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  • Author or Editor: G. L. Wheeler x
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In 1993, the Arkansas poultry industry produced 1.048 billion broilers with a total live weight of 2.54 million metric tons. Depending on the type of processing used, from 30% to 50% of live weight can end up in the waste stream. Three primary waste-stream products are generated by the poultry industry: feather meal, poultry meal, and bone meal. Feather meal contains ≈14% N, poultry meal 11% N, and bone meal 8% N. Byproduct additions were made to tomato, marigold, and impatiens transplants at the rate of 6, 12, 24 and 48 g/10-cm pot. The two highest rates killed plants outright, while the lower rates resulted in some growth reduction when compared to the control. Studies are under way to further evaluate the use of these byproducts in an organic production system for tomatoes and bedding plants.

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Eight species of woody nursery stock were grown in 4 liter containers and fertilized with a conventional resin-coated slow release material (at 3.5 g N per container) or composted poultry manure applied as a top dressed or incorporated with nitrogen rates ranging from 1.0 to 11.2 g N per container. In all cases the conventional resin-coated product outperformed composted poultry manure by factors of 2 to 3 times (for height, dry weight and quality score). Although a rate response was observed with the composted, even the highest rate of nitrogen application produced plants with dry weights of 1/2 that of the control. When comparing the sources of composted poultry manure alone, the 4-4-4 product outperformed the 2-2-2 compost, even with equivalent rates of nitrogen, for 3 of the 8 species studied. Incorporation proved superior to topdressing for the 4-4-4 source but topdressing was superior for the 2-2-2 material. These studies are part of a nutrient partitioning experiment being conducted to determine the fate of nitrogen released from composted poultry manure.

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Twelve to 15 year old silver maple and wild cherry trees were top pruned severely to a height of 5m and then trunk injected with Prunit 20g/l at 0, 0.1, 0.5 or 1.0 g/inch of trunk diameter or were treated with a trunk pour of Prunit 50W at the rate of 0, 0.5 or 1.0 g/inch of trunk diameter. Treatment effects were not obvious on any trees until 12 months after treatment. After 36 months maples receiving the two highest rates had made less than 50 cm of growth above the pruned top of the tree whereas the untreated control had produced 3 m of new shoot growth. The 0.1 g rate produced less aesthetic disruption to the appearance of the tree and reduced growth to 1.2 m. Wild cherry trees responded similarly but the amount of regrowth following pruning was less. Maple trees receiving the trunk pour treatment exhibited a 50% reduction in new shoot growth 36 months after treatment.

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Twelve to 15 year old silver maple and wild cherry trees were top pruned severely to a height of 5m and then trunk injected with Prunit 20g/l at 0, 0.1, 0.5 or 1.0 g/inch of trunk diameter or were treated with a trunk pour of Prunit 50W at the rate of 0, 0.5 or 1.0 g/inch of trunk diameter. Treatment effects were not obvious on any trees until 12 months after treatment. After 36 months maples receiving the two highest rates had made less than 50 cm of growth above the pruned top of the tree whereas the untreated control had produced 3 m of new shoot growth. The 0.1 g rate produced less aesthetic disruption to the appearance of the tree and reduced growth to 1.2 m. Wild cherry trees responded similarly but the amount of regrowth following pruning was less. Maple trees receiving the trunk pour treatment exhibited a 50% reduction in new shoot growth 36 months after treatment.

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`Lynwood Gold' forsythia and `Jessica' chrysanthemum were grown for 12 weeks in a nursery mix consisting of 5 parts composted pine bark, 1 part composted hardwood bark and 1 part sand. Fertilization was by topdress applications of composted poultry manure at rates of 1, 2 and 3 g N per container, resin coated slow release fertilizer at 3 g N per container, or with constant liquid fertilization at 200 mg N per liter. Leachate samples were collected weekly and nitrate, nitrite, ammonium and total nitrogen determined. At 12 weeks, plant dry weight and the amount of nitrogen in the plant, media and leachate determined. Total nitrogen loss in the leachate for the compost was rapid during the first three weeks and then fell to low levels. The resin coated fertilizer released a higher and constant nitrogen flux during the study than the composted manure but total nitrogen loss over the 12 week period was lower than for compost. The leachate nitrogen in the constant liquid fertilization treatment increased during the study. The relative proportion of nitrogen in the medium, compost and leachate will be discussed.

