Containerized Production of Atlantic White Cedar Seedlings

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Date

2004-05-24

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Abstract

Growth of containerized Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] seedlings was examined in three experiments. In experiment 1, seedlings were grown for 16 weeks at 18/14°, 22/18°C, or 26/18°C in controlled-environment chambers in the Southeastern Plant Environment Laboratories at N.C. State University in Raleigh. Four water table treatments were used in 8-in pots (pot-in-pot) containing a pine bark substrate: 1) control (fully drained), 2) one-third full, 3) two-thirds full, and 4) completely full. Growth (height, stem diameter, and dry weight) increased with increasing temperature regime, but temperature effects were minimal for flooded plants. For most variables, growth was quadratically related to water table level, and linearly related to temperature. Maximum height and dry weight occurred when pots were one-third to two-thirds full of water. Flooded plants yielded far less growth, and had much lower height/diameter ratios, compared to other water regimes. Root systems of flooded plants tended to form a mat near the soil surface. In experiment 2, two commercially available controlled-release fertilizers (CRF) were applied at four rates, plus a non-fertilized control, to containerized Atlantic white cedar seedlings. After 16 weeks, plants were evaluated for growth (height, stem diameter, and total dry weight) and foliar nutrient concentrations. All growth indices were significantly affected by fertilizer and application rate, with no interaction. Osmocote yielded plants 11% taller, 20% larger in caliper, and 50% heavier than Polyon, probably due to differences in availability of phosphorus. Growth was negatively affected at the highest application rate of Polyon. Most of the potential height growth was realized with 4.8 to 7.2 kg/m3 of CRF. Experiment 3 evaluated germination and growth of Atlantic white cedar in response to four container volumes (98 cm3 to 530 cm3), two substrates (NCFS container mix, and 3:1 bark: peat), two controlled-release fertilizer sources (Osmocote 15-9-12, 12-14 month Southern, and Polyon NPK+ 19-6-12, 9 month), and three water regimes. Although growth was strongly correlated with container volume, the optimum volume for production of 1-year-old seedlings appeared to be 164 to 262 cm3. The higher peat content and water holding capacity of the NCFS substrate resulted in the best growth. Osmocote yielded larger and heavier plants than Polyon. Water frequency only affected dry weights, which increased 12% from 2x to 3x daily, and began to plateau at the 4x frequency.

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Keywords

media, irrigation, container volume, fertilizer, growth, chamaecyparis thyoides

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Degree

MS

Discipline

Horticultural Science

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