bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of GA4+7 plus 6-Benzyladenine as a Frost-rescue Treatment for Apple
Authors: McArtney Steven , Greene Duane , Robinson Terence , Wargo James
Published: December 2018

Freeze events during bloom can be a relatively frequent occurrence in many apple (Malus ×domestica) production areas in the United States that significantly reduce orchard productivity and profitability. This study investigated the potential for a proprietary mixture of gibberellin A4 + A7 and 6-benzyladenine (GA4+7 plus 6-BA) to increase fruit set and cropping of apple following freeze events at three locations across the United States during bloom in 2012. GA4+7 plus 6-BA increased fruit set in two of five experiments, and increased fruit number and yield per tree in three of five experiments. GA4+7 plus 6-BA increased fruit set and yield of ‘Taylor Spur Rome’ following freezes on two consecutive days during bloom when the minimum temperature reached 23.9 and 28.4 °F. Fruit set was increased due to a stimulation of parthenocarpic fruit growth. Using locally obtained market prices, GA4+7 plus 6-BA treatments increased the crop value of ‘Taylor Spur Rome’, ‘Ginger Gold’, and ‘Jonagold’ by $3842, $977, and $6218 per acre, respectively. Although GA4+7 plus 6-BA application(s) after a freeze increased fruit set and cropping in some instances, tree yields were well below the average yields previously obtained in the test orchards.
Improving Peer Relations of Elementary School Students through a School Gardening Program
Authors: Kim Seong-Sil , Park Sin-Ae , Son Ki-Cheol
Published: December 2018

For older elementary school students, amicable peer relationships are important to meeting developmental challenges, such as socialization. Thus, in this study, the effectiveness of a school gardening program to promote positive social relationships among elementary school students was assessed. The participants in this study were fifth and sixth grade students from four elementary schools in Wonju, South Korea. The experimental and control groups consisted of 123 students each (total 246) from fifth and sixth grade classrooms. The gardening program included a range of activities, such as sowing seeds and harvesting produce, and was designed to improve peer status, peer relations, and sociality. The program was embedded in the school curriculum; sessions were 90 minutes per week for 10 weeks from 16 April through 25 June 2012. The results revealed the school gardening program brought about meaningful differences in both persistence of friendship (P = 0.04) and adaptability between friends (P = 0.03), which were subcategories of peer relationships, in the experimental group. There were also significant improvements in sociality (P < 0.001) and its various subcategories, especially in law-abiding (P < 0.001) and collaboration (P < 0.001). Finally, the peer status results showed that there was significantly a greater increase in the peer status after the school gardening program, but there was no significant change in the control group. In conclusion, the school gardening program for elementary school students had a positive influence on peer relationships, sociality, and peer status. Implementing a garden program in schools will effectively contribute to the improvement of social relationships among elementary school students.
Reducing Injury of Lettuce from Phosphine Fumigation
Authors: Liu Samuel S. , Liu Yong-Biao
Published: December 2018

Fumigation with cylindered pure phosphine free of ammonia has been used commercially at low temperatures in recent years to control pests on harvested fresh fruit and vegetables. However, long fumigation treatments cause injuries to lettuce (Lactuca sativa) and prevent its commercial use on lettuce. We evaluated whether absorbents for carbon dioxide (CO2) and ethylene can prevent injuries to lettuce in phosphine fumigation, hypothesizing that an accumulation of CO2 or ethylene be responsible for the injuries. Head and romaine lettuce were fumigated in chambers in the presence or absence of CO2 and ethylene absorbents for 3 days at 2 °C. The use of absorbents prevented lettuce injury associated with fumigation and resulted in higher lettuce quality. In the absence of the absorbents, both head and romaine lettuce sustained significant injuries in the form of brown stain, a typical symptom of CO2 injuries, and significantly reduced quality as compared with fumigation in the presence of absorbents. The injuries were likely caused by CO2 based on the facts that injuries were identical to CO2 injuries and the prevention of the injuries by the use of CO2 absorbent. The findings of this study have important implications for developing safe and effective phosphine fumigation protocols at low temperature for controlling insect pests on fresh commodities, especially when a long treatment time is required.
Evaluation of Tomato Varieties under Organic Production Practices in Georgia
Authors: Boyhan George E. , Tate Suzzanne , McNeill Ryan , McConnaughey Jeffrey
Published: December 2018

