Response of “Alamo” switchgrass tissue chemistry and biomass to nitrogen fertilization in West Tennessee, USA

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 2011-01, Vol.140 (1-2), p.289-297
• Main Authors: Garten, Charles T., Brice, Deanne J., Castro, Hector F., Graham, Robin L., Mayes, Melanie A., Phillips, Jana R., Post, Wilfred M., Schadt, Christopher W., Wullschleger, Stan D., Tyler, Donald D., Jardine, Phillip M., Jastrow, Julie D., Matamala, Roser, Miller, R. Michael, Moran, Kelly K., Vugteveen, Timothy W., Izaurralde, R. Cesar, Thomson, Allison M., West, Tristram O., Amonette, James E., Bailey, Vanessa L., Metting, F. Blaine, Smith, Jeffrey L.
• Format: Article
• Language: English
• Subjects: 09 BIOMASS FUELS; Agronomy. Soil science and plant productions; Allocations; BIOFUELS; Biological and medical sciences; BIOMASS; C:N ratio; CARBON; CARBON CYCLE; Carbon stocks; CHEMISTRY; FERTILIZATION; FERTILIZERS; Fertilizing; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; GRAMINEAE; NITROGEN; Nitrogen balance; Nitrogen fertilization; Nitrogen stocks; Nitrogen, phosphorus, potassium fertilizations; Panicum virgatum; Root biomass; Root:shoot ratio; Roots; SAMPLING; SEASONS; Shoot biomass; Soil (material); Soil-plant relationships. Soil fertility. Fertilization. Amendments; SOILS; STORAGE; Switchgrass; Tissue chemistry
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2010.12.016

▶ High N fertilization decreased root:shoot ratios in 5-year old switchgrass (Panicum virgatum). ▶ Nitrogen fertilization increased root nitrogen concentrations and decreased root C:N ratios. ▶ There was more carbon and nitrogen stored in belowground biomass than aboveground. ▶ Fertilization impacted tissue chemistry in ways that potentially affect soil carbon storage. Switchgrass (Panicum virgatum) is a perennial, warm-season grass that has been identified as a potential biofuel feedstock over a large part of North America. We examined above- and belowground responses to nitrogen fertilization in “Alamo” switchgrass grown in West Tennessee, USA. The fertilizer study included a spring and fall sampling of 5-year old switchgrass grown under annual applications of 0, 67, and 202kgNha−1 (as ammonium nitrate). Fertilization changed switchgrass biomass allocation as indicated by root:shoot ratios. End-of-growing season root:shoot ratios (mean±SE) declined significantly (P≤0.05) at the highest fertilizer nitrogen treatment (2.16±0.08, 2.02±0.18, and 0.88±0.14, respectively, at 0, 67, and 202kgNha−1). Fertilization also significantly increased above- and belowground nitrogen concentrations and decreased plant C:N ratios. Data are presented for coarse live roots, fine live roots, coarse dead roots, fine dead roots, and rhizomes. At the end of the growing season, there was more carbon and nitrogen stored in belowground biomass than aboveground biomass. Fertilization impacted switchgrass tissue chemistry and biomass allocation in ways that potentially impact soil carbon cycle processes and soil carbon storage.