Date of Award
Master of Science
Nitrate (NO₃)̄ is a major pollutant in much of the surface water in the nation. High concentrations of N0₃ ̄are common in runoff from container-production nurseries. Our objective was to investigate effects of four fertigation treatments (Miracle Gro Excel[Superscript Tm] 21N-2.2P-16.6K x 65 or 75% media moisture, respectively) combined with three rates of controlled-release fertilizer (CRF) (Osmocote[Registered trade mark symbol] 18N-2.6P-9.9K, 8-9 month release) on nitrate (NO₃)̄ runoff, N uptake, and growth of winterberry (Ilex verticillata L.'Stoplight') and red-osier dogwood (Cornus sericea L.). In 1999, 12 treatments were arranged in a randomized block design with eight replications. Treatment combinations of fertigation and CRF [(WSF mgÃÂ·L⁻ÃÂ¹applied at 65 or 75% media moisture)/ CRF (g) NÃÂ·pot⁻ÃÂ¹)] were a 4x3 factorial for each species: [(1.84, 3.62, 4.98, or 6.08) x (0, 0.57, or 1.15)] for L verticillata and [(3.45, 4.09, 7.73, 8.48) x (0, 0.57, 1.15)] for C sericea.Shoot dry weight (SDW) and shoot nitrogen content were higher in I. verticillata with increased rates of fertigation. Root dry weight (RDW) decreased as CRF rates increased. Root-to-shoot ratio (R:S ratio) and N efficiency decreased as fertigation and CRF increased. In C. sericea SDW, RDW, and R:S ratio were not affected by fertigation or CRF treatments. Shoot N increased as CRF rate increased and root N increased as fertigation rate increased. As CRF rate increased, N0₃⁻ leaching increased for both I. verticillata and C. sericea. These data suggest that fertigation and CRF management are important to increase growth of I. Verticillata while in this experiment C. sericea did not respond to increasing N input. Applying higher rates of CRF in addition to fertigation resulted in higher NO₃-N leaching for both species.
Thomas Lee Schultz
Schultz, Thomas Lee, "Growth, nitrogen content, and leaching from container-grown Cornus and Ilex amended with combinations of moisture and fertilizer" (2000). Retrospective Theses and Dissertations. 17485.