USE OF SUBIRRIGATION TO REDUCE FERTILIZER RUNOFF

摘要

The growth of areca palm {Dypsis lutescens (H.Wendl.) Beentje & J. Dransf.) and philodendron (Philodendron Schott. 'Hope') plants was compared between subirriga-tion and overhead irrigation systems. Plants were fertilized with top-dress application ofOsmocote 15N-4.1P-9.96K at 7, 10, or 14 g per pot. The amount of water used by both irrigation systems as well as the amount of nitrate-nitrogen (N03-N) lost to the environment from each system also was recorded. Ten times less water was used per squaremeter of bench space with the subirrigation system than with the overhead system. No N