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Orchard floor treatments of total weed control with herbicides, disking, mowing, grass control only with herbicides, and no control of vegetation were maintained in a 3 × 3-m area underneath young pecan [Carya illinoinensis (Wangehn.) K. Koch] trees. Soil compaction in treated areas was compared to heavily trafficked row middles. Mean cone index (CI) readings obtained from a cone penetrometer for the heavily trafficked areas were higher, indicating greater compaction than all other treatments in the 4.7- to 11.8-cm soil depth range. Heavily trafficked areas had severe compaction (>2.0 MPa) at the 9.5- to 22.9-cm soil depths. Mowed plots had similar CI readings at 14.2- to 54.3-cm depth as those heavily trafficked. The mowed areas had severe compaction at the 14.2- to 22.9-cm depth range. Grass control only with herbicides and plots with no control of vegetation had low CI throughout the soil profile. Disking, grass control, and no control treatments had similar effects, except at the 4.7-cm depth, where disking reduced compaction. An orchard floor management practice that minimized traffic near young trees, but also reduced weed competition, appears to be the best choice.

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Lysimeters have been used extensively in the study of soil water and the movement of compounds in solution. In the management of landscape plantings where the use of various fertilizer application methods is common, loss of NO3-N from the fertilizer source may limit plant growth and be less cost-effective. During a study examining the influence of mulch type (cottonseed hulls, cypress wood, pine bark, and pine straw) and fertilizer application method (granular, liquid, and time-release), a simple lysimeter was constructed to examine NO3-N loss under normal irrigation and cultural practices in annual beds. Losses of large quantities of NO3-N were initially seen in all treatments during the 1st week followed by a gradual decline to the study's end. Liquid and time-release fertilization methods contained NO3-N as a partial source of N and limited plant growth due to early rapid N loss. Granular fertilizer contained no NO3-N source and demonstrated the greatest plant growth at the lowest cost per square meter.

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Scarification treatments (a control, a 10-minute vacuum, or a 1.5-minute ultrasound), different media (modified Norstog and Van Waes) and growth regulators [benzyladenine (BA) at 0, 1, 1.5, or 2 mg·L-1 and 6-(r,r-dimethylallylamino)-purine riboside (2iPR) at 0, 1, 1.5 or 2 mg·L-1] were used in combination to increase seed germination of Cypripedium calceolus var. parviflorum. Seeds treated with ultrasound had higher germination (58.0%) than those treated with vacuum (27.4%) or controls (19.2%). Germination rates increased with 2iPR level and reached a maximum between 1.5 and 2 mg·L-1. Seeds on Van Waes medium, which were not transferred to fresh medium after germination, had a severe browning problem causing many protocorms to die. Those on Norstog medium continued to grow into seedlings with less browning. Germination rates of Calopogon tuberosus × Calopogon `Adventure' and Liparis liliifolia were determined on the different media and growth regulator treatments. Multiple shoots of Calopogon developed from single seeds on media containing growth regulators. Flower buds formed in vitro on Calopogon in media containing 1 mg·L-1 or higher BA 5 months after germination. L. Iiliifolia seeds in Norstog medium had a higher proportion of germination than those in Van Waes medium.

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Radish (Raphanus sativus cv. Giant White Globe) and lettuce (Lactuca sativa cv. Waldmann's Green) plants were grown for 25 days in growth chambers at 23 °C, ≈300 μmol·m-2·s-1 PPF, and 18/6 photoperiod, and four CO2 concentrations: 400, 1000, 5000, and 10,000 μmol·mol-1. Average total dry mass (g/plant) at the 400, 1000, 5000 and 10,000 μmol·mol-1 treatments were 6.4, 7.2, 5.9, and 5.0 for radish and 4.2, 6.2, 6.6, and 4.0 for lettuce. Each species showed an expected increase in yield as CO2 was elevated from 400 to 1000 μmol·mol-1, but super-elevating the CO2 to 10,000 μmol·mol-1 resulted in suboptimal growth. In addition, many radish leaves showed necrotic lesions at 10,000 μmol·mol-1 by 17 days and at 5000 μmol·mol-1 by 20 days. These results are consistent with preliminary tests in which radish cvs. Cherry Belle, Giant White Globe, and Early Scarlet Globe were grown for 16 days at 400, 1000, 5000, and 10,000 μmol·mol-1. In that study, `Giant White Globe' produced the greatest total dry mass at 1000 (3.0 g/plant) and 5000 μmol·mol-1 (3.0 g/plant), and the least at 10,000 μmol·mol-1 (2.2 g/plant). `Early Scarlet Globe' followed a similar trend, but `Cherry Belle' showed little difference among CO2 treatments. Results suggest that super-elevated CO2 can depress growth of some species, and that sensitivities can vary among genotypes.

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Peanut (Arachis hypogaea L.) plants were grown hydroponically, using continuously recirculating nutrient solution. Two culture tray designs were tested; one tray design used only nutrient solution, while the other used a sphagnum-filled pod development compartment just beneath the cover and above the nutrient solution. Both trays were fitted with slotted covers to allow developing gynophores to reach the root zone. Peanut seed yields averaged 350 g·m-2 dry mass, regardless of tray design, suggesting that substrate is not required for hydroponic peanut production.

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