bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Wine Grape Cultivars on Growth and Leaf Blade and Petiole Mineral Nutrients
Authors: Fallahi Esmaeil , Shafii Bahman , Stark Jeffrey C. , Fallahi Bahar , Hafez Saad L.
Published: December 2018

Cane growth, leaf blade area, blade and petiole fresh and dry weights and mineral nutrients of six grape (Vitis vinifera) cultivars were evaluated in 2000 and 2001 under climatic conditions of southwestern Idaho. The cultivars were: `Barbera 02', `Cabernet Sauvignon 02', `Cabernet Sauvignon 04', `Chardonnay 29', `Merlot 01', and `Sangiovese 04'. No differences were found in cane growth of different cultivars. `Sangiovese 04' and `Merlot 01' had larger leaf area and heavier leaves (both blades and petioles) and higher concentrations of blade nitrogen (N), while `Merlot 01' and `Chardonnay 29' had higher petiole nitrate-N than all other cultivars. `Merlot 01' had relatively the highest potassium (K) concentrations in both blade and petiole tissues. `Chardonnay 29' had lower concentration of calcium (Ca) and `Sangiovese 04' had lower concentrations of magnesium (Mg) in both blade and petiole tissues than other cultivars although differences were not always significant. `Barbera 02' had higher blade iron (Fe) and tended to have higher blade copper (Cu) than other cultivars. However, `Chardonnay 29' had higher petiole Fe than `Barbera 02', `Cabernet Sauvignon 04', and `Sangiovese 04'. `Merlot 01' had higher blade manganese (Mn) than `Sangiovese 04'.
Early Field Detection of Bolting in Celery
Authors: Jenni Sylvie , Gamache Isabelle , Côté John Christopher , Stewart Katrine A.
Published: December 2018

Growers of early stalk celery (Apium graveolens var. dulce) often experience financial losses due to bolting (the premature and rapid elongation of the main celery stem) in temperate regions. A method was developed to provide early warning of bolting in field-grown celery, on the basis of two criteria, one visual and one microscopic, for inflorescence development. Bolting could be detected 40 days after transplanting using the visual criterion, and as early as 30 days after transplanting using the microscopic criterion. Early detection of bolting using the visual and microscopic criteria provided celery growers with periods of, respectively, 25 days and up to 35 days to consider harvesting earlier, before the length of the celery stems exceeded commercial standards. This method could be effective in minimizing financial losses due to bolting when coupled with agro-economic studies.
The Organic Farming Movement in Turkey
Authors: Sayin Cengiz , Brumfield Robin G. , Mencet M. Nisa , Ozkan Burhan
Published: December 2018

In the past decade, organic production has become a growing segment of the healthy food market. Organic farming is expanding gradually in many countries, and consumption of organic products is gaining a huge importance in the developed countries, such as the U.S., countries in the European Union (EU), Canada, and Japan. The increase of domestic market demand in developed countries and export potential for developing countries has stimulated organic agricultural production. In this report, we briefly examine the development of the world organic market and examine regulations with regard to production and certification. We also provide a detailed review of the current structure of organic food production and marketing in Turkey, a developing country with advantages to increase organic production. The overall picture of organic products in Turkey seems very positive. The size of the domestic market for organic products is estimated to be $3 to $5 million, with annual growth projected to be about 50% for the next 5 years. Eighty percent of current production in Turkey is export-oriented. The EU has been the main export destination. The positive market outlook will no doubt create a renewed interest in organic products among Turkish farmers and policy makers.
Effects of Phosphorous and Phosphoric Acids on Growth and Phosphorus Concentrations in Container-grown Tropical Ornamental Plants
Authors: Broschat Timothy K.
Published: December 2018

Chinese hibiscus (Hibiscus rosa-chinensis), shooting star (Pseuderanthemum laxiflorum), downy jasmine (Jasminum multiflorum), areca palm (Dypsis lutescens), and `Jetty' spathiphyllum (Spathiphyllum) were grown in containers using Osmocote Plus 15-9-12 (15N-3.9P-10K), which provided phosphorus (two experiments), or resin-coated urea plus sulfur-coated potassium sulfate, which provided no phosphorus (one experiment). Plants were treated with water drenches (controls), drenches with metalaxyl fungicide only, drenches with phosphoric acid (PO4-P), drenches with metalaxyl plus phosphorus from phosphoric acid, drenches with PhytoFos 4-28-10 [4N-12.2P-8.3K, a fertilizer containing phosphorous acid (PO3-P), a known fungicidal compound], or a foliar spray with PhytoFos 4-28-10. Plants receiving soil drenches with equivalent amounts of P from PhytoFos 4-28-10, PO4-P, or PO4-P+metalaxyl generally had the greatest shoot and root dry weights and foliar PO4-P concentrations. There were no differences between the control and metalaxyl-treated plants, indicating that root rot diseases were not a factor. Therefore, responses from PhytoFos 4-28-10 were believed to be due to its nutrient content, rather than its fungicidal properties. Foliar-applied PhytoFos 4-29-10 produced plants that were generally similar in size to control plants or those receiving metalaxyl only drenches. Fertilizers containing PO3-P appear to be about as effective as PO4-P sources when applied to the soil, but are relatively ineffective as a P source when applied as a foliar spray. A distinct positive synergistic response for shoot and root dry weights and foliar PO4-P concentrations was observed for the PO4-P+metalaxyl treatment when no P was applied except as a treatment.
A Collaborative Effort to Train Green Industry Professionals
Authors: VanDerZanden Ann Marie , McMahan Linda R. , Bell Neil , Ries Paul , Williams Patty , McAuliffe Aimee
Published: December 2018

