bluuebunny/crossref_metadata_2025 huggingface dataset:
Survey of Consumer Interest in Organic, Sustainable, and Local Container-grown Plants in Maine
Authors: Hawkins Gwendolyn , Burnett Stephanie E. , Stack Lois B.
Published: December 2018

In 2008, we administered a survey to participants at four venues in Maine to determine: 1) the degree of interest in organically, sustainably, and locally grown plants; 2) whether respondents would pay more for these plants compared with conventional plants; and 3) which demographic groups expressed the greatest interest in organically, sustainably, or locally grown plants. Respondents were highly interested in organic and sustainable vegetable/herb and ornamental plants; median interest was 9 on a scale of 1 to 10 where 1 indicated low interest and 10 indicated high interest. They were less interested in locally grown plants; respondents’ median interest in local plants was 6 on the same scale. Survey respondents stated that they would pay 15% more (vegetable/herbs) or 10% more (ornamentals) for organic, sustainable, or local plants than they would for conventionally grown plants. Several demographic factors indicated that respondents were either willing to spend more money on nonconventional plants, or were at least more interested in these kinds of plants. Income and education were positively correlated with the amount of money respondents stated they would spend on nonconventional plants. Younger participants were more interested than older participants in sustainable and organic plants, but they were not willing to pay more for these plants than older participants. Similarly, women were more interested than men in nonconventional plants, but were not likely to spend more on them than men. This survey indicated that there is a strong market for organic and sustainable vegetable, herb, and ornamental plants. Growers could potentially charge 10% to 15% more for these plants than for conventionally grown plants. They would likely receive the highest premium for organic and sustainable plants from individuals with higher incomes and education levels.
Efficacy of Cork Granulates as a Top Coat Substrate Component for Seed Germination as Compared to Vermiculite
Authors: Bozzolo Arianna , Evans Michael R.
Published: December 2018

A top coat is a lightweight substrate component used in seed germination. The seeds are typically placed on a substrate such as peat and then the seeds are covered with a layer of the top coating substrate. The top coat serves to maintain adequate moisture around the seeds and to exclude light. Vermiculite and cork granulates (1 mm) were used as top coat substrates for seed germination to determine if cork granulates could be successfully used as an alternative to vermiculite. The cork granulates had a bulk density of 0.16 g·cm−3, which was higher than that of vermiculite that had a bulk density of 0.12 g·cm−3. Cork granulates had an air-filled pore space of 22.7% (v/v), which was higher than vermiculite which was 13.2%. The water-holding capacity of vermiculite was 63.4% (v/v), which was higher than that of cork granulates that was 35.1%. Seeds of ‘Rutgers Select’ tomato (Solanum lycopersicum), ‘Dazzler Lilac Splash’ impatiens (Impatiens walleriana), ‘Orbital Cardinal Red’ geranium (Pelargonium ×hortorum), ‘Better Belle’ pepper (Capsicum annuum), and ‘Cooler Grape’ vinca (Catharanthus roseus) were placed on top of peat and covered with a 4-mm top coating of either vermiculite or cork granulates. For tomato, impatiens, and vinca, days to germination were similar between seeds germinated using vermiculite and granulated cork as a top coat. Days to germination of geranium and pepper were significantly different with geranium and pepper seeds coated with cork granulates germinating 0.7 and 1.5 days earlier than those coated with vermiculite. For tomato, impatiens, and geranium, the number of seeds germinating per plug tray was similar between the top coats. Number of seeds germinating per tray for pepper and vinca were significantly different. Pepper had an average of 2.8 more seeds germinating per tray, and vinca had an average of 2.4 more seeds germinating per tray if seeds were germinated using granulated cork vs. vermiculite. For all species, dry shoot and dry root weights were similar for seedlings germinated using cork and vermiculite top coats.
Optimal Ripeness Stage for Processing ‘Kent’ Mangoes into Fresh-cut Slices
Authors: Dea Sharon , Brecht Jeffrey K. , Cecilia do Nascimento Nunes Maria , Baldwin Elizabeth A.
Published: December 2018

The optimal ripeness stage for processing and marketing fresh-cut mangoes (Mangifera indica ‘Kent’) with best quality and maximum shelf life was determined. The initial ripeness stage selection was based on whole fruit firmness because this quality attribute was more reliable in predicting fresh-cut shelf life than flesh color or soluble solids content (SSC). Overall, the visual quality deteriorated differently and at different rates among ripeness stages. The shelf life, based on subjective visual evaluation, was 10, 7, and 5 days for ripeness stages corresponding to an average flesh firmness of 35, 30, and 25 N, respectively, and was mainly limited by desiccation and development of off-odor for the two firmer ripeness stages or symptoms of edge tissue damage and spoilage for the least firm stage. The slices from fruit with the highest initial firmness remained firmer during storage, had the lowest pH and SSC to titratable acidity (TA) ratio, and had the highest contents of volatile ketones and esters. The softest slices had the highest pH, SSC:TA ratio, and total ascorbic acid (TAA) content, as well as the lowest TA and highest volatile aldehyde and alcohol contents. Intermediate firmness slices had intermediate pH, SSC:TA ratio, color, and TAA content. Also, they had less volatile alcohols and aldehydes than slices from riper fruit but had similar content of esters as slices from the less ripe fruit. Therefore, based on the results from this study, an initial firmness of 30 N is recommended to process mangoes into fresh-cut slices because it assures the best quality and maximum shelf life based on textural, visual, and compositional attributes.
Differences in Tolerance of Broccoli and Cabbage Cultivars to Clomazone Herbicide
Authors: Harrison Howard F. , Farnham Mark W.
Published: December 2018

