Browse

You are looking at 1 - 10 of 28,387 items for

Open access

Laura Jalpa, Rao S. Mylavarapu, George J. Hochmuth, Alan L. Wright and Edzard van Santen

Use efficiency of applied nitrogen (N) is estimated typically to be <50% in most crops. In sandy soils and warmer climates particularly, leaching and volatilization may be primary pathways for environmental loss of applied N. To determine the effect of N fertilization rate on the N use efficiency (NUE) and apparent recovery of N fertilizer (APR), a replicated field study with ‘BHN 602’ tomato (Solanum lycopersicum) grown in sandy soils under a fertigated plastic-mulched bed system was conducted using ammonium nitrate as the N source at four different rates (0, 150, 200, and 250 lb/acre). Spring tomato was followed by fall tomato in the same field, a typical cropping sequence in north Florida. Fertigation of N fertilizer was applied weekly in 13 equal doses for both seasons. The highest NUE was 12.05% (spring) and 32.38% (fall), and the highest APR was 6.11% (spring) for the lowest rate of N applied (150 lb/acre). In the fall, APR was unaffected by fertilizer N rates and ranged from 12.88% to 19.39%. Nitrogen accumulation in tomato plants were similar among the three N fertilizer rates applied (150, 200, and 250 lb/acre), though compared with no N fertilizer application, significant increases occurred. Whole plant N accumulation, NUE, and APR declined or remained similar when N rates increased above 150 lb/acre. Additionally, a regression analysis and derivative of the quadratic fresh yield data showed that yields were maximized at 162 and 233 lb/acre N in the spring and fall seasons, respectively.

Open access

Jasmine Jenji Mah, David Llewellyn and Youbin Zheng

One principle for reducing undesirable stem extension in greenhouse production is to counteract the decrease in red-to-far red ratio that occurs naturally during twilight periods. This study evaluated three lighting treatments on the morphology of easter lily (Lilium longiflorum): 1) a 1-hour end-of-day treatment providing 20 μmol·m−2·s−1 of monochromatic red light (EOD R), 2) blackout curtains closed 45 to 75 minutes before sunset and kept closed until 0 to 60 minutes after sunrise (BO), and 3) a control with natural twilight (CTRL). Plants under the BO treatment were 11% shorter than CTRL, while plants exposed to EOD R did not differ in height compared with BO or CTRL. There were no treatment effects on any other measured parameters, including aspects of flowering.

Open access

Liming Chen, Matthew Wallhead, Michael Reding, Leona Horst and Heping Zhu

Laser-guided variable-rate intelligent spray technology is designed to significantly reduce pesticide use with a positive impact on the environment. However, there have been no reports on applying this technology to commercial fruit farms. Comparative experiments of intelligent variable-rate and conventional constant-rate spray applications for pesticide use and pest control were conducted at a fruit farm in Ohio during two consecutive growing seasons. Apple (Malus pumila), peach (Prunus persica), blueberry (Vaccinium section Cyanococcus), and black raspberry (Rubus occidentalis) were used for the tests. Pest severity of codling moth (Cydia pomonella), oriental fruit moth (Grapholitha molesta), scab (Venturia inaequalis), and powdery mildew (Podosphaera leucotricha) in apple; oriental fruit moth, brown rot (Monilinia fructicola), and powdery mildew (Podosphaera pannosa) in peach; spotted wing drosophila (Drosophila suzukii), mummy berry (Monilinia vaccinii-corymbosi), and phomopsis (Phomopsis vaccinii) in blueberry; and anthracnose (Elsinoe veneta) in black raspberry were assessed. There was equal severity of pests between intelligent and conventional spray applications, whereas the intelligent spray reduced pesticide use by 58.7%, 30.6%, 47.9%, and 52.5% on average for apple, peach, blueberry, and black raspberry, respectively. These results illustrate that intelligent spray technology is more environmentally friendly than conventional standard spray technology and equally or more effective for control of insect and disease pests in fruit production.

