2009 Annual Report
1a.Objectives (from AD-416)
The objective of this unified research effort is to improve the efficiency of plant production through a multi-disciplinary team approach that focuses on scheduling, the environment, energy, nutrient, water, and chemical growth regulator resources.
1b.Approach (from AD-416)
Develop protocols to flower plants at a specified plant size for the retail environment, and extending the marketing season by producing early- or late-flowering plants for different locations in the U.S. A single product or tank mix growth retardant applications for new crops that reduce elongation most without delaying flowering and whether innovative practices such as rewetting of foliage increases efficiency of growth regulators. Identify the crops and stages of development in which lighting is most effective. In addition, photoperiodic lighting is increasingly being used to induce earlier flowering during the winter and spring. Determine how photoperiodic lighting can be maximized by investigating how light quantity, quality, and duration (including cyclic lighting) impact flowering of a range of popular garden plants. Potential energy savings will be quantified by optimizing light and temperature to produce crops in the most efficient and cost-effective manner for different locations in the U.S. Develop tools and techniques that allow growers to more precisely control and manipulate flowering of greenhouse crops. Techniques will be developed for producing 'programmed' liners that have the branching, height potential, and flower bud development necessary so that the liner can be simply transplanted and quickly finished. "Bud meters" will be developed for important floriculture crops so that growers can manage greenhouse environments in order to properly time flowering on finished crops or to possibly reduce greenhouse temperatures to save fuel costs while still hitting the targeted market dates. Determine optimal fertilziation rates and tissue nutrient levels to maximize growth of flowering plants and characterize the symptoms of nutritional disorders. Measure nutrient uptake through leaves, stems, and roots at different stages of rooting under greenhouse and controlled hydroponic conditions to match fertilizer supply with demand. Quantify the interaction of applied water and fertilizer rates on leaching of different forms of nutrients from propagation media. Identify the fertigation strategies that reduce nutrient leaching while maintaining crop health.
This Congressionally-mandated Specific Cooperative Project works in concert with four other projects for improvements in the efficient production of bedding plants. This aspect of the project focuses primarily on how managing the light and temperature environment in a production environment can improve the quality and energetic efficiency of crop production. In the past year, temperature and the photosynthetic daily light integral (DLI) were quantified in how they regulate plant development of over 25 herbaceous ornamental crops. Plants were grown at temperatures ranging from 14 to 26 °C under two DLIs in two different experimental periods. Data was collected on time to flower and flowering characteristics, such as flower number. Data analysis is ongoing and a result will be in the creation of mathematical models that will be used to predict effects of temperature and light on production time. This information will be utilized by Virtual Grower software from the parent USDA-ARS project to estimate heating costs given different production scenarios, different locations, and different times of the year. In the next year, crops will be grown at various fluctuating day/night temperatures to validate the generated models. A second area of study has been on the use of plant growth regulators on greenhouse crops. The use of a high strength, experimental formulation of paclobutrazol was studied to control internode elongation of floriculture crops. Currently, the work is being repeated to determine if there are differences among application strategies (spray versus drench). In addition, work continues with abscisic acid to evaluate its potential use on bedding plants to increase the postharvest tolerance to drought conditions. A third area of study is on providing inductive photoperiods to bedding plants. The length of the juvenile period and the minimum number of inductive photoperiods necessary for floral induction was determined for more than ten bedding plant crops. Additionally, the effects of the number of inductive cycles and timing of exposure to the inductive photoperiod on crop quality parameters were evaluated. This will allow for the development of production schedules that reduce production time without compromising crop quality. Progress of this cooperative project was monitored through weekly electronic (email) communication, shared participation in industry-related educational courses, and twice annual face-to-face communication at national meetings.