Clomazone herbicide is registered for cabbage (Brassica oleracea Capitata group) in the United States but not for other crop groups within the species. Greenhouse and field experiments were designed to compare the tolerance of broccoli (B. oleracea Italica group) and cabbage cultivars to clomazone to assess its potential for weed management in broccoli. Four broccoli cultivars (Captain, Green Magic, Legacy, and Patron) and four cabbage cultivars (Bravo, SC 100, Stone Head, and Vantage Point) were evaluated in all experiments. In a greenhouse experiment where seedlings were transplanted into potting medium containing clomazone at 0, 1.0, 2.0, and 4.0 parts per million (ppm), ‘Bravo’ cabbage was most susceptible. Its injury ratings and shoot weight reduction at 1.0 ppm were similar to ratings and shoot weight reduction for the other cabbage cultivars at 4.0 ppm. Among the broccoli cultivars, Patron was highly susceptible, exhibiting injury and shoot weight reduction similar to Bravo. Green Magic was the most tolerant broccoli cultivar, and it exhibited injury and growth reduction similar to the tolerant cabbage cultivars. In a field experiment where clomazone was applied pretransplanting at 0.25, 0.5, and 1.0 lb/acre, 0.25 lb/acre caused moderate chlorosis to the susceptible cultivars, Bravo and Patron. At 0.50 and 1.0 lb/acre, most cultivars exhibited chlorosis at 2 weeks after transplanting (WAT); however, tolerant cultivars recovered and injury was often not observed at 6 WAT. At 1.0 lb/acre, chlorosis persisted until maturity on ‘Bravo’ and ‘Patron’ foliage. Clomazone did not reduce mean broccoli head weight or the percentage of plants producing market-size heads. Mean cabbage head weight for ‘Bravo’ was reduced by clomazone at 1.0 lb/acre. This study indicates that the variability in clomazone tolerance among broccoli cultivars may be similar to that among cabbage cultivars and suggests that the herbicide can be used safely on tolerant broccoli cultivars at rates that are recommended for cabbage.
Temperature Effects on the Speed and Completion of Germination of 19 Commercially Available Seeded Bermudagrass Cultivars
Authors: Deaton Michael T. , Williams David W.
Published: December 2018

The use of seeded bermudagrasses (Cynodon dactylon) is increasing as athletic field and golf course turf. Anecdotal evidence indicates probable and important differences in germination rates among cultivars when established in late spring or early summer. Germination studies were completed in May 2011 in the Turfgrass Science Laboratory at the University of Kentucky on 19 commercially available seeded bermudagrass cultivars. Evaluations for germination rate and total germination under varying temperature regimes representing 20-year average day/night temperatures for seeding times from 15 May to 1 Aug. were conducted to quantify any differences in germination characteristics among cultivars as affected by temperature. There were highly significant differences (P < 0.0001) among cultivars in germination rate and total germination when grown under 20-year average day/night temperatures. The cultivars Casino Royale and Riviera consistently represented the fastest/slowest to germinate and highest/lowest total seeds germinated across all temperature regimes, respectively. Significant differences (P < 0.0001) were also observed within cultivars for total germination across the temperature regimes tested. The average temperatures of 15 May and 1 Aug. represented slowest/fastest to germinate and lowest/highest total seeds germinated across all temperature regimes, respectively.
Canopy Light Effects in Multiple Training Systems on Yield, Soluble Solids, Acidity, Phenol and Flavonoid Concentration of ‘Frontenac’ Grapes
Authors: Bavougian Christina M. , Read Paul E. , Schlegel Vicki L. , Hanford Kathryn J.
Published: December 2018

Phenolic compounds contribute greatly to the sensory attributes of wine and have a wide range of human health benefits as well. In this study, four trellis/training systems were evaluated for effects on fruit-zone light environment, fruit chemical composition (including phenol and flavonoid concentrations), and yield of ‘Frontenac’ grapes (Vitis sp. MN 1047) grown in southeastern Nebraska over two growing seasons. Photosynthetically active radiation (PAR) was measured above the canopy and within the fruiting zone at berry set, veraison, and harvest. Point quadrat canopy analysis was performed at veraison. Both bound and free (unbound) flavonoid and total phenolic contents were determined for the skins and seeds of fruit samples in 2008. At all sampling dates in 2008, vines grown on Geneva double curtain (GDC) and high cordon (HC) had higher midday percentage PAR transmittances than vines grown on Smart-Dyson (SD) and vertical shoot positioned (VSP) training systems. In 2009, transmittance relationships between trellises were not consistent throughout the season. In both years, leaf layer number (LLN) was lower for GDC and HC than for SD and VSP. Flavonoid and total phenol concentrations of the bound seed and bound skin extracts did not differ among trellises. Within the free extracts, VSP had higher total phenol concentration than SD (GDC and HC were intermediate) and there were no differences in flavonoid concentration. In 2008, GDC had higher pH than other trellises and higher soluble solids than SD and VSP; titratable acidity (TA) was lower in GDC and HC than in SD and VSP. In 2009, SD and VSP had the highest soluble solids concentrations; HC had lower pH than SD and VSP and there were no differences in TA. Results were inconclusive regarding light environment effects on fruit chemical composition.
Moisture Content Measurements of Green Roof Substrates Using Two Dielectric Sensors
Authors: Kargas George , Ntoulas Nikolaos , Nektarios Panayiotis A.
Published: December 2018

