Showing papers in "Horttechnology in 2007"

Nitrogen Sources for Organic Vegetable Crops

Abstract: Fertilization is the most expensive cultural practice for the increasing numbers of organic vegetable growers in the United States. Nitrogen (N) is the most important and costly nutrient to manage, and cost-effective N management practices are needed for efficient organic vegetable production. There is a wide array of organic N sources available, but they vary in cost, N content, and N availability. Compost and cover crops are commonly used sources of N for vegetables because they are relatively inexpensive and offer additional nutrients or soil improvement qualities in addition to N. Studies have shown that compost quality factors that affect N mineralization vary by source and among different batches from the same source. Compost carbon to N ratio should be equal to or less than 20:1 to assure net short-term mineralization. Cover crops also vary in N content and mineralization rate after incorporation. Leguminous cover crops decompose and release N more rapidly than grass or cereal cover crops at the preheading stage typically incorporated. Even the most efficient N-supplying composts, cover crops, or other organic N sources do not release appreciable N to a subsequent crop beyond 6 to 8 weeks from incorporation, and this burst of early N may not synchronize with N requirements for many vegetable crops. Other potential organic fertilizer N sources have been evaluated for vegetables, and they vary in N cost and N mineralization rate. Materials evaluated include seabird guano, liquid fish, feather meal, corn meal (Zea mays), blood meal, and liquid soybean meal (Glycine max) among others. Of those evaluated, feather meal, seabird guano, and liquid fish stand out as more economical organic sources of available N. Organic sources generally lack uniformity and are bulky, unstable, and inconsistent as a group, and this contributes to additional hidden management costs for organic growers. Liquid organic N sources for use in microirrigation systems may have additional disadvantages caused by loss of valuable nutrient N that is removed by filters.

Worldwide Blackberry Production

Abstract: A survey of worldwide blackberry (Rubus spp.) production was conducted in 2005. Results indicated there were an estimated 20,035 ha of blackberries planted and commercially cultivated worldwide, a 45% increase from 1995. Wild blackberries still make a significant contribution to worldwide production, with 8000 ha and 13,460 Mg harvested in 2004. There were 7692 ha of commercially cultivated blackberries in Europe, 7159 ha in North America, 1640 ha in Central America, 1597 ha in South America, 297 ha in Oceania, and 100 ha in Africa. Worldwide production of cultivated blackberries was 140,292 Mg in 2005. Of the blackberry area worldwide, 50% was planted to semierect cultivars, 25% to erect, and 25% to trailing types. 'Thornfree', 'Loch Ness', and 'Chester Thornless' were the most important semierect types, and 'Brazos' and 'Marion' the most common erect and trailing types, respectively. In general, erect and semierect cultivars are grown for fresh market and trailing cultivars for processing. Fresh fruit are usually picked into the final container in the field, whereas 75% of trailing blackberries for processing are picked by machine. Common production problems are reported. Production systems for field-grown blackberry differ with type grown and region. For example, in Mexico, production systems are modified to extend the production season for 'Tupy' and other erect-type cultivars from mid-October to June. Organic blackberry production is expected to increase from the 2528 ha planted in 2005. An estimated 315 ha of blackberries were grown under tunnels, mainly to protect against adverse weather and target high-priced markets. Based on this survey, there may be 27,032 ha of commercial blackberries planted worldwide in 2015, not including production from harvested wild plants.