Open access

Verónica De Luca, Diego Gómez de Barreda, Antonio Lidón and Cristina Lull

Due to restrictions on pesticide and nitrogen use in high-input European agricultural systems, many of the biostimulants used in horticulture are being incorporated into turfgrass management programs—although often with little understanding. A set of experiments was carried out on perennial ryegrass (Lolium perenne) cultivated in pots in a greenhouse in 2013 and 2014 to test the effect of three biostimulants: two composed of nitrifying bacteria (B1 and B2), and the other a mixture of amino acids, polysaccharides, nitrogen, and micronutrients (B3). Apart from the biostimulant treatment, nutritional stress was incorporated into the study to demonstrate if biostimulants could temporarily replace the fertilization role and so lessen the environmental impact. Turfgrass treated with B1 resulted in an increase in quality compared with untreated turf, and the positive effect lasted 2 and 3 months in 2013 and 2014, respectively. Additionally, an extended benefit was observed when the B1 interval application was longer, even temporarily replacing fertilization when applied on stressed turfgrass. The B2 produced similar results to B1, the effect was longer, and the turf exhibited a darker color—although it caused phytotoxicity at the tip of the leaves. The B3 led to a beneficial effect on turfgrass, especially under nutritional stress; it showed a better quality, darker green color, and more growth and yield than untreated turf (despite adding less nitrogen than during either mineral fertilizer treatment). Overall results show that the tested biostimulants increase turfgrass quality even when inducing a nutritional stress.

Open access

Clydette Alsup-Egbers, Patrick Byers, Kelly McGowan, Pamela B. Trewatha and William E. McClain

Commercial garlic (Allium sativum) is a relatively new crop for Missouri growers. While U.S. production is primarily in California, Oregon, Washington, and New York, little information is available regarding growing garlic in Missouri’s climate and soil conditions. Therefore, research is needed to investigate the optimum planting date for garlic in southwest Missouri. Comparisons between one spring and four fall planting dates using two garlic cultivars (Inchelium Red and German White) and the leek (Allium ampeloprasum) known as elephant garlic (A. ampeloprasum ssp. ampeloprasum) were planted at two replicated sites. Postharvest data were collected on bulb weight and diameter and clove weight and quantity. Although the numbers were not always statistically different, the overall results indicated that earlier planted garlic (September and early-October) had higher yields in 2016–17 than garlic planted later; however, in 2017–18, garlic planted in mid-October and early-November out-yielded garlic planted in September and early-October. Fall planting is preferred based on the results of our study, but spring-planted garlic can still yield a profitable crop for commercial growers. Future research on a variety of planting dates will give producers a better choice on when to plant in southwest Missouri.

Open access

Frederic B. Ouedraogo, B. Wade Brorsen, Jon T. Biermacher and Charles T. Rohla

Pecan (Carya illinoinensis) trees were pruned using varying intensities at planting to determine the effect of pruning on trunk development and shoot growth. Data on trunk diameter, number and length of shoots, as well as the total shoot growth were recorded annually from a completely randomized design experiment that assigned 0%, 50%, and 75% pruning of above-ground height to single-trunk transplants. The results suggest that pruning intensity has little effect on trunk diameter. The pruned trees had fewer shoots initially and more growth per shoot, leading to a difference of 7 cm/shoot higher for the 50% pruning group than the control group and to a difference of 11 cm/shoot higher for the 75% pruning group compared with the control group. The total length of all shoots was not significantly different across treatments. Because previous research has sometimes shown that pruning increases tree survival and this research shows that trees can recover from pruning, there is no need to change the current recommendation of pruning seedlings at planting.

Open access

Carol A. Miles, Travis R. Alexander, Gregory Peck, Suzette P. Galinato, Christopher Gottschalk and Steve van Nocker

Hard cider, made by fermenting apple (Malus ×domestica) juice, was at one time the most widely consumed alcoholic beverage in America. Largely abandoned after Prohibition, within the past 2 decades the rise in popularity of craft beverages has led to the reemergence of hard cider as an alternative to beer, wine, and spirits. Today, hard cider represents one of the fastest growing sectors within the craft beverage industry. The recent interest in cider presents additional marketing opportunities for apple growers and businesses currently involved in, or considering entering, the apple cider or craft beverages industries. However, the lack of a strong history or experience in selecting, producing, and using cider apples poses a significant challenge to this emerging market. This article reviews the current state of research in cider apple production, including economic feasibility, mechanized management, and cultivar evaluation and improvement.

