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Janet L. Carlino, Kimberly A. Williams, and Earl R. Allen

Chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] growth and nutrient leaching of three clinoptilolite-based root media—NZ, EZ1, and EZ2—were compared to the performance of control plants grown in Sunshine Mix #2 [3 peat : 1 perlite (v/v)]. The control received 210 mg·L−1 N from an 18N-4P-15K soluble fertilizer at each irrigation. NZ contained untreated zeolite and received the same soluble fertilizer as the control but leached lower concentrations of NH4-N, K, and PO4-P during most of the production cycle compared to the control. EZ1 was formulated to provide N, P, and K as fertilizer nutrients and produced plants similar to the control based on ratings, height, width, and dry mass, but not fresh mass, at harvest when the fertilizer rate was half of that applied to the control—105 mg·L-1N. EZ2 did not receive P or K from soluble fertilizer and produced plants similar to the control based on rating, height, and dry mass, but not width or fresh mass, with soluble fertilizer input reduced to N alone. Tissue N, P, and K concentrations of plants grown in EZ1 and EZ2 were lower than those of control plants. With further refinements, these zeolitebased products show promise for decreasing nutrient leaching during crop production and allowing for application of lower rates of soluble fertilizers.

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Jaime K. Morvant, John M. Dole, and Earl Allen

Pelargonium hortorum Bailey `Pinto Red' plants were grown with 220 mg·L−1 N (20N-4.4P-16.6K) using hand (HD), microtube (MT), ebb-and-flow (EF), and capillary mat (CM) irrigation systems. At harvest, root balls were sliced into three equal regions: top, middle, and bottom. A negative correlation existed between root medium electrical conductivity (EC) and N concentration to root number such that the best root growth was obtained with low medium EC and N concentrations. EF root numbers were greatest in the middle region. The two subirrigation systems (EF and CM) had higher average root numbers than the two surface-irrigation systems (HD and MT). For all irrigation systems, root numbers were lowest in the top region. In general, less difference in medium soluble salt and N concentrations existed between regions for surface-irrigated than for subirrigated root balls. Soluble salt concentration was lowest in the bottom and middle regions of EF and the bottom region of MT and CM. For subirrigation, the highest medium soluble salt and N concentration was in the top region. For all systems, pH was lowest in the bottom region. Plant growth for all irrigation systems was similar. EF and MT systems required the least water and EF resulted in the least runoff volume.