bluuebunny/crossref_metadata_2025 huggingface dataset:
Paclobutrazol Concentration and Substrate Moisture Status Impact Efficacy of Liner Dips for Size Control of Three Bedding Plants
Authors: Schnelle Rebecca A. , Barrett James E.
Published: December 2018

The influence of several environmental and cultural factors on the efficacy of paclobutrazol liner dips were evaluated for three species of bedding plants: ‘Fancy’ scaevola (Scaevola aemula), ‘Suncatcher Plum’ petunia (Petunia ×hybrida), and ‘Double Fiesta Rose’ impatiens (Impatiens walleriana). The impact of paclobutrazol concentration in the dip solution, location of treatment, root substrate moisture status, and time in the dip solution were investigated. Before the liner dip application, the rooting substrate was brought to a specific percentage of container water capacity (20%–100%). Liners were then dipped in a paclobutrazol solution of the prescribed concentration (1–16 mg·L−1) for a prescribed time interval (10–300 s) in a specific location (open-wall greenhouse, polyethylene-glazed greenhouse under 80% shade fabric, three-wall potting shed, or building interior). Plant size data were collected when the untreated control plants reached a marketable stage. Paclobutrazol concentration and root substrate moisture status had a significant effect on size control, but location and dip duration did not. Size suppression varied by species. Following a liner dip at 2 mg·L−1, scaevola, impatiens, and petunia plants were 44%, 26%, and 11% smaller than the untreated controls, respectively. Petunia plants dipped in a 8 mg·L−1 paclobutrazol solution with substrate moisture status of 100%, 90%, 80%, 70%, 50%, or 20% of container capacity were 11%, 8%, 25%, 30%, 41%, or 42% smaller than the untreated control, respectively (30 s dip duration, open-wall greenhouse). Petunia plants dipped in a solution of 8 mg·L−1 paclobutrazol for 10, 30, 120, or 300 s were all between 18% and 23% smaller than the control (50% of container capacity, open-wall greenhouse). Petunia plants dipped in an 8 mg·L−1 paclobutrazol solution in all four locations were all 20% to 21% smaller than the untreated control.
Preliminary Findings on the Correlation between Water-soluble Carbohydrate Content in Stolons and First Year Green-up of Seeded Bermudagrass Cultivars
Authors: Macolino Stefano , Serena Matteo , Leinauer Bernd , Ziliotto Umberto
Published: December 2018

Warm-season grasses are not widely accepted in Mediterranean countries because they lose color during the winter months. A study was conducted at the University of Padova (Padova, Italy) to determine whether fall and spring water-soluble carbohydrate (WSC) content in stolons of seeded bermudagrass cultivars (Cynodon dactylon) influenced spring green-up in the first year of establishment. Nine bermudagrass cultivars (La Paloma, Mohawk, NuMex Sahara, Princess 77, Riviera, SR 9554, Barbados, Contessa, and Yukon) were seeded in July 2005, and dry weight and WSC content in stolons were measured in Fall 2005 and again in Spring 2006. The percentage of green cover and days needed to achieve 80% green cover (D80) were regressed against November and March values of stolon dry weight and WSC content to determine if they were good predictors of D80. ‘Yukon’ showed earliest spring green-up by end of April, and ‘Princess 77’ and ‘Riviera’ were slowest, needing 43 to 46 days more than ‘Yukon’ to reach D80. There was a significant inverse relationship between November (r2 = 0.57) and March (r2 = 0.77) WSC content in stolons and D80 for all nine bermudagrass cultivars. These results suggest that bermudagrass cultivars with high WSC in stolons recover more rapidly from dormancy during establishment than those with low WSC content.
An Economic Analysis of Two Grafted Tomato Transplant Production Systems in the United States
Authors: Rivard Cary L. , Sydorovych Olha , O'Connell Suzanne , Peet Mary M. , Louws Frank J.
Published: December 2018

The grafting of herbaceous vegetables is an emerging development in the United States. This report provides an estimate of the variable costs of grafting within U.S. tomato (Solanum lycopersicum) transplant production systems. Grafted and nongrafted plants were propagated at two commercial farming operations in Ivanhoe, NC (NC) and Strasburg, PA (PA) and the farm in NC produced certified organic transplants. Detailed economic production sequences were generated for each site, and grafted and nongrafted transplant production costs were $0.59 and $0.13 in NC, and $1.25 and $0.51 in PA, respectively. Direct costs associated with grafting (e.g., grafting labor, clips, chamber, etc.) accounted for 37% to 38% of the added cost of grafting, and grafting labor was 11.1% to 14.4% of the cost of grafted transplant production. Seed costs represented 52% and 33% of the added cost of grafting at the two sites, and indirect costs (e.g., soil, trays, and heating) accounted for 10% and 30% of the added cost of grafting. Our findings suggest that under current seed prices and with similar production practices, the feasibility of grafting in the United States is not disproportionately affected by domestic labor costs. Additionally, the economic models presented in this report identify the cost of production at various transplant stages, and provide a valuable tool for growers interested in grafted tomato transplant production and utilization.
Estimated Nursery Liner Production Costs for Woody Ornamental Plant Stock
Authors: Jeffers Andrew H. , Klingeman William E. , Hall Charles R. , Palma Marco A. , Buckley David S. , Kopsell Dean A.
Published: December 2018