Tomato (Solanum lycopersicum) is a popular crop among organic growers, particularly open-pollinated varieties; however, there is a lack of information evaluating these varieties in comparison with commercial F1 hybrids. This study was undertaken to compare conventionally produced commercial F1 tomato varieties available in the southeastern United States with open-pollinated varieties popular among organic growers. Nineteen tomato varieties were evaluated in 2011 and 2012 using the U.S. Department of Agriculture National Organic Program guidelines; however, the land used had not been in 3 years of organic production. Staked tomatoes were grown on plastic mulch. Data collected included early and total graded yield. In general, F1 hybrid, determinate or semideterminate varieties, had the best early and total yields compared with open-pollinated varieties. HSX 8115H and ‘Celebrity’ had the highest early total yield. ‘Costoluto Fiorentino’, an open-pollinated variety, also had good early total yield, but significantly less than HSX 8115H or ‘Celebrity’. ‘Costoluto Fiorentino’ was the only open-pollinated variety among the five highest yielding varieties for early total yield. In addition, ‘Celebrity’ had the greatest total yield of all the entries tested. All of the top five varieties for total yield were F1 hybrids and either determinate or semideterminate types. ‘Costoluto Fiorentino’ had total yield of 22,046 lb/acre, which was 14.3% lower than the lowest yielding variety in the top five yielding varieties. ‘Florida Pink’ had the largest average fruit weight, which also had the lowest total yield of all the entries. Although the open-pollinated varieties, popular among organic and local growers, yielded less than F1 hybrids, they may possess characteristics of color, flavor, or texture that are desired and were not evaluated in this study. This may be an opportunity for plant breeders to develop varieties desired by local organic growers that have unique characteristics, in addition to high yields and disease resistance.
Consumer Horticulture Outreach: Communication Challenges and Solutions
Authors: Bauske Ellen M. , Bachman Gary R. , Bradley Lucy , Jeannette Karen , O’Connor Alison Stoven , Bennett Pamela J.
Published: December 2018

Communication is a critical issue for consumer horticulture specialists and extension agents. They must communicate effectively with the public interested in gardening, with Extension Master Gardener (EMG) volunteers and with other scientists. A workshop was held at the Annual Conference of the American Society for Horticultural Science on 22 July 2013 in Palm Desert, CA, with the intent of sharing tips and techniques that facilitated consumer horticulture and EMG programming. Presentations focused on communication. One program leader reported on the North Carolina Master Gardener web site, which integrates an online volunteer management system (VMS) with widely available web tools to create one-stop shopping for people who want to volunteer, get help from volunteers, or support volunteers at both the county and state level. Another program used the state VMS to house videos providing continuing education (CE) training required for EMG volunteers. This training is available 24 hours per day and 7 days per week. Agents created the videos by recording live presentations with widely available, screen capture software and a microphone. Features that make the social media site Pinterest a strong tool for gathering together focused programming resources and professional collaboration were outlined. Finally, the use of a compact, subirrigated gardening system that uses peat-based potting mix was suggested as a means to simplify communication with new urban gardeners and address their unique gardening issues.
Mechanizing Chile Peppers: Challenges and Advances in Transitioning Harvest of New Mexico’s Signature Crop
Authors: Walker Stephanie J. , Funk Paul A.
Published: December 2018

New Mexican-type red and green chile (Capsicum annuum) is important to New Mexico’s identity and economy. Producers began experimenting with mechanical harvest in the mid-1960s, but efforts stalled in the 1970s. Adverse impact to production following the implementation of the North American Free Trade Agreement spurred renewed interest in chile mechanization. Through private and public collaboration, the red chile industry in New Mexico has successfully transitioned with more than 80% of domestic acreage currently mechanized. Green chile has proven to be more challenging with fruit damage and lack of efficient mechanical stem removal posing key obstacles. Recent identification and developments in equipment have provided necessary components for mechanization of green chile, but must be scaled-up to production volumes.
Breeding Highbush Blueberry Cultivars Adapted to Machine Harvest for the Fresh Market
Authors: Olmstead James W. , Finn Chad E.
Published: December 2018

In recent years, world blueberry (Vaccinium sp.) production has been split evenly between processing and fresh fruit markets. Machine harvest of highbush blueberry {northern highbush blueberry [NHB (V. corymbosum)], southern highbush blueberry [SHB (V. corymbosum interspecific hybrids)], and rabbiteye blueberry [RE (V. virgatum)]} typically has been used to obtain large volumes of fruit destined for processing. Because of financial and labor concerns, growers are interested in using machine harvesting for fruit destined to be fresh marketed. Bush architecture, harvest timing, loose fruit clusters, easy detachment of mature berries compared with immature berries, no stem retention, small stem scar, a persistent wax layer, and firm fruit are breeding goals to develop cultivars amenable to machine harvest. Progress in selecting for these traits has been made in existing highbush blueberry breeding programs, but will likely intensify as the need for cultivars suitable for machine harvest for the fresh market increases.
The Productivity of Strawberry Plants Growing Under Plastic High Tunnels in a Wet Subtropical Environment
Authors: Menzel Christopher M. , Smith Lindsay A. , Moisander Jenny A.
Published: December 2018

The effect of plastic high tunnels on the performance of two strawberry (Fragaria ×ananassa) cultivars (Festival and Rubygem) and two breeding lines was studied in southeastern Queensland, Australia, over 2 years. Production in this area is affected by rain, with direct damage to the fruit and the development of fruit disease before harvest. The main objective of the study was to determine whether plants growing under tunnels had less rain damage, a lower incidence of disease, and higher yields than plants growing outdoors. Plants growing under the tunnels or outdoors had at best only small differences in leaf, crown, root, and flower and immature fruit dry weight. These responses were associated with relatively similar temperatures and relative humidities in the two growing environments. Marketable yields were 38% higher under the tunnels compared with yields outdoors in year 1, and 24% higher in year 2, mainly due to less rain damage. There were only small differences in the incidences of grey mold (Botrytis cinerea) and small and misshaped fruit in the plants growing under the tunnels and outdoors. There were also only small differences in postharvest quality, total soluble solids, and titratable acidity between the two environments. These results highlight the potential of plastic high tunnels for strawberry plants growing in subtropical areas that receive significant rainfall during the production season.
Maintenance, Modifications, and Water Use in Private Gardens of Alt Empordà, Spain
Authors: Cubino Josep Padullés , Subirós Josep Vila , Lozano Carles Barriocanal
Published: December 2018

