Spotlight

Precise Heating with Diesel Fuel Reduces Greenhouse Tomato Production Cost

Hanna and Henderson (p. 290) report that air heated by diesel fuel and released inches away from plant roots was more efficient than air heated by natural gas and released above plant tops. This system reduced energy consumption by 6% and fuel cost by 32% (based on fuel price at the time of conducting the experiment), raised root-media temperature to near the optimum level for tomato growth, and increased total yield by 9.5%. Less energy use, more cost-effective fuel, and increased yields reduced heating cost per production unit by 43%.

Grape Storage in Boxes with Internal Plastic Liners versus External Wraps

Table grapes packed with sulfur dioxide-releasing pads for refrigerated storage and transport are either 1) packed inside a box with a perforated plastic liner and then cooled, or 2) packed in boxes, palletized, cooled, and then wrapped in plastic. Lichter et al. (p. 206) compared the quality of three grape varieties after different storage times. When packed in plastic boxes, fruit quality was either similar in both packaging methods or superior in the external wrap method. When packed in cardboard boxes, the quality of grapes packed with an internal plastic liner was superior.

Box Liners Improve Quality and Shelf Life of ‘Friar’ Plums

Plums are climacteric fruits that undergo rapid deterioration after ripening, including softening, dehydration, and decay. Even under the best storage conditions, plums have a limited postharvest life due to storage disorders such as flesh browning, gel breakdown, mealiness, flesh translucency, and overripening. Cantin et al. (p 261) demonstrated that modified atmosphere packaging (MAP) liners can reduce weight loss of ‘Friar’ plums and maintain flesh appearance for cold periods of up to 45 days. MAP liners were not recommended for cold storage periods longer than 45 days because of enhanced flesh translucency, gel breakdown, and development of “off-flavor.”

Containerized Junipers Tolerate Glyphosate Applications

Often there are no selective herbicides available for weed control in field- and container-grown ornamentals. Low rates of glyphosate have the potential to provide a low-cost cleanup/rescue treatment of weed-infestions. Although the use of glyphosate over-the-top of ornamentals is an off -label use, several ornamentals have been known to exhibit good tolerance to applications of glyphosate. In a 2-year study, Czarnota (p. 239) found that injury to three containerized juniper species did not exceed 23% with glyphosate rates of up to 2.5 lb/acre.

Woodchip Mulches Suppress Weeds in Containerized Ornamentals

Weed control in nursery containers usually is achieved using chemical herbicides, as there are few non-chemical options. By choosing woodchips from trees with allelochemicals, woodchip mulches represent an environmentally friendly weed suppression method. Using container-grown dogwood and crape myrtle plants sown with large crabgrass and pigweed, Ferguson et al. (p. 266) showed that woodchip mulches from southern redcedar and southern magnolia can be used effectively for weed suppression and significantly reduce the use of herbicides.

Cover Crops and Compost Necessary for Optimum Organic Pepper Yields

Organic vegetable crop production has increased to 98,525 acres in the United States as the organic industry continues to grow 20% annually. Certified organic vegetable producers are required to implement a soil-building plan based on combinations of organic fertilizers and cover crops. Delate et al. (p. 215) found that organic pepper growth and yields equaled or surpassed conventional production when nitrogen was provided at 50 or 100 lb/acre from compost-based organic fertilizer. An additional side-dress application of 50 lb/acre nitrogen was necessary in strip-tilled plots of hairy vetch and rye to obtain pepper yields equivalent to conventional and organic fertilizer treatments.

Tomato Leaf Gas Exchange under High Electrical Conductivity

Increasing electrical conductivity (EC) improves flavor of hydroponic tomato fruit; however, too-high EC may reduce yields. Wu and Kubota (p. 271) determined photosynthetic and transpirational responses of five greenhouse tomato varieties grown under three EC levels. They found that the responses were variety and growth-stage specific. For all varieties, increasing the EC to the moderate level of around 4.8 dS·m−1 during the reproductive growth stage did not negatively impact photosynthesis, transpiration, or stomatal conductance of plants.

Student Use of Campus Green Spaces Affects Perceived Quality of Life

Researchers have found that students’ perception of their overall academic experience and the campus environment are related to academic accomplishment. This study investigated undergraduate university student use of campus green spaces and perceptions of quality of life using a survey distributed at one university in Texas. McFarland et al. (p. 232) found that more than half the students were ranked as “high-users” of campus green spaces. Additionally, students who used campus green spaces more frequently perceived their quality of life as higher when compared to those students who used green spaces less frequently.