Ornamental plant growers must be able to accurately assess production costs associated with woody liner stock to gain profit potential in a highly competitive industry. Fixed and variable cost inputs may not be intuitive or readily apparent to growers and may even differ between common types of production in the trade. To help liner producers identify profit-based price points for their woody ornamental liner stock, we modeled costs associated with producing familiar species and cultivars of a representative deciduous shade tree, a broadleaf evergreen, and a needle leaf evergreen liner. Production costs are projected down to individual plant units for each of the three most common liner production systems, including a field ground bed system, a polyhouse-covered (plant protection structure sheathed with one layer of 6-mil polyethylene film) ground bed system, and a polyhouse-covered container system. Production costs for individual plants varied due to the actual growing space available within each system. The field ground bed system offered greatest flexibility in crop planting density, with cost potentially distributed among the largest number of salable units. In addition to modeled costs, advantages and disadvantages of each liner cropping system are discussed.
Making Cents of Green Industry Economics
Authors: Hall Charles R.
Published: December 2018

The green industry complex includes input suppliers (manufacturers and distributors); production firms such as nursery, greenhouse, and sod growers; wholesale distribution firms including importers, brokers, re-wholesalers, and transporters; horticultural service firms providing landscape and urban forestry services such as design, installation, and maintenance; and retail operations including independent garden centers, florists, home improvement centers, and lawn/garden departments at home centers, mass merchandisers, or other chain stores. Many current economic trends and driving forces point to the fact that the green industry is in a period of hypercompetitive rivalry due to the maturing consumer demand. A number of firms have already been forced out of the green industry during the 2008–09 recessionary shakeout period and others continue to exit. To address this issue, a workshop was organized by G. Zinati for the 2009 ASHS annual meeting entitled “Managing and Thriving in Tough Times, When Every Dime Counts!”, which was sponsored by the Nursery Crops (NUR) and Marketing and Economics (MKEC) Working Groups and the American Nursery and Landscape Association (ANLA). This lead-off workshop presentation: 1) provided an overview of current economic conditions and trends and their influence on the green industry, 2) discussed supply-side methods and technologies for controlling costs during an economic downturn, and 3) addressed proactive demand-side differentiation and pricing strategies that will not only help ensure survival, but will also better position green industry firms for competing profitably in this period of hypercompetition.
Strategies Producers in the Northeastern United States Are Using to Reduce Costs and Increase Profits in Tough Economic Times
Authors: Brumfield Robin G.
Published: December 2018

The environmental horticulture industry (sometimes referred to as the “green industry”) is usually divided into nursery and floriculture crops. The green industry in the northeastern United States is an important component of agricultural production, with over $2 billion in farm cash receipts, equating to 22.4% of all farm cash receipts in the northeastern United States. It is the number one agricultural commodity in five northeastern U.S. states. Competition in the green industry has become fierce. Many factors have put downward pressure on price. These include the recent volatility of fossil fuels and general energy prices, domestic competition, off-shore production, a weakened and stressed economy, and the growth of the mass market. Nationally, the number of producers continues to decline as a direct result of the newly defined economic risks. The industry's profit margins are typically low, leaving little room for growers to absorb significant increases in costs or decreases in revenues. Unlike farmers who produce field crops, nursery and greenhouse firms bear the entire price, market, and production risks because these crops have had no government support programs. This article will discuss what strategies producers in the northeastern United States are using to reduce costs and increase profits in tough economic times. It will analyze how producers have they honed their marketing and management skills to continue to survive and respond to current trends.
Influence of Shoot Pruning on Bacterial Spot Infestation on Tomato Cultivars
Authors: Vallad Gary E. , Santos Bielinski M.
Published: December 2018

Field studies were conducted in Florida to determine the effect of early shoot pruning on the severity of bacterial spot, and on the growth and yield of different tomato (Solanum lycopersicum) cultivars. Two tomato cultivars, two inoculation regimes of bacterial spot pathogen (Xanthomonas perforans), and three shoot pruning programs were arranged in a split-split plot design. The tomato cultivars were Tygress and Security-28; shoot pruning included none, light, and heavy; and X. perforans treatments consisted of non-inoculated plots and plots inoculated with a suspension of the pathogen. Tomato plant height was not influenced by any of the three factors or their interactions, whereas the disease severity was higher in inoculated plots versus non-inoculated plants. Early extra-large fruit weight was affected by tomato cultivars and the inoculation with the bacterial spot pathogen, but not by pruning programs or the interaction among factors. Tomato plants inoculated with X. perforans reduced their extra-large fruit weight by 31% in comparison with non-inoculated plants. There were no differences on early marketable fruit weight among the combinations of each cultivar and the three pruning programs. All three factors individually influenced the seasonal marketable fruit weight of tomato, with no difference between light-pruned plants and the non-pruned control for seasonal marketable fruit weight, regardless of tomato cultivars. However, heavy pruning did reduce seasonal yields by 10% in comparison with the non-pruned control. These results indicated that light shoot pruning, which is the standard grower practice in Florida, did not improve bacterial spot control or tomato yields of total and extra-large marketable fruit, which might save up to $50/acre in reduced labor costs for Florida tomato growers.
Fertilization Improves Cold Tolerance in Coconut Palm
Authors: Broschat Timothy K.
Published: December 2018