A collaborative project between the Oregon State University Extension Service, and the green industry and allied professional organizations resulted in an educational seminar series for landscape professionals. In 2003 and 2004, the seminar series consisted of seven 3.5-hour sessions covering a range of horticultural topics and capitalized on expertise of extension personnel and green industry professionals. After the 2004 series, a survey was sent to all participants to determine attendance, overall evaluation, usefulness and applicability of information, participant learning, and behavior change as a result of the seminars. The response rate was 31%. Overall, participants gave the seminars a positive rating. A majority (83%) of respondents reported they had applied information learned at the seminar(s), and showed a significant increase in understanding of a subject as a result of participating in the seminar(s). Further, 98% of those who applied this information reported making multiple changes to their practices or recommendations to clients in the 6 months following the seminars.
A Daylight Climate Chamber for Testing Greenhouse Climate Control Strategies and Calculating Canopy Carbon Dioxide Exchange
Authors: Jensen Lise T. , Aaslyng Jesper M. , Rosenqvist Eva
Published: December 2018

A daylight climate chamber was designed with the aim of testing new greenhouse climate control strategies on a small scale. Precise control and measure ment of the chamber climate and long-term measurement of canopy carbon dioxide (CO2) exchan ge was possible. The software was capable of simulating a climate computer used in a full-scale greenhouse. The parameters controlled were air temperature, CO2 concentration, irradiance, air flow, and irrigation. The chamber was equipped with a range of sensors measuring the climate in the air of the chamber and in the plant canopy. A chamber perfor mance experiment with chrysanthemum (Chrysanthemum grandiflorum `Coral Charm') plants grown in perlite was carried out over the course of 3 weeks. Five air temperature treatments at a day length of 13 hours were carried out, all with the same 24-hour mean temperature of 20 °C, but different day temperatures (18.0 to 25.1 °C) and night temperatures (14.0 to 22.4 °C). Rate of canopy CO2 exchange in the chambers was calculated. In the range of day temperatures used, rates of canopy photosynthesis were almost equal. The results showed that leaf area and plant dry weight after 3 weeks were not significantly different among temperature treatments, which is promising for further investigations of how climate control can be used to decrease energy consumption in greenhouse production.
Chlorothalonil, Trifloxystrobin, and Mancozeb Decrease Anthracnose Symptoms on Three Cultivars of Wintercreeper Euonymus
Authors: Schupbach-Ningen Stephanie L. , Cole Janet C. , Cole James T. , Conway Kenneth E.
Published: December 2018

The effectiveness of chlorothalonil, mancozeb, and trifloxystrobin applied alone or in rotations of two or three fungicides to control anthracnose symptoms caused by Colletotrichum gloeosporioides was evaluated on three cultivars of field- and container-grown wintercreeper euonymus (Euonymus fortunei) during the 2001 growing season. Studies were conducted at Stillwater, Okla.; Fayetteville, Ark.; and Park Hill, Okla. Rooted cuttings of wintercreeper euonymus `Emerald Gaiety', `Emerald 'n Gold', and `Emerald Surprise' were transplanted from 1-gal plastic containers into field soil at the Oklahoma State University Nursery Research Station and at the University of Arkansas Horticulture Farm on 10 May 2001. In a parallel study, recently transplanted rooted cuttings of the same cultivars in 1-gal pots containing substrate consisting of pine bark and sand were placed in a shadehouse under 30% shade at Stillwater and Fayetteville and 73% shade at Park Hill on 11 May 2001. `Emerald Gaiety' had fewer disease symptoms than `Emerald 'n Gold' or `Emerald Surprise' in the field and in containers at Stillwater and Fayetteville. At Fayetteville, mancozeb applied alone or in rotation with chlorothalonil or trifloxystrobin provided better anthracnose control than treatments without mancozeb, but no fungicide eliminated anthracnose symptoms. Application of fungicides in rotations that include mancozeb and use of resistant cultivars can help decrease anthracnose symptoms.
Performance of Containerized and Bare-root Transplants with Soil Fumigants for Florida Strawberry Production
Authors: Gilreath James P. , Santos Bielinski M. , Noling Joseph W. , Locascio Salvadore J. , Dickson Donald W. , Rosskopf Erin N. , Olson Steven M.
Published: December 2018

Field studies were conducted in three Florida locations (Bradenton, Gainesville, and Quincy) during 1998-99 and 1999-2000 to: 1) compare the performance of two transplant systems under diverse MBr alternative programs in `Chandler' strawberry (Fragaria ×ananassa), and 2) determine the efficacy of these treatments on soilborne pest control in strawberry. Fumigant treatments were: 1) nonfumigated control, 2) methyl bromide plus chloropicrin (MBr + Pic) at a rate of 350 lb/acre, 3) Pic at 300 lb/acre and napropamide at 4 lb/acre, 4) 1,3-dichloropropene (1,3-D) plus Pic at 35 gal/acre and napropamide at 4 lb/acre, 5) metam sodium (MNa) at 60 gal/acre and napropamide at 4 lb/acre, and 6) MNa followed by 1,3-D at 60 and 12 gal/acre and napropamide at 4 lb/acre, respectively. Strawberry transplants were either bare-root or containerized plugs. There were no significant fumigant by transplant type interactions for strawberry plant vigor and root weight per plant, whereas ring nematode (Criconema spp.) and nutsedge (Cyperus rotundus and C. esculentus) populations, and total marketable fruit weight were only infl uenced by fumigant application. The nonfumigated plots had the lowest strawberry plant vigor and root weight per plant in all three locations. In most cases, plant vigor and root biomass per plant increased as a response to any fumigant application. With regard to the transplant type, bare-root transplants had similar plant vigor as plugs in two of the three locations. Fumigation improved nutsedge and ring nematode control. All fumigants had higher early and total marketable yield than the nonfumigated control, whereas transplant type had no effect on total fruit weight.
Response of Six Bermudagrass Cultivars to Different Irrigation Intervals
Authors: Baldwin C.M. , Liu H. , McCarty L.B. , Bauerle W.L. , Toler J.E.
Published: December 2018

