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Dr. Amanda Bayer
University of Massachusetts, Amherst

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0 Fertilization
0 Irrigation Management
0 Perennials
0 Plant Production
0 Ornamental Plants

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Journal article
Published: 16 March 2021 in Horticulturae
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Improved irrigation and fertilization practices, such as reduced applications, are needed to improve the sustainability of container plant production. The objective of this study was to assess growth of Visions astilbe (Astilbe chinensis ‘Visions’) and Mellow Yellow coneflower (Echinacea purpurea ‘Mellow Yellow’) grown at two controlled-release fertilizer (CRF) rates (100% or 50% of the medium bag rate) and two volumetric water contents (VWC; 40% and 18%). For coneflower, there were no significant treatment effects for height, growth index, shoot dry weight, or leaf size. There was a significant VWC effect on number of flowers with the 40% treatment having more flowers (5.6) per plant than the 18% treatment (2.7). Shoot dry weight, growth index, and leaf size of astilbe were greater for the 40% VWC treatment than the 18% VWC treatment with no fertilizer rate effect. Astilbe height and number of flowers was not significant. These results indicate that there is a species-specific effect of VWC on growth whereas reduced fertilizer applications are possible for both species without impacting growth. Although a substrate VWC of 18% is likely too low to produce salable plants, a VWC below 40% can potentially be used to support adequate growth.

ACS Style

Amanda Bayer. Astilbe and Coneflower Growth as Affected by Fertilizer Rate and Substrate Volumetric Water Content. Horticulturae 2021, 7, 52 .

AMA Style

Amanda Bayer. Astilbe and Coneflower Growth as Affected by Fertilizer Rate and Substrate Volumetric Water Content. Horticulturae. 2021; 7 (3):52.

Chicago/Turabian Style

Amanda Bayer. 2021. "Astilbe and Coneflower Growth as Affected by Fertilizer Rate and Substrate Volumetric Water Content." Horticulturae 7, no. 3: 52.

Journal article
Published: 16 September 2020 in Horticulturae
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Research has shown that reduced irrigation and fertilizer rates can still produce good plant growth when irrigation is applied efficiently to reduce leaching. The impact of reduced irrigation and fertilizer rate on flowering and plant growth would provide additional information on the potential for reduced production inputs. The objective of this research was to quantify the impact of reduced irrigation and fertilizer rate on growth and flowering of Ruby Candle beardtongue (Penstemon × ‘Ruby Candle’). A soil moisture sensor automated irrigation system was used to maintain plants at 40% volumetric water content [VWC; well-watered (WW)] or 18% VWC (reduced irrigation, RI). A controlled release fertilizer was applied at 100%, 50%, and 25% of the bag rate (12 g/plant). There was not a significant treatment effect on any flower parameter. Average plant height was greatest for plants receiving the 50% fertilizer rate (75.9 cm) and was lowest for the 100% fertilizer rate (64.5 cm). Internode length was greater for WW plants (36.9 mm) than RI plants (32.4 mm). Well-watered plants had greater fresh weight (99.1 g) than RI plants (79.2 g) and 100% fertilizer rate (97.1 g) was greater than the 25% fertilizer rate (82.7 g).

ACS Style

Amanda Bayer. Fertilizer Rate and Substrate Water Content Effect on Growth and Flowering of Beardtongue. Horticulturae 2020, 6, 57 .

AMA Style

Amanda Bayer. Fertilizer Rate and Substrate Water Content Effect on Growth and Flowering of Beardtongue. Horticulturae. 2020; 6 (3):57.

Chicago/Turabian Style

Amanda Bayer. 2020. "Fertilizer Rate and Substrate Water Content Effect on Growth and Flowering of Beardtongue." Horticulturae 6, no. 3: 57.

Journal article
Published: 01 June 2020 in HortTechnology
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Reduced irrigation (RI) can be used to reduce irrigation volume as well as to control plant growth. The timing and duration of RI applications can affect overall plant growth and flowering. Knowledge of plant response to RI can allow growers to control growth and plant form. The objective of this study was to quantify flower and overall plant growth of ‘PAS702917’coneflower (Echinacea purpurea) and ‘Helbro’ sneezeweed (Helenium hybrida) in response to RI. A soil-moisture sensor automated irrigation system was used to apply four irrigation treatments: RI and well-watered (WW) controls (25% or 38%) and two alternating treatments to apply RI for either the first 2 weeks (25% followed by 38%, RIWW treatment) or final 4 weeks (38% followed by 25%, WWRI treatment) of the 6-week study. For the sneezeweed experiment, RI was reduced to 20%. For coneflower, peduncle length was greater for the WW (36.8 cm) and RIWW treatments (35.7 cm) than the RI (27.0 cm) and WWRI treatments (26.6 cm). Shoot dry weight, compactness, leaf area, and flower number were not significant. For sneezeweed, WW plants were taller (57.2 cm) and had greater shoot dry weight (49.8 g) than plants in other treatments. WW plants also had more flowers (99) than WWRI (63) and RI (67) plants, which were more compact. Total leaf area did not differ between treatments for either species. Total irrigation volume was greatest for WW plants (5.2 and 15.1 L/plant for coneflower and sneezeweed, respectively), with RI at any point during the experiment resulting in water savings.

ACS Style

Amanda Bayer. Effect of Reduced Irrigation on Growth and Flowering of Coneflower and Sneezeweed. HortTechnology 2020, 30, 315 -321.

AMA Style

Amanda Bayer. Effect of Reduced Irrigation on Growth and Flowering of Coneflower and Sneezeweed. HortTechnology. 2020; 30 (3):315-321.

Chicago/Turabian Style

Amanda Bayer. 2020. "Effect of Reduced Irrigation on Growth and Flowering of Coneflower and Sneezeweed." HortTechnology 30, no. 3: 315-321.