Coconut palms (Cocos nucifera) in a field planting that were fertilized with a 8N–0.9P–10K–4Mg fertilizer four times per year or were never fertilized experienced chilling injury (CI) temperatures in 2008, 2009, and 2010. Fertilized coconut palms had significantly less foliar necrosis in each year than unfertilized palms and also retained more of their fruits. The number of leaves supported by each palm, a measure of potassium (K) deficiency severity, was improved by fertilization and was negatively correlated with percentage of necrosis of the foliage caused by cold temperatures. Nitrogen and K concentrations in leaf 1 of coconut palms were also negatively correlated with CI severity.
Hoophouse Contributions to Economic Viability: Nine Michigan Case Studies
Authors: Conner David S. , Waldman Kurt B. , Montri Adam D. , Hamm Michael W. , Biernbaum John A.
Published: December 2018

Relatively low-cost season extension structures have the potential to contribute to farm economic viability in temperate climates by providing a means to continue sales beyond the limits of outdoor-only field production. These structures, commonly called hoophouses, high tunnels, passive solar greenhouses, or unheated greenhouses, allow for the extension of heat-tolerant (warm season) crops on both ends of the production time frame and at winter harvesting of cold-tolerant (cool season) crops. In this study, results are presented from a multiyear investigation into the economic impacts of year-round production and harvesting, with a focus on profitability of the structure and crop production as a whole. The results of case studies from nine Michigan farms reveal a very broad range of outcomes across farms in construction time, labor allocation and returns, and gross and net revenue. The economic implications of farmer use, including projected investment payback time, are discussed.
Effects of Paclobutrazol Sprays on Inflorescences of Three Potted Moth Orchid Clones
Authors: Newton Linsey A. , Runkle Erik S.
Published: December 2018

Inflorescences of some moth orchid (Phalaenopsis and Doritaenopsis) hybrids can become very tall, which can pose shipping challenges for commercial producers and be unwieldy for consumers. We determined the efficacy of paclobutrazol as a foliar spray to inhibit inflorescence elongation of these genera and intergeneric hybrids. A single application of 15, 30, or 45 mg·L−1 palcobutrazol at a volume of 0.2 L·m−2 was applied to Doritaenopsis Miss Saigon, Doritaenopsis Andrew, and Phalaenopsis ‘Smart Thing’ grown at 23 °C to induce flowering. Applications were made after inflorescence emergence but before flower initiation (inflorescences were 1 to 2 cm long) or after flower initiation (inflorescences were 10 to 18 cm long). None of the paclobutrazol applications inhibited total inflorescence elongation of ‘Smart Thing’ or Miss Saigon. However, paclobutrazol inhibited inflorescence elongation from treatment until first flowering of Andrew by 19% to 23% when plants were treated with 15 or 45 mg·L−1 before flower initiation and 30 or 45 mg·L−1 after flower initiation. One or more concentrations of paclobutrazol applied after flower initiation reduced the length of the internode between the first and second flower on all three orchid clones. Paclobutrazol delayed flowering only on Miss Saigon (by 2 days) and only when applied after flower initiation. Paclobutrazol application did not affect the number of inflorescences or flowers, diameter of the first flower, number of new leaves formed, or increase in leaf span. Growers are advised to perform small-scale trials with paclobutrazol solutions starting at 30 to 45 mg·L−1 within 1 week of inflorescence emergence, although higher concentrations may be appropriate for the most vigorous varieties. Furthermore, a late spray application can cause unwanted crowding of the flowers.
Abscisic Acid Applications Decrease Stomatal Conductance and Delay Wilting in Drought-stressed Chrysanthemums
Authors: Waterland Nicole L. , Finer John J. , Jones Michelle L.
Published: December 2018

Drought stress during shipping and retailing reduces the postproduction quality and marketability of potted plants. Plants respond to drought stress by closing their stomata and reducing transpirational water loss. This stress response is mediated by the plant hormone abscisic acid (ABA). Exogenous applications of s-abscisic acid (s-ABA), the biologically active form of the hormone, can enhance drought tolerance and extend shelf life in a variety of bedding plants. However, little is known about the effectiveness of s-ABA at enhancing drought tolerance in perennial crops like chrysanthemum (Chrysanthemum ×morifolium). ‘Festive Ursula’ chrysanthemum plants were drenched (0, 125, 250, or 500 mg·L−1) or sprayed (0, 500, or 1000 mg·L−1) with s-ABA. All applications containing s-ABA effectively delayed wilting by reducing stomatal conductance (gS). Shelf life was extended from 1.2 to 4.0 days depending on the concentration of s-ABA. Spray applications of 500 mg·L−1 s-ABA to six additional chrysanthemum cultivars increased shelf life from 1.6 to 3.8 days following drought stress. s-ABA treatment also allowed severely drought-stressed chrysanthemums to recover and remain marketable after rewatering. Growers can treat chrysanthemums with s-ABA to reduce water use during shipping and to delay wilting if plants are not adequately watered during retailing.
Adolescent Involvement at Public Horticulture Institutions
Authors: Purcell Keelin Blaith , Lyons Robert E. , Dierking Lynn D. , Fischel Helen
Published: December 2018

While public gardens typically offer educational programming for adults and elementary school–aged children, many institutions struggle with serving the teenage audience. This study gathered information on the institutional benefits, challenges, and strategies of offering successful programming for youth aged 13–19 years. Institutional members of the American Public Gardens Association were surveyed, followed by case study research at two large institutions and phone interviews with three smaller institutions. Seven institutional benefits emerged, the three foremost being building relationships with new audiences, building interest in horticulture, and supporting the institution's mission and growth. In addition, seven potential challenges were identified, most notably funding, staff time, and adolescent interest. Seven overarching strategies also emerged, highlighting the areas of high quality staff, curriculum, partnerships, youth decision-making, compensation, engaging activities, and evaluation.
Response of Selected Foliage Plants to Four Herbicides in Irrigation Water
Authors: Gettys Lyn A. , Haller William T.
Published: December 2018

