Portland.
When asked how the plants you buy are packaged? Nine percent of the Los Angeles (LA) sample said they purchased trees as balled and burlapped (B & B) while over 40% of the consumers from the other regions purchased trees as B & B. Over 40% of all respondents purchased shrubs in “container”.
When asked how would you like to have landscape plants packaged? While only 31% of the LA sample chose to purchase trees as B & B, over 70% of the consumers from other regions preferred to buy in a B & B form. More than 50% of all respondents also preferred to purchase trees in “Container”. By a two to one margin consumers chose to purchase ornamental shrubs in “Container”. Regardless of the region of the country, “bare-root” and “plastic package” were least desired. About 1/2 of the respondents were couples, 80% owned their own homes, over 50% had an income of $25,000 to $75,000 and more than 75% did own plantings.
Fenton E. Larsen and Stewart S. Higgins
Abscisic acid (ABA) was tested as a defoliant for nursery trees of `Bartlett' pear (Pyrus communis L.) and the apple (Malus×domestica Borkh.) cultivars Imperial Gala, Gibson Golden Delicious, Scarlet Spur Delicious, Law Red Rome, Granny Smith, Braeburn, and Red Fuji. ABA was sprayed once or twice, with 1 intervening week, at 500, 1000, or 2000 ppm. Percentage defoliation was assessed at 1-week intervals for 4 weeks. For all cultivars, two applications of 2000 ppm ABA ranked among the most effective treatments for rapid defoliation; this treatment led to at least 95% defoliation for all cultivars. For many cultivars, however, other treatments caused similar defoliation percentages by digging time. All tested cultivars were effectively defoliated (>80%) by two 1000-ppm applications ABA or one 2000-ppm application. One or two 500-ppm applications effectively defoliated `Bartlett', `Gibson Golden Delicious', and `Law Red Rome'. Nursery managers, therefore, need to consider a range of ABA concentrations and alternative application protocols to obtain optimum benefit from ABA. Although ABA shows promise as a defoliant, it lacks government approval for commercial use.
Andrew Ristvey and John Lea-Cox
Nutrient release patterns from several different controlled-release fertilizers (CRF) were studied during the overwintering period of a long-term nutrient uptake, leaching, and loss study of Azalea (Rhododendron) cv. `Karen' and Holly (Ilex cornuta) cv. `China Girl', under sprinkler and drip irrigation. In Maryland, diurnal winter temperatures can vary from ≈10 °C to above 15 °C. Most growers, therefore, cover frames with opaque plastic for cold protection from November through April. This is also the period when many growers apply CRFs on those plant species that take more than 1 year to produce. Few data are presently available on the release patterns of CRFs under variable temperature conditions in late winter/early spring. We hypothesized that substrate temperatures warmer than 15–16 °C will result in CRFs releasing nutrients at a time when root systems are inactive, with a major loss of nutrients with the first few irrigations in Spring. This 105-day study quantified nitrogen (N) and phosphorus release patterns from four brands of CRF (Osmocote, Nutricote, Scotts High N, and Polyon) with 270- and 360-day release rates, under these conditions. Each CRF was top dressed onto blocks of 18-month-old holly or azalea (n = 112) in 11.5-L (3-gal) containers, at a (low) rate of 6.1 g N per container. Ten randomly selected pots from each treatment were sampled every 15 days using two sequential leachings of distilled water, for a target leaching fraction of 25%. Leachates were recovered and analyzed for nitrate and orthophosphate concentrations. Ambient canopy temperatures were recorded continuously with remote temperature (HoBo) sensors from which degree days above 15–16 °C were calculated and correlated with CRF release patterns.
C. Chong, P. Purvis, G. Lumis, B. E. Holbein, R. P. Voroney, H. Zhou, and H.-W. Liu
Wastewaters from farm and composting operations are often rich in certain nutrients that can be reutilized in crop production. Liners of silverleaf dogwood (CornusalbaL. `Argenteo-marginata'), common ninebark [Physocarpusopulifolius(L.) Maxim.], and `Anthony Waterer' spirea (Spiraea×bumaldaBurvenich) were grown in 6-L containers filled with a medium consisting of 73% bark, 22% peat, and 5% pea gravel, by volume. Plants were fertigated daily via a computer-controlled multi-fertilizer injector with three recirculated fertilizer treatments: 1) a stock solution with macro- and micronutrients, electrical conductivity (EC) 2.2 dS·m-1; 2) wastewater from a mushroom farm; and 3) process wastewater from anaerobic digestion of municipal solid waste. The wastewaters used in both treatments 2 and 3 were diluted with tap water, and the computer was programmed to amend, dispense, and recirculate nutrients, based on the same target EC as in treatment 1. For comparison, there was a traditional controlled-release fertilizer treatment [Nutryon 17–5–12 (17N–2P–10K) plus micronutrients incorporated into the medium at a rate of 6.5 kg·m-1, nutrients not recirculated]. All three species responded similarly to the three recirculated fertilizer treatments. Growth in the recirculated treatments was similar and significantly higher than that obtained with controlled-release fertilizer. A similar trend in EC was observed in the media near harvest. Throughout the study, there was no sign of nutrient toxicity or deficiency with any of the species or treatment.