A 2-year greenhouse study was conducted at Clemson University, Clemson, S.C., in 2003 and 2004 to determine drought responses of six bermudagrass (Cynodon spp.) cultivars at four irrigation intervals. Cultivars selected from the 2002 National Turfgrass Evaluation Program Bermudagrass Trial were `SWI-1012', `Arizona Common', `Tift No.3', `Tifsport', `Aussie Green', and `Celebration'. Treatments included 5-, 10-, and 15-day irrigation intervals plus a control (irrigated daily). Volumetric soil water content (VSWC) and evapotranspiration (ET) rates were recorded every 3 days. Turfgrass quality (TQ) was observed weekly and root weight was measured at the end of a 6-week study. `Aussie Green' and `Celebration' produced the highest TQ rating (>7) at week 4 when watered daily. After 4 weeks of the 5-day irrigation interval, all cultivars showed unacceptable quality ratings (<7). However, `Aussie Green' and `Celebration' were able to maintain an acceptable TQ rating (7), compared to `Arizona Common' (5.1) and `Tift No.3' (5.8) at week 2 (5-day treatment). `Celebration' produced 114% and 97% greater root weight than `Tifsport' and `Aussie Green', respectively, when pooled across all irrigation treatments. At the 15-day irrigation interval treatment, six bermudagrass cultivars pooled together produced 78%, 22%, and 11% greater root weight vs. control, 5-day, and 10-day treatments, respectively. When pooled for all treatments, `Aussie Green' and `Celebration' VSWC was 5% and 7% lower than `Tift No.3', and ET rates were 26% and 30% greater than `Arizona Common'. Based on these results, irrigating bermudagrass in 5-day intervals should be carefully monitored.
The United States Food and Drug Administration's Approach to Training International Suppliers in Food Safety and Security
Authors: Rushing James W. , Walsh Christopher S.
Published: December 2018

In 1998 the U.S. Food and Drug Administration (US-FDA) published formal guidelines for the microbial safety of fresh produce. The guidelines identify and suggest the use of good agricultural practices (GAP) and good manufacturing practices (GMP) for producers and handlers. To extend this important information to international producers and suppliers, an agreement was made to create a GAP and GMP training program through the Joint Institute for Food Safety and Applied Nutrition (JIFSAN). JIFSAN combined resources of US-FDA, the University of Maryland, and other universities to reach audiences outside the U.S. with food safety information. The program is based on the train-the-trainer concept. Its success depends on the ability of the newly trained program participants to reach key audiences in the target country. We present an overview of the development of a training manual and its content, the selection of a teaching team and target countries, and the methods for implementation of the training. Examples of activities in various countries are summarized. Results of a program review conducted in 2004, following nine program deliveries, are also discussed. Future needs are identified and current programming plans are provided.
Nutrient Management of Nursery Runoff Water using Constructed Wetland Systems
Authors: Taylor Milton D. , White Sarah A. , Chandler Stewart L. , Klaine Stephen J. , Whitwell Ted
Published: December 2018

Substantial quantities of water and nutrients are required for the production of high value nursery and greenhouse crops. As water quality criteria are strengthened locally and nationally, horticultural enterprises will have to meet stricter limits on nutrients in discharge water. This study examined the efficacy of an established vegetated surface-flow constructed wetland to mediate nitrogen (N) and phosphorus (P) in runoff water from a commercial nursery over a period of 38 months. Maximum oxidized nitrogen [nitrate-N (NO3-N) + nitrite-N (NO2-N)] inputs occurred during the spring fertilization period of March through May (11.1 to 29.9 mg·L–1 N) and minimum inputs occurred during winter plant dormancy between December and February (2.8 to 5.2 mg·L–1 N). Nitrogen remediation efficiency averaged 94.7% for March through November sampling dates but declined to a mean of 70.7% between December and February when mean wetland water temperature dropped below 15 °C. Orthophosphate phosphorus (PO4-P) concentrations in nursery runoff showed no dramatic changes over months, seasons, or years. Mean wetland influent orthophosphate concentration ranged from 0.7 to 2.2 mg·L–1 PO4-P with an overall mean of 1.41 mg·L–1 PO4-P for all months sampled. Mean discharge orthophosphate concentration ranged from 0.5 to 2.1 mg·L–1 PO4-P with a mean of 1.45 mg·L–1 PO4-P. Phosphorus remediation efficiency varied widely and there was no correlation with water temperature. This 9.31-acre surface-flow constructed wetland was highly efficient at removing N from nursery runoff from a 120-acre catchment (large container production area), although it failed to consistently lower orthophosphate levels in runoff. This type of constructed wetland is suitable for removing oxidized N forms from nursery runoff and, depending on size, is capable of handling the large volumes of runoff generated by medium to large nursery and greenhouse operations.
Analysis of Antioxidant Compounds and Hydroxymethylfurfural in Processing Tomato Cultivars
Authors: Helyes Lajos , Pék Zoltán , Brandt Sára , Lugasi Andrea
Published: December 2018