‘Miami Beauty’ anthurium (Anthurium andreanum), ‘Frieda Hemple’ caladium (Caladium ×hortulanum), ‘Debbie’ spathiphyllum (Spathiphyllum), and ‘Regina Red’ syngonium (Syngonium podophyllum) were irrigated with water treated with bispyribac-sodium, quinclorac, topramezone, and trifloxysulfuron to identify herbicide concentrations that cause phytotoxic effects. Plants were irrigated four times over a 11-day period with the equivalent of 0.5 inch of treated water during each irrigation and were then irrigated with well water until they were harvested 43 days after the first herbicide treatment. Visual quality and dry weight data revealed that caladium was the most sensitive of the foliage plants, regardless of herbicide mode of action. Noticeable reductions in visual quality and dry weight of caladium were evident after exposure to 182, 144, 186, and 1135 ppb of bispyribac-sodium, quinclorac, topramezone, and trifloxysulfuron, respectively. Of the four herbicides evaluated in these experiments, only quinclorac caused noticeable damage to plants when applied at a concentration similar to the proposed use rate.
Cultivar Evaluation and Lipid and Protein Contents of Virginia-grown Edamame
Authors: Carson Luther C. , Freeman Joshua H. , Zhou Kequan , Welbaum Gregory , Reiter Mark
Published: December 2018

Few studies have compared the growth and yield of commercial edamame (Glycine max) cultivars in the mid-Atlantic United States. This study determined yield potential, yield components, and lipid and protein contents of five edamame cultivars [BeSweet 292 (BS292), BeSweet 2015 (BS2015), BeSweet 2001 (BS2001), Midori Giant (MG), and Sunrise (SR)] grown in Painter, VA, during 2008 and 2009. Pod yield ranged between 5002 and 7521 lb/acre. There were no differences in total yield among ‘MG’, ‘BS292’, or ‘SR’. ‘BS2015’ had the lowest yield, while the yield of ‘BS2001’ was not different from other cultivars tested. Percent marketable pods ranged from 74.3% to 85.6%, with no differences among cultivars. ‘SR’ had the greatest average seed weight in 2008 and ‘BS2001’ had the smallest; intermediate was ‘MG’, ‘BS292’, and ‘BS2001’, although ‘MG’ was not different from ‘SR’. ‘MG’ had the greatest average seed weight in 2009; there were no differences among the remaining cultivars. The cultivar lipid content was numerically lower in 2009 than in 2008 for all five cultivars. ‘BS292’ and ‘BS2001’ had the least and greatest protein concentrations with 36.1% and 38.3% in 2008, respectively. In 2009, ‘MG’ and ‘SR’ had the least and greatest protein concentrations with 35.7% and 39.5%, respectively. Edamame appears to be a viable alternative crop for Virginia with yields similar to snap beans (Phaseolus vulgaris). ‘MG’, ‘BS292’, and ‘SR’ produced consistently high yields and quality and are viable cultivar choices for the mid-Atlantic United States.
Use of Reduced Irrigation Operating Pressure in Irrigation Scheduling. I. Effect of Operating Pressure, Irrigation Rate, and Nitrogen Rate on Drip-irrigated Fresh-market Tomato Nutritional Status and Yields: Implications on Irrigation and Fertilization Management
Authors: Poh Bee Ling , Gazula Aparna , Simonne Eric H. , Di Gioia Francesco , Hochmuth Robert C. , Alligood Michael R.
Published: December 2018

Increasing the length of irrigation time by reducing the operating pressure (OP) of drip irrigation systems may result in decreased deep percolation and may allow for reduced nitrogen (N) fertilizer application rates, thereby minimizing the environmental impact of tomato (Solanum lycopersicum) production. The objectives of this study were to determine the effects of irrigation OP (6 and 12 psi), N fertilizer rate (100%, 80%, and 60% of the recommended 200 lb/acre N), and irrigation rates [IRRs (100% and 75% of the target 1000–4000 gal/acre per day)] on fresh-market tomato plant nutritional status and yields. Nitrate (NO3−)–N concentration in petiole sap of ‘Florida 47’ tomatoes grown in Spring 2008 and 2009 in a raised-bed plasticulture system was not significantly affected by treatments in both years and were within the sufficiency ranges at first-flower, 2-inch-diameter fruit, and first-harvest growth stages (420–1150, 450–770, and 260–450 mg·L−1, respectively). In 2008, marketable yields were greater at 6 psi than at 12 psi OP [753 vs. 598 25-lb cartons/acre (P < 0.01)] with no significant difference among N rate treatments. But in 2009, marketable yields were greater at 12 psi [1703 vs. 1563 25-lb cartons/acre at 6 psi (P = 0.05)] and 100% N rate [1761 vs. 1586 25-lb cartons/acre at 60% N rate (P = 0.04)]. Irrigation rate did not have any significant effect (P = 0.59) on tomato marketable yields in either year with no interaction between IRR and N rate or OP treatments. Hence, growing tomatoes at 12 psi OP, 100% of recommended N rate, and 75% of recommended IRR provided the highest marketable yields with least inputs in a drip-irrigated plasticulture system. In addition, these results suggest that smaller amounts of irrigation water and fertilizers (75% and 60% of the recommended IRR and N rate, respectively) could be applied when using a reduced irrigation OP of 6 psi for the early part of the tomato crop season. In the later part of the season, as water demand increased, the standard OP of 12 psi could be used. Changing the irrigation OP offers the grower some flexibility to alter the flow rates to suit the water demands of various growth stages of the crop. Furthermore, it allows irrigation to be applied over an extended period of time, which could better meet the crop's needs for water throughout the day. Such an irrigation strategy could improve water and nutrient use efficiencies and reduce the risks of nutrient leaching. The results also suggest that OP (and flow rate) should be included in production recommendations for drip-irrigated tomato.
Use of Reduced Irrigation Operating Pressure in Irrigation Scheduling. II. Effect of Reduced Irrigation System Operating Pressure on Drip-tape Flow Rate, Water Application Uniformity, and Soil Wetting Pattern on a Sandy Soil
Authors: Poh Bee Ling , Gazula Aparna , Simonne Eric H. , Hochmuth Robert C. , Alligood Michael R.
Published: December 2018

