Can regulated deficit irrigation in an ebb and flow system alleviate the effects of salinity stress on poinsettia? Two cultivars of poinsettia (Euphorbia pulcherrima Willd ex Klotzsch) were grown under partial- or full-saturation irrigation using a standard fertilizer solution, with or without the addition of 0.5 g·L−1 NaCl. The volumetric water content of the medium averaged 0.25 and 0.33 L·L−1 before irrigation, and 0.5 and 0.67 L·L−1 following irrigation, for partial- or full-saturation regimes, respectively. Plants had lower fresh weight with partial than full saturation. Sodium concentrations in bract, leaf, and stem tissues were higher (P ≤ 0.05) in plants exposed to salinity, and these plants accumulated less K in stems and less P in bracts. Eight cultivars were grown in a second study with or without salinity of 1.2 g·L−1 NaCl under drip or ebb and flow watering. Cultivar and watering had effects on plant fresh weight, but salinity did not. Of the cultivars tested, ‘DaVinci’, ‘Premium Picasso’, and ‘Prestige Red’ had the highest sodium in bracts under salinity with drip irrigation, whereas ‘Snowcap’ had the least. ‘Ruby Frost’ had the most sodium in stems, whereas ‘Snowcap’ had the least. For all cultivars, added salinity resulted in lower K in leaves and stem. Snowcap was the cultivar with the least sodium in stems and bracts under saline irrigation, with either drip or ebb and flow. Our research demonstrates that regulated deficit irrigation resulting in partial saturation of the growing medium is an effective water management option, when control of plant height and overall crop growth are desirable, and it limits the accumulation of sodium when raw water contains elevated salinity.
Martin P.N. Gent, Wade H. Elmer, Kranti Macherla, and Richard J. McAvoy
Richard J. McAvoy, Harry W. Janes, Gene A. Giacomelli, and Michael S. Giniger
The accuracy of a computer planning model for the management of a single-truss tomato (Lycopersicon esculentum Mill.) production system was tested in the greenhouse. The model was used to generate a production schedule for 24 successive crops during a 15-month study. The time, in days, required for an emerging seedling to reach anthesis and the total fresh weight fruit yield were predicted for each of the 24 crops by the planning model. Correlation analysis, used to compare the expected crop response (i.e., data generated by the planning model) to the actual crop response, indicated that both the number of days from emergence to anthesis and fresh weight fruit yield were accurately forecast, r 2 = 0.76 and 0.83, respectively. More important, the cropping schedule that was generated by the planning model successfully produced a continuous harvest of tomatoes from sequential crops.
William J. Sciarappa, Jim Simon, Ramu Govindasamy, Kathleen Kelley, Frank Mangan, Shouan Zhang, Surendran Arumugam, Peter Nitzsche, Richard Van Vranken, Stephen Komar, Albert Ayeni, Gene McAvoy, Chung Park, William Reichert, David Byrnes, Qingli Wu, Brian Schilling, and Ricardo Orellana
The rapid expansion of Asian populations in the United States presents significant opportunities and challenges for the eastern U.S. produce sector to take advantage of their close proximity to densely populated areas. Initial crop studies followed by ethnic consumer and crop surveys were conducted to examine vegetable, leafy green, and herb consumption and expenditures among Chinese, Asian Indians, and other Asian groups. Consumer choices were used to prioritize subsequent production trials. Family expenditures were determined for specific Asian produce types and total produce purchases. This market data were extrapolated to the east coast Asian populations to assess potential market size (90% confidence interval, error margin 5.6%). Chinese consumer values ranged from $245 to $296 million per annum and Asian Indians ranged from $190 to $230 million per annum. The average annual fresh fruit and vegetable expenditures by both Asian groups were 2 to 3.5 times respective national averages. Leading Chinese vegetables determined by average expenditures were baby bok choy, pak choy, oriental eggplant, snow pea, oriental spinach, and napa cabbage. Highest expenditure of leafy greens and herbs for Chinese consumers were chives and garland chrysanthemum. This market-driven survey reported consumption of over 100 Asian crops and 42 cultivars were ranked “feasible” to grow in the eastern section of the United States. Horticultural matrices of selection criteria narrowed the list to the most promising candidates for production. As a result, 28 cultivars were then grown in University research and demonstration plots at Massachusetts, New Jersey, and Florida in determining growth characteristics and yield to focus horticultural crop producers. Leading vegetable cultivars for Asian Indian consumers were bitter gourd, eggplant, fenugreek leaves, cluster beans, and bottle gourd. Leading leafy greens and herbs for Asian Indians were turmeric, fenugreek, sorrel spinach, and radish greens. Most of these Asian cultivars were demonstrated to grow well in the three main growing zones of 5, 7, and 9. Phytochemical attributes such as antioxidant activity, polyphenols, and mineral contents were analyzed for several of the leading crop candidates. This initial field and laboratory data shows that many of these ethnic crops can be grown in the eastern United States to direct production opportunities and are nutrient rich to help drive consumer demand.