Little is known about the accuracy of soil moisture dielectric sensors in coarse-textured root zones and green roof substrates. In the present study, the accuracy of two dielectric sensors of different technologies (frequency domain and time domain dielectric sensor) in measuring moisture content was investigated in six coarse-textured green roof substrates. Calibration equations were developed for both sensors, and the effect of electrical conductivity (EC) on substrate moisture content calculation was determined. It was found that for frequency domain sensor the relationship between dielectric permittivity square root () and actual substrate moisture content (θm) was strongly linear for all tested substrates. However, for each substrate a distinct specific calibration equation of was required. The correlation between substrate permittivity and EC was linear for frequency domain sensor for all moisture levels (0% to 35%). In the case of time domain sensor, each green roof substrate was also described from a different calibration curve between actual substrate moisture content and period of time that was recorded by the device. It was found that their relationship was quadratic for all substrates. In addition, time domain sensor output responded in a quadratic manner to increasing levels of EC. This response was found to interact with actual substrate moisture content as well. It was concluded that the most reliable results for moisture content determination of the coarse-textured green roof substrates were obtained by substrate-specific calibration curves for both dielectric sensors.
Steam as a Preplant Soil Disinfestant Tool in California Cut-flower Production
Authors: Rainbolt Christine M. , Samtani Jayesh B. , Fennimore Steven A. , Gilbert Celeste A. , Subbarao Krishna V. , Gerik James S. , Shrestha Anil , Hanson Bradley D.
Published: December 2018

Methyl bromide (MB) has been widely used in California cut-flower production for effective control of a broad range of soil pests, including plant pathogens and weeds. However, MB is an ozone-depleting substance, and its availability to growers is limited according to the Montreal Protocol guidelines. Steam has been suggested as a nonchemical option for preplant soil disinfestation. Five trials were conducted in protected greenhouse structure or open-field cut-flower nurseries in Monterey, San Luis Obispo, and Ventura counties to evaluate the effect of steam application, alone or in combination with solarization, on soilborne plant pathogen populations, weed densities, and crop growth. Several steam application methods were used including steam blanket, spike-hose, buried drip irrigation lines, or drain tile, and these varied among trials. Calla lily (Zantedeschia aethiopica) nursery trials initiated in 2007 and 2008 showed that steam alone or with solarization was similar to or more effective than MB:chloropicrin (MBPic), applied via drip lines, in controlling weeds and Verticillium dahliae at 6-inch depth. Trials conducted in Spring and Fall 2009 in an oriental hybrid lily (Lilium sp.) nursery showed that, 112 days after steam treatment (DAT) in the spring, the steam (spike-hose) treatment had fewer Fusarium oxysporum propagules than the MB treatment. Lily plant growth in the steam-treated plots was similar to MB-treated plots and taller than in control plots. In the fall trial, fewer lily plants emerged by 44 DAT in the untreated control than in steam- and MB-treated plots and steam was not as effective as MB in reducing Pythium populations. In the 2010 sunflower (Helianthus annuus) and bupleurum (Bupleurum griffithii) trial, all steam treatments reduced Pythium and Phytophthora cactorum survival compared with the untreated control plots, whereas weed densities were reduced only in the spike-hose steam-treated plots. These trial studies showed that steam appeared as effective as MB in suppressing pathogens and weeds and improving crop growth in cut-flower nurseries. However, additional information on fuel consumption, treatment time efficiency, and long-term effects of steam treatment on soil health are needed before steam can be recommended as a viable alternative to MB in California cut-flower nurseries.
Proposed Learning Outcomes for Four-year Horticulture Programs in the United States
Authors: Pritts Marvin P. , Park Travis
Published: December 2018

Most institutions that offer a degree in horticulture have established a set of learning outcomes for the major or are in the process of doing so. Because horticulture programs are being subsumed into larger entities, and because there is no process for providing consistency of expectations for horticulture majors, a group of horticulture administrators from across the United States initiated an effort to develop a common set of learning outcomes that would be appropriate for any four-year horticulture program. The intent was to identify learning outcomes that could be made more specific for an institution’s local conditions and capacities, or expanded to accommodate broader plant science-type majors. Five outcomes with specific goals were identified. An increasing level of higher-order thinking skills is associated with later learning outcomes. The outcomes are knowledge acquisition; knowledge integration; synthesis, creativity and problem-solving; communication; and demonstration of professionalism and proficiency. Adopting these learning outcomes can provide students with guidance in choice of major, faculty with a tool for curriculum development and program assessment, and employers with expectations for new horticulture graduates.
Pre- and Postharvest Muskmelon Fruit Cracking: Causes and Potential Remedies
Authors: Fernández-Trujillo Juan Pablo , Lester Gene E. , Dos-Santos Noelia , Martínez Juan Antonio , Esteva Juan , Jifon John L. , Varó Plácido
Published: December 2018

