121 Fertilizer Formulation, Placement, and Tex-R Geodiscs Influence the Growth of `Compacta' Holly

Abstract

A study was conducted to compare four different controlled-release fertilizers when used in conjunction with Tex-R Geodiscs on the growth of Ilex crenata Thunb. ex J.A. Murray `Compacta' in 3.8 L (#1) containers. The fertilizers used were Osmocote Plus Southern Formula (18N-3.9P-10K), Osmocote Plus Northern Formula (18N-3.9P-10K), Wilbro (15N-1.7P-7.5K), and Nutricote T-360 (17N-2.6P-6.6K) all applied at the rate of 1.8 kg N/m3. Geodisc treatments were: 1) no disc, 2) fertilizer placed on top of the disc, and 3) fertilizer placed beneath the disc. At 2 and 4 months after the initiation of the study, the growth indices for plants grown with both Osmocote Plus fertilizers were larger than for either of the other two fertilizers. After 7 months, final growth indices were greater for the Osmocote Plus and Wilbro treatments compared to Nutricote. Final leaf, stem, and root dry masses were all greater for the Osmocote Plus fertilizers compared to the other two, as was final plant quality. Plants with fertilizer placed on top of the disc were smaller compared to the no disc or beneath the disc treatments. Geodisc treatment had no influence on shoot dry mass or final plant quality. Data for leachate nutrient analysis and evapotranspiration will also be presented.