Exploring the Benefits of Organic Nutrient Sources for Crop Production and Soil Quality

Abstract: Consumer demand for organically grown produce has increased dramatically over the past decade, most likely because of the perceived benefits to the environment and human health. A major component of organic production is providing organic sources of nutrients to promote plant growth as well as sustain soil quality. Organic nutrition of plants can present opportunities and challenges to the grower. The primary objective of this article is to review scientifically based information dealing with the effects of organic nutrient sources on crop yields and quality, soil properties, and environmental risks. Effects of organic nutrient sources are often evaluated by comparison with conventional production, but this approach can be problematic because nutrient source may be confounded with many other cropping system components. Despite these drawbacks, a careful examination of the literature suggests the following conclusions. Soil quality is generally improved with application of organic nutrient sources, but careful management is required to avoid environmental risks of nitrate (NO3) leaching and phosphorus accumulation. Provided that nutrient supply is equal, yields with organic sources tend to be similar to those with inorganic sources. However, lack of available nitrogen (N) that is synchronous with plant demand often limits yields in organic cropping systems. Limited N availability and varied supply of other nutrients from organic sources may contribute to the differences sometimes observed in dry matter content, tissue NO3 and mineral concentration, vitamin C and other phytochemicals, and taste. Phytonutrient content also may be affected by differences in pest control strategies among cropping systems regardless of nutrient source. There is a slight, but significantly, increased risk of produce contamination by Escherichia coli and other enteric bacteria contamination on produce when organic nutrient sources are used, but if proper guidelines are followed, contamination with the lethal serotype O157:H7 does not appear to be a major concern. Appropriate management of organic inputs is critical to achieving potential benefits for crop production and soil quality.

Abiotic Factors Influencing Root Growth of Woody Nursery Plants in Containers

Abstract: Container production has many advantages over traditional in-ground (field) production, including less damage occurring to the root system when transplanted, better establishment after transplanting, decreased labor and land acquisition costs for production, and increased product availability and longevity in the retail market. Growing plants in containers, however, alters root growth and function and can change root morphology. Numerous factors influence root growth in containers. Roots of container-grown plants are subjected to temperature and moisture extremes not normally found in field production. The effects of substrate aeration (Ea) as well as water holding capacity (Pv) interact with different pot characteristics, resulting in changes to root morphology. Successful plant establishment after transplanting is often linked to root health. This review focuses on the roles of substrate physical and chemical properties, container characteristics, and temperature in altering root growth in container-grown woody nursery crops. Root circling, planting too deeply or "too-deep syndrome" (TDS), and the use of composts as container substrates will also be examined.

Managing Potassium for Organic Crop Production

Abstract: An adequate potassium (K) supply is essential for both organic and conventional crop production. Various organic certification agencies have different regulations governing allowable sources of K. The release of K from soil minerals is discussed along with the behavior of various allowed K sources for organic crop production. Potassium is an essential nutrient for plant growth, but it generally receives less attention than N and P. All of the Western U.S. states remove more K from the soil in crop harvests than are returned to the soil in fertilizer and manure (Fig 1). This net export of soil nutrients ultimately results in a depletion of nutrients and increasing occurrences of deficiency.

1-Methylcyclopropene Influences ‘Empire’ and ‘Delicious’ Apple Quality during Long-term Commercial Storage

Abstract: This study evaluated the effects of 1-methylcyclopropene (1-MCP) on ‘Empire’ and ‘Delicious’ apples (Malus ·domestica) in commercial controlled atmosphere (CA) storage for 12 months and in commercial cold storage for 6 months. Apples were harvested and delivered by growers to a local commercial storage facility. Four different grower lots were chosen for each of three ‘Empire’ and two ‘Delicious’ storage rooms. Fruit were treated with 1-MCP ( 0.8–1.0 ppm) for 24 hours, while control fruit samples were held in a similar nearby storage room. After treatment, control samples were placed with matching 1-MCP-treated samples into either CA (2.5%O2 + 2.5%CO2 at 2.2 Cor 0 C for ‘Empire’ and ‘Delicious’, respectively) or air storage at 0 to 1 C. Initial maturity was relatively uniform among the grower lots, with internal ethylene concentration (IEC) averaging less than 1 ppm for ‘Empire’ and 2 to 3 ppm for ‘Delicious’. IECwas lower in apples treated with 1-MCP after air (3 or 6 months) or CA (6, 9, or 12 months) storage, but this effect was reduced after a 14-day ripening period at 22 C, and was less dramatic in fruit from CA than from air storage. Apples treated with 1-MCP were also firmer than non-treated fruit upon removal from air or CA storage, and this difference became greater with increased poststorage time at 22 C. 1-MCP-treated apples stored in air had higher soluble solids concentration (SSC), while there was no significant effect of 1-MCP on SSC in fruit held inCA.Core browningdeveloped in ‘Empire’ held in air for 6months or inCA for 9 or 12 months, and in ‘Delicious’ after 9 or 12 months in CA. 1-MCP decreased the incidence of core browning in ‘Empire’, but increased the incidence in ‘Delicious’. There was no significant effect of 1-MCP on the incidence of internal browning and storage rots, which developed in both cultivars.