Journal article
Published: 01 November 2016 in HortScience
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Controlling the elongation of ornamental plants is commonly needed for shipping and aesthetic purposes. Drought stress can be used to limit elongation, and is an environmentally friendly alternative to plant growth regulators (PGRs). However, growers can be reluctant to expose plants to drought stress because they do not want to negatively affect overall plant quality and marketability. Knowing how and when stem elongation is affected by water availability will help to increase our understanding of how elongation can be controlled without reducing plant quality. Rooted Hibiscus acetosella Welw. ex Hiern. cuttings were grown in a growth chamber set to a 12-hour photoperiod at 25 °C. Two plants of similar size were used for each replication of the study to compare growth under well-watered and drought-stressed conditions. Time lapse photography was used to determine the diurnal patterns of elongation over the course of the replications. Evapotranspiration was measured using load cells. Well-watered and drought-stressed plants had similar diurnal patterns of elongation and evapotranspiration, demonstrating that both follow circadian rhythms and are not just responding to environmental conditions. Stem elongation was greatest at night and coincided with evapotranspiration decreases, with greatest elongation shortly after the onset of darkness. Elongation was minimal between 800 and 1000 hr when evapotranspiration increases. During the drought-stress portion of the replications, elongation of drought-stressed plants was 44% less than well-watered plants. Final plant height and shoot dry weight for the drought-stressed plants were 21% and 30% less than well-watered plants, respectively. Total leaf area, number of leaves, and number of new visible internodes were greater for well-watered plants than drought-stressed plants. Average length of visible internodes and leaf size were similar for drought-stressed and well-watered plants. If growers want to use drought stress for elongation control, they should ensure that plants are drought stressed before the onset of and during the dark period, when most elongation occurs.

ACS Style

Amanda Bayer; John Ruter; Marc van Iersel. Elongation of Hibiscus acetosella Under Well-watered and Drought-stressed Conditions. HortScience 2016, 51, 1384 -1388.

AMA Style

Amanda Bayer, John Ruter, Marc van Iersel. Elongation of Hibiscus acetosella Under Well-watered and Drought-stressed Conditions. HortScience. 2016; 51 (11):1384-1388.

Chicago/Turabian Style

Amanda Bayer; John Ruter; Marc van Iersel. 2016. "Elongation of Hibiscus acetosella Under Well-watered and Drought-stressed Conditions." HortScience 51, no. 11: 1384-1388.

Journal article
Published: 01 July 2015 in HortScience
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Excessive irrigation and leaching are of increasing concern in container plant production. It can also necessitate multiple fertilizer applications, which is costly for growers. Our objective was to determine whether fertilizer and irrigation water can be applied more efficiently to reduce leachate volume and nutrient content without negatively impacting aboveground growth of Gardenia jasminoides ‘MAGDA I’. Plants were fertilized with one of three rates of a controlled-release fertilizer (subplots) (Florikan 18–6–8, 9–10 month release; 18.0N–2.6P–6.6K) [100 (40 g/plant), 50 (20 g/plant), and 25% of bag rate (10 g/plant)] and grown in 5.4-L containers outside for 137 days. Soil moisture sensor-controlled, automated irrigation was used to provide plants with one of four irrigation volumes (whole plots) (66, 100, 132, or 165 mL) at each irrigation event. All plants were irrigated when the control treatment (66 mL irrigation volume, 100% fertilizer treatment) reached a volumetric water content (VWC) of 0.35 m3·m−3. Plants in the different irrigation treatments were irrigated for 2, 3, 4, or 5 minutes, thus applying 66, 100, 132, or 165 mL/plant in the different irrigation treatments. Fertilizer rate had a greater effect on aboveground growth than irrigation volume with the 25% fertilizer rate resulting in significantly lower shoot dry weight (18.7 g/plant) than the 50% and 100% rates (25.3 and 27.3 g/plant respectively). Growth index was also lowest in the 25% fertilizer rate. Leachate volume varied greatly during the growing season due to rainfall and irrigation volume effects on leachate were most evident during the third, eighth, and ninth biweekly leachate collections, during which there was minimal or no rainfall. For these collections the control treatment of 66 mL resulted in minimal leachate (less than 130 mL over the 2-week leachate collection period), whereas leachate volume increased with increasing irrigation volumes. Pore water electrical conductivity (EC), leachate EC, NO3-N content, and PO4-P content were all highest with the 100% fertilizer rate, with the 66 mL irrigation treatment having the highest leachate EC for all fertilizer treatments. Cumulative leachate volumes for the 66 and 100 mL irrigation treatments were unaffected by fertilizer rate, whereas the 132 and 165 mL had greater leaching at the 25% fertilizer rate. Lower irrigation volumes resulted in reduced water and nutrient leaching and higher leachate EC. The higher leachate EC was the result of higher concentration of nutrients in less volume of leachate. The results of this study suggest that a combination of reduced fertilizer rates (up to 50%) and more efficient irrigation can be used to produce salable plants with reduced leaching and thus less environmental impact.

ACS Style

Amanda Bayer; John Ruter; Marc van Iersel. Optimizing Irrigation and Fertilization of Gardenia jasminoides for Good Growth and Minimal Leaching. HortScience 2015, 50, 994 -1001.

AMA Style

Amanda Bayer, John Ruter, Marc van Iersel. Optimizing Irrigation and Fertilization of Gardenia jasminoides for Good Growth and Minimal Leaching. HortScience. 2015; 50 (7):994-1001.

Chicago/Turabian Style

Amanda Bayer; John Ruter; Marc van Iersel. 2015. "Optimizing Irrigation and Fertilization of Gardenia jasminoides for Good Growth and Minimal Leaching." HortScience 50, no. 7: 994-1001.