For shallow-rooted vegetables grown in sandy soils with low water-holding capacity (volumetric water content <10%), irrigation water application rate needs to provide sufficient water to meet plant needs, to avoid water movement below the root zone, and to reduce leaching risk. Because most current drip tapes have flow rates (FRs) greater than soil hydraulic conductivity, reducing irrigation operating pressure (OP) as a means to reduce drip emitter FR may allow management of irrigation water application rate. The objectives of this study were to determine the effect of using a reduced system OP (6 and 12 psi) on the FRs, uniformity, and soil wetted depth and width by using three commercially available drip tapes differing in emitter FR at 12 psi (Tape A = 0.19 gal/h, Tape B = 0.22 gal/h, and Tape C = 0.25 gal/h). Reducing OP reduced FRs (Tape A = 0.13 gal/h, Tape B = 0.17 gal/h, and Tape C = 0.16 gal/h) without affecting uniformity of irrigation at 100 and 300 ft lateral runs. Flow rate was also reduced at 300-ft lateral length compared with 100 ft for all three tapes. Uniformity was reduced [“moderate” to “unacceptable” emitter flow variation (qvar) and “moderate” coefficient of variation (cv)] at 300 ft for Tape B and C compared with “good” qvar and “moderate” to “excellent” cv at 100 ft. Using soluble dye as a tracer, depth (D) of the waterfront response to irrigated volume (V) was quadratic, D = 4.42 + 0.21V − 0.001V2 (P < 0.01, R2 = 0.72), at 6 psi, with a similar response at 12 psi, suggesting that depth of the wetted zone was more affected by total volume applied rather than by OP itself. The depth of the wetted zone went below 12 inches when V was ≈45 gal/100 ft, which represented ≈3 h of irrigation at 6 psi and 1.8 h of irrigation at 12 psi for a typical drip tape with FR of 0.24 gal/h at 12 psi. These results show that, for the same volume of water applied, reduced OP allowed extended irrigation time without increasing the wetted depth. OP also did not affect the width (W) of the wetted front, which was quadratic, W = 6.97 + 0.25V − 0.002V2 (P < 0.01, R2 = 0.70), at 6 psi. As the maximum wetted width at reduced OP was 53% of the 28-inch-wide bed, reduced OP should be used for two-row planting or drip-injected fumigation only if two drip tapes were used to ensure good coverage and uniform application. Reducing OP offers growers a simple method to reduce FR and apply water at rates that match more closely the hourly evapotranspiration, minimizing the risk of leaching losses.
Physical Properties of and Plant Growth in Peat-based Root Substrates Containing Glass-based Aggregate, Perlite, and Parboiled Fresh Rice Hulls
Authors: Evans Michael R.
Published: December 2018

Aggregates produced from finely ground waste glass [Growstones (GS); Earthstone Corp., Santa Fe, NM] have been proposed to adjust the physical properties of peat-based substrates. The GS had a total pore space (TPS) of 87.4% (by volume), which was higher than that of sphagnum peat and perlite but was similar to that of parboiled fresh rice hulls (PBH). The GS had an air-filled pore space (AFP) of 53.1%, which was higher than that of sphagnum peat and perlite but lower than that of PBH. At 34.3%, GS had a lower water-holding capacity (WHC) than sphagnum peat but a higher WHC than either perlite or PBH. The bulk density of GS was 0.19 g·cm−3 and was not different from that of the perlite but was higher than that of sphagnum peat and PBH. The addition of at least 15% GS to sphagnum peat increased the AFP of the resulting peat-based substrate. Substrates containing 25% or 30% GS had a higher AFP than substrates containing equivalent amounts of perlite but a lower AFP than substrates containing equivalent PBH. Substrates containing 20% or more GS had a higher WHC than equivalent perlite- or PBH-containing substrates. Growth of ‘Cooler Grape’ vinca (Catharanthus roseus), ‘Dazzler Lilac Splash’ impatiens (Impatiens walleriana), and ‘Score Red’ geranium (Pelargonium ×hortorum) was similar for plants grown in GS-containing substrates and those grown in equivalent perlite- and PBH-containing substrates.
Urea Ammonium Nitrate Additive and Raking Improved Mesotrione Efficacy on Creeping Bentgrass
Authors: Xie Lijuan , Li Deying , Fang Wenjuan , Howatt Kirk
Published: December 2018