Fruit cracking is an important disorder that can cause severe loss of marketable yield and revenue in the muskmelon (Cucumis melo) fruit industry. The physiological and environmental factors causing cracking are poorly understood. Although generally considered a physiological disorder caused by fluctuating environmental conditions, current evidence indicates that this disorder also has a genetic as well as a genotype × environment component. Certain cultivars are more susceptible than others, but wide fluctuations in irrigation, temperature, and nutrition during late fruit maturation stages appear to predispose fruit to cracking. This article summarizes the current state of our understanding of the causes of fruit splitting in muskmelons.
Determination of Strawberry Nutrient Optimum Ranges through Diagnosis and Recommendation Integrated System Analysis
Authors: Bottoms Thomas G. , Bolda Mark P. , Gaskell Mark L. , Hartz Timothy K.
Published: December 2018

Diagnosis and recommendation integrated system (DRIS) leaf blade and petiole optimum nutrient ranges were developed through tissue sampling in 53 commercial strawberry (Fragaria ×ananassa) fields in the coastal valleys of central California in 2010 and 2011. All fields were in an annual production system using the day-neutral cultivar Albion. Leaf blades and petioles were sampled five times from early flowering through the fruit harvest period. Data on soil nutrient availability and grower fertilization practices were also collected. DRIS analysis was used to develop nutrient optimum ranges based on nutrient concentrations observed in nutritionally balanced, high-yield fields. Blade nitrogen (N), phosphorus (P), and potassium (K) concentrations declined from the vegetative stage until the main harvest period, and stabilized thereafter. Blade calcium (Ca), boron (B), and iron (Fe) increased over time while magnesium (Mg), sulfur (S), manganese (Mn), zinc (Zn), and copper (Cu) decreased. The blade N optimum range was lower than previously published sufficiency ranges during the fruit harvest period, and the Zn optimum range was lower throughout the season. Other nutrients were in general agreement with previously established sufficiency ranges with the exception of Ca, Mn, and Fe, which were higher. Petiole nitrate-nitrogen (NO3-N) was highly variable among high-yield fields, was not correlated with soil NO3-N at any growth stage, and was therefore of limited value as an indicator of crop N status. Comparison of soil nutrient availability with grower fertilization practices suggested that significant improvement in fertilizer management was possible.
Nutrient and Water Use of Fresh Market Spinach
Authors: Heinrich Aaron , Smith Richard , Cahn Michael
Published: December 2018

In recent years, vegetable growers on the central coast of California have come under increasing regulatory pressure to improve nutrient management and reduce nitrate losses to ground and surface waters. To achieve this goal, growers must understand the nutrient uptake and water use characteristics of their crops. For fresh market spinach (Spinacia oleracea), production methods and cultivars have greatly changed in the last 10–15 years, and as a result, few publications are available on nutrient uptake by modern spinach production methods. This study evaluated nutrient uptake and water use by spinach to provide strategies to better manage nitrogen (N) fertilizer and irrigation applications. In 2011, four fertilizer trials and a survey of 11 commercial fields of spinach grown on high-density plantings on 80-inch beds were conducted on the central coast of California. During the first 2 weeks of the crop cycle, N, phosphorus (P), and potassium (K) uptake was 7.0, 0.6, and 7.2 lb/acre, respectively. In the subsequent 2–3 weeks before harvest the N, P, and K uptake rate was linear and was 4.3, 0.6, and 7.8 lb/acre per day, respectively. N uptake at harvest for the three commercial size categories baby, teenage, and bunch was 74, 91, and 120 lb/acre N, respectively. Of the N in aboveground biomass at harvest, 41% was left in the field following mechanical or hand harvest. Growers at 14 of 15 study sites applied on average 111% more N than was taken up in aboveground biomass at harvest. Results from four fertility trials showed that first crops of the season had low initial soil nitrate concentrations (≤10 ppm), and an at-planting fertilizer application was necessary for maximum yields. For fields following a previous crop (second- or third-cropped) with initial soil nitrate concentrations >20 ppm, at-planting and midseason fertilizer applications could be greatly reduced or eliminated without jeopardizing yield. Rooting depth and density evaluations at four sites showed that 95% of roots were located in the top 16 inches of soil at harvest. To mitigate environmentally negative N losses, the N use efficiency (NUE) can be increased by the use of soil testing done at two critical time points: at-planting and before the first midseason fertilizer application.
Two Cultivars of Oakleaf Hydrangea Respond to Ancymidol, Uniconazole, or Pinching
Authors: Cole Janet C. , Brown Robert O. , Payton Mark E.
Published: December 2018