Good Yields of Common Purslane with a High Fatty Acid Content Can Be Obtained in a Peat-based Floating System

Abstract: Interest in cultivating common purslane (Portulaca oleracea) as a food crop has grown since its identification as an exceptionally rich source of bioprotective substances considered essential for normal human growth, health promotion, and disease prevention. However, little is known about the suitable cultural systems, substrates, and irrigation systems for common purslane’s commercial production. In this study, we examined the effects of various substrates in a floating system on common purslane’s yield and fatty acid content during 2003 and 2004. We carried out three experiments using peat, vermiculite, coir, perlite, and mixtures of peat and perlite (3:1 and 1:1 v/v). In 2003, highest yields were obtained in plants grown in either peat (1806 g m) or vermiculite (1982 g m) and far exceeded those grown in coir (1254 g m) or perlite (834 g m). In 2004, plants grown in peat or 3 peat:1 perlitemixture yielded the best (2000 g m), whereas the lowest yieldswere obtained in plants grown in either coir or perlite (534 and 601 g m, respectively). Plants grown in peat substrate had the highest total fatty acid content, alpha-linolenic acid, and linoleic acid, whereas the highest proportion of alpha-linolenic acid to total fatty acids was obtained in plants when grown in either coir or perlite.

Connecticut Nursery and Landscape industry preferences for solutions to the sale and use of invasive plants.

Abstract: Survey data from 114 members (42% response rate) of the Connecticut Nursery and Landscape Association were analyzed to evaluate preferences for different potential solutions to reduce the annual sale of billions of dollars of invasive ornamental plants. The majority of respondents accurately identified key invasive plant characteristics, considered themselves to be knowledgeable about invasive plants, and cited trade journals and professional organizations as their sources of invasive plant information. Although industry members generally considered norway maple (Acer platanoides), japanese barberry (Berberis thunbergii), and winged euonymus (Euonymus alatus) to be invasive, only 14.5% and 8.1%, respectively, considered the emerging invasive species japanese silver grass (Miscanthus sinensis) and butterfly bush (Buddleja davidii) to be invasive. In comparing different approaches to reducing the sale of invasive ornamental plants, strong support was expressed for marketing noninvasive alternative plants (mean rank of 2.5) and for development of genetically altered sterile forms of invasive ornamentals (mean rank of 2.9; on a scale from 1 = most favorable to 6 = least favorable). Respondents strongly disfavored taxation as a method of reducing invasive plants sales (mean rank of 5.0) even if proceeds were directed toward invasive plant control and research. Plant bans (mean rank of 4.1) were also an unpopular choice for economically important crops, and respondents desired provisions for cultivars with reduced invasive risk to be included in plant bans. To foster maximum green industry participation in invasive plant control efforts, future directions should focus on creation of sterile forms of popular landscape plants, identification of consumer preference for noninvasive alternatives, and development of strong consumer education programs.

