D.J. Marconi

Bio: D.J. Marconi is an academic researcher from North Carolina State University. The author has an hindex of 1, co-authored 1 publications receiving 46 citations.

Nitrate, phosphate, and potassium leaching from container-grown plants fertilized by several methods

Abstract: Spathiphyllum Schott. «Mauna Loa Supreme» and areca palm (Chrysalidocarpus lutescens H. Wendl.) were grown for 6 months in 3.5-liter containers using a pine bark-sedge peat-sand container medium or a native sand soil. Plants were fertilized with equivalent amounts of a 21N-3P-12K fertilizer applied weekly as a liquid, monthly as a soluble granular, bimonthly as a lightly coated controlled-release, or every 6 months as a heavily coated controlled-release fertilizer. All leachates were collected and analyzed weekly for NO 3 -N, PO 4 -P, and K. Amounts of all three nutrients leached per week varied considerably in response to fertilizer reapplications or high rainfall. Nitrate leaching generally decreased over time, PO 4 -P leaching increased, and K remained relatively constant. Shoot dry weights of spathiphyllum were equivalent for all fertilization methods, but areca palm shoot dry weights were highest with liquid fertilization and lowest with the soluble granular fertilizer. Nutrient leaching for all three ions was highest for the soluble granules and lowest for the two controlled-release formulations

Leachate Electrical Conductivity and Growth of Potted Poinsettia with Leaching Fractions of 0 to 0.4

Abstract: Poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch 'V-14 Glory') were grown in a greenhouse for 70 days in 1.3 liters of medium (13 cm deep in 15-cm pots) with a leaching fraction (LF) of 0, 0.1, 0.2, or 0.4. Plants were fertigated with 300 mg N/liter from 20 N-4.4P-16.6K. The electrical conductivity (EC) of the fertigation solution was 2.1 dS·m -l . The leachate EC increased from 2 dS· m -l initially to plateaus of 6, 9, and 15 dS·m -l for LFs of 0.4, 0.2, and 0.1, respectively. Poinsettia height, shoot fresh and dry mass, and leaf and bract areas were not significantly different among the LF treatments. Leachate pH decreased from 6.1 initially to 5.1 at the end, but there was no significant difference among the LF treatments. The EC of a saturated medium extract (EC e) was between 17% and 48% higher in the lower third of the medium than in the middle third. The difference was greater with a lower LF. The EC, was 8.9, 7.3, 5.2, and 3.4 dS·m -1 in the lower third of the pot for a LF of 0, 0.1, 0.2, and 0.4, respectively. Under conditions of this study, container poinsettias required no leaching. Leaching water and dissolved substances out the bottom of the container has received major attention recently because it wastes water and fertilizer and may contaminate groundwater with fertilizers and pesticides (Biernbaum and Fonteno, 1989). One beneficial aspect of leaching is that it removes excess salts and prevents salinity buildup in the rootzone (Richards, 1954). Therefore, environmentally sound crop management dictates that the negative aspects of leaching should be minimized by pro- viding only enough leaching to control salinity. This strategy has been developed extensively for field crops using the con- cepts of the LF and leaching requirement (LR) (Ayers and West- cot, 1976). The LF is defined as (volume of solution leached (Vi))/(volume of solution applied to the crop (V a)). The LF

National Proceedings: Forest and Conservation Nursery Associations-2005

Abstract: This proceedings is a compilation of 24 papers that were presented at the regional meetings of the forest and conservation nursery associations in the United States in 2005. The Western Forest and Conservation Nursery Association meeting was held at the Yarrow Resort Hotel and Conference Center in Park City, UT, on July 18 to 20. The meeting was hosted by the Utah Division of Forestry, Fire, and State Land, Lone Peak Nursery. Morning technical sessions were followed by field trips to restoration projects on the middle reach of the Provo River, McAffee Hill, and Dry Canyon, as well as tours of the Swaner Nature Preserve outside Park City, UT. Subject matter for the technical sessions included restoration outplanting, native species propagation, bareroot and container nursery culturing, greenhouse management, and gene conservation. The Northeastern Forest and Conservation Nursery Association meeting was held on August 1 to 4 at the University Plaza Hotel in Springfield, MO. The meeting was hosted by the Missouri Department of Conservation, George O. White State Forest Nursery. Technical sessions were followed by tours of the Hammons Products Company walnut processing facility and Hammons Sho-nuf Walnut Plantation in Stockton, MO, and the George O. White State Forest Nursery in Licking, MO. Subject matter for the technical sessions included bareroot and container nursery culturing, hardwood management, and insect and disease monitoring.

Nitrogen leaching and plant uptake from controlled-release fertilizers

Abstract: Controlled-release N fertilizers are commonly used in the production of container-grown ornamental crops, yet the relative effects of various nutrient sources on N leaching are not well known. A 27-week experiment was conducted to evaluate N leaching loss and plant growth following two applications of six controlled-release N fertilizers and one soluble N fertilizer to container-grownEuonymus patens Rehd. The controlled-release fertilizers evaluated were (noncoated) isobutylidene diurea, oxamide, urea formaldehyde, and (coated) Osmocote, Prokote Plus, and sulfur-coated urea. Of the fertilizers tested, the coated fertilizers generally out-performed the noncoated fertilizers in reducing N leaching losses, stimulating plant growth, and increasing tissue N concentrations. Low N concentrations in the leachate of some treatments indicated efficient nutrient use by the plant. In other treatments, low N concentrations in the leachate merely reflected incomplete N release from the fertilizer. A daily application of NH4NO3 resulted in a constant rate of N loss but was not the most effective in promoting growth. Plant growth, tissue N concentrations, and N leaching losses were all increased by doubling the fertilizer application rate from 1 kg N m−3 to 2 kg N m−3.

Leaching of nitrogen and phosphorus during production of forest seedlings in containers.

Abstract: Little information is available concerning the contamination risk caused by forest seedling nurseries to local surface and ground waters compared with agricultural and horticultural production. Leaching of nitrogen (N) and phosphorus (P) through peat growing medium in containers and nutrient uptake of seedlings were monitored in production of silver birch (Betula pendula Roth), Norway spruce [Picea abies (L.) Karst], and Scots pine (Pinus sylvestris L.) seedlings. About half of the applied nutrients (total amount applied = 149 to 260 kg N ha(-1) and 60 to 108 kg P ha(-1)) was premixed into the peat medium, as is usual in Finnish nursery practice, and the other half was applied to seedlings in liquid form with mobile booms. Depending on tree species, 11 to 19% of the applied N was recovered in leachates and 15 to 63% in seedlings. The undiscovered proportion varied from 19 to 71%. The amounts of leached N were 19 to 41 kg ha(-1). Only 5 to 31% of the applied P was recovered in seedlings; 16 to 64% (11 to 56 kg ha(-1)) was found in leachates. Total N and P load to the environment may increase substantially if nutrients applied in liquid fertilization outside container trays are included. Consequently, it is important to determine the sources of nutrient load in container seedling production to mitigate the risk of environment contamination.