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- Author or Editor: David J. Beattie x
An interactive spreadsheet program was developed to demonstrate how a landscape bid is estimated. Information from a profit and loss statement, entered periodically, is retained for succeeding bids. Machine and labor costs are determined separately. For an individual bid, inputs include cost of materials, overhead, labor and machine times, contingency, and profit. Labor costs are automatically modified to reflect crew efficiency, and materials costs reflect storage, freight, and other charges. Overhead is based on the relationship between annual direct and indirect costs. The calculations section displays intermediate steps of the final bid estimate. Summaries from calculations include a final bid estimate. A printing option allows the user to selectively print any of the sections, a customer's copy, or the entire bid. The program uses an Apple Macintosh computer, was written for Microsoft Excel software, and uses macro programs. Its concept can be adapted to any electronic spreadsheet and can be protected to allow entry of only certain input data. The program can be used for small landscape businesses, classroom instruction, and/or extension instruction in which higher-order thinking skills are emphasized.
A study of applying growth retardants under overhead and subsurface irrigation systems was conducted on bermudagrass (Cynodon dactylon L. cv. Tifway) grown from rhizomes in 15-cm pots containing sand medium. Paclobutrazol (50%) at 2 mg/pot was used as foliar spray or charged-hydrophilic polymers (Super Sorb C) and either incorporated or put below medium surface. Mefluidide (28%) at 0.01% ml/pot was used only as foliar spray. Before spray treatments, grasses were cut at 2 cm from medium surface, and the second cut was made at the 6th week from treatment. All growth retardant treatments reduced grass height compared to non-treated plants. The lowest grass height was produced by paclobutrazol as foliar spray under overhead irrigation in the 6th and 9th week. By the 9th week, all hormonal treatments under the two irrigation systems had no effect on grass quality, color, and establishment rate. Both paclobutrazol foliar spray and below medium surface charged-polymer treatments under subsurface irrigation had the lowest water loss and dry weight by the 6th and 9th week. The paclobutrazol charged-polymer treatment under subsurface irrigation had also the the lowest root dry weight among all treatments. Although mefluidide foliar spray was less effective on grass height than paclobutrazol, they had similar effect on water loss and shoot dry weight.
Four rates of two slow-release fertilizers were tested for optimum growth of five hosta cultivars: Hosta sieboldiana `Elegans', Hosta plantaginea `Aphrodite', Hosta `Jade Scepter', Hosta `Hadspen Blue', and Hosta `Francee'. Tissue-cultured hostas from 2.5-cm plugs were planted in 6-inch (15-cm) pots filled with a commercial soilless medium, and the slow-release fertilizer was dibbled into the medium at 0, 3, 6, or 12 g/pot. The plants were maintained for 4 months. Root and shoot fresh and dry weights were recorded at the end of the experiment. In addition, foliar nutrient analysis was conducted on `Aphrodite', `Francee', and `Jade Sceptor'. Overall, hostas grew best when the medium was amended with 3 g of either Osmocote 14N-6P-11.5K or Sierrablen 17N-6P-12K slow-release fertilizer.
A characteristic problem with peat moss is its difficulty in initial wetting and rewetting, especially in a subirrigation system. Wetting agents improve wetting characteristics primarily by reducing the surface tension of water. This results in a rapid, uniform movement of water by capillary rise through the growing medium.
Two methods were used to compare the effectiveness of different wetting agents: gravimetric and electrical. Ten cm pots containing peat moss were placed in a subirrigation system. The gravimetric method used a laboratory scale where pots were periodically weighed to determine the amount of water absorbed. The electrical method utilized thin beam load cells, which have strain gages bound to the surface, to determine the weight of a suspended object. Load cells were coupled with a Campbell Scientific datalogger to collect data every minute without removing the pot from subirrigation. Because the effect of buoyancy altered the true weights, equations were generated to adjust the water uptake values. Corrected weights were used to create absorption curves for comparison of the slopes to determine which wetting agent has the fastest rate of absorption. The load cell reliably and accurately described the wetting characteristics of Peat moss and we found good agreement with the gravimetric method.
