Production physiology of three native ornamental shrubs intercropped in a young longleaf pine plantation

Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.The production of woody floral products -- the fresh or dried stems that are used for decorative purposes -- may be an attractive option for southeastern landowners looking to generate income from small landholdings. Since many shrubs native to the understory of the longleaf pine ecosystem have market potential, one possibility is the intercropping of select species in the between-row spacing of young longleaf pine plantations. The objective of this study was to evaluate how competition affects the physiology, and thus the productivity of American beautyberry (Callicarpa americana L.), wax myrtle (Morella cerifera (L.) Small) and inkberry (Ilex glabra (L.) A.Gray) when intercropped in a longleaf pine (Pinus palustris Mill.) plantation in the southeastern United States. The effect of competition was assessed via comparisons of mortality, biomass, light transmittance, gas exchange and soil moisture between intercropping and monoculture (treeless) treatments. Overall, shrubs in the intercropping treatment performed worse than those in the monoculture, with higher mortality, and reductions in biomass of 75.5 [percent], 50.6 [percent], and 68.7 [percent] for C. americana, M. cerifera and I. glabra, respectively. Root-shoot ratios for all species were significantly higher and soil moisture during dry periods was significantly lower in the intercropping treatment. Light transmittance below the pine canopy was high (57.7 [percent]) and I. glabra was the only species that exhibited reduced photosynthesis due to shading. These results suggest that the effect of shading is minimal and belowground competition is likely the most important determinant of productivity in this system.Donald L. Hagan (1), Shibu Jose (1), Mack Thetford (2), and Kimberly Bohn (3) ; 1. School of Forest Resources & Conservation, University of Florida, Gainesville, FL USA 32611. 2. Department of Environmental Horticulture, University of Florida, Milton, FL, USA 32583. 3. School of Forest Resources & Conservation, University of Florida, Milton, FL, USA 32583.Includes bibliographical references

Competition for applied 15N fertilizer in a longelaf pine/native woody ornamental intercropping system

Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.The cultivation of ornamentals to produce woody floral products -- the fresh or dried stems that are used for decorative purposes -- may be an attractive option for southeastern landowners looking to generate income from small landholdings. Since many shrubs native to the understory of the longleaf pine (Pinus palustris Mill.) ecosystem have market potential, one possibility is the intercropping of select species in the between-row spacing of young longleaf pine plantations. The objective of this study was to evaluate how interspecific competition affects the fate of 15N fertilizer when American beautyberry (Callicarpa americana L.), wax myrtle (Morella cerifera (L.) Small) and inkberry (Ilex glabra (L.) A.Gray) are intercropped with longleaf pine. Nitrogen derived from fertilizer (NDF), utilization of fertilizer N (UFN) and recovery of fertilizer N (RFNsoil) were compared between agroforestry and monoculture (treeless) treatments to assess the effect of competition. Results varied by species, with NDF being higher for C. americana foliage and lower for all M. cerifera tissues in the agroforestry treatment. No effect was observed for I. glabra. UFN was lower for all species in the agroforestry treatment. RFNsoil was higher in the agroforestry treatment for I. glabra, but no treatment effects were observed for C. americana or M. cerifera. Overall, while it is clear that interspecific competition was present in the agroforestry treatment, the inefficiency of fertilizer use suggests that nitrogen was not the most limiting resource. Management interventions, particularly those that address competition for water, will likely be critical to the success of this system.Donald L. Hagan (1), Shibu Jose (1), Mack Thetford (2), and Kimberly Bohn (3) ; 1. School of Forest Resources and Conservation, University of Florida, Gainesville, FL USA 32611. 2. Department of Environmental Horticulture, University of Florida, Milton, FL, USA 32583. 3. School of Forest Resources & Conservation, University of Florida, Milton, FL, USA 32583.Includes bibliographical references