Water scarcity in developed countries along the Mediterranean coast may be aggravated in the near future due to rising water demand. The recent growth of low-density urban developments in these regions has led to an increase in the number of private domestic gardens. These particular landscapes may account for a large proportion of total domestic water use. This article examines the features and management practices of private gardens in relation to their relative water requirements. To calculate this variable, we use a method based on the relative water needs of garden species and the area of vegetation cover. In addition, transformations in the layouts of the gardens over the last 5 years, as well as various expected changes, are assessed. In total, 258 domestic gardens along the coast of Catalonia were investigated and their owners interviewed. A list of all plants growing in the gardens was recorded. The results indicate that the presence of turf is related to professional landscaping design, property age, and swimming pool presence. Moreover, gardens with greater landscape water requirements have more efficient watering systems. We present a progressive strategy for garden restructuring that may reduce water use while increasing the number of orchards and fruit trees.
Performance of 19 Pecan Cultivars and Selections in Southern Georgia
Authors: Conner Patrick J.
Published: December 2018

Nineteen pecan (Carya illinoinensis) clones were evaluated over a period of 18 years in a test orchard located in southern Georgia. Clones tested were primarily U.S. Department of Agriculture selections, but two grower-discovered cultivars, Jubilee and Surprize, were also trialed. Annual yields were measured for each tree in the test throughout the test period and the alternate bearing intensity of each cultivar was calculated. Average annual in-shell nut production in years 1–10 ranged from 12 lb in the precocious USDA 76-4-41 to 0 lb in the non-precocious USDA 72-8-4. Wide variation was seen in nut production of trees in years 11–18, averaging from 10 to 60 lb nut yield per year. A subsample of nuts was taken from each tree annually and percent kernel, nuts per pound, specific gravity, and nut volume were determined. Significant differences were found between clones for each of these traits. Differences were also found for the presence of damage from pecan scab [Fusicladium effusum (synonym Cladosporium caryigenum)] and black pecan aphid (Melanocallis caryaefoliae). Most clones were not acceptable for use in Georgia due to small nut size or poor kernel quality, but two clones merit further testing in this region. USDA 70-3-34 produced a large nut with good quality and scab resistance, but needs to be evaluated with mechanical crop thinning to improve kernel quality in high crop-set years. USDA 74-1-12 produced good yields of excellent quality, medium-sized pecans and should be trialed with greater tree numbers. Several other clones were found to have traits of interest to pecan breeding programs including: pecan scab resistance, large nut size, and high kernel percentage. Results of this trial suggest that cultivar development programs in Georgia should place greater selection emphasis on large nut size.
Effect of Sprayer Output Volume and Adjuvants on Efficacy of Clove Oil for Weed Control in Organic Vidalia® Sweet Onion
Authors: Johnson W. Carroll , Davis Jerry W.
Published: December 2018

Timely cultivation with a tine weeder and hand weeding are the primary tools for successful weed control in organic sweet onion (Allium cepa), but conditions frequently arise that delay the initial cultivation. Weeds that emerge during the delay are not effectively controlled by cultivation and herbicides derived from natural products may have a role to control the emerged weeds. It has been reported that clove oil herbicide was more effective when sprayers were calibrated for higher output (>50 gal/acre) compared with sprayers calibrated at ≈25 gal/acre. However, when clove oil was applied at the recommended rate of 10% by volume, herbicide cost was doubled when sprayer output volume was doubled. It was theorized that herbicide adjuvants might improve clove oil efficacy and reduce weed control cost by not needing to increase sprayer output volume. Trials were conducted from 2010 to 2012 to evaluate all possible combinations of two sprayer output volumes and five herbicide adjuvants used with clove oil (10% by volume) for cool season weed control. Sprayer output volumes evaluated were 25 and 50 gal/acre, using spray tips of differing orifice size. Adjuvants evaluated were a material composed of saponins, citric acid plus garlic extract, an emulsified petroleum oil (EPO) insecticide, a conventional petroleum oil adjuvant (POA), no adjuvant used with clove oil, and a nontreated control. Weed control was not consistently improved by applying clove oil (10% by volume) with a sprayer calibrated at 50 gal/acre compared with sprayer calibrated at 25 gal/acre. Improvements in weed control that were occasionally seen did not affect onion yield. Adjuvants provided minimal improvement in weed control from clove oil and did not consistently improve onion yield. Based on these results, clove oil does not provide suitable levels of weed control in organic Vidalia® sweet onion production to justify the expense.
Pecan Planting Trends in Georgia
Authors: Wells Lenny
Published: December 2018

