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United States Department of Agriculture

Agricultural Research Service

Research Project: Improved Production Methods: North South Initiative (Clemson University)

Location: Application Technology Research Unit

2010 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.


3.Progress Report

Significant progress has been made on the two phases of this project. The big picture goal of this project is to identify the best management practices for water use during the propagation of herbaceous ornamentals and compare those to the actual mist propagation practices of commercial propagators. These practices will improve water use efficiency and will improve production success by minimizing the myriad problems that result from placing excess water on cuttings in propagation. In the first phase of this project, we are examining the physiological performance of unrooted poinsettia cuttings beginning from the time the cutting is harvested from the stock plant, continuing through the postharvest and propagation environment until the cuttings are rooted. This data will allow us to determine the actual water requirements for cuttings in propagation. Gas exchange and water uptake measurements have been made on poinsettia cuttings throughout the propagation cycle and the data are currently being processed and analyzed. The second phase involves surveying commercial propagators about their current water-use practices. We visited 20 greenhouses this past winter and made water-use measurements under 50 different propagation systems. This data allows us to know the volume of water applied during each mist event. An interview with each propagator is currently being performed to understand and be able to simulate the decision-making process for determining the frequency of the mist events during each day of the propagation. This information is currently being processed and the end result will be an overview of current mist propagation practices to which we can compare to the targeted best management practices identified from the first phase. Activity was monitored through face-to-face meetings throughout the year (4) and monthly email communication.


Last Modified: 11/27/2014
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