Shearing is an important cultural practice for maintaining plant size and appearance during nursery crop production. However, oakleaf hydrangea (Hydrangea quercifolia) is susceptible to dieback after shearing. The objective of this study was to determine whether foliar or substrate surface applications of ancymidol or uniconazole can reduce plant growth of oakleaf hydrangea similar to pinching, which was used to simulate shearing. ‘Alice’ or ‘Pee Wee’ oakleaf hydrangea plants were treated in 2002 or 2006, respectively, with ancymidol or uniconazole as a substrate surface application at 0, 1, 2, or 4 ppm; ancymidol as a foliar application at 0, 25, 50, or 100 ppm; or uniconazole as a foliar application at 0, 12.5, 25, or 50 ppm. Both cultivars received the same plant growth regulator treatments in 2012, and a pinched control was included in the 2012 experiment. Ancymidol and uniconazole had limited and inconsistent effects on growth of ‘Alice’ and ‘Pee Wee’ plants regardless of application method. Uniconazole was more effective at controlling growth of ‘Alice’ in 2002 when the study was conducted from October through December than in 2012 when the study was conducted during a more typical growing season of May through September. Plants treated with either ancymidol or uniconazole by either application method usually grew more during the first 2 weeks after application than those that were pinched. During the remainder of the growing season, little difference in growth between pinched plants and growth regulator-treated plants occurred. At harvest in 2012, pinched ‘Alice’ plants had more leaves but a smaller leaf area per leaf than plants treated with growth regulators resulting in no difference in total leaf area or in leaf, shoot, or root dry weight among the treatments. ‘Pee Wee’ treated with uniconazole using either application method or uniconazole as a foliar application had fewer leaves than pinched plants.
Growth and Nutrient Content of Hybrid Bermudagrass Grown for Nursery Purposes at Different Nitrogen, Phosphorus, and Potassium Rates
Authors: Baldi Ada , Lenzi Anna , Nannicini Marco , Pardini Andrea , Tesi Romano
Published: December 2018

The objective of this research was to study the effect of different nitrogen (N), phosphorus (P), and potassium (K) rates on growth and nutrient content of hybrid bermudagrass (Cynodon dactylon × C. transvaalensis) grown in pots for nursery purposes (producing stolons to obtain one-node sprigs to be used as propagation material). Starting from control N, P, and K rates (314, 52, and 198 mg·L−1 substrate, respectively), each element was reduced to zero, halved, doubled, or tripled while the other two were kept unchanged (13 treatments in all). As expected, N, P, and K proved to be necessary for plant growth and development. In fact, when one element was not supplied, plants showed reduced growth and pale-green color. The dry weight of aerial part (shoots plus stolons) was mainly affected by N and increased along with this element with a nonlinear less than proportional trend. Phosphorus had a larger effect than N or K on the number of primary stolons, which varied along with P rate fitting a nonlinear regression model. Potassium rate influenced the characteristics of primary stolons (length, number of nodes, and ramifications) more than N or P. A significant linear regression was observed for the number of ramifications (secondary stolons), while stolon length and the number of nodes fit a nonlinear regression model. Plant growth response to the imposed rates revealed the possibility to halve N or P in respect to control rates, while for K the control rate proved to be necessary. In fact, when K rate was halved, the number of nodes, which is a main parameter for nursery purposes, significantly decreased. Half N, half P, and control K rates also ensured a satisfactory plant mineral composition, consistent with values previously reported for bermudagrass. Potassium competition with both calcium and magnesium was observed. Nitrogen, P, or K rates higher than the respective controls are not advisable since they did not enhance plant growth or mineral content.
Unique Fruit Development of Ornamental ‘Teapot’ Jujube
Authors: Yao Shengrui
Published: December 2018

Jujube or chinese date (Ziziphus jujuba) has fruit that is developed mainly from ovary plus some nectary disk tissue, and the fruit can appear smooth or bumpy on the surface. The objective of this study was to investigate the unique fruit development of ornamental ‘Teapot’ jujube. Unlike ‘Li’ and ‘Lang’, ‘Teapot’ jujube fruit had one to five protuberances on the shoulder of the fruit and few entirely lack protuberances. The stamens of ‘Teapot’ jujube flowers were fewer in number, misplaced in location, and deformed in shape—some stamens were anthers only while others were filament only. Deformed stamens of ‘Teapot’ jujube were always anchored in the nectary disk instead of at their normal location—near the edge of the nectary disk. After bloom, the residue of stamens, nectary disk, and ovary were all constituents of the developing fruit. The deformed stamens developed into the fleshy protuberances and equaled them in number. Fruit with only two protuberances predominated, which is how the ‘Teapot’ jujube acquired its name, but the ratio among protuberance categories varied between trees. With its unique and decorative fruit shape, and acceptable fruit quality, ‘Teapot’ jujube could be used as a backyard tree, both as an ornamental and for its fruit.
Testing, Promoting, and Launching a Mobile Application as an Extension Tool: A Case Study with IPMPro
Authors: Fulcher Amy , White Sarah A. , Chong Juang-Horng (JC) , Neal Joseph C. , Williams-Woodward Jean L. , Adkins Craig R. , Braman S. Kristine , Chappell Matthew R. , Derr Jeffrey F. , Dunwell Winston C. , Frank Steven D. , Gill Stanton A. , Hale Frank A. , Klingeman William E. , LeBude Anthony V. , Rane Karen , Windham Alan S.
Published: December 2018

