Progress 09/01/07 to 08/31/08
Outputs
OUTPUTS: Three crops were grown between 9/1/2007 and 8/31/2008. Two cultivars of Chrysanthemum, Donna and Nancy, were grown from August to October 2007 in 8-inch pots. Plants representative of all positions on each floor were weighed before and after each watering to measure uptake of water. Height, diameter of the crown, and fresh weight were measured on 10/10/2008. The root medium was extracted to determine salt concentrations. Plants removed at 1st color and early flower were held at the University of Connecticut in a simulated retail environment greenhouse to measure leaf chlorophyll and flower longevity. Poinsettia cultivar Prestige Red was grown in 6-inch pots from October 2007 to February 2008. Some plants were inoculated with cultures of Pythium aphanidermatum and Phytophthora. At each watering non-inoculated plants were examined for symptoms of disease. Samples of solution from the irrigation reservoirs were filtered and the residue was placed on selective agar to determine density of pathogens. Copper ionization and hydrogen peroxide were used to sterilize the nutrient solutions. At peak maturity and late maturity, plants were placed in a simulated indoor environment at the University of Connecticut to follow leaf and bract color. Geranium, cultivar Allure Hot Coral, was grown in 6-inch pots from March to June 2008. Electronic moisture sensors were placed in six pots on each floor. On 6/4/2008 root balls were rated for root density appearing against the outside of the pots, and disease rating in terms of brown or black roots. Plant height and fresh weight were determined. Some plants were inoculated with Pythium ultimum. At each watering non-inoculated plants were examined for symptoms of disease. The information resulting from these studies was disseminated to Extension personnel and Horticultural scientists via meetings of the NE 1017 regional research committee (2008). It was disseminated to commercial growers at a meeting of the Connecticut Greenhouse Growers Association (2008), and to the general public in Connecticut by demonstration plots at the annual public open house at our experimental farm. PARTICIPANTS: Joseph Geremia, owner of Geremia Greenhouse, devoted 20% of his time to this project. Mr. Geremia is the scientific and technical director of the work described here. Martin Gent and Wade Elmer, Agricultural Scientists at the Connecticut Agricultural Experiment Station, devoted 5% of their time to this project. Dr Gent examined watering, nutrient uptake, and plant growth. Dr Elmer provided cultures of pathogens, and analyzed solutions and plant tissues for pathogens. Richard McAvoy, professor at the University of Connecticut, devoted 5% of his time to this project. Dr McAvoy evaluated the quality of the crop and made observations of plants in a post harvest environment. Michael Short and Peter Thiel, Research Technicians, devoted 10% of their time to watering and maintain the plants and processing samples of plants and solutions. TARGET AUDIENCES: The target audiences are extension personnel and horticultural scientists, both national and international, and commercial growers and greenhouse consultants in Connecticut, and nationally. There were several channels used to deliver this science-based knowledge to stakeholders to increase awareness and alter actions or practices. Information resulting from these studies was disseminated to Extension personnel and Horticultural scientists via meetings of the NE 1017 regional research committee. Information was conveyed to commercial growers and consultants via by conversations at growers meeting in Connecticut, and by demonstrations at the experimental farm of the Connecticut Agricultural Experiment Station. The general public was informed of the results through demonstrations and displays at the public open house at the experimental farm. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
More water was taken up and used by chrysanthemum plants in the control compared to PSEFW treatment. Water content of the root medium was 38 to 55% compared to 58 to 67%, for PSEFW and control watering, respectively. The uppermost layer of root medium had 5-fold more salts than the lower layers, and watering method did not affect this stratification of nutrients. By early flower opening, Nancy was taller and weighed more, but leaves had less chlorophyll, under control compared to PSEFW, respectively. Development of flowers was delayed in Nancy by PSEFW, but it was advanced in Donna. Poinsettia plants took up 0.96 and 0.66 L per watering, under control and PSEFW regimes, respectively. The lower layers of root medium had more salts under control compared to PSEFW treatment, but PSEFW increased the stratification between layers. One month after placing plants inoculated with Pythium on the floors, twenty non-inoculated plants developed symptoms of disease on the control floor. No plants developed symptoms under the PSEFW regime. The density of pathogens was lowered by copper ionization at about 1 ppm free copper, and by hydrogen peroxide at about 0.01 w/v%. The pattern of post-harvest bract color change did not differ between plants raised in the control and PSEFW regimes until 28-days in the post-harvest environment, when plants were no longer marketable. Leaves did not differ in color. After watering geranium, the root medium water content was 50% compared to 55 to 62%, with PSEFW and control regimes, respectively. Geraniums harvested at full flower were shorter and had less fresh weight under PSEFW than under control watering. Plant height and weight did not differ with position on each floor. Pythium was recovered from the irrigation water early in the study, but very few plants showed symptoms of disease. Pythium was isolated from all the roots sampled on 6/4/2008. Root disease ratings were 53% and 41%, for control and PSEFW, respectively. When placed in a simulated retail environment, the color of upper leaves did not differ between treatments. Lower leaves had less chlorophyll under control than PSEFW regimes. All lower leaves on control plants senesced after 1-week, while only 33% senesced on PSEFW plants. Flower longevity in the post-harvest environment was not affected by irrigation regime. Crops produced with the partial saturation ebb and flood watering system (PSEFW) developed by Geremia Greenhouse used less water and fertilizer compare to a crop grown with a typical long-duration watering cycle. There were fewer symptoms of disease. A short duration of watering lowered the weight of plants, but did not affect flower quality. In some instances post-harvest keeping quality was prolonged by the PSEFW regime. PSEFW watering would conserve water and fertilizer use by flower growers, and help maintain flower quality in a post-harvest environment.