Selective control of creeping bentgrass (Agrostis stolonifera) is desirable when it has escaped into other turfgrasses. The objective of this study was to evaluate the influence on creeping bentgrass control from adding urea ammonium nitrate (UAN) to mesotrione plus non-ionic surfactant (NIS) spray solution, and raking to remove dead tissues of creeping bentgrass. A 2-year field study was conducted with a split-plot design, where raking was the whole plot treatment and herbicide was the sub-plot treatment. Herbicide treatments included application of mesotrione at 56 and 70 g·ha−1 singly and sequentially with 0.25% (v/v) NIS or 0.25% (v/v) NIS plus 2.5% (v/v) UAN solution. Sequential applications were made three times on a 2-week interval. Removing the dead clippings by raking improved the creeping bentgrass control from 60% to 73% averaged over rates, timings, adjuvants, and years. Adding UAN to NIS plus mesotrione improved creeping bentgrass control from 78% to 98% with three sequential applications at 70 g·ha−1.
Impact of Paclobutrazol on Root-pruned Live Oak
Authors: Martínez-Trinidad Tomás , Watson W. Todd , Book Russell K.
Published: December 2018

This study evaluated the impact of paclobutrazol (PBZ) on the overall growth and vitality of root-pruned, field-grown live oak (Quercus virginiana). Live oak trees with 10-cm trunk diameter (measured 30 cm aboveground) were treated with full rate (0.8 g·cm−1 trunk diameter) of PBZ as basal drenches, full or half rate (0.8 or 0.4 g·cm−1 trunk diameter) of PBZ and trenching at 45 cm from trunk, full or half rate of PBZ and trenching at 60 cm from trunk, trenching alone at 45 or 60 cm from trunk, and only water. Trunk diameter and canopy growth was significantly reduced (P < 0.001) and new root growth was also reduced by applications of PBZ, root pruning, or both. Starch content in twigs decreased and glucose content increased on treatment by full-label rates of PBZ and root pruning at 60 cm. PBZ and/or root pruning caused slight improvements in chlorophyll fluorescence (Fv/Fm). Results of this research indicate that PBZ (full rate) in combination with root pruning (45 cm) reduces tree growth and exhibits an overregulation effect for at least 16 months after treatment. Therefore, PBZ applications on root-pruned trees can temporarily decrease root and tree growth and improve foliage chlorophyll fluorescence.
Effect of Time of Planting, Plant Size, and Nursery-growing Environment on the Performance of ‘Festival’ Strawberry in a Subtropical Environment
Authors: Menzel C.M. , Smith L.
Published: December 2018

Experiments were conducted to determine the effect of time of planting, plant size, and nursery-growing environment on the performance of bare-rooted ‘Festival’ strawberry plants (Fragaria ×ananassa) at Nambour in southeastern Queensland, Australia, over 3 years. Yields were best with a planting in mid-March (1013 g/plant), with lower yields with a planting in early March (711 g/plant), late March/early April (765 g/plant), mid-April (671 g/plant), or late April/early May (542 g/plant). Plants obtained from Stanthorpe in southern Queensland, a warm-growing environment, were just as productive (695 g/plant) as those from Toolangi in Victoria (710 g/plant) or Kempton in Tasmania (701 g/plant), two cool-growing environments. In contrast, large plants from these nurseries with crown diameters ranging from 10 to 17 mm had 17% higher yields than small plants with crown diameters ranging from 6 to 10 mm (751 vs. 642 g/plant). These results suggest that planting in mid-March is optimal for ‘Festival’ in this environment. Lower yields with an earlier planting reflected the small size of the plants, whereas lower yields with later plantings reflected the shorter growing seasons. It can also be concluded that plant size is more important than nursery-growing environment in determining the productivity of strawberry fields in southeastern Queensland.
Opportunities and Challenges to Sustainability in Aquaponic Systems
Authors: Tyson Richard V. , Treadwell Danielle D. , Simonne Eric H.
Published: December 2018

Aquaponics combines the hydroponic production of plants and the aquaculture production of fish into a sustainable agriculture system that uses natural biological cycles to supply nitrogen and minimizes the use of nonrenewable resources, thus providing economic benefits that can increase over time. Several production systems and media exist for producing hydroponic crops (bench bed, nutrient film technique, floating raft, rockwool, perlite, and pine bark). Critical management requirements (water quality maintenance and biofilter nitrification) for aquaculture need to be integrated with the hydroponics to successfully manage intensive aquaponic systems. These systems will be discussed with emphasis on improving sustainability through management and integration of the living components [plants and nitrifying bacteria (Nitrosomonas spp. and Nitrobacter spp.)] and the biofilter system. Sustainable opportunities include biological nitrogen production rates of 80 to 90 g·m−3 per day nitrate nitrogen from trickling biofilters and plant uptake of aquaculture wastewater. This uptake results in improved water and nutrient use efficiency and conservation. Challenges to sustainability center around balancing the aquaponic system environment for the optimum growth of three organisms, maximizing production outputs and minimizing effluent discharges to the environment.
Greenhouse and Landscape Performance of Bedding Plants in Biocontainers
Authors: Kuehny Jeff S. , Taylor Matt , Evans Michael R.
Published: December 2018