Tomato (Lycopersicon esculentum) fruit is an important source of antioxidants, which are important in the prevention of many cancer types and cardiovascular diseases. In ripe tomato fruit, one of the most significant antioxidant compounds is lycopene. In this study, effects of the cultivars and the environmental conditions on the lycopene content were investigated. Temperature effect was characterized by calculating growing degree-day (GDD). Relationships among lycopene, total polyphenols, organic acid, and total antioxidant status (TAS) were analyzed. A variation of more than 30% was found among the lycopene levels of five processing tomato cultivars. Lycopene content ranged from 79.7 to 155.0 mg·kg–1 fresh weight. There was a significant difference between the lycopene concentrations of fruit harvested at two different dates. The values were higher at the second harvest, probably due to the cooler weather conditions preceding that harvest. Total polyphenols correlated strongly with TAS but the other antioxidants did not have any relationship to TAS. GDD were strongly and positively correlated with hydroxymethylfurfural content in fresh tomatoes.
A Comparison of Student Grades, Floral Design Laboratory Skill Scores, and Course Satisfaction of Traditional and Online Sections of a University Floral Design Course
Authors: Henss S.R. , Zajicek J.M. , Lineberger R.D.
Published: December 2018

Performance of college-level floral design students was compared using a sample of 140 students from Texas A&M University. The experimental group was enrolled in the online version of the course, while the control group was enrolled in the traditional version of the course. Students in both groups were asked to fill out surveys at the beginning and end of the semester. In addition, student floral designs were evaluated at the beginning and end of the semester, and student grades were compared at the end of the semester. No statistically significant differences were noted in terms of student course satisfaction. However, differences were noted in course grades, with those enrolled in the traditional section of the course outperforming those in the online section. Overall, the students in both sections of the course did well in terms of grades, floral design skill scores, and course satisfaction. Results indicated that certain student characteristics may be indicators for student success in online courses.
Nitrogen, Phosphorus, and Potassium Nutrition Increases Growth and Total Polyphenol Concentrations of Bush Tea in a Shaded Nursery Environment
Authors: Mudau Fhatuwani N. , Soundy Puffy , du Toit Elsa S.
Published: December 2018

The objective of this investigation was to determine the effects of simultaneous applications of nitrogen (N), phosphorus (P), and potassium (K) nutrition on growth and chemical analysis of bush tea (Athrixia phylicoides). Four consecutive trials were conducted at Morgenzon (Louis Trichardt, Limpopo Province, South Africa), a commercial nursery, one at each season (autumn, winter, spring, and summer) under 50% shade. Treatments comprised three levels of N (300, 350, 400 kg·ha−1), three levels of P (250, 300, 350 kg·ha−1), and three levels K (150, 200, 250 kg·ha−1). The experimental design was a 3 × 3 × 3 factorial experiment arranged in a randomized complete-block design with four replications. Parameters recorded were plant height, number of branches and leaves, fresh and dry stem weight, fresh and dry root weight, stem girth, fresh and dry shoot weight, leaf area, and percent concentration of leaf and root tissue N, P, K, and total polyphenol concentrations as influenced by season in a shaded nursery environment. Treatment combinations of N and P at rates of 300 kg·ha−1 and K at 200 kg·ha−1 increased fresh and dry shoot weight, number of leaves, leaf area, and concentration of total polyphenols. Other treatments did not consistently affect concentrations of leaf N, P, or K during the study period, although the treatment that received combinations of N and P at rates of 300 kg·ha−1 and K at 200 kg·ha−1 always had the highest concentrations of leaf N, P, and K and lowest root N, P, and K concentrations. No differences in plant height, number of branches, number of flower buds (autumn and winter), stem girth, fresh and dry root weight, and fresh and dry stem weight due to treatment combinations were observed.
Soil Fumigants to Replace Methyl Bromide for Weed Control in Ornamentals
Authors: Uhlig Robert E. , Bird George , Richardson Robert J. , Zandstra Bernard H.
Published: December 2018

A field study was conducted to evaluate fumigant alternatives for methyl bromide (MB). Iodomethane (IM), chloropicrin (CP), 1,3-dichloropropene (1,3-D), metham sodium (MS), and MB in various combinations were applied to a sandy soil field site in Sept. 2002. Some treatments were tarped. Plant injury, plant growth, fresh weight, and dry weight were evaluated for seven ornamental species: cushion spurge (Euphorbia polychroma), globe thistle (Echinops bannaticus ‘Blue Globe’), common lavender (Lavandula angustifolia ‘Hidcote Blue’), hosta (Hosta ‘Twilight PP14040’), silvermound artemisia (Artemisia schmidtiana ‘Silver Mound’), shasta daisy (Leucanthemum ×superbum ‘Snow Lady’), and thread leaf coreopsis (Coreopsis verticillata ‘Moonbeam’). Weed control was evaluated in Apr. 2003, July 2003, and May 2004. All treatments gave almost complete control of all annual weeds, except for IM 50% + CP 50% (200 lb/acre, tarped) and MS (75 gal/acre, 1:4 water, not tarped), which did not give adequate control of common chickweed (Stellaria media), mouseear cress (Arabidopsis thaliana), common lambsquarters (Chenopodium album), or common purslane (Portulaca oleracea). None of the treatments caused visual injury to any crop species. Treatments did not affect plant size in Nov. 2003. However, some treatments resulted in larger thread leaf coreopsis and silvermound artemisia plants in May 2004. There was no difference in dry weight at harvest between treatments for all species.
Naphthaleneacetic Acid, Ethephon, and Gibberellin A4 + A7 Have Variable Effects on Flesh Firmness and Return Bloom of Apple
Authors: McArtney Steven , Unrath Dick , Obermiller J.D. , Green Ann
Published: December 2018