Georgia is the largest pecan (Carya illinoinensis) producing state in the United States, accounting for ≈30% of national production. Georgia’s pecan acreage has undergone at least three significant expansions since the industry’s establishment in the early 1900s. The most recent expansion was likely a result of recent price increases driven by the export market for pecans. This stimulus also led to the planting of additional pecan acreage throughout the pecan growing regions of the United States. A survey of pecan producers throughout Georgia was conducted from Jan. through Mar. 2010, 2012, 2013, and 2014 regarding the planting of pecan trees. The current survey documents the planting of 391,488 pecan trees and 15,328 additional pecan acres since 2010 in Georgia. New orchard plantings averaged 40, 35, 42, and 62 acres in size for 2010, 2012, 2013, and 2014, respectively. The state’s pecan producers planted 14 to 30 different pecan cultivars, depending on the survey year. Aside from nongrafted seedling trees planted in 2010, ‘Desirable’ and ‘Pawnee’ accounted for the highest percentage of trees planted annually until 2014, both in percentage of total trees planted and percentage of producers planting trees. The survey also indicates a shift toward the planting of pecan trees at higher density by Georgia pecan producers since 2010.
Development and Evaluation of Methods to Identify Sea Oats Breeding Lines for Beaches with Shallow Dunes
Authors: Nabukalu Pheonah , Knott Carrie A.
Published: December 2018

Sea oats (Uniola paniculata) is an aesthetically pleasing native plant used for beach restoration along the northern Gulf of Mexico coast. Many beaches in this region have shallow, saturated dune profiles, which reduces sea oats survival. The objective of this study was to develop methods to identify saturation-tolerant sea oats breeding lines. Sea oats seedlings were evaluated for saturation tolerance in greenhouse, beach, and field environments from 2010 to 2012. In 2010, sea oats grown under eight treatments (seven greenhouse treatments and a natural beach site) were examined. In 2010, sea oats seedling survival 2 and 3 months after transplanting (MAT) was greatest for four greenhouse treatments (nonflooded control, 6 cm cyclic flood, 6 cm static flood, and 10 cm cyclic flood) and least at the beach environment (Holly Beach, LA). In 2011 and 2012, sea oats grown under six treatments (four greenhouse treatments, a natural beach site, and a saturated field site) were examined. In 2011, sea oats seedling survival 3 MAT ranged from 0.3% to 98%. The nonflooded greenhouse control had the greatest survival, whereas plants grown on dry bench regularly watered with 35 parts per thousand (ppt) saline solution had the least survival. Sea oats constantly flooded with 14 cm of saline water in the greenhouse had the least survival 2 and 3 MAT, 70% and 41%, respectively. Sea oats survival when flooded with 14 cm of fresh water 3 MAT correlated with a saturated beach environment, Holly Beach, LA, 6 MAT (r = 0.970, P = 0.030) and a saturated field environment, Baton Rouge, 6 MAT (r = 0.994, P = 0.006). These findings suggest that survival of sea oats grown in a greenhouse in 14 cm fresh water for 3 months correlates to sea oats survival at saturated beaches after 6 months, in the absence of significant storm events. Identifying protocols for selection of saturation-tolerant sea oats lines is essential to increase the efficiency and effectiveness of northern Gulf of Mexico sea oats breeding programs.
Comparing Flowering Responses of Long-day Plants under Incandescent and Two Commercial Light-emitting Diode Lamps
Authors: Kohyama Fumiko , Whitman Catherine , Runkle Erik S.
Published: December 2018

When the natural daylength is short, commercial growers of ornamental long-day plants (LDP) often provide low-intensity lighting to more rapidly and uniformly induce flowering. Incandescent (INC) lamps have been traditionally used for photoperiodic lighting because their spectrum, rich in red [R (600 to 700 nm)] and far-red [FR (700 to 800 nm)] light, is effective and they are inexpensive to purchase and install. Light-emitting diodes (LEDs) are much more energy efficient, can emit wavelengths of light that specifically regulate flowering, and last at least 20 times longer. We investigated the efficacy of two new commercial LED products developed for flowering applications on the LDP ageratum (Ageratum houstonianum), calibrachoa (Calibrachoa ×hybrida), two cultivars of dianthus (Dianthus chinensis), and two cultivars of petunia (Petunia ×hybrida). Plants were grown under a 9-hour short day without or with a 4-hour night interruption (NI) delivered by one of three lamp types: INC lamps (R:FR = 0.59), LED lamps with R and white (W) diodes [R + W (R:FR = 53.35)], and LED lamps with R, W, and FR diodes [R + W + FR (R:FR = 0.67)]. The experiment was performed twice, both at a constant 20 °C, but the photosynthetic daily light integral (DLI) during the second replicate (Rep. II) was twice that in the first (Rep. I). In all crops and in both experimental replicates, time to flower, flower or inflorescence and node number, and plant height were similar under the R + W + FR LEDs and the INC lamps. However, in Rep. I, both petunia cultivars developed more nodes and flowering was delayed under the R + W LEDs compared with the INC or R + W + FR LEDs. In Rep. II, petunia flowering time and node number were similar under the three NI treatments. Plant height of both dianthus cultivars was generally shorter under the NI treatment without FR light (R + W LEDs). These results indicate that when the DLI is low (e.g., ≤6 mol·m−2·d−1), FR light is required in NI lighting for the most rapid flowering of some but not all LDP; under a higher DLI, the flowering response to FR light in NI lighting is apparently diminished.
Yield, Labor, and Fruit and Juice Quality Characteristics of Machine and Hand-harvested ‘Brown Snout’ Specialty Cider Apple
Authors: Miles Carol A. , King Jaqueline
Published: December 2018