Biodegradable and plastic containers were evaluated for greenhouse and landscape production of ‘Score Red’ geranium (Pelargonium ×hortorum), ‘Grape Cooler’ vinca (Catharanthus roseus), or ‘Dazzler Lilac Splash’ impatiens (Impatiens wallerana) at Louisiana State University (LSU), Baton Rouge, LA; Longwood Gardens (LWG), Kennett Square, PA; and University of Arkansas (UA), Fayetteville, AR. Of the 5-inch containers, the highest geranium and vinca shoot growth occurred in plastic containers compared with bioplastic and rice straw containers. Of the 4-inch containers, paper containers produced the greatest geranium shoot growth compared with the peat containers at LSU and LWG. Shoot growth in impatiens was similar for all container types at all three locations. When all container types were considered, there was no difference in the root growth of geranium or impatiens at all three locations. However, vinca had the highest root growth in paper containers compared with that in peat and coconut fiber. The root:shoot (R:S) ratio of geranium were mixed for all pot sizes, types, and locations. Vinca R:S ratio was highest in both the 4- and 5-inch plastic control containers at LSU and lowest in both plastic containers at LWG. Direct plant containers generally performed well in the landscape as the plants grown in plastic containers at LWG. Plants grown in all tested containers produced marketable plants for both the retail and landscape markets. However, growers and landscapers should be aware of growth differences that may occur when using biodegradable containers and align production practices accordingly.
Foliar Application of Zinc and Boron Improves Walnut Vegetative and Reproductive Growth
Authors: Keshavarz Karim , Vahdati Kourosh , Samar Mahmoud , Azadegan Behzad , Brown Patrick H.
Published: December 2018

An experiment was conducted in a persian walnut (Juglans regia) orchard in the north of Iran to evaluate the effects of zinc (Zn) as zinc sulfate and/or boron (B) as boric acid in foliar spray with different concentrations and combinations. Three B and three Zn concentrations (0, 174, and 348 mg·L−1 for B and 0, 1050, and 1750 mg·L−1 for Zn) were applied either independently or in combination. Leaf nutrient concentrations, pollen germination, fruit set, leaf chlorophyll index, nut and kernel characteristics, vegetative growth, nut weight, and nut yield were measured to assess the effects of treatments. The results showed that all B and Zn applications and combinations had a significant effect on all traits except nut and kernel diameter, shell percent, husk thickness, and pistillate flower abscission (PFA). Pollen germination, fruit set, vegetative growth, nut weight, kernel percent, nut and kernel length, and chlorophyll index were highest when B and Zn were applied simultaneously at 174 and 1050 mg·L−1 concentrations, respectively.
Cover Crop and Floor Management Affect Weed Coverage and Density in an Establishing Oregon Vineyard
Authors: Fredrikson Levi , Skinkis Patricia A. , Peachey Ed
Published: December 2018

Five vineyard floor management treatments were evaluated for effects on weed control over two growing seasons in an establishing ‘Chardonnay’ (Vitis vinifera) vineyard in the Willamette Valley of Oregon. Four cover crop management treatments and an unplanted treatment were compared to assess the effects on vine row and alleyway weed coverage and densities of broadleaf and grass weeds. A winter annual cover crop was grown in alleyways of the cover-cropped treatments and was mowed in spring. The mowed residue was managed as follows: 1) residue transferred in-row as mulch representing the industry practice of “mow-and-throw,” 2) residue transferred in-row as mulch at three times the rate of the earlier treatment, 3) mowed residue incorporated into alleyways, and 4) removal of mowed cover crop residue from the vineyard. Weed coverage was assessed visually within a 1.0-m2 quadrat placed randomly in alleyways and vine rows, and densities of broadleaf and grass weeds were determined by counting and grouping individual weeds within each quadrat. Vine row weed coverage and densities were lower in treatments with residue mulch at each sampling date in 2009 and 2010, with nearly 100% in-row weed suppression by the heavier mulch treatment. Alleyway weed coverage was lowest when residue was incorporated and highest in the unplanted treatment at some sampling dates. Grass weed densities in alleyways were similar between treatments at all sampling dates. Results of this study indicate that in-row mulch of cover crop residues at fresh weight densities of 2.5–15.0 kg·m−2 provided effective weed control in a non-irrigated vineyard in western Oregon. Also, alleyway weed coverage may be reduced through incorporation of mowed cover crop residues.
Green-up of Seeded Bermudagrass Cultivars as Influenced by Spring Scalping
Authors: Rimi Filippo , Macolino Stefano , Leinauer Bernd , Ziliotto Umberto
Published: December 2018

Winter dormancy is the main impediment to a wide acceptance of warm-season turfgrasses in the Mediterranean countries of Europe due to a loss of color during the winter months. Scalping during late winter or early spring has been recommended anecdotally to enhance spring green-up of bermudagrass (Cynodon dactylon); however, information is lacking on the effectiveness of this practice. A study was conducted to investigate the effects of spring scalping on spring green-up of eight bermudagrass cultivars (Barbados, Contessa, La Paloma, Mohawk, NuMex Sahara, Princess-77, SR 9554, and Yukon) grown in a transition zone environment. The trial was carried out in Spring of 2009 and 2010 on plots established in July 2005 at the experimental farm of the University of Padova (northeastern Italy). Half of the plots for each cultivar were subjected to spring scalping, which was applied in both years on 13 Mar. with a rotary mower set at a height of 28 mm. Soil temperatures were recorded hourly during the research period at a depth of 2.5 cm. The percentage of green cover was estimated weekly from 0 to 98 days after spring scalping (DASS). Soil temperatures in scalped plots were greater than in unscalped plots. Among the cultivars tested, ‘Yukon’ showed earliest spring green-up, with no difference between the scalping treatments, reaching 80% green cover by the end of April. For all other cultivars, scalped plots reached 80% green cover 10 to 18 days earlier than unscalped plots. Results showed that scalping enhanced spring green-up, primarily for cultivars that recover slowly from winter dormancy.
Sensing of Crop Nitrogen Status: Opportunities, Tools, Limitations, and Supporting Information Requirements
Authors: Tremblay Nicolas , Fallon Edith , Ziadi Noura
Published: December 2018