Experiments were conducted in commercial apple (Malus ×domestica) orchards in the southeastern U.S. between 1998 and 2006 with the primary objective of evaluating the effects of naphthaleneacetic acid (NAA) and ethephon on return bloom. NAA increased return bloom in six of 10 experiments, whereas ethephon increased return bloom in four of seven experiments. Four biweekly applications of 5 ppm NAA during June and July (early summer NAA) increased return bloom more consistently than fewer applications. Four weekly preharvest applications of 5 ppm NAA increased return bloom of ‘Delicious’ and ‘Golden Delicious’ as effectively as early summer applications. Combining NAA and ethephon in early summer sprays did not consistently increase return bloom compared with either material alone. The flower cluster density of ‘Golden Delicious’ in the year of treatment had a negative effect on return bloom that was more pronounced on control trees than trees sprayed 5 weeks after bloom with 444 ppm ethephon (48 fl oz/acre Ethrel). Combining four early summer sprays of 316 ppm ethephon (24 fl oz/acre Ethrel) with 15 ppm gibberellin A4 + A7 (GA4+7) increased return bloom of ‘Cameo’ but had no effect on return bloom of ‘Mutsu’ or ‘Golden Delicious’. Growth regulator treatments did not have a consistent effect on fruit firmness in the year of treatment. Naphthaleneacetic acid or ethephon treatments in the on year of a biennial bearing cycle can promote return bloom of apple spurs. However, the positive effect on return bloom may be minimal in cultivars with a strong natural tendency toward biennial bearing or when bloom or initial fruit set are heavy in the year of treatment.
Infiltration and Survival of Salmonella spp. on Tomato Surfaces Labeled Using a Low-energy Carbon Dioxide Laser Device
Authors: Yuk Hyun-Gyun , Warren Benjamin R. , Schneider Keith R.
Published: December 2018

Infiltration and survival of a rifampicin-resistant five-serovar Salmonella cocktail was investigated in laser-etched tomatoes (Lycopersicum esculentum) and smooth (untreated) and punctured (dye solution only) tomato surfaces in storage for 14 days at 25 °C/60% relative humidity. Surviving Salmonella populations were enumerated on tryptic soy agar supplemented with the antibiotic rifampicin. In the first survival study (laboratory-etched tomatoes), the population of Salmonella spp. in wounds increased to 6.8 log cfu/fruit, whereas cells on smooth surfaces decreased to undetectable levels during 14 days of storage. For etched tomatoes, the storage reduced 2.7 log cfu/fruit after the first 3 days; however, an increase was observed at 7 days, followed by a population decreased to 2.9 log cfu/fruit at 14 days. In the second survival study (pilot plant-etched tomatoes), the populations decreased a total of 3.5 log cfu/fruit and 2.5 log cfu/fruit comparing 1 day with 14 days for smooth and etched surfaces respectively. Infiltration of the dye solution or Salmonella beyond the area of immediate tissue damage was not observed on any tomato surface tested.
Solutions to Overcome Pitfalls of Two Automated Systems for Direct Measurement of Greenhouse Tomato Water Uptake
Authors: Vermeulen Kristof , Steppe Kathy , Janssen Katrien , Bleyaert Peter , Dekock Jan , Aerts Jean-Marie , Berckmans Daniel , Lemeur Raoul
Published: December 2018

Two promising techniques to measure water uptake in a direct way were evaluated on substrate-grown truss tomato plants (Lycopersicon esculentum ‘Clothilde’). The first technique, which is called the mass-balance technique, determines tomato water uptake using automated weight measurements of substrate mass and collected leachate. It was found that leachate could not be recorded appropriately in a 1-minute time interval by the tipping bucket gauges used in this study. Therefore, the tipping bucket readings had to be corrected and modified. The second technique computes the water uptake by a single tomato plant based on the thermal energy balance of a stem segment and, therefore, it is called the heat-balance technique. The stem segment was carefully selected at the base of a tomato stem so that the whole-plant water uptake could be determined. However, it was found that an independent measurement of minimum water uptake during the night was needed to correctly calculate water uptake during the whole day. As a result, the major pitfalls of the two techniques were identified. With appropriate modifications, a good correlation between the measurements was found, even during a period of imposed drought stress.
A Modified Nutrient Film Technique System Offers a More Uniform Nutrient Supply to Plants
Authors: Puerta Alejandro R. , Sato Suguru , Shinohara Yutaka , Maruo Toru
Published: December 2018