In this 2-year study of ‘Brown Snout’ specialty cider apple (Malus ×domestica) grafted onto Malling 27 (M.27) and East Malling/Long Ashton 9, we compared weight of total harvested fruit, labor hours for harvest, tree and fruit damage, and fruit and juice quality characteristics for machine and hand harvest. Machine harvest was with an over-the-row small fruit harvester. There were no significant differences due to rootstock; however, there were differences between years for most measurements. Weight of harvested fruit did not differ because of harvest method; however, harvest efficiency was 68% to 72% for machine pick and 85% to 89% for machine pick + clean-up weight (fruit left on trees and fruit knocked to the ground during harvest) as compared with hand harvest. On average for the 2 years, hand harvest required 23 labor-hours per acre at a total cost of $417, while machine harvest required 5 labor-hours per acre at a cost of $93. There were no differences due to harvest method on damage to spurs (four to eight spurs damaged per tree) or limbs (0.5–0.8 limbs damaged per tree). Although there were also no differences due to harvest method on fruit bruising (100% for both harvest methods in this study), 10% of fruit were sliced and 4% of fruit were cut in half inadvertently with machine harvest, and none were sliced or cut with hand harvest. Harvest method had no effect on fruit quality characteristics, specifically, soluble solids concentration (SSC), pH, specific gravity, titratable acidity (malic acid equivalents), or percent total tannin, when fruit was pressed immediately after harvest or stored for 2, 3, or 4 weeks before pressing. Juice quality characteristics were affected by storage, and SSC increased 11% in 2011 (3 weeks storage), and 12% and 18% in 2012 (2 and 4 weeks storage, respectively). Similarly, specific gravity increased both years after storage, 1% in 2011, and 1% and 2% in 2012 (a 1% increase in juice specific gravity corresponds to a potential 1.3% increase in alcohol by volume after fermentation for cider). Both years, juice pH tended to decline when fruit was stored (0.01 pH units in 2011, 0.06–0.12 pH units in 2012). Overall, cider apple harvest with an over-the-row small fruit machine harvester used four times less labor than hand harvest, yield reached 87% that of hand harvest (when clean-up yield was included), and juice quality characteristics were not negatively affected. These results suggest that machine harvest may be suitable for cider apples if equipment is available and affordable.
Finishing Bedding Plants: A Comparison of an Unheated High Tunnel versus a Heated Greenhouse in Two Geographic Locations
Authors: Currey Christopher J. , Lopez Roberto G. , Mattson Neil S.
Published: December 2018

Energy accounts for one of the largest costs in commercial greenhouse (GH) production of annual bedding plants. Therefore, many bedding plant producers are searching for energy efficient production methods. Our objectives were to quantify the impact of growing annual bedding plants in an unheated high tunnel (HT) compared with a traditional heated GH environment at two northern latitudes. Ten popular bedding plants [angelonia (Angelonia angustifolia), vinca (Catharanthus roseus), celosia (Celosia argentea), dianthus (Dianthus chinensis), geranium (Pelargonium ×hortorum), petunia (Petunia ×hybrida), french marigold (Tagetes patula), viola (Viola ×cornuta), snapdragon (Antirrhinum majus), and osteospermum (Osteospermum ecklonis)] were grown both in an unheated HT and a glass-glazed GH with an 18 °C temperature set point beginning on 1 Apr. 2011 at both Cornell University (Ithaca, NY) and Purdue University (West Lafayette, IN). Although seven of the species exhibited a delay in flowering in the HT as compared with the heated GH, there were no differences in days to flower (DTF) for geranium, osteospermum, and viola grown at Cornell and viola at Purdue. The remaining species exhibited delays in flowering in the HT environment, which varied based on species. At Purdue, several species were lost because of a cold temperature event necessitating a second planting. For the second planting, osteospermum was the only species grown that flowered significantly later in the HT; 7 days later than the GH-grown plants. Production of cold-tolerant annuals in unheated or minimally heated HTs appears to be a viable alternative for commercial producers aiming to reduce energy costs.
Influence of Pine Bark Particle Size and pH on Cation Exchange Capacity
Authors: Altland James E. , Locke James C. , Krause Charles R.
Published: December 2018

Cation exchange capacity (CEC) describes the maximum quantity of cations a soil or substrate can hold while being exchangeable with the soil solution. Although CEC has been studied for peatmoss-based substrates, relatively little work has documented factors that affect CEC of pine bark substrates. The objective of this research was to determine the variability of CEC in different batches of pine bark and determine the influence of particle size, substrate pH, and peat amendment on pine bark CEC. Four batches of nursery-grade pine bark were collected from two nurseries, and a single source of sphagnum moss was obtained, separated in to several particle size classes, and measured for CEC. Pine bark was also amended with varying rates of elemental sulfur and dolomitic limestone to generate varying levels of substrate pH. The CEC varied with pine bark batch. Part of this variation is attributed to differences in particle size of the bark batches. Pine bark and peatmoss CEC increased with decreasing particle size, although the change in CEC from coarse to fine particles was greater with pine bark than peatmoss. Substrate pH from 4.02 to 6.37 had no effect on pine bark CEC. The pine bark batch with the highest CEC had similar CEC to sphagnum peat. Amending this batch of pine bark with sphagnum peat had no effect on composite CEC.
Effects of Reclaimed Water Irrigation on Growth and Nitrogen Uptake of Turfgrass
Authors: Fan Jinghua , Hochmuth George , Kruse Jason , Sartain Jerry
Published: December 2018