Publications
- No publications reported this period
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Progress 09/01/06 to 08/31/07
Outputs
An experimental greenhouse was constructed in winter 2007 and completed in April 2007. The greenhouse operated according to specifications, with two completely separate flooded floor watering systems. The shortest practical watering cycle In the Partial Saturation Ebb and Flood Watering System (PSEFW) floor was a 2-minute supply, followed by a 2-minute drain period. A floor of standard design was operated with a 10 to 15-minute flood duration followed by a 4-minute drain. Unused solution was completely recycled, and the total volume of water taken up in each watering cycle was measured accurately. Geraniums in 6-inch pots were grown in April to June 2007 to compare the effects of short cycle PSEFW watering to a longer-duration watering. Pots watered by PSEFW retained less water at the end of a watering cycle, than those watered for a longer duration, 68 to 74% compared to 85 to 87% of water holding capacity, respectively. By the time that another watering was required,
the pots had a similar amount of water, 12 to 14% of capacity. Consequently, more water was taken up and used by plants in the full compared to the partial saturation treatment, an average of 550 and 430 mL per plant per water cycle, respectively. At the end of production, the pots and root medium were frozen and cut into one-inch layers that were weighed, dried, and analyzed to determine the gradient in water and nutrients in the root medium. The two watering treatments had similar concentrations of nutrients in the lowest layer of the pots. There were about 10% more nutrients in the middle two layers with full saturation watering. The uppermost layer had a high concentration of salts, 7 and 11 fold higher than in some other layers, for full and partial saturation watering, respectively. Potassium, calcium and sodium were the elements that contributed most to the high EC of the upper layer of root medium. The PSEFW treatment affected the growth of the plants. The fresh weight per
plant, and the difference between watering treatments, increased approximately linearly over time. At maximum flower development, plants under full saturation watering weighed 20% more than those under partial saturation, 130 and 107 grams per plant, respectively. Neither shoot height nor height to the base of the flowers varied between watering treatments. Geraniums were held for two weeks in either a shaded greenhouse or under fluorescent lights, starting at initial color and continuing for one-week past peak bloom. Leaf color, leaf chlorophyll, and flower quality were measured weekly. Chlorophyll concentrations declined dramatically after 14-days in the post-harvest environment (P<0.0001) for geraniums produced under both watering treatments. Similar trends were observed in plants held in the shaded greenhouse as well as the indoor environment. The pre-harvest watering treatments did not significantly alter post-harvest leaf senescence. Geraniums remained saleable for 7 days in the
indoor environment, while plants remained saleable for 14 days in the shaded greenhouse.
Impacts
The partial saturation ebb and flood watering system developed by Geremia Greenhouse restricts the uptake of water. A short duration of water supplied during an ebb and flood watering event restricts the amount of water and fertilizer taken up by geraniums grown in a greenhouse. A crop was produced using less water and fertilizer compare to a crop grown with a typical long-duration watering cycle. A short duration of watering lowered the weight of plants, but did not affect plant height or flower quality. Post-harvest keeping quality of the geraniums was not affected by the pre-harvest watering treatments.
Publications
- No publications reported this period
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