In nutrient film technique (NFT) vegetable production, the use of low-concentration nutrient solutions might lead to a nutrient concentration gradient along the bed, which can translate into nonuniform plant growth. The authors modified a conventional NFT system (cNFT) and propose a modified NFT (mNFT) that enables the production of lettuce (Lactuca sativa) plants of uniform fresh weight along elongated cultural beds. Two experiments were carried out to compare the systems when long cultural beds are used (18 m) in terms of uniformity of plant and nutrient solution characteristics. The results indicated that fresh weight of plants in cNFT decreased as the distance from the nutrient inlet increased, whereas no such trend was observed in mNFT. Leaf nitrate concentration in mNFT was uniform, whereas it was higher near the outlet of cNFT. Ascorbic acid concentration was also uniform in mNFT, but it was found to be lower near the outlet of cNFT. During Expt. 2, the oxygen content along the bed decreased from inlet to outlet in cNFT; however, in mNFT, it remained relatively constant at all sampling positions. Regarding the concentration of the nutrient solution along beds, no significant differences were found between inlet and outlet in both systems. It is suggested that the lower concentration of oxygen found at the outlet of cNFT might have reduced nutrient uptake, thus attenuating the difference in concentration between inlet and outlet. The temperatures of the nutrient solution along mNFT during Expt. 2 tended to be slightly lower than those of cNFT. However, temperatures were still too high and plant growth was negatively affected. The results of this study demonstrate that plants of uniform size and quality can be achieved in long cultural beds (up to 18 m long) supplied with a low-concentration fertilizer solution by using the proposed mNFT.
Greener Voices: An Exploration of Adult Perceptions of Participation of Children and Youth in Gardening Planning, Design, and Implementation
Authors: Eames-Sheavly Marcia , Lekies Kristi S. , MacDonald Leigh , Wong Kimberly J.
Published: December 2018

This article discusses Greener Voices, a 3-year extension-research integration project intended to enhance the participation of children and youth in school- and community-based gardening settings and presents findings from a study of adult leaders’ perceptions about the participation of children and youth at their sites. The project included six sites in New York and Pennsylvania consisting of rural, suburban, and urban settings; children at those sites ranged in age between 3 and 18 years. Over a 2-year period, as part of the extension activity, sites were provided with consultation and written materials, a web site, and opportunities to attend a related workshop and conference. Interviews with adult leaders indicated moderate to high levels of participation at most of the sites, variation by age of participants and stage of project, the usefulness of a ladder of children's participation in raising awareness, barriers to participation, attitudinal and behavior changes, and positive impacts on the youth. Ongoing efforts are needed to assist sites/leaders, including strategies to expand thinking about the capabilities of children and youth, help children and youth adjust to new roles, and identity ways for younger children to increase their participation.
Management Challenges in a Maturing Industry: A Teaching Case Study of Melon Farming in Latin America
Authors: Hinson Roger A. , Motsenbocker Carl E. , Westra John V.
Published: December 2018

This is a horticulture case study of the export market for melons (Cucumis melo) from Central America to the United States. Melons have provided growers an excellent production and marketing opportunity since the early 1980s. “Off-season” shipments have changed from a consumer novelty to a commodity. The case documents how this producer entered the industry and became a dominant firm using a cost leadership strategy that included adopting advanced production technology and generating large sales volume to take advantage of its opportunity. As the product moved through the cycle from new product to mature market, there were changes in behavior by competing firms, a slowdown in growth of the markets, and reduced profits. Other management practices such as creating profit centers, using employee incentives at all levels, and outsourcing transportation and brokerage services were used to supplement the cost leader strategy. The development of the market and of the firm is documented, providing the basis for discussion of management and marketing issues in courses at the university level in horticulture and agribusiness.
Rice Hulls, Leaf-waste Pellets, and Pine Bark as Herbicide Carriers for Container-grown Woody Ornamentals
Authors: Samtani Jayesh B. , Kling Gary J. , Mathers Hannah M. , Case Luke
Published: December 2018

An integrated approach to weed control in nursery containers is crucial if herbicide applications during the growing season are to be reduced. This experiment, conducted in 2002 and 2003 in Urbana, Ill., evaluated rice hulls, leaf-waste pellets, and pine bark as herbicide carriers for the preemergence herbicides oryzalin at 2 lb/acre a.i. and diuron at 1 lb/acre a.i. The efficacy of the treatments in controlling annual weeds and the phytotoxic effects of the treatments on the woody plant species were evaluated in separate completely randomized designs. For the efficacy experiment, no ornamental plants were present and containers were each seeded with a mixture of 1:1:1 (by volume) of annual bluegrass (Poa annua), common groundsel (Senecio vulgaris), and shepherd's purse (Capsella bursa-pastoris) immediately after treatment applications. For the phytotoxicity experiment, ‘Goldflame’ spirea (Spiraea japonica), ‘Hetz Midget’ american arborvitae (Thuja occidentalis), and ‘Snowmound’ nippon spirea (Spiraea nipponica) were evaluated. No weed seeds were sown in the phytotoxicity containers. Treatments for both experiments included spray applications of herbicides with water or with one of the organic mulches as a carrier or one of the mulches alone. Evaluations were done 45 and 120 days after treatment (DAT) in both years. The organic carriers with herbicide sprays gave efficacy visual ratings equivalent to water as a carrier for both herbicides. Phytotoxicity was not observed in the spirea species in either year. For ‘Hetz Midget’ american arborvitae in 2002, diuron with water had the highest visual phytotoxicity rating. Diuron phytotoxicity on the ‘Hetz Midget’ american arborvitae was alleviated when diuron was applied with any of the three mulches as a carrier. Pine bark treatments increased plant biomass for ‘Goldflame’ spirea in 2003, 45 DAT. At 120 DAT in 2002, pine bark gave increased plant biomass as compared with no organic mulch treatments for ‘Goldflame’ spirea. The study was conducted to ascertain whether the use of organic mulches as carriers could reduce phytotoxic effects of a herbicide on container-grown woody ornamentals, improve crop plant biomass, and act as a herbicide carrier for container-grown woody ornamentals.
Leaf Area Distribution of Tomato Plants as Influenced by Polyethylene Mulch Surface Color
Authors: Decoteau Dennis R.
Published: December 2018