Mobile device applications (apps) have the potential to become a mainstream delivery method, providing services, information, and tools to extension clientele. Testing, promoting, and launching an app are key components supporting the successful development of this new technology. This article summarizes the considerations and steps that must be taken to successfully test, promote, and launch an app and is based on the authors’ experience developing two horticulture apps, IPMPro and IPMLite. These apps provide information for major pests and plant care tasks and prompt users to take action on time-sensitive tasks with push notifications scheduled specifically for their location. App testing and evaluation is a continual process. Effective tactics for app testing and evaluation include garnering focus group input throughout app development and postlaunch, in-house testing with simulators, beta testing and the advantages of services that enhance information gained during beta testing, and postlaunch evaluations. Differences in promotional and bulk purchasing options available among the two main device platforms, Android and iOS, are explored as are general preparations for marketing the launch of a new app. Finally, navigating the app submission process is discussed. Creating an app is an involved process, but one that can be rewarding and lead to a unique portal for extension clientele to access information, assistance, and tools.
A Miniature Instrumented Sphere to Understand Impacts Created by Mechanical Blueberry Harvesters
Authors: Li Changying , Yu Pengcheng , Takeda Fumiomi , Krewer Gerard
Published: December 2018

The majority of U.S. northern highbush blueberry (Vaccinium corymbosum) and southern highbush blueberry (V. corymbosum hybrids) for the fresh market is hand harvested because of the high bruising damage to the fruit caused by current machine harvesters. To reduce bruising, it is important to understand how the harvester’s machine parts interact with the fruit. A miniature instrumented sphere, hereafter referred to as Smart Berry, was developed to mimic a blueberry (Vaccinium species and hybrids) fruit and to quantitatively measure mechanical impacts experienced by a real blueberry fruit during mechanical harvesting. The Smart Berry sensor recorded impacts using three single-axis accelerometers with a maximum sampling frequency of 3 kHz and ±500 gn sensing range. Calibration tests showed that the maximum error of the measurement was 0.53% of the output span. The diameter of the sensor (1 inch) was only half of that for the current smallest instrumented sphere on the market. Used together with a close-up video, the fully calibrated sensors were used to identify and measure mechanical impacts occurring in a commercial rotary blueberry harvester. The data suggested that the catch pan created the largest single mechanical impacts. Thus, reducing the drop height or padding the surface could be effective measures to reduce bruising damage caused by the catch pans. The Smart Berry was also used to compare harvesters with two different detaching mechanisms. The rotary detaching mechanism created significantly fewer and lower-magnitude impacts than the slapper mechanism (P ≤ 0.05). Manual drop tests demonstrated that the impact data recorded by the Smart Berry can be correlated with bruising damage experienced by blueberry fruit. Taken together, the data can be used to improve the design of the current machine harvesters for reduction of bruising damage to blueberry fruit destined for the fresh market, and potentially lead to enhanced highbush blueberry production efficiency in the long run.
Effects of Preplant Potassium Sources and Rates for Tomato Production
Authors: Santos Bielinski M.
Published: December 2018

A two-season study was conducted to assess the effects of preplant potassium (K) fertilization rates and sources on the growth and yield of beefsteak tomato (Solanum lycopersicum). Fourteen treatments resulted from the combination of two K sources: sulfate of potash [SOP (0N–0P–42K)] and muriate of potash [MOP (potassium chloride, 0N–0P–50K)] and seven preplant K rates (0, 50, 100, 200, 300, 400, and 500 lb/acre). Soil electrical conductivity (EC) at 4 weeks after transplanting was influenced by the interaction between preplant K rates and sources. When SOP was applied, soil EC increased from 0.4 dS·m−1 with no preplant K application to ≈1.3 dS·m−1 with a rate of 500 lb/acre of preplant K. However, the soil EC steadily increased from 0.4 to 3.0 dS·m−1 as preplant K rates increased from 0 to 500 lb/acre when MOP was used as the nutrient source. The combined effect of the preplant application of K rates and sources influenced the seasonal extra-large and total marketable fruit weight, which increased steadily with K rates, regardless of the sources, from 0 to 300 lb/acre. At K rates between 300 and 500 lb/acre, there were no extra-large and total fruit weight differences among rates when SOP was applied. In contrast, extra-large and total marketable fruit weight declined when rates increased from 300 to 500 lb/acre of K and MOP was applied to the soil. Data demonstrated that plots treated with MOP at rates higher than 300 lb/acre of K increased soil EC and caused a decline on extra-large and total marketable fruit weight of tomato.
Economic Profitability of Growing Lettuce and Tomato in Western Washington under High Tunnel and Open-field Production Systems
Authors: Galinato Suzette P. , Miles Carol A.
Published: December 2018

Lettuce (Lactuca sativa) and tomato (Solanum lycopersicum) are popular fresh market vegetable crops. In western Washington, there is interest in growing them in high tunnel production systems because of the region’s mild, coastal climate. The objectives of this study were to contrast the economic potential of growing lettuce and tomato under high tunnel and open-field production systems, and identify the main factors affecting profitability within each production system. Economic data for this study were collected by interviewing experienced lettuce and tomato growers in western Washington during focus group sessions. Costs of production varied by crop and production system, and findings indicated that it was five times more costly to grow lettuce and eight times more costly to grow tomato in a high tunnel than in the open field in western Washington. For lettuce, the labor cost per square foot of growing area was found to be 6 times greater in a high tunnel than in the open field; and for tomato, labor costs were 10 times greater in a high tunnel than in the open field. Total labor cost comprised more than 50% of the total production costs of lettuce and tomato in both the high tunnel and open-field systems. The percentage of total labor cost was similar in both the high tunnel and open-field production for lettuce, but was higher in high tunnel tomato production than in the open field. Tunnel-grown lettuce and tomato had three and four times greater marketable yield compared with field-grown, respectively. Given the base crop yield and average price, it was 43% more profitable to grow lettuce in the open field than in the high tunnel, while in contrast, high tunnel-grown tomato was three times more profitable than open-field tomato production.
Evaluation of Preemergence and POST-directed Herbicides on Rootstock Safety in Field-grown Almond Nursery Stock
Authors: Abit Mary Joy M. , Hanson Bradley D.
Published: December 2018