Diagnosing nitrogen (N) sufficiency in crops is used to help insure more effective management of N fertilizer application, and several indicators have been proposed to this end. The N nutrition index (NNI) offers a reliable measurement, but it is relatively difficult to determine. This index is based on the relationship between plant tissue N concentration and the biomass of the plant's aerial parts. However, a good estimate of the NNI should be obtained by nondestructive methods that can be carried out quickly. Although dependent on sites, chlorophyll meter (CM) measurements have been correlated with the NNI in corn (Zea mays). Since chlorophyll can be estimated through remote sensing, the possibility of quickly obtaining measurements for large surface areas points to practical applications for precision agriculture. When combined with the mapping of soil properties such as apparent electrical conductivity (EC), elevation and slope, such chlorophyll measurements make it possible to derive N fertilization recommendations by taking into account natural variations in the soil. Recently, an instrument called the Dualex (FORCE-A, Orsay, France) is marketed, which uses measurement methods based on the fluorescent properties of plant tissues. It is similar to the CM in terms of its operating principle but it measures polyphenolics (Phen), compounds that accumulate in the epidermis of leaves under N stress. Epidermal transmittance to ultraviolet light is assessed by the fluorescence excitation ratio F(ultraviolet)/F(REF), where F(ultraviolet) is the fluorescence excitation detected following ultraviolet excitation, and F(REF) is the fluorescence detected on excitation at a reference wavelength, not absorbed by the epidermis. Although the Dualex generally did not identify more differences among treatments than the CM in our studies on wheat (Triticum aestivum), corn, and broccoli (Brassica oleracea ssp. italica), combining the two measurements in a chlorophyll/Phen ratio improved the relationships with crop N nutrition status appreciably. This ratio can also be estimated by remote sensing techniques. The NNI on its own does not constitute an economically optimal recommendation for N fertilizer [economically optimal N rate (EONR)]. The EONR is the N rate at which profit is greatest. Work is currently being done to use overfertilized reference plots for this purpose and to permit an improved correlation between the indicator (NNI or chlorophyll) and EONR.
Crop Nitrogen Status Assessment Tools in a Decision Support System for Nitrogen Fertilization Management of Potato Crops
Authors: Goffart Jean-Pierre , Olivier Marguerite , Frankinet Marc
Published: December 2018

A decision support system (DSS) was based on the splitting of total nitrogen (N) fertilizer application combined with in-season assessments of crop N requirements aimed to matching, at field scale, potato (Solanum tuberosum) total crop N requirements and mineral N supply from soil and fertilizers. After the preplanting establishment of the total N recommendation based on the predictive balance-sheet method at a specific field scale, 70% of the recommended amount was applied to the crop at planting. Subsequently, at 20–50 days after emergence (DAE) the need for supplemental N was assessed through noninvasive measurements of leaf chlorophyll concentration directly in the field. A simple conditional relationship was established to support potato growers’ decisions on the usefulness of applying the remaining 30% N. This required a crop N status (CNS) assessment in the fertilized field and within a small, untreated area (zero-N for reference). The strategy developed is economically feasible, easy to operate, and validated for several potato varieties. It also gives the grower the possibility of improving N use efficiency (NUE). Several tools to assess CNS have been investigated, or are currently being investigated, at the Walloon Agricultural Research Center in Gembloux, Belgium (CRA-W) for integration into this strategy. All the tools are evaluated for four main characteristics: measurement accuracy and precision, sensitivity to N, specificity to N, and feasibility. There are invasive or noninvasive tools. The use of a chlorophyll meter (CM) has been currently developed in the DSS. Current CRA-W research is investigating the potential of crop light reflectance as an indicator of CNS (ground-based radiometers for near remote sensing and satellite multispectral imagery for spatial remote sensing).
The Relationship between Farming Experiences and Attitudes Toward Locally Grown Foods Among Japanese Children
Authors: Taniguchi Takaho , Akamatsu Rie
Published: December 2018

In Japan, introducing farming experiences in the context of school has become popular in promoting “locally produced, locally consumed” foods. This study examined the relationship between farming experience and “attitudes toward locally grown foods” and “attachment to region” among Japanese children. In total, 1464 fifth-grade children in Japan participated in this study and completed questionnaires on their farming experiences, attitudes toward locally grown foods, and attachment to the region in which they live. The scales concerning “attitudes toward locally grown foods” and “attachment to region” were scored, and the scores were compared according to whether the child had farming experience using the Kruskal–Wallis test. About one-quarter of the children (25.6%) responded that they “very often” had farming experiences, and the scores for “attitudes toward locally grown foods” and “attachment to the region” were highest among the children who answered that they had experienced farming “very often” (both P < 0.001). Additionally, significant positive relationships between farming experience and “attitudes toward locally grown foods” (partial correlation coefficient r = 0.171, P < 0.001) and “attachment to region” (r = 0.156, P < 0.012) were found, even after adjusting for demographic characteristics. The results suggest that having the opportunity to experience farming was associated with more positive attitudes toward locally grown foods and the sense of attachment to one's region among children.