The influence of polyethylene (plastic) mulch surface color (white versus black) on leaf area distribution of tomato (Lycopersicon esculentum) was investigated in simulated planting beds at two sampling periods: an early sampling with relatively young plants that had been in the mulch treatment for 22 days and a late sampling with relatively mature plants that had been in the mulch treatments for 50 days. At the early sampling period, tomato plants grown with white mulch had more axillary leaves than plants in the black mulch, resulting in a greater axillary:main leaf area ratio for the plants with white mulch. Leaf area for total leaves (main + axillary) and plant biomass was unaffected by mulch surface color at the early sampling period. Tomato plants grown in black mulch at the early sampling period had significantly more area of main leaves partitioned to node 3, whereas plants grown in white mulch had more area of main leaves in nodes 8 and 9. Plants grown in the white mulch treatment had significantly more axillary leaf area at nodes 1, 2, and 3, whereas plants in black mulch had more axillary leaf area at node 6. At the later sampling period, most of the leaf area from both mulch treatments was recorded in the axillary leaves and there was no effect of mulch surface color on the amount of total leaf area partitioned to main, axillary, or total leaves; to the amount of biomass of the measured top growth; or to the nodal distribution of leaf area among main leaves or axillary leaves. Tomato plants in white mulch had significantly more fruit on plants at the later sampling period than plants in the black mulch. Mulch surface color also affected the plant light environment and soil temperatures. These results suggest that the polyethylene mulch surface color can induce changes in the plant microclimate and affect leaf area distribution of young tomato plants (as recorded at the early sampling) and fruiting of relatively more mature plants (as recorded at the later sampling).
Evaluation of a Manual Energy Curtain for Tomato Production in High Tunnels
Authors: Both A.J. , Reiss E. , Sudal J.F. , Holmstrom K.E. , Wyenandt C.A. , Kline W.L. , Garrison S.A.
Published: December 2018

The impact of a manually operated energy curtain on the recorded nighttime inside air and soil temperatures, relative humidity (RH), and daily light integrals during early-season high tunnel tomato (Lycopersicon esculentum) production in central and southern New Jersey were examined. Environmental data (air and soil temperatures, RH, and photosynthetically active radiation) were collected from late March through mid-May at two New Jersey locations for the 2004 and 2005 growing seasons. The continued impact of the early use of an energy curtain was further evaluated by collecting light, temperature, and marketable fruit yield data for the remainder of both growing seasons for one of the two experimental sites. Results showed that although the use of the curtain modestly increased early season nighttime inside air and soil temperatures and RH, the curtain reduced accumulated light integral during the first 7 weeks after transplanting and resulted in a marginal early yield increase. The main benefit of the energy curtain occurred on cold nights when an early season crop might otherwise be exposed to potentially damaging low temperatures.
Using Leaf Temperature as a Nondestructive Procedure to Detect Root Rot Stress in Geranium
Authors: Omer Medani , Locke James C. , Frantz Jonathan M.
Published: December 2018

Diagnosis of incipient disease based on visual symptoms of geraniums (Pelargonium ×hortorum) exposed to water mold pathogens is often difficult, especially when the plants are maintained under optimum growing conditions. Such plants tend to be asymptomatic until late in the infection process when control methods are less effective and the aesthetic value of the finished crop is diminished. To circumvent such a problem and to be able to predict the susceptibility of the plants to infection, we used infrared transducers to measure leaf surface temperature, in addition to other parameters, in geranium plants exposed to a number of soil pathogens that are commonly associated with greenhouse production. Differences in leaf temperature among treatments were noticeable by 2 week after inoculation and were the greatest in week 7. However, visual disease symptoms were not detected until 3 weeks after inoculation. Results of this study suggest that leaf temperature measurements are a versatile, nondestructive way of rapidly determining whether plants are under pathogen stress before visual symptoms develop.
Differing Blanketflower Cultivar and Ecotype Responses to Plant Growth Regulators
Authors: Hammond Helen E. , Schoellhorn Richard K. , Wilson Sandra B. , Norcini Jeffrey G.
Published: December 2018

Two different plant growth regulators were applied to ‘Torch Flame’ blanketflower (Gaillardia pulchella) and a native blanketflower ecotype to reduce pedicel elongation and final production size. Uniconazole was applied as a spray at 60, 120, and 180 mg·L−1 or as a drench at 6, 12, and 24 mg·L−1 one and two times per plant. Ethephon was applied as a spray at 500 and 1000 mg·L−1 one and two times per plant. When applied as a spray, uniconazole had no effect on torch blanketflower, but when applied as a drench, growth indices were reduced by 12% to 30% without delayed flowering. When treated with ethephon spray, torch blanketflower was 15% to 25% more compact than untreated controls, but flowering was delayed. The blanketflower ecotype did not respond to uniconazole or Ethephon treatments, regardless of the application rate, number, or method.
Risk-rated Economic Return Analysis for Southern Highbush Blueberries in Soil in Georgia
Authors: Fonsah Esendugue Greg , Krewer Gerard , Harrison Kerry , Bruorton Michael
Published: December 2018