Producers of fruit and nut tree nursery stock need effective weed control for maximum production of vigorous, high-grade planting material. Current weed practices include methyl bromide fumigation, preemergence herbicides, hand labor, and multiple tillage operations. As methyl bromide use is phased out due to air quality concerns, and fuel and labor costs continue to increase, herbicides are likely to become even more important for weed management in the nursery industry. Before new herbicides can be registered and used in stonefruit (Prunus sp.) tree nurseries, weed control efficacy and crop safety data are needed under local conditions. Eleven experiments were conducted from 2007 to 2011 in California tree nurseries to evaluate the crop safety of preemergence (PRE) and postemergence (POST-directed) applications of various herbicides on commonly grown peach (Prunus persica), plum (Prunus domestica), and peach/plum hybrid rootstocks budded to almond (Prunus dulcis) scions. Rootstocks grown from cuttings generally were more tolerant to herbicides than those grown from seed. Crop safety was adequate in seeded and vegetatively propagated rootstocks with oryzalin, pendimethalin, and isoxaben, all of which are labeled for use in tree nurseries. The unregistered herbicides, dithiopyr, rimsulfuron, oxyfluorfen, and foramsulfuron; as well as lower rates of indaziflam and penoxsulam; applied PRE and POST-directed can provide good to excellent weed control in some stonefruit rootstocks. However, because slight crop injury was occasionally observed, additional work on application rates, timing, and method of application, especially on nonlabeled herbicides is needed before these materials can be considered for registration and broad scale use in tree nurseries.
Evaluation of Seven Complex Pennisetum Hybrids for Container and Landscape Performance in the Pacific Northwestern United States
Authors: Contreras Ryan N. , Owen Jim , Hanna Wayne , Schwartz Brian
Published: December 2018

Ornamental grasses such as fountaingrass or napiergrass, collectively called pennisetums, belong to the genus Pennisetum, which is a diverse genus with over 80 species adapted to a wide range of climatic regions and known for its drought tolerance. Breeding efforts have led to improvements such as more intense purple foliage color, disease resistance, and apparent sterility. These improved forms have been developed and tested in the eastern United States. The objective of this research was to evaluate container and field performance of seven new complex hybrid pennisetums in the Pacific northwestern United States. Two completely randomized experiments with three replications were conducted over 2 years (2010 and 2011) at two locations. We selected seven trispecific hybrid pennisetums resulting from interploid and interspecific crossing that were given accessions Tift 5, Tift 6, Tift 10, Tift 11, Tift, 13, Tift 15, and Tift 26. Experiment 1 evaluated container performance in Corvallis, OR, while Expt. 2 evaluated field performance in Aurora, OR. Size index (SI), growth form rating, and color rating were collected and analyzed separately by location. In the container study, significant differences were observed among selections for growth form in 2010 and color ratings in both 2010 and 2011. In 2010, Tift 6, Tift 11, Tift 13, and Tift 15 had the highest growth form rating. For color rating, Tift 5, Tift 10, and Tift 26 were among the four highest rated selections in both years. In the field study, Tift 5, Tift 10, Tift 11, and Tift 26 had the highest SI when data were pooled over the 2 years, but all selections reached acceptable size for landscape use during both years of the study. Similarly, there were color differences among selections with Tift 5, Tift 10, Tift 15, and Tift 26 being highest rated. None of the selections survived below winter temperatures of −5 °C at either location during either year of the study. Our evaluations indicate that these selections have potential in the Pacific northwestern United States as annuals. Differences in complex hybrid pennisetums were observed in SI, growth form rating, and color rating. These differences demonstrated the variation among selections and will allow producers to choose desired traits based on market preference.
Factors Affecting Nutrient Availability, Placement, Rate, and Application Timing of Controlled-release Fertilizers for Florida Vegetable Production Using Seepage Irrigation
Authors: Carson Luther C. , Ozores-Hampton Monica
Published: December 2018

This publication summarizes the factors influencing controlled-release fertilizer (CRF) nutrient release, CRF placement, CRF rate, and CRF application timing for the two major seepage-irrigated vegetable production systems (plasticulture and open-bed) in Florida. One of several best management practices for vegetable production, CRF helps growers achieve total maximum daily loads (TMDLs) established in Florida under the Federal Clean Water Act. Several factors intrinsic to CRF and to the vegetable production systems affect CRF nutrient release, making implementation of CRF fertility programs challenging. Increasing or decreasing soil temperature increases or decreases nutrient release from CRF. Soil moisture required for uninhibited plant growth is within the soil moisture range for optimum CRF nutrient release. CRF substrate affects nutrient release rate, which is inversely related to coating thickness and granule size. Soil microbes, soil texture, and soil pH do not influence nutrient release rate. Field placement of CRFs in seepage-irrigated, plasticulture, and open-bed production should be in the bottom mix at bed formation and soil incorporated or banded at planting, respectively. In plasticulture production systems, soil fumigation and delayed planting for continuous harvest may add a 14- to 21-day lag period between fertilization and planting, which along with different season lengths will influence CRF release length selected by growers. Using a hybrid fertilizer system in plasticulture production or incorporating CRF at planting in open-bed production allows for up to a 25% reduction in the nitrogen (N) rate needed.
The Metabolic Costs of Gardening Tasks in Children
Authors: Park Sin-Ae , Lee Ho-Sang , Lee Kwan-Suk , Son Ki-Cheol , Shoemaker Candice A.
Published: December 2018