Physical and Chemical Characteristics of a Commercial Potting Substrate Amended with Vermicompost Produced from Two Different Manure Sources

Abstract: Interest in using alternative materials for potting substrate is increasing in response to availability and rising costs of peat and other conventional materials. Vermicompost (VC) is one such material. It is important to understand physical and chemical changes in potting substrate when amended with VC produced from different waste sources, pig (PVC) and beef cattle (BVC) manure in this study. Distribution of particles greater than 2 mm decreased, particles 0.5 to 1 mm increased, and particles less than 0.5 mm remained unchanged as PVC and BVC amendment increased. Dry bulk density and water-holding capacity increased with increasing PVC and BVC amendment. Porosity and air volume were inversely related to VC amendment, decreasing with increasing VC amendment. Saturated substrate extract sampling revealed nitrate nitrogen, phosphorus, calcium, magnesium, zinc, copper, iron content as well as electrical conductivity increased with increasing PVC and BVC amendment.

Landscape Architects' Use of Native Plants in the Southeastern United States

Abstract: In their efforts to provide better land stewardship and management, landscape architects are increasingly addressing site ecology in a wide variety of project types. From urban developments to rural properties, designers are using more sustainable design and management techniques, which include the expanded use of regional native plants. This survey study explores the use of native plants by landscape architects in the southeastern United States. Survey results show that southeastern United States designers are using a significant proportion of regional native plant species in their project specifications. Rather than using native plants strictly for conservation measures, landscape architects have found local species to be better suited to difficult or unique site conditions. The findings show that there is potential for expansion in the production and marketing of plant species indigenous to the southeastern United States.

Development and Commercialization of a Complete Vineyard Mechanization System

Abstract: A major research thrust of the University of Arkansas Enology and Viticulture Program for the past 37 years has been the development of a total vineyard mechanization system. This new system allows the mechanization of almost all practices in vineyard operations, including dormant and summer pruning, leaf removal, shoot and fruit thinning, canopy management, and harvesting while fruit quality is maintained or enhanced. Research efforts aimed to accomplish these tasks on the 12 major trellising systems used throughout the industry and to derive plans for the sequencing and timing of operations on each of the trellis systems. In 2002, the University of Arkansas patented the Morris-Oldridge Vineyard Mechanization System (M-O System). OXBO International Corp., Clear Lake, WI, purchased the patent and market M-O System components under the name Korvan Vineyard System. The objective of this study was to evaluate the effectiveness of mechanized (machine-farmed) pruning, shoot thinning, and fruit thinning using the M-O System vs. traditional methods of canopy management using hand labor (hand-farmed) in a commercial Vitis vinifera vineyard in the central coast region of California. V. vinifera cultivars evaluated included Chardonnay, Sauvignon blanc, and Syrah trellised on a lyre system and Merlot, Zinfandel, and Sangiovese trellised on a vertical shoot-positioned (VSP) system. Yield, fruit growth, fruit composition, wine quality, wine sensory attributes, and economics of mechanization were evaluated on machine- and hand-farmed grapes. Mechanized studies were initiated at French Camp Vineyards, Santa Margarita, CA, in 2002. French Camp Vineyards used a balanced cropping concept which incorporated three operations: 1) machine dormant pruning, 2) machine shoot thinning, and 3) machine fruit thinning. Results of research from 2002 to 2005 showed that yield and quality characteristics of machine-farmed grapes were not statistically different from those of hand-farmed grapes for the V. vinifera cultivars in this study. Wines from each cultivar and treatment were produced at a commercial winery and after appropriate aging, were sensory-evaluated by a professional wine analysis service. Few sensory differences were found between wines from the two farming systems. Further objective analyses of the wine components showed no commercially practical differences. In 2006, cost estimates were derived for the three vineyard activities necessary to achieve balanced cropping. Use of machine farming for balanced cropping operations resulted in savings over hand farming of 45% on the lyre trellis, 49% on the VSP system, and 62% on the quadrilateral trellis for the operations studied. Studies of mechanization of vineyard activities using the M-O System to achieve balanced cropping have shown that grapes and their wines were equivalent to those obtained using hand labor for these operations with the added benefit of cost savings for the operations evaluated.