Commercially cooled bulbs of five genetically dwarf Asiatic hybrid lilies were stored frozen at -2 C. Every 4 weeks for a total of 40 weeks, they were potted and forced in controlled environment chambers at 10, 15, 20, or 25 C. For each temperature, days from the time of potting to shoot emergence, visible bud appearance, and anthesis generally decreased as storage time increased. The number of flowers per plant and plant height were not significantly affected by storage time. Compared with those at 15, 20, or 25 C, plants at 10 C required significantly more time from potting to shoot emergence, visible bud, and anthesis. However, the temperature effects on forcing time were not linear. There was a 30-50 day decrease from potting to anthesis when temperature was increased from 10 to 15 C, but there was only a decrease of about 10 days when temperature was increased from 15 to 20 C. In contrast, there was no significant difference in forcing time between plants at 20 and 25 C. This indicates there is no need to force these lilies above 20 C. Plants at 25 C had more aborted flower buds than those at 10, 15, or 20 C. Plants at 10 C were taller then those at 15, 20, or 25 C.
Two distinct patterns of whole-plant transpiration (WPT) were observed in `Moonlight' rose (Rosa hybrida L.) using an automated system that integrated a greenhouse climate computer, a heat-balance sap-flow gauge, an electronic lysimeter, and an infrared leaf temperature sensor. One pattern consisted of a steady rate of transpiration in a stable greenhouse environment. The second pattern consisted of large oscillations in transpiration unrelated to any monitored microclimate rhythms. These oscillations had a sine-wave pattern with periods of 50 to 90 minutes and ranged from 2 to 69 g·h-1 in natural light and 3 to 40 g·h-1 under high-pressure sodium lamps at night. Leaf-air temperature difference (T1 - Ta) also oscillated and was inversely related to transpiration rate. Oscillatory transpiration has not been reported in roses. Plant scientists need to recognize the complex and dynamic nature of plant responses such as the oscillatory pattern of WPT monitored in Rosa hybrida when selecting monitoring and control strategies.
Plants suitable for extensive green roofs must tolerate extreme rooftop conditions, and the substrates in which they grow must fulfill horticultural and structural requirements. Deeper substrates may retain more water for plants during dry periods, but will also weigh more, especially when near saturation. A study in central Pennsylvania was conducted to evaluate the influence of substrate type and depth on establishment of five green roof plants. Two stonecrops [white stonecrop (Sedum album) and tasteless stonecrop (Sedum sexangulare)], one ice plant (Delosperma nubigenum), and two herbaceous perennials [maiden pink (Dianthus deltoides) and saxifrage pink (Petrorhagia saxifraga)] were planted in three depths (30, 60, and 120 mm) of two commercially available green roof substrates (expanded shale and expanded clay). Study flats inside a plasticulture tunnel received three drought treatments (no drought, 2 weeks early drought, and 2 weeks late drought). The two stonecrops performed well under most conditions, although tasteless stonecrop was stunted by early drought. Ice plant only grew well when provided with water. When subjected to any drought, the herbaceous perennials had the fewest survivors in the expanded shale. Saxifrage pink flowered profusely wherever it survived. The study plants were most affected by substrate depth, except for maiden pink, which responded solely to drought. When subjected to early drought conditions, the herbaceous perennials did not survive in 30 mm of either substrate, or in 60 mm of expanded shale. Although the stonecrops performed well in 60 mm of substrate when subjected to drought, their performance was superior in the expanded clay compared with shale.
Impatiens wallerana `Accent Red' were grown in a peat : perlite : vermiculite (PPV) or bark : peat : perlite (BPP) medium amended with SuperSorb-C (SS) or Soil Moist (SM) hydrophilic polymer and/or AquaGro-G (AG) wetting agent. In PPV or BPP, neither SS nor SM significantly increased shoot dry weight. In PPV, quality ratings were higher for plants grown in nonamended or SS- or SM- amended medium than for plants in AG-amended medium. In BPP, quality ratings were highest for plants grown in nonamended, AG-, or SM + AG-treated medium. Number of days from final irrigation to permanent wilting point (PWP) was greater in AG, SS + AG, or SM + AG treatments in PPV than in control, SS, or SM treatments, due to smaller plants in AG-amended media. In both media, root dry weight was not significantly greater with the use of either hydrophilic polymer or wetting agent. However, in PPV, AG suppressed root growth compared to the control.
An undergraduate major in Landscape Contracting was established at The Pennsylvania State University in 1989. Since its inception, women have been consistently underrepresented (13%). From department records and a survey instrument, we examined the academic performance, postgraduate job perceptions, and gender related issues of 319 male and female graduates. Our results showed that women students academically outperformed their male peers in courses specific to the Landscape Contracting curriculum. Survey results indicated that female graduates were represented in all job categories and performed similar types of work as their male peers. In addition, women did not differ significantly from their male peers in regard to job performance and satisfaction levels.