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United States Department of Agriculture

Agricultural Research Service

Research Project: Improved Production Methods: North South Initiative (North Carolina State University)
2013 Annual Report


1a.Objectives (from AD-416):
The objective of this research will focus on research to optimize nutrition and irrigation rates during different stages in floriculture crop development taking into account stock plant, propagation, and finishing environments.


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. Over the five-year period, some of our key findings show how crop production inputs affect crop performance. For New Guinea impatiens, as storage time decreased quality increased. A humidity tent environment produced the highest quality of cuttings by visual inspection of cutting quality. Callused New Guinea impatiens cuttings were tolerant 9 days of storage at a broad range of temperatures from 3.9 to 14.4°C. For 12 days of storage, cuttings needed to be held at 7.2 to 14.4°C as cold damage occurred at 3.9°C. At 10°C storage temperature callused cuttings developed roots one day after sticking when stored for 3 days and during storage when stored for 9 or 12 days. In contrast, un-callused cuttings required 11 days to produce the first root. Application of plant growth regulators (PGRs) not only control excessive plant growth, but also reduced water use. Producers should consider the water use reduction from using PGRs in addition to the traditional benefit of growth control as a best management practice.

This project relates to two sub-objectives of the parent project. Sub-objective 1a: Elucidate the optimal tissue concentration of P and B 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.


Last Modified: 12/19/2014
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