Growth and Yield of Vegetable Soybean (Edamame) in Mississippi

Abstract: Soybean (Glycine max) grown as a vegetable is gaining in popularity in the U.S. and demand is expected to increase over the long term. However, information on production in the U.S. is limited because most of the product is imported. Field experiments were conducted at Stoneville, Miss., in 2004 and 2005 to evaluate the production and yield potential and to estimate the net returns for sustainable production in the Mississippi Delta. In 2004, four vegetable soybean varieties were evaluated and 23 varieties were evaluated in 2005. The varieties varied from maturity group III to VII. The late-maturing varieties were generally taller, had more nodes/plant, pods/plant, and fresh green pod yield at R6 stage (full seed) than the early-maturing varieties. Fresh green bean yield ranged from 1438 to 19,119 lb/acre in 2004. The mean bean yield for the 18 Apr. 2005 planting was 26,538 lb/acre compared with a mean of 18,131 lb/acre for the 10 May 2005 planting. Interaction occurred between planting date and variety as well as soil type and variety for all the variables evaluated. ‘Envy’ produced the lowest yield, whereas ‘Garden Soy 01’, ‘Garden Soy 21’, ‘Midori Giant’, ‘Mojo Green’, and ‘Moon Cake’ produced the highest fresh bean yield. The estimated net returns, using the Mississippi State Budget Generator as a guide, indicated more than twice the returns from growing the regular commodity soybean. The data suggest that vegetable soybean can fit well into the existing cropping system and could be a viable alternative crop for growers in the Mississippi Delta who want to capitalize on a niche market.

Nutrient Management in Organic Greenhouse Herb Production: Where Are We Now?

Abstract: Consumer demand for fresh market organic produce combined with the increasing market share of ready-to-eat products indicates the potential for expansion of an organic culinary herb market. Barriers to organic herb greenhouse production are high as a result of lack of available technical information and the low number of producers experienced in this area. There is a critical need for information and technologies to improve the management of organic soil and fertilizer amendments to optimize crop yields and quality, manage production costs, and minimize the risk from groundwater nitrogen (N) contamination. Because of limited information specific to organic culinary herb production, literature on organic vegetable transplants and conventional basil (Ocimum basilicum) production was also considered in this review. Managing N for organic crops is problematic as a result of the challenge of synchronizing mineralization from organic fertilizer sources with crop N demand. A combination of materials, including locally formulated composts, supplemented with standardized commercially formulated fertilizer products is one method to ensure crops have access to mineral N throughout their development. In experimental greenhouse systems, local raw materials are frequently used as media amendments to satisfy partial or complete crop fertility requirements. This makes comparisons among experiments difficult as a result of the wide variety of raw materials used and the frequent interactions of fertilizer source and planting media on nutrient availability. Nitrogen mineralization rates are also influenced by additional factors such as the environmental conditions in the greenhouse and physical and chemical properties of the media and fertilizer. Despite the variability within and among experimental trials, yields and quality of organically grown crops are frequently similar to, and occasionally better than, conventionally grown crops.

Influence of Plant Density on Yield and Fruit Quality of Greenhouse-grown Galia Muskmelons

Abstract: . Olson, S.M., E.H. Simonne, W.M. Stall, P.D. Roberts, S.E. Webb, T.G. Taylor, and S.A. Smith. 2006. Cucurbit production in Florida, p. 191–237. In: S.M. Olson and E. Simonne (eds.). Vegetable production handbook for Florida 2006–2007. Univ. of Fla./Inst. of Food and Agr. Sci. Coop. Ext Serv., Gainesville, FL. Papadopoulos, A.P. and S. Pararajasingham. 1997. The influence of plant spacing on light interception and use in greenhouse tomato (Lycopersicum esculentum Mill.): A review. Sci. Hort. 69:1–29. Paris, H.S., T.G. McCollum, H. Nerson, D.J. Cantliffe, and Z. Karchi. 1985. Breeding of concentrated-yield muskmelons. J. Hort. Sci. 60:335–339. Paris, H.S., H. Nerson, Y. Burger, M. Edelstein, Z. Karchi, T. McCollum, and D.J. Cantliffe. 1988. Synchrony of yield of melons as affected by plant type and density. J. Hort. Sci. 63:141–147. Rodriguez, J.C., D.J. Cantliffe, N.L. Shaw, and Z. Karchi. 2006. Soilless media and containers for greenhouse production of ‘Galia’ type muskmelon. HortScience

Taxonomy and Nomenclature of Baldcypress, Pondcypress, and Montezuma Cypress: One, Two, or Three Species?