Reclaimed water (RW) is increasingly viewed as a valuable resource for supplying irrigation water and nutrients for landscape plants growing in urban environments. A greenhouse experiment was conducted to determine if nitrogen (N) in RW contributes significantly to turfgrass plant nutrition and to measure N use efficiency and the effects of irrigation with RW on N leaching. The factorial experiment was replicated four times and conducted in a greenhouse on the University of Florida campus for 1 year using ‘Floratam’ st. augustinegrass (Stenotaphrum secundatum) and ‘Empire’ zoysiagrass (Zoysia japonica). Treatments included irrigation with tap water (control), irrigation with RW from University of Florida wastewater treatment facility, irrigation with RW with additional N supplied from ammonium nitrate to achieve 5, 9, and 13 mg·L−1 N solutions, and a dry prilled fertilizer treatment based on the recommended N application rate for turfgrass in northern Florida. The average total N and phosphorus (P) concentrations of RW, based on 1 year weekly monitoring were 3.31 mg·L−1 total N with 2.14 mg·L−1 nitrate-N and 0.46 mg·L−1 ammonium-N, and 2.00 mg·L−1 P composed of 1.92 mg·L−1 orthophosphate. Turfgrass growth responded positively (P < 0.05) to N concentration in the irrigation water. The concentration of N in the unamended university campus RW was not sufficient for optimal turfgrass growth. Grass quality and turfgrass clippings yield maximized when the total N concentration in the irrigation water was at least 5 mg·L−1. Turfgrass receiving dry synthetic N fertilizer resulted in greater growth and 2-fold greater N leaching than with the remaining treatments for both turf types. The highest N recovery percentage for both turf types was found when the N concentration in the solution was 5 mg·L−1.
Overwintering Potential of Onion in Kentucky
Authors: Coolong Timothy , Williams Mark A.
Published: December 2018

Eight cultivars of onion (Allium cepa) representing, long, intermediate, and short-day types were evaluated for their ability to be overwintered in Kentucky. Onion seedlings were transplanted in Nov. 2007 and Oct. 2008. Plants were covered with spunbonded rowcovers or wheat (Triticum sp.) straw mulch in December and mature bulbs were harvested in June and July. Bulbing was initiated in ‘Yellow Granex’ (short-day) during transplant production, thus it was not planted in the field in either year of the experiment. The use of rowcovers compared with straw mulch increased survival rates in all cultivars. The intermediate-daylength cultivars, Candy, Superstar, and Expression, had greater percentages of bolting when grown under rowcovers compared with straw mulch. This resulted low marketable yields despite high survival rates. Rowcover/mulch treatment and cultivar interacted (P ≤ 0.05) to affect yields. The long-day cultivars, Olympic, Ailsa Craig, and Walla Walla had the highest yields when grown under rowcovers. ‘Olympic’, the highest yielding cultivar, produced a large percentage of jumbo-sized bulbs. The short-day cultivar, WI-131, had low survival rates and yields under rowcovers and straw mulch. Pungencies were lowest in ‘WI-131’ and ‘Olympic’. In general, long-day onion cultivars had high rates of survival, low rates of bolting, and higher yields compared with intermediate-day types. This suggests that they would be preferred for overwinter production in Kentucky.
Effect of Nitrogen Fertilization Rate on Aesthetic Quality of Landscape-grown Vines and Groundcovers
Authors: Shober Amy L. , Moore Kimberly A. , Hasing Gitta S. , Wiese Christine , Denny Geoffrey C. , Knox Gary W.
Published: December 2018

Research supporting recommendations for fertilizer needs of landscape-grown vines and groundcovers is lacking. The objectives of our study were to (1) evaluate the quality response of selected vine and groundcover species to nitrogen (N) fertilization at five rates and (2) validate the recommended N fertilizer rates (from the initial evaluation) by monitoring quality of additional landscape-grown vine and groundcover species. Three vine species and two groundcover species were planted in west-central Florida into raised beds containing subsoil fill material in a completely randomized design. Plants were fertilized every 6 weeks with a controlled release fertilizer (20N–0P–0K–23S) at an annual N rate of 0, 2, 4, 6, or 12 lb/1000 ft2. Plant aesthetic quality (0–5 scale) was assessed every 6 weeks for 30 weeks after planting. Although quality of some species increased significantly as N rate increased, all plants supplied with at least 4 lb/1000 ft2 per year N fertilizer had acceptable quality ratings of 3 or better. Screening of three additional vines and four additional groundcovers fertilized with controlled release fertilizer (42N–0P–0K) at an annual N rate of 3, 5, or 7 lb/1000 ft2 confirmed that fertilization with 2 to 4 lb/1000 ft2 per year should be adequate to maintain acceptable vines and groundcovers grown in the landscape in west-central Florida.
Job Task Analysis Survey for the Horticultural Therapy Profession
Authors: Starling Leigh Anne , Waliczek Tina Marie , Haller Rebecca , Brown Beverly J. , Malone René , Mitrione Stephen
Published: December 2018