The metabolic cost of 10 gardening tasks was measured in children to determine the exercise intensities associated with these tasks. Seventeen children [(mean ± sd) aged 12.4 ± 0.7 years and body mass index 21.6 ± 4.0 kg·m−2] participated in this study. The children performed the 10 gardening tasks at a garden previously established in Cheongju, Chungbuk, South Korea. They visited the garden twice and performed five different tasks on each visit. Five minutes were provided to complete each gardening task and a 5-minute rest was allowed between each task. The children wore a portable telemetric calorimeter and a heart rate monitor for measurement of oxygen uptake and heart rate during the gardening tasks. The results show that the 10 gardening tasks represented moderate- to high-intensity physical activity for the children [4.3 ± 0.5 to 6.6 ± 1.6 metabolic equivalents (MET)]. Digging (6.6 ± 1.6 MET) and raking (6.2 ± 1.5 MET) were high-intensity physical activities, and digging was more intense than the other gardening tasks performed in this study (P < 0.05). Tasks such as weeding (5.8 ± 1.1 MET), mulching (5.5 ± 1.3 MET), hoeing (5.3 ± 0.7 MET), sowing seeds (5.0 ± 1.1 MET), harvesting (4.8 ± 0.6 MET), watering (4.6 ± 1.1 MET), mixing growing medium (4.4 ± 0.6 MET), and planting transplants (4.3 ± 0.5 MET) were moderate-intensity physical activities. The MET data for the gardening tasks will facilitate the development of garden-based exercise interventions for children, which can promote health and physically active lifestyle.
Comparison of Paper Bags, Calcium Carbonate, and Shade Nets for Sunscald Protection in ‘Murcott’ Tangor Fruit
Authors: Tsai Meng-Shiun , Lee Tan-Cha , Chang Pai-Tsang
Published: December 2018

‘Murcott’ tangor (Citrus reticulata × Citrus sinensis) is susceptible to sunscald injury due to high temperatures during summer in Chiayi, Taiwan. The average rate of sunscald damage in ‘Murcott’ tangor fruit is 13.6% when no protective measures are used. The objective of this study was to compare the effects of covering developing fruit with white paper bags, calcium carbonate, or shade nets to reduce the effects of sunscald. A significant reduction in sunscald was realized when using white paper bags, calcium carbonate spray, or white, green, and black shading nets. Calcium carbonate spraying was the most rapid method, but was less effective in controlling sunscald, and resulted in the lowest photosynthetic rate. Compared with trees under shade nets, those under black netting had larger and heavier fruit. There were no significant differences in peel color, titratable acid (TA), total soluble solids/titratable acid (TSS/TA) ratio, or respiration rate for the evaluated treatments. Although all shading materials reduced sunscald, the use of shade net was the most effective in controlling damage related to this, and thus can have significant benefits for commercial citrus (Citrus sp.) orchard operations.
Implementation of Wireless Sensor Networks for Irrigation Control in Three Container Nurseries
Authors: Chappell Matthew , Dove Sue K. , van Iersel Marc W. , Thomas Paul A. , Ruter John
Published: December 2018

Water quality and quantity are increasingly important concerns for agricultural producers and have been recognized by governmental and nongovernmental agencies as focus areas for future regulatory efforts. In horticultural systems, and especially container production of ornamentals, irrigation management is challenging. This is primarily due to the limited volume of water available to container-grown plants after an irrigation event and the resultant need to frequently irrigate to maintain adequate soil moisture levels without causing excessive leaching. To prevent moisture stress, irrigation of container plants is often excessive, resulting in leaching and runoff of water and nutrients applied to the container substrate. For this reason, improving the application efficiency of irrigation is necessary and critical to the long-term sustainability of the commercial nursery industry. The use of soil moisture sensing technology is one method of increasing irrigation efficiency, with the on-farm studies described in this article focusing on the use of capacitance-based soil moisture sensors to both monitor and control irrigation events. Since on-farm testing of these wireless sensor networks (WSNs) to monitor and control irrigation scheduling began in 2010, WSNs have been deployed in a diverse assortment of commercial horticulture operations. In deploying these WSNs, a variety of challenges and successes have been observed. Overcoming specific challenges has fostered improved software and hardware development as well as improved grower confidence in WSNs. Additionally, growers are using WSNs in a variety of ways to fit specific needs, resulting in multiple commercial applications. Some growers use WSNs as fully functional irrigation controllers. Other growers use components of WSNs, specifically the web-based graphical user interface (GUI), to monitor grower-controlled irrigation schedules.