Abstract: As interest in issues such as seed source, provenance, genetic pollution, and threatened and endangered plant species grows, so does the need for an understanding of the relatedness and evolutionary history of plants. Appropriate taxonomy and nomenclature become much more important. Taxodium (L.) Rich. is a genus of landscape trees included in many plant materials courses across the country. It has been treated variously in the horticulture literature as having one, two, or three species. The most appropriate treatment is one species with three botanical varieties: baldcypress [Taxodium distichum (L.) Rich. var. distichum], pondcypress [T. distichum var. imbricarium (Nutt.) Croom], and montezuma cypress [T. distichum var. mexicanum Gordon].

Evaluation of a Manual Energy Curtain for Tomato Production in High Tunnels

Abstract: 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.

Viticultural Performance of Red and White Wine Grape Cultivars in Southwestern Idaho

Abstract: A collection of 23 red and six white wine grape (Vitis vinifera) cultivars were evaluated for viticultural performance in Parma, ID. Vine yield, fruit composition, and vegetative growth were measured over four growing seasons, and data were used to compare relative cultivar performance based on yield to pruning ratio and fruit maturity. Relative differences among cultivars in budbreak day of year [96 (6 Apr.) to 122 (2 May)] and days from budbreak to harvest (143 to 179 days) varied from year to year. The earliest and latest maturing cultivars in 3 of 4 years were ‘Blauer Portugieser’ (143 days), ‘Nebbiolo’ (177 days), ‘Barbera’ (179 days), ‘Orange Muscat’ (144 days), ‘Flora’ (149 days), ‘Muscat of Alexandria’ (166 days), and ‘Viognier’ (168 days). Cultivars differed in yield (2.4 to 7.0 tons/acre), vegetative vigor (4.6 to 20.4 yield/pruning weight), and harvest soluble solids concentration (21.1 to 26.5), but differences in harvest pH (3.0 to 4.1) and titratable acidity (2.48 to 13.03 g!L) varied from year to year. Average heat unit accumulation (1646) was 160 units higher than the 78-year site average. Few (less than 150) units accumulated in April and October, most units accumulated in July, and diurnal difference in air temperature was "15 !C. Performance results from this study can assist cultivar site selection by comparing climate data for an intended site with that of Parma. For example, the low acidity and earliness of ‘Blauer Portugieser’ suggests it is best suited to a site with less heat unit accumulation than Parma, and the high acidity and late maturity of ‘Barbera’, ‘Nebbiolo’, and ‘Carignan’ suggest these cultivars are best suited to a site with more heat unit accumulation than Parma. The inconsistent relationship between onset of budbreak and earliness observed in this study suggests opportunity to match short-season cultivars late to break bud such as Flora to short-season growing sites prone to late-season frost.

Nitrogen, Phosphorus, and Potassium Nutrition Increases Growth and Total Polyphenol Concentrations of Bush Tea in a Shaded Nursery Environment

Abstract: 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), three levels of P (250, 300, 350 kg ha), and three levels K (150, 200, 250 kg ha). 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 and K at 200 kg ha 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 and K at 200 kg ha 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.

Greener Voices: An Exploration of Adult Perceptions of Participation of Children and Youth in Gardening Planning, Design, and Implementation

Abstract: This article discusses Greener Voices, a 3-year extension-research integration project intended to enhance the participation of children and youth in schooland 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.

