EFFECT OF FERTILIZER CONCENTRATION AND METHOD OF APPLICATION ON MEDIA NUTRIENT CONTENT, NITROGEN RUNOFF AND GROWTH OF EUPHORBIA PULCHERRIMA V-14 GLORY.

Euphorbia pulcherrima V-14 Glory were grown with three concentrations of N and K (100, 200 and 400 mg liter^-1) and five different methods of constant liquid fertilizer application (subirrigated, top watered with 0, 12, 25, or 50% leaching fractions (LF)). Root media samples were analyzed by SME every two weeks for pH, conductivity, NO₃-N, P, K, Ca, and Mg.
Plant height and fresh weight, leaf and bract area, leaf, bract, stem and root dry weights were also measured every two weeks.
Soluble salts (EC), NO₃-N, P, K, Ca, and Mg concentrations in the soil increased with increased fertilizer concentration and decreased leaching.
At 16 weeks after planting, the EC ranged from 1.0 to 8.7 mS, NO₃-N from 46 to 1600 mg liter^-1 and K from 90 to 1000 mg liter^-1. The effect of fertilizer concentration on media EC was less with a high LF compared to a low LF. The effect of LF on root media EC was less at low concentrations than at high concentrations.
Root media EC and nutrient content in the root zone was similar with subirrigation or top watering with no leaching or 12% leaching.
The amount of N applied ranged from 620 mg/pot to 6500 mg/pot.
Estimated nitrogen runoff from top watering with 400 mg liter^-1 N and 50% LF was approximately 40 times that from 100 mg liter^-1 and 12% LF. Plant quality was acceptable with all treatment combinations with the main difference in appearance being a decrease in plant height with increasing media EC. Plant height, fresh and dry weight, and leaf and bract area at 16 weeks generally increased with decreasing root media EC except with 100 mg liter^-1 N and 50% LF.

Symposium on Bedding and Pot Plant Culture

Mark V. Yelanich, John A. Biernbaum

https://doi.org/10.17660/ActaHortic.1990.272.26