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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

2013 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 fertilization 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:

This is the final report for this project. Experiments were run in controlled environments to determine the effect of irradiance, temperature and humidity on water evaporation from leaf surfaces and transpiration from unrooted cuttings. The effect of media water content on adventitious root formation was determined for poinsettia and osteospermum cuttings. A simple sampling procedure was developed to provide growers with a practical tool for identifying the media water content of their media in their propagation facility. The procedure uses a single Ellepot or Fertiss cell that is placed on a piece of round filter paper, and the time for water from the cell to saturate the filter paper is used to estimate the media water content.

The media water content experimentation was conducted with only one growing media. Currently, we are conducting an experiment to determine if the optimal media water content varies with the type of propagation media. To accomplish this, the fraction of water, air and solid in the media matrix was altered by changing the ratio of the media components, e.g. perlite and peat moss. This experimentation will be completed by the Fall 2013.

A Propagation Weather Station (PAWS) continues to be developed to utilize environmental sensors placed in commercial greenhouses to quantify water use in commercial propagation facilities. PWS was set up in five commercial facilities so far in 2013. The data include environmental measurements (solar radiation, daily light integral, temperature, relative humidity), while water is monitored with a leaf wetness sensor, lysimeters and a tipping bucket rain gauge to measure the leaching fraction. The sensors are connected to a datalogger that sends a radio signal to a computer located in the business’ offices which graphs the data on a real-time basis. The data can be observed over the internet which facilitates interactive discussion between our lab and the grower concerning water use. This tool allows us to continue to learn how to manage water in the propagation environment and communicate this knowledge with commercial propagators.

This project relates to two sub-objectives of the parent project. Sub-objective 1a: Elucidate the optimal tissue concentration of phosphorus and boron in different light environments for major production species and how their susceptibility to foliar and root pathogens are influenced by nutrient status and light; and sub-objective 2b: Improve the Virtual Grower software model to enable growers to optimize their production systems by making more informed economic decisions about energy use, plant growth, and scheduling to meet premium market windows. Each 12-month milestone adds 6 to 8 new species, and this project will assist in meeting that goal. Additionally, features such as supplemental lighting, water use, nutrient use, can be added and improved, and additional model validation will be accomplished. It is planned that every 12 months, an additional version will be publicly released.

Last Modified: 4/21/2014
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