Hybrid impatiens (Impatiens Wallerana Hook. F.) were planted in six root media containing either 70% (by volume) rockwool, coir, or four types of sphagnum peat and 30% perlite. The six media varied in cation exchange capacities (CEC) (from 5 to 76 meq·L-1) and the amount of a dolomitic hydrated lime [Ca(OH)2 and Mg(OH)2 at 0 to 4.5 kg·m-3) required to obtain an initial pH of ≈6.0. Two additional treatments were produced by using a dolomitic carbonate lime (CaCO3 and MgCO3) at 8.4 kg·m-3 instead of the hydrated lime in two of the sphagnum peat media. Plants were subirrigated for 17 weeks using three nutrient solutions (NS) that contained at 200N-20P-200K mg·L-1 but had a variable NH4 : NO3 ratio and Ca2+ and Mg2+ content. The NS were designed to produce either acidic, neutral, or basic reactions in the medium. In media containing the hydrated lime, the NS was the primary factor controlling medium pH. However, within each NS treatment, the media did have some effect on buffering the pH over time. There was a linear increase in shoot-tissue Ca and Mg as the applied concentration of Ca2+ increased from 18 to 156 mg·L-1 and that of Mg2+ increased from 5 to 56 mg·L-1. Linear regression analysis of shoot-tissue Ca and Mg based on their concentration in the NS indicated a similar overall decrease in the Ca and Mg supply in all six root media over time. For plants grown in media containing the carbonate lime, shoot dry mass was similar to that of plants grown in the same media with hydrated lime. The presence of the carbonate lime in the media increased the pH buffering capacity against decreasing pH with the acidic and neutral NS but not against increasing pH with the basic NS. In the media containing the carbonate lime and given the acidic NS, root-medium and shoot-tissue Ca and Mg increased by weeks 12 and 17 compared to that of the same medium containing the hydrated lime. There were minimal differences in root-media and shoot-tissue Ca and Mg concentration between lime treatments when given the neutral or basic NS.
William R. Argo and John A. Biernbaum
Erin James and Marc van Iersel
Water conservation is increasingly important for growers in the United States, but there is little information on the use of alternative irrigation systems, such as ebb and flow, for the production of bedding plants. The objective of this study was to quantify the growth of Petunia ×hybrida Hort. Vilm.-Andr. `Blue Frost' and Begonia ×semperflorens-cultorum Hort. `Ambassador Scarlet' grown in an ebb and flow system in three soilless media and fertilized with P at 0, 50, or 100 mg·L-1 in the fertigation solution. After 5 weeks, plants grown with 50 or 100 mg·L-1 P had greater dry weight, height, and width than plants grown with 0 mg·L-1 P. Begonias grown with 50 or 100 mg·L-1 P had 38% more flowers than did those grown without P. Petunias flowered 4 to 7 days earlier when no P included in the fertilizer. Growing media had little effect on the plants. Begonias grown in Metro-Mix 220 had more inflorescences than those grown in Metro-Mix 366Coir. Changes in electrical conductivity (EC) and pH of all three media were similar over the course of the experiment. The EC dropped during the third and fourth week and rose again in the fifth week. The pH of the leachate from all three media dropped by an average of 1 unit during the experiment. The results indicate that petunias and begonias may be grown successfully with ebb and flow irrigation, using a variety of fertilizers and growing media. However, P must be included in the fertigation solution for optimal plant quality.
William R. Argo and John A. Biernbaum
Hybrid impatiens (Impatiens Wallerana Hook. F.) were planted in a peat-based medium containing two dolomitic liming materials (1.8 kg Ca(OH)2·Mg(OH)2/m3 or 8.4 kg CaCO3·MgCO3/m3) and subirrigated for 17 weeks using four irrigation-water sources (IWSs) with varied bicarbonate alkalinity, Ca2+, Mg2+, and SO4-S content and three water-soluble fertilizers (WSFs) that contained (in mg) 200N-20P-200K/liter but a variable NH4: NO3 ratio, Ca2+, Mg2+, and SO4-S content. The factorial arrangement of the IWS and WSF resulted in a range of Ca2+, Mg2+, and SO4-S concentrations varying by a factor of 10. After 8 weeks, medium pH ranged from 4.5 to 8.5. The maximum critical medium pH for PO4-P uptake was 7.4 to 7.7, which probably was due to a change in most of the water-soluble P to the less-available HPO4 2- form. Lime type did not affect the long-term increase in medium pH, Ca2+, and Mg2+ concentrations with nutrient solutions containing low NH4 +-N and high Ca2+ and Mg2+. The carbonate lime buffered the medium pH and Ca2+ and Mg2+ concentrations with nutrient solutions containing high NH4 +-N and low Ca2+ and Mg2+ compared to that measured with the hydrated lime. With both lime types, there was a linear increase in tissue Ca and Mg as the applied concentrations of the various nutrient solutions increased from 18 to 210 mg Ca2+/liter and 7 to 90 mg Mg2+/liter. The relationship was similar for both lime types up to week 8, after which tissue Ca and Mg decreased more rapidly with the hydrated lime and low solution Ca2+ and Mg2+ compared to that of the same carbonate lime treatments. The minimum critical SO4-S concentration in the applied nutrient solution for plant uptake was 30 to 40 mg S/liter. Below this concentration, tissue S decreased rapidly; above, there was little effect on tissue S.
Juana C. García-Santiago, Luis A. Valdez-Aguilar, Armando Hernández-Pérez, Andrew D. Cartmill, and Jesús Valenzuela-García
; Siddiqi et al., 1998 ; van Os, 1999 ). Among closed irrigation systems, subirrigation with nutrient and water recirculation is an excellent method to enhance plant production, quality, yield, and potentially the profitability of important cultivated
Dustin P. Meador, Paul R. Fisher, Philip F. Harmon, Natalia A. Peres, Max Teplitski, and Charles L. Guy
Horticultural operations are increasingly using recirculating subirrigation systems and runoff water collected in catchment basins to supplement decreasingly available potable water sources for irrigation ( Obreza et al., 2010 ). Irrigation water
Paraskevi A. Londra, Angeliki T. Paraskevopoulou, and Maria Psychoyou
irrigation and capillary mat sub-irrigation are the most common irrigation methods for begonia production. In this article, the water–air balance of four soilless substrates on the growth of Begonia × elatior ‘The President’ was investigated under two
Laura A. Warner, Alexa J. Lamm, Peyton Beattie, Sarah A. White, and Paul R. Fisher
avoid foliar diseases subirrigation: ebb-and-flood irrigation delivery from below the container, usually combined with a collection tank to hold water and reduce leaching and foliar diseases soil moisture sensors: timing of irrigation based on automated
Szu-Chin Peng, Iou-Zen Chen, and Cheng-Yung Cheng
water potential of cuttings and it has increased the rooting percentage in many plant species ( LeBude et al., 2004 ; Mudge et al., 1995 ). Subirrigation is another common system used to reduce water stress for successful rooting of cuttings ( Owen et
Mariateresa Cardarelli, Youssef Rouphael, Delia Muntean, and Giuseppe Colla
, Northern Lights Red, and White Peacock) grown in closed subirrigation system. Materials and Methods Plant materials, growth conditions, and experimental design. The experiment was carried out in Autumn 2012 growing season, in a 300 m 2 polyethylene
Erin J. Yafuso and Paul R. Fisher
) subirrigation, where 180 mL of nutrient solution was applied in a 12.7-cm-diameter saucer holding the pot. Plant species included the same Calibrachoa and Lobelia cultivars from Expt. 1A., and Pelargonium × hortorum ‘Patriot Red’. The experiment was a