Capillary Mats Save Labor and Water in Retail Nurseries

Maintenance of annual and perennial plants in small containers can be challenging in retail nurseries, especially during summer when multiple irrigations are required daily. Schuch et al. (p. 250) found that plants were irrigated with approximately two-thirds less water when capillary mats were used as compared to overhead irrigation. Significant economic savings were realized when capillary mats were compared to hand watering. The high initial setup cost of a capillary mat system was offset in less than 1 year by savings in labor. The majority of the 12 species tested in this study performed well under either irrigation system.

Surfactant with Alkyl Polyglucoside (APG) Tested on Bark Substrates

Bark substrates repel water and require horticultural surfactants to increase their wetting ability. Some common horticultural surfactants include alkyl phenol ethoxylates (APEs) or block co-polymers (BLK). APEs are starting to be phased out due to environmental concerns. A synergistic blend of surfactants containing alkyl polyglucoside plus BLK (APG/BLK) was drenched onto bark substrates, and wettability and leaching fraction was determined following several wetting cycles (Olszewski et al., p. 295). Overall, APG/BLK was not as effective as APE at reducing leaching fraction and increasing wettability but had significant beneficial qualities that indicated potential future use as a horticultural surfactant.

Fertilizer Analysis Affects Quality of Landscape Palms in Florida

When landscape plants are fertilized, nitrogen traditionally has been the element of greatest concern. Broschat et al. (p. 278) treated st. augustinegrass turf and a variety of herbaceous and woody ornamental plants with no fertilizer, a 2N:1K2O ratio fertilizer, or a 2N:3K2O ratio fertilizer. They found that areca palms and cannas, which have similar nutritional requirements, had higher quality when grown with the 2N:3K2O ratio fertilizer than with the 2N:1K2O ratio fertilizer or no fertilizer at all. However, turfgrass and dicot ornamental plants showed little or no response to fertilization of any kind.

Linear Garden Facilitates Plant Identification and Beautifies Roadside

With minimal installation and maintenance costs, a linear garden (3 ft wide × 2426 ft long) was established along the length of the road perpendicular to the University of Florida entrance (Wilson et al., p. 318). Eight-hundred seventeen plants from 237 different taxa were planted with spacing adjusted to accommodate their mature plant width. The garden was designed to showcase specimen plants and display other common landscape plants utilized in south-central Florida with attention to foliage type and texture, flower color, plant size and form, and seasonality.

Plastic Mulch and Variety Selection Improve Garlic Over-wintering, Yield, and Quality

Consumer demand for locally produced garlic has prompted grower interest in this crop as a sale item for midwestern U.S. direct markets. Walters (p. 286) found that black plastic provided greater winter protection than a bare-soil production system with straw mulch applied in the spring, and directly led to greater marketable weights and bulb diameters. Two varieties, ‘Idaho Silverskin’ and ‘Persian Star’, were the best of those evaluated for the lower midwestern United States with 100% winter survival (regardless of production method), high bulb quality, low foliar disease, high marketable yields with low cull production, and low bulb rot.

Economics of Muscadine Grape Production in the Southeastern U.S.

Carpio et al. (p. 308) compared the profitability of muscadine grape production under single-wire (SW) and Geneva double curtain (GDC) trellis systems with and without drip irrigation. Irrigated vineyards were more profitable than non-irrigated vineyards and GDC was more profitable than SW. The estimated return to land and management was $447/acre for the irrigated GDC system while the initial investment can be recovered in the 10th year and the net present value was estimated to be $4484.

Top-Stop Nipper Reduces Leader Growth of Fraser Fir Christmas Trees

In the United States, Christmas trees are mechanically sheared annually to increase branch and foliage density. Rutledge et al. (p. 256) found that the Top-Stop Nipper (TSN), which injures the prior-year leader by placing precision cuts through the bark, reduced current-year leader elongation, resulting in trees more natural in appearance compared to trees sheared with knives. Only half of the treated trees had leaders of the desired length, so the TSN is unlikely to be used alone as a substitute for standard shearing. It might be useful in combination with standard knife shearing and/or treatment of leaders with growth regulators.

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