Southern highbush blueberries (Vaccinium corymbosum × V. darrowii hybrids) are a rapidly emerging crop with a bright future in Georgia; however, blueberries, like other fruit crops, are subject to price and yield fluctuation. These volatilities depend on several factors, including the cultivar produced and sold (i.e., fresh or frozen), locality, aggregate productivity, targeted market, and timing. As a result, profit margin is hard to determine. The objective of this study was to estimate total costs of cultivating southern highbush blueberries in soil under Georgia conditions and determine profitability, if any. Although there are several methods of profit determination, the risk-rated method was adopted for this study. The first-year establishment and maintenance cost of growing southern highbush blueberry in soil in Georgia using high organic matter (greater than 3%) spodic-type or allied sand soil series with supplemental pine bark incorporated was estimated at $9585.55/acre. The second-year establishment and maintenance cost of growing, harvesting, and marketing was $3691.99/acre less return from receipts of $2375.00/acre equal to $1316.99/acre. The third-year establishment and maintenance cost was $7068.20/acre. The total returns for the same year were $9500.00/acre. Subtracting the cost of $7068.20 from $9500.00 gives a net return of $2431.80/acre. The fourth-year cost, which was considered to be the first year of actual full production, was estimated at $13,547.35/acre. The compounded and recaptured establishment annual costs were $2176.43/acre. The risk-rated expected returns over total costs 66% of the time were $5452.65/acre. The chances of making profit were 92% and the base-budgeted net revenue was $6456.00/acre. Total budgeted cost was $3.38/lb. The estimated annual total fixed machinery cost was $290.41/acre. Total annual cost of solid set irrigation was $657.81/acre.
Yield and Quality of Triploid Miniwatermelon Cultivars and Experimental Hybrids in Diverse Environments in the Southeastern United States
Authors: Hassell Richard L. , Schultheis Jonathan R. , Jester Wilfred (Bill) R. , Olson Stephen M. , Maynard Donald N. , Miller Gilbert A.
Published: December 2018

The goal of this study was to evaluate miniwatermelon (Citrullus lanatus) cultivars/experimental hybrids (cultigens) for yield, quality, and adaptability in various growing environments. Eighteen cultigens were evaluated in field locations at southern Florida (Bradenton), northern Florida (Quincy), central South Carolina (Blackville), coastal South Carolina (Charleston), and eastern North Carolina (Kinston). Fruit at each site were harvested when watermelons in several plots were at market maturity. Fruit were categorized as marketable if they weighed between 3.0 and 9.0 lb. Fruit were categorized by size as follows: ≤3.0 lb (cull), 3.1–5.0 lb, 5.1–7.0 lb, 7.1–9.0 lb, and ≥9.1 lb (cull). Fruit were graded according to U.S. Department of Agriculture (USDA) grading standards for all watermelon fruit. We found that eight cultigens (Meilhart, Petite Perfection, Precious Petite, Little Deuce Coupe, RWT 8162, Master, Bibo, and Vanessa) were consistently among the top yielding and four cultigens (HA 5138, HA 5117, Petite Treat, and Valdoria) were consistently among the lowest yielding. These had a consistent yield response regardless of location. Within the small marketable melon category (3.1–5.0 lb), ‘Bibo’, ‘Precious Petite’, and RWT 8162 produced a uniform fruit over the five locations. Within the medium marketable melon category (5.1–7.0 lb) ‘Meilhart’, ‘Little Deuce Coupe’, HA 5109, ‘Xite’, ‘Mohican’, SR 8101, and ‘Vanessa’ produced uniform fruit size over the five locations. HA 5117, HA 5109, ‘Extazy’, ‘Mohican’, ‘Petite Treat’, and ‘Valdoria’ produced more fruit in the larger category. Those cultigens that produced melons that were consistently >9.0 lb were HA 5138, HA 5117, Bobbie, and Valdoria. The larger USDA marketable class (7.1–9.0 lb) was considered too large to be in the miniwatermelon market. We found five cultigens that provided consistently high soluble solids readings at each location: Master, RWT 8162, Betsy, Bobbie, and Bibo. We sampled only five fruit at each location for internal quality, and found dark seeds in all of the cultigens in at least one of the locations. Rind thickness and fruit shape did not appear to be influenced by test site location.
Stand Establishment and Yield Potential of Organically Grown Seeded and Transplanted Medicinal Herbs
Authors: Kleitz Kathryn M. , Wall Marisa M. , Falk Constance L. , Martin Charles A. , Remmenga Marta D. , Guldan Steven J.
Published: December 2018

Field studies were conducted in 1995 and 1996 at Las Cruces, New Mexico, and Alcalde, New Mexico, to compare direct seeding to transplanting for stand establishment and yield estimates of calendula (Calendula officinalis), catnip (Nepeta cataria), lemon balm (Melissa officinalis), stinging nettle (Urtica dioica), and globemallow (Sphaeralcea spp.). Calendula established well from seed or transplants at both sites. Transplanting increased establishment of lemon balm, catnip, stinging nettle, and globemallow. Lemon balm establishment was increased by 230% to 400% at Las Cruces, and catnip establishment was increased by 84% to 100% at Alcalde by transplanting. Direct seeding resulted in little or no stand establishment for stinging nettle and globemallow at Alcalde. In 1996, transplants increased lemon balm and stinging nettle dry weight yields by a factor of three or more at both sites. Dry weight yields of transplanted catnip were 4.86 t·ha−1 in 1995 and 7.90 t·ha−1 in 1996 in Las Cruces. Alcalde yields for transplanted dried catnip were 2.43 t·ha−1 in 1995 and 5.12 t·ha−1 in 1996. Transplanted globemallow dry weight yields were 6.04 t·ha−1 in 1995 and 9.17 t·ha−1 in 1996 for Las Cruces. Transplanted stinging nettle yield in Alcalde was 5.91 t·ha−1 for plants that overwintered and were harvested in the second season. Transplanting versus direct seeding medicinal herbs has the potential to substantially increase stand establishment and yield in New Mexico, particularly in the more northern and cooler part of the state.