Open access

Shana G. Brown and James E. Klett

Stock plant productivity is an important concern for growers of ‘Snow Angel’ coral bells (Heuchera sanguinea) because this variety produces a limited number of basal cuttings. The objective of the study was to determine the best growth substrate and container size combination to maximize productivity of stock plants. A secondary objective was to determine if the stock plant treatments influenced the rooting of vegetative cuttings. The study used three different container sizes (2.8, 11.4, and 14.6 L) and four commercial soilless substrates that were primarily composed of the following: bark, peat, and perlite (substrate 1); bark, peat, and vermiculite (substrate 2); bark, peat, and coarse perlite (substrate 3); and peat (substrate 4). Two stock plant experiments were conducted using the same 12 treatment combinations, and a subset of those stock plants was randomly selected for the rooting studies that immediately followed each stock plant experiment. Stock plants responded to substrate treatments differently depending on the batch of substrate in which they were grown. The most successful stock plants, which produced more cuttings per plant and per square foot, as well as larger cuttings, were those grown in substrate 3 (Expt. 1) and substrate 2 (Expt. 2). Regardless of the substrate, the highest number of cuttings per square foot was obtained from stock plants grown in 2.8-L containers, indicating that the smaller containers allow for the most efficient use of space when growing ‘Snow Angel’ stock plants for 6 to 8 months. The rooting of vegetative cuttings was successful (98% to 100% of cuttings rooted after 4 weeks under mist) for all treatment combinations, although higher numbers of visible roots were produced during the second study and may be due to larger fresh weights of cuttings.

Open access

Derald Harp, Gaye Hammond, David C. Zlesak, Greg Church, Mark Chamblee and Steve George

Griffith Buck (Iowa State University) bred roses (Rosa sp.) to survive long, cold winters and hot, humid summers yet still retain their foliage without fungicides. Unfortunately, there is little known about the performance of Buck roses in the southern United States. Thirty-eight Buck rose cultivars were evaluated for flowering, disease resistance, drought tolerance, and overall landscape performance in alkaline soils with no fertilizer, no pesticides, and only limited irrigation. Flowering occurred on a bimodal basis, with the highest per plant mean bloom number (16.3 blooms) and bloom coverage (9.7%) in April, and a second flowering in the fall, with 13.7 blooms per plant and 6.9% bloom coverage in October. Drought stress symptoms were most evident in October, with a wide range of symptom severity across cultivars. Black spot (Diplocarpon rosae) and powdery mildew (Podosphaera pannosa) incidence were rare across all roses and years. Landscape performance scores, rated using a 0 to 10 scale with 10 representing a perfect plant and 0 a dead plant, were highest in April (6.5) and lowest in June (4.6) and July (4.6). Landscape performance was not correlated with bloom number or coverage. While unable to recommend many of the Buck roses for north-central Texas, the cultivars April Moon and Freckles, and possibly a few other roses, can join Carefree Beauty™ (BUCbi) as recommended roses for the area.

Open access

W. Garrett Owen, Brian E. Jackson, William C. Fonteno and Brian E. Whipker

Processed loblolly pine (Pinus taeda) wood has been investigated as a component in greenhouse and nursery substrates for many years. Specifically, pine wood chips (PWCs) have been uniquely engineered/processed into a nonfibrous blockular particle size suitable for use as a substrate aggregate. The objective of this research was to compare the dolomitic limestone requirements of plants grown in peat-based substrates amended with perlite or PWC. In a growth trial with ‘Mildred Yellow’ chrysanthemum (Chrysanthemum ×morifolium), peat-based substrates were amended to contain 0%, 10%, 20%, 30%, 40%, or 50% (by volume) perlite or PWC for a total of 11 substrates. Substrates were amended with dolomitic limestone at rates of 0, 3, 6, 9, or 12 lb/yard3, for a total of 55 substrate treatments. Results indicate that pH of substrates amended with ≥30% perlite or PWC need to be adjusted to similar rates of 9 to 12 lb/yard3 dolomitic limestone to produce similar-quality chrysanthemum plants. In a repeated study, ‘Moonsong Deep Orange’ african marigold (Tagetes erecta) plants were grown in the same substrates previously formulated (with the exclusion of the 50% ratio) and amended with dolomitic limestone at rates of 0, 3, 6, 9, 12, or 15 lb/yard3, for a total of 54 substrate treatments. Results indicate a similar dolomitic limestone rate of 15 lb/yard3 is required to adjust substrate pH of 100% peatmoss and peat-based substrates amended with 10% to 40% perlite or PWC aggregates to the recommended pH range for african marigold and to produce visually similar plants. The specific particle shape and surface characteristics of the engineered PWC may not be similar to other wood products (fiber) currently commercialized in the greenhouse industry, therefore the lime requirements and resulting substrate pH may not be similar for those materials.