Water Use and Fertilizer Response of Azalea Using Several No-leach Irrigation Methods

Abstract: Although research has shown that plants grown with subirrigation systems such as ebb-and-flow and capillary mat require less water and fertilizer inputs than traditional overhead irrigation methods, similar information for capillary wick irrigation has not been available. We compared the growth and water use response of azalea (Rhododendron sp. ‘George Tabor’) grown in 6.5-inch-diameter ‘‘azalea’’ containers with three irrigation methods [overhead (OVR), subirrigation (SUB), and capillary wick (WCK)] and four fertilizer nitrogen (N) rates 0.5 to 2.0 lb/yard supplied by an incorporated, resin-coated, controlled-release fertilizer (Nutricote 17N–3.1P–6.7K, 180 d at 77 F). OVR volume was adjusted to deliver 100% of evapotranspiration (ET) loss. For all irrigation treatments, the lowest N rate resulting in maximum plant growth was 1.0 lb/yard, which was less than the label recommendation of 1.5 lb/yard. At the N-limiting N rate of 0.5 lb/yard, irrigation method had no effect (P < 0.05) on azalea growth. At N rates higher than 1.0 lb/yard, decreased growth was observed for OVR compared with SUB and WCK. This negative effect on plant growth was attributed to salt injury as indicated by excessive pour-through electrical conductivity (EC) levels in OVR containers. At the end of the experiment, substrate EC was highest in the uppermost layer of SUB and WCK containers, reflecting the upward movement of water associated with these two irrigation methods. Water use efficiency, which ranged from 1.9 to 2.8 g shoot dry weight per liter of water lost through ET, was unaffected (P < 0.05) by irrigationmethod at the N rate of 1.0 lb/yard.We concluded that the growth response of azalea to fertilizer N rate was similar for WCK and SUB despite periodic pour-through EC tests indicating higher substrate nutrient levels with WCK.

The Effect of a Garlic Extract and Root Substrate on Soilborne Fungal Pathogens

Abstract: Pythium aphanidermatum, Pythium irregulare, Pythium ultimum, Phytophthora cinnomomi, Phytophthora nicotianae, Rhizoctonia solani, Fusarium oxysporum, and Thielaviopsis basicoli grew and eventually covered petri plates containing a nutrient solution alone, but they failed to grow in nutrient solutions containing 10% or higher levels of garlic extract or a fungicide control. When plugs containing the fungal organisms exposed to 10% garlic (Allium sativum) extract solution for 48 h were washed and transferred to fresh cornmeal agar (CMA) growth medium, only F. oxysporum displayed growth. However, growth of F. oxysporum was limited to no greater than 2 mm from the original inoculum plug. After a single application of a solution containing at least 35% garlic extract or two applications containing 25%, viable P. aphanidermatum could not be recovered from a peat-based root substrate. By contrast, after a single application of a solution containing 25% garlic extract or two applications of 10%, we were unable to recover viable P. aphanidermatum from a sand substrate. When peat treated with increasing concentrations of garlic extract was placed on CMA inoculated with P. aphanidermatum, the first visual sign of a zone of inhibition occurred for peat saturated with 30% garlic extract solution and the zone increased as the garlic extract concentration increased. By contrast, when sand treated with increasing concentrations of garlic extract was placed on CMA inoculated with P. aphanidermatum, the first visual sign of a zone of inhibition occurred when saturated with 10% garlic extract solution. Therefore, the garlic extract was found to be fungicidal against a broad range of soilborne fungal organisms, but the concentration required to kill the organisms varied depending on root substrate.

