use of both water and fertilizers; however, the initial cost of automated subirrigation systems is high ( Ferrarezi et al., 2015a ; Thomas, 1993 ). Ebb-and-flow subirrigation is relatively cheap and easy-to-use compared with other subirrigation
Leqi Yang, Xiao Yang, Hong Zhao, Danfeng Huang, and Dongqin Tang
Martin P.N. Gent and Richard J. McAvoy
, 1977 ). The runoff of water, fertilizer, and pesticides resulting from these irrigation methods is a potential risk to the quality of the environment in proximity to a greenhouse operation. Subirrigation, and in particular ebb and flow, systems are more
Rhuanito Soranz Ferrarezi, Marc W. van Iersel, and Roberto Testezlaf
plants were sprayed with 0.4 g·L −1 of 8.5% acetamiprid (TriStar; Cleary Chemicals LLC, Dayton, NJ) to exterminate caterpillars. Plants were grown on 10 ebb-and-flow benches with 1.52 m length × 0.91 m width × 4 cm height (MidWest GroMaster, St. Charles
Marc van Iersel and Ron Oetting
Ebb-and-flow systems can be used to apply systemic pesticides to greenhouse crops without worker exposure or runoff. However, there is little information on the efficacy of pesticides applied with ebb-and-flow systems. We are using silverleaf whitefly (Bemisia argentifolii) control on poinsettia (Euphorbia pulcherrima) with imidacloprid as a model system to study pesticide efficacy in ebb-and-flow systems. The objective of this study was to determine the effect of the amount of insecticide taken up by the pot on the efficacy of whitefly control. Different amounts of imidacloprid uptake were obtained by not watering the plants for 0, 1, 2, or 4 days before the imidacloprid application. The imidacloprid (132 g·L–1) was applied once when the roots of the cuttings had reached the side of the pots. These treatments were compared to an untreated control on ebb-and-flow and a standard drench application (100 mL) to hand-watered plants. Pots in the different subirrigation treatments absorbed 12 to 175 mL of imidacloprid solution. Four days after the application, leaf tissue of the hand-watered plants contained 8 to 20 times more imidacloprid than the subirrigated plants. Efficacy was determined from the percentage of surviving mature whiteflies after 2 days on the plants and by counting the number of immatures after 2 weeks. Surprisingly, imidacloprid efficacy was better in the subirrigated imidacloprid treatments than in the hand-watered treatment. Whitefly control in all subirrigated imidacloprid treatments was excellent, irrespective of the amount of imidacloprid solution taken up by the pots.
Erin James and Marc van Iersel
Univ. of Georgia. Mention of brand names is for informational purposes only and does not imply its approval to the exclusion of other products that may also be suitable. We would like to thank Sunbelt Greenhouses for their donation of plant material and
Marsha Ann Bower, David H. Trinklein, and John M. Brown
Recent trends in greenhouse container production suggest using ebb and flow irrigation for water conservation and pollution control. A major problem in this system is management of soil borne pathogens. Some species of Trichoderma, a beneficial fungi, are known to control Pythium and Phytopthora in container production. This study investigates the potential of applying a Trichoderma conidial spore suspension in an ebb and flow irrigation system. Trichoderma conidia were collected from culture and placed in 101 l stock solution tanks at 10-2 and 10-4 colony forming units (CFU) per ml. Six inch container grown Dendranthema grandiflora `Delano', were irrigated as needed. To determine Trichoderma density in the root environment, soil samples were acquired from the container at 7 day intervals. Results showed that initial population densities of 10-4 CFU/ml were required to achieve adequate container populations to control disease after one irrigation. This study successfully demonstrated that Trichoderma could be dispersed through irrigation water into container plants in an ebb and flow system.
Erin James and Marc van Iersel
The negative effects of nutrient runoff on the environment has come more to the forefront of greenhouse issues in the past few years. Alternative irrigation systems that reduce or eliminate runoff that are widely used in Europe have not yet gained much popularity in the southeastern United States, in part due to a lack of available information on their use. One such system is ebb-and-fl ow, which is a completely closed recirculating system, having no runoff whatsoever. In order to learn more about optimum growing practices using the ebb-and-fl ow system for bedding plants, marigolds and sunflowers were grown under a variety of conditions. After a 6-week period, pH of growing media of both marigolds and sunflowers decreased by 1, while EC increased by ≈1 dS/m. There were also significant differences in EC due to the different media types. The soilless medium with the highest percentage of vermiculite and lowest percentage of pine bark had the highest EC. Different types of fertilizer and fertilizer rates will be discussed, as well as interactions between fertilizer and media.
Martin P.N. Gent, Wade H. Elmer, Kranti Macherla, and Richard J. McAvoy
; however, studies have shown over-watering by 10% to 30% is recommended to prevent salinity buildup in the root medium ( Mastalerz, 1977 ). By comparison, subirrigation, and in particular ebb and flow, systems use water more efficiently ( Dole et al., 1994
Myung Min Oh, Young Yeol Cho, Kee Sung Kim, and Jung Eek Son
Subirrigation, such as the ebb-and-flow culture (EBB) system, is a popular method in containerized plant production for controlling the application of fertilizer, water, and pesticides, and for improving production efficiency ( Dole et al., 1994
Rhuanito Soranz Ferrarezi, Geoffrey Matthew Weaver, Marc W. van Iersel, and Roberto Testezlaf
) ( Fig. 5 ). Similar designs, now known as ebb-and-flow systems, subsequently became popular ( Bauerle, 1990 ; Biernbaum, 1988 , 1990 ; Elliott, 1990 , 1992 ) and are the most common type of subirrigation used in the greenhouse industry ( Uva et al