The objective of this study was to quantify the effects of cyclic irrigation on growth and physiology of container-grown conifer species in pot-in-pot (PIP) production in the upper Midwest. Trees of four conifer species (Picea glauca var. densata, Picea pungens, Abies fraseri, and Pinus strobus) were grown in 25-L containers and assigned to one of four combinations of irrigation rate (low or high) and daily irrigation cycle frequency (one or four). Irrigation rates were based on common nursery practice in the region (2 cm rainfall equivalent/day) and one-half the standard rate (1 cm rainfall equivalent/day). Cyclic irrigation increased relative height growth and relative caliper growth of Pinus strobus by over 80% and 35%, respectively, compared with once-daily irrigation. The high-rate irrigation increased relative caliper growth of Picea pungens by 40% compared with the low rate. The effects of irrigation regime on needle- or shoot-level gas exchange varied by species and date of measurement. Carbon isotope discrimination (Δ13C) of needle and wood tissue was positively correlated (r ≥ 0.64, P < 0.001) with needle conductance to water vapor (gwv) and negatively correlated (r ≤ −0.60, P< 0.001) with intrinsic water use efficiency (WUEi). Carbon isotope discrimination of wood and needle tissue decreased with the low irrigation rate, indicating increased WUEi associated with reduced gwv. Cyclic irrigation had relatively little effect on Δ13C except for Pinus strobus. Our findings suggest that carbon isotope composition of wood and needle tissue provides a sensitive and accurate representation of plant response to varying moisture availability. From a water management perspective, identifying optimal irrigation rates appears to be more important than number of daily cycles for these crops grown in the midwestern United States.
Amanda J. Taylor, R. Thomas Fernandez, Pascal Nzokou, and Bert Cregg
Fulya Baysal-Gurel and Ravi Bika
Ninebark (Physocarpus opulifolius) is a popular ornamental shrub and considered a hardy and tough plant that can thrive in different environmental conditions and resist diseases. However, powdery mildew, caused by Podosphaera physocarpi, can severelyaffect ninebark, deteriorating the ornamental value and making them unmarketable. Only a few studies have been done in managing powdery mildew of ninebark. The current study focuses on evaluating and identifying effective products (sanitizers, biorational products, and fungicides) for the management of powdery mildew disease of ninebark. A total of 12 treatments, including nontreated control, were studied. The experiment was arranged in randomized complete block design with four-single ‘Mindia Coppertina®’ ninebark plant per treatment and repeated twice. Powdery mildew disease severity, growth parameters, and phytotoxicity were assessed in the study. All treatments significantly reduced the powdery mildew disease severity and disease progress [area under disease progress curve (AUDPC)] compared with the nontreated control. The treatments, such as azoxystrobin + benzovindiflupyr at 0.17 and 0.23 g·L–1 total active ingredients (a.i.) applied, chlorothalonil + propiconazole at 1.12 mL·L–1 total a.i. applied, azoxystrobin + tebuconazole at 0.11 and 0.16 g·L–1 total a.i. applied, and giant knotweed extract [Reynoutria sachalinensis (0.5 mL·L–1 total a.i. applied)] were the most effective treatments in reducing disease severity and disease progress in both trials. The treatments had no significant effects on the plant growth parameters such as height and width. In Expt. 2, azoxystrobin + benzovindiflupyr and hydrogen peroxide + peroxyacetic acid treated plants showed the low level of phytotoxic symptoms. The phytotoxicity of these two treatments in Expt. 2 could be related to higher environmental temperature during the experimental period.
Janet C. Cole and Lee Newell
Five container substrates—3 pine bark (PB) : 1 peat (PT) : 1 sand (SD), 3 PB : 1 recycled paper (RP) : 1 SD, 2 PB : 2 RP : 1 SD, 3 vermiculite (VM) : 1 RP : 1 SD, and 2VM : 2 RP : 1 SD—were used to grow rose-of-sharon (Hibiscus syracus L. `Double Purple') and forsythia (Forsythia ×intermedia Zab. `Lynwood Gold') for 4.5 months. The control substrate (3 PB:1 PT:1 SD) had higher concentrations of NH4 * in leachate than other substrates at each of four sample times during the growing season except 4 Aug. Leaf number and leaf area per plant and height of rose-of-sharon were greater and the leaf area per leaf was smaller in all substrates containing recycled paper than in substrates without recycled paper. Forsythia plants had greater stem and root dry weights and were taller in substrata without recycled paper than plants in substrates with recycled paper. Processed recycled paper is a possible component for container nursery plant production, but further testing on a large number of species is needed before widespread implementation.
Shannon Caplan, Bryan Tilt, Gwen Hoheisel, and Tara A. Baugher
Increasing labor costs and changes in labor forces have prompted an increased demand for automation in specialty crop production. Implementation of technological innovations in the agricultural sector tends to be slow, thus this study investigated motivations and perceptions of technology. Using qualitative interviewing and analysis, this study used a diffusion of innovations framework to gain insight into what channels of communications impacted planned adoption rates and what aspects of technology influence the decision-making process. Interview participants emphasized the inevitability of implementing new technologies while considering the capital investment of more complex technology, changes in labor management to integrate technology, applicability of technology to current practices, and trust in technology designers.
Karla M. Addesso, Anthony L. Witcher, and Donna C. Fare
( Southern Nursery IPM Working Group, 2014 ). In field and container nursery production in the southeastern United States, these pests are generally managed through cultural practices and rotations of conventional pesticides ( North Carolina State University
Matthew R. Chappell, Sarah A. White, Amy F. Fulcher, Anthony V. LeBude, Gary W. Knox, and Jean-Jacques B. Dubois
Ornamental nursery production is an economically important sector of specialty crop agriculture in the United States, with 8226 growers producing nursery crops with a farm gate revenue of $4.3 billion [ U.S. Department of Agriculture (USDA), 2015
Anthony LeBude, Amy Fulcher, Jean-Jacque Dubois, S. Kris Braman, Matthew Chappell, J.-H (J.C.) Chong, Jeffrey Derr, Nicole Gauthier, Frank Hale, William Klingeman, Gary Knox, Joseph Neal, and Alan Windham
= 10), G2 ( n = 40), G3 ( n = 74)] in the southeastern United States. Sixty percent of growers who attended the workshops in 2014 indicated they had changed their nursery production practices previously as a result of attending a workshop or lecture
Timothy K. Broschat
fertilization was essential for Mexican fan palms, areca palms did not respond to supplemental P in this study or in another on a nearby plot ( Broschat, 2015 ). Although rapid growth is a primary concern for nursery production of palms, plant height was highly
Amy Fulcher, Anthony LeBude, Sarah A. White, Matthew R. Chappell, S. Christopher Marble, J.-H (J.C.) Chong, Winston Dunwell, Frank Hale, William Klingeman, Gary Knox, Jeffrey Derr, S. Kris Braman, Nicole Ward Gauthier, Adam Dale, Francesca Peduto Hand, Jean Williams-Woodward, and Steve Frank
this early funding, SNIPM established an advisory board that rotates membership among leaders in the nursery production industry (one to two per state) representing ≈7500 operations in member states ( U.S. Department of Agriculture, 2014 ). The working
Emilie A.K. Justen, Cynthia Haynes, Ann Marie VanDerZanden, and Nancy Grudens-Schuck
Iowa between Sept. 2007 and Mar. 2008. The target population was English-speaking managers of Latino workers from the golf course, nursery production, and landscaping sectors of the Iowa horticulture industry. In July 2007, 241 letters requested