Dipping bedding plant liners in paclobutrazol or uniconazole inhibits subsequent stem extension

Abstract: An increasingly popular technique for applying plant growth regulators (PGRs) to floriculture crops is to dip or soak the root medium of a transplant in a chemical solution before transplanting. This PGR application method, termed a ‘‘liner dip,’’ can be an effective height-control strategy for greenhouse crop production. However, few studies have quantified how bedding plant species respond to different chemicals and application rates. Argyranthemum (Argyranthemum ·hybrida ‘Sunlight’), calibrachoa (Calibrachoa ·hybrida ‘Callie Dark Blue’), petunia (Petunia ·hybrida ‘Cascadias Vivid Red’), scaevola (Scaevola albida ‘Jacob’s White’), and verbena (Verbena ·hybrida ‘Rapunzel Red’) liners were dipped in paclobutrazol at 4, 8, or 16 mg L or in uniconazole at 2, 4, or 8 mg L for 30 seconds and subsequently transplanted into 4.5-inch-diameter round pots. At 28 days after transplant, all rates of paclobutrazol and uniconazole inhibited subsequent stem elongation by 21% to 67% in calibrachoa, petunia, scaevola, and verbena. In argyranthemum, stems were 33% to 42% shorter in plants treated with paclobutrazol at 8 or 16 mg L or uniconazole at all rates. In some species, the liner dip delayed flowering and reduced flower number compared with that of nontreated plants. This pretransplant PGR application technique can be useful on vigorous ornamental species when grown together in the same container with less aggressive species without a PGR application.

A Simple and Effective Method for Quantifying Leaf Variegation

Abstract: A simple and effective method for quantification of leaf variegation was developed. Using a digital camera or a scanner, the image of a variegated leaf was imported into a computer and saved to a file. Total pixels of the entire leaf area and total pixels of each color within the leaf were determined using an Adobe Photoshop graphics editor. Thus, the percentage of each color’s total pixel count in relation to the total pixel count of the entire leaf was obtained. Total leaf area was measured through a leaf area meter; the exact area of this color was calculated in reference to the pixel percentage obtained from Photoshop. Using this method, variegated leaves of ‘Mary Ann’ aglaonema (Aglaonema x), ‘Ornate’ calathea (Calathea ornate), ‘Yellow Petra’ codiaeum (Codiaeum variegatum), ‘Florida Beauty’ dracaena (Dracaena surculosa), ‘Camille’ dieffenbachia (Dieffenbachia maculata), and ‘Triostar’ stromanthe (Stromanthe sanguinea) were quantified. After a brief training period, this method was used by five randomly selected individuals to quantify the variegation of the same set of leaves. The results were highly reproducible no matter who performed the quantification. This method, which the authors have chosen to call the quantification of leaf variegation (QLV) method, can be used for monitoring changes in colors and variegation patterns incited by abiotic and biotic stresses as well as quantifying differences in variegation patterns of plants developed in breeding programs.

Diploid Watermelon Pollenizer Cultivars Differ with Respect to Triploid Watermelon Yield

Abstract: As triploid watermelons (Citrullus lanatus) increase in popularity, production has shifted away from seeded watermelons. To achieve successful fruit set in triploid watermelons, a diploid watermelon cultivar must be planted as a pollen source. Three diploid cultivars in 2005 and seven diploid cultivars in 2006 were evaluated at one and three locations, respectively, to determine their effectiveness as pollenizers. Each cultivar was planted within plots of the triploid watermelons ‘Tri-X 313’ (2005) and ‘Supercrisp’ (2006) with buffers on all sides of the plots to contain pollen flow within individual plots. Performance of pollenizers was based on triploid watermelon yield, soluble solids concentration, and incidence of hollowheart. In 2005, there were no significant differences in total weight, fruit per acre, average weight, or soluble solids concentration among pollenizers. In 2006, significant differences in yield were observed, and plots with ‘Sidekick’ as a pollenizer yielded the highest but were not significantly different from ‘Patron’, ‘SP-1’, ‘Jenny’, or ‘Mickylee’. In 2006, there were no significant differences in fruit per acre, soluble solids concentration, or incidence of hollowheart between pollenizers. The experimental design was successful in isolating pollenizers and there was minimal pollen flow outside of experimental plots as indicated by minimal fruit set in control plots.