Research reflective of the specific knowledge, skills, and abilities required to fulfill the job of a horticultural therapist is lacking. Past research indicated a majority of horticultural therapists agreed that a certification test is necessary for the advancement of horticultural therapy as a profession. The goals of this project are to identify the knowledge, skills, and abilities currently used and/or performed by horticultural therapists, as well as to use data to develop a generalized horticultural therapist job description based on current practice, to understand how the profession has changed since previous research was conducted, and to collect data to develop a certification exam. Job descriptions of horticulture-related occupations from the Department of Labor, therapeutic recreation job analysis components from the National Council for Therapeutic Recreation Certification (NCTRC), previous horticultural therapy job analysis information, and a concept analysis of membership-solicited job descriptions were used to construct a knowledge, skills, and ability survey. The web-based survey was sent to 227 current professionally registered members of the American Horticultural Therapy Association (AHTA). The questionnaire consisted of 95 items. A Likert-scale rating system was used by respondents to rate the importance of each item in their current profession. Eighty-five responses were acquired for a response rate of 37%. Survey respondents rated all statements of job knowledge, skills, and abilities presented at least “moderately important” for professional practice. The job task analysis is foundational to the establishment of future training requirements and in the development of a certification exam for horticultural therapy.
Substitution of a Soilless Medium with Yard Waste Compost for Basil Transplant Production
Authors: DeKalb Courtney D. , Kahn Brian A. , Dunn Bruce L. , Payton Mark E. , Barker Allen V.
Published: December 2018

Four experiments were conducted under greenhouse conditions in Oklahoma. Pelleted ‘Genovese’ basil (Ocimum basilicum) seeds were sown in polystyrene flats with six different blends of a peat-lite mix (PL0) and yard waste compost [YWC (this batch designated C0)] in 2012 for the first two experiments. The proportions by volume of PL0:C0 included 100%:0%, 80%:20%, 60%:40%, 40%:60%, 20%:80%, and 0%:100%. Seedling establishment was unaffected consistently, but there was a distinct decline in seedling height and dry weight between 100% PL0 and 80% PL0:20% C0, followed by smaller decreases as the percentage of compost increased in the blends. A third experiment was conducted in 2013 with a different batch of peat-lite (PL1) after the compost had aged 17 months (now designated C1). Treatments were 100% PL1, 80% PL1:20% C1, and 80% PL1:20% C1 mixed with sulfur (S) at 1, 2, or 3 lb/yard3 of blend to acidify the media. The 100% PL1 treatment delayed seedling emergence and suppressed height and dry weight relative to seedlings grown in 80% PL1:20% C1 blends. The PL1 subsequently was found to have been produced in 2010, and the wetting agent had apparently degraded. The aged 2012 compost (C1) was not inhibitory to basil seedling growth when blended at 20% with the PL1, and in fact restored utility to the PL1. The carbon:nitrogen ratio of the original 2012 compost (C0) was 10.8:1, suggesting stability. It appeared that the main reason the C0 compost was inhibitory was that mineralization was slow or immobilization occurred, causing a lack of plant-available nitrogen, especially nitrate. Treatments with S lowered pH of the media, but there were no differences in basil seedling growth between the unamended 80% PL1:20% C1 blend and blends with added S. A fourth experiment compared three peat-lite media: PL1; a batch of the same medium as PL1 that was produced in 2013 (PL2); and a different medium also produced in 2013 (PL3). Peat-lite media were either used unblended, or blended with 20% C1 or 20% C2 (a fresh batch of YWC obtained from the same facility that had produced the original C0). The unamended PL1 was again inhibitory to basil seedling establishment and development. The two “fresh” peat-lite media (PL2 and PL3) were not inhibitory and were similar to each other in performance. A blend of 80% PL2 or 80% PL3 with 20% compost produced similar (C2) or somewhat better (C1) results than were obtained with the unamended peat. We conclude that a blend of 80% peat-lite medium and 20% YWC can be used to produce basil transplants. However, producers must consider the quality of the peat-lite medium and the compost based on the age and composition of the components.
Foliar 2,4-D Application after Physiological Fruit Drop Reduces Fruit Splitting of Mandarin
Authors: Stander Ockert P.J. , Theron Karen I. , Cronjé Paul J.R.
Published: December 2018

Various mandarin (Citrus reticulata) cultivars are prone to fruit splitting, a physiological disorder that entails cracking of the rind, starting from the stylar end of the fruit, with eventual splitting of the endocarp and abscission of the fruit. On two mandarin cultivars, Marisol and Mor, foliar applications of 2,4-dichlorophenoxyacetic acid (2,4-D), calcium (Ca), and potassium (K) were evaluated over two growing seasons for efficacy to reduce fruit splitting in Paarl, South Africa (lat. 33°69′S, long. 18°95′E). Foliar treatment of 10 mg·L−1 2,4-D directly after physiological fruit drop (APFD) compared with later dates in January and February, either alone or in combination with K, increased rind thickness and reduced fruit splitting of ‘Marisol’ and ‘Mor’ by up to 50%, without negatively affecting internal fruit quality. Treatments increased rind thickness and rind strength throughout fruit development in addition to fruit diameter, length, and growth rate, with no significant effect on rind coarseness. There was a slight reduction in juice content and titratable acidity (TA), but no effect on the total soluble solids (TSS). Application of 2,4-D APFD is thought to increase rind integrity due to a direct strengthening effect on the rind during early stages of fruit development.
Warm-season Turfgrass Species Generate Sports Surfaces with Different Playability
Authors: Lulli Filippo , de Bertoldi Claudia , Armeni Roberto , Guglielminetti Lorenzo , Volterrani Marco
Published: December 2018

Synthetic sports surfaces are increasingly subject to standardization of athlete-surface and ball-surface interactions (playability parameters). Such standardizations have led to an increase in the level of the engineering and predictability of these surfaces, and as such may be beneficial also for natural turf. In warm and temperate climates, many natural turf sports surfaces are established with warm-season (C4) turfgrass species due to their suitability to the environment in such areas. This study was aimed at evaluating the Féderation Internationale de Football Association (FIFA)-standard playing characteristics of different sports turf surfaces obtained from three commonly used C4 turfgrass species: 1) ‘Tifway 419’ hybrid bermudagrass (Cynodon dactylon var. dactylon × C. transvaalensis), 2) ‘Zeon’ manilagrass (Zoysia matrella), and 3) ‘Salam’ seashore paspalum (Paspalum vaginatum) for factors concerning leaf tissue (silica, lignin, water content) and canopy structure (shoot density, leaf architecture, stolon density, etc.). Results showed that surfaces of different C4 turfgrass species generate different playability parameters, with seashore paspalum being a harder faster surface, manilagrass being a softer slower surface, and hybrid bermudagrass showing intermediate characteristics. These playing quality results were associated with certain specific canopy biometrical/morphological parameters such as shoot density, horizontal stem density (HSD), leaf section, and, to a lesser extent, to certain plant tissue compounds (lignin, silica).
An Automated System for Monitoring Soil Moisture and Controlling Irrigation Using Low-cost Open-source Microcontrollers
Authors: Ferrarezi Rhuanito Soranz , Dove Sue K. , van Iersel Marc W.
Published: December 2018

Substrate volumetric water content (VWC) is a useful measurement for automated irrigation systems. We have previously developed automated irrigation controllers that use capacitance sensors and dataloggers to supply plants with on-demand irrigation. However, the dataloggers and accompanying software used to build and program those controllers make these systems expensive. Relatively new, low-cost open-source microcontrollers provide an alternative way to build sensor-based irrigation controllers for both agricultural and domestic applications. We designed and built an automated irrigation system using a microcontroller, capacitance soil moisture sensors, and solenoid valves. This system effectively monitored and controlled VWC over a range of irrigation thresholds (0.2, 0.3, 0.4, and 0.5 m3.m−3) with ‘Panama Red’ hibiscus (Hibiscus acetosella) in a peat:perlite substrate. The microcontroller can be used with both regular 24-V alternating current (AC) solenoid valves and with latching 6- to 18-V direct current (DC) solenoid valves. The technology is relatively inexpensive (microcontroller and accessories cost $107, four capacitance soil moisture sensors cost $440, and four solenoid valves cost $120, totaling $667) and accessible. The irrigation controller required little maintenance over the course of a 41-day trial. The low cost of this irrigation controller makes it useful in many horticultural settings, including both research and production.
Performance and Biodegradation in Soil of Novel Horticulture Containers Made from Bioplastics and Biocomposites
Authors: Kratsch Heidi A. , Schrader James A. , McCabe Kenneth G. , Srinivasan Gowrishankar , Grewell David , Graves William R.
Published: December 2018

The container-crops industry relies heavily on single-use plant containers made from petroleum-based plastics, most of which contribute to the solid waste stream in landfills. Plant containers made from biorenewable materials have potential to be more sustainable, but most commercially available biocontainers are either not durable enough for common production cycles or do not effectively biodegrade in soil after use. In 2012 and 2013, we evaluated 28 novel biocontainers (injection-molded prototypes) for their performance during plant production and their biodegradation in soil at two sites with dissimilar soil and climate in Iowa and Nevada, and we compared their performance to that of commercially available biocontainers. Prototype containers made of blends or composites of polylactic acid (PLA) or polyhydroxyalkanoates (PHA) performed well during crop production, and many showed an effective rate of biodegradation in soil. Their rates of biodegradation in Nevada were either similar or lower than they were in Iowa, but the highest rated containers were acceptable for use in both locations. Adding biobased fibers of distiller’s dried grains with solubles or corn stover to form composite materials improved biodegradation over that of the base polymers (PLA or PHA) and had little effect on container performance under greenhouse conditions. Many of the injection-molded prototypes performed as well as the petroleum control containers during crop production, yet biodegraded at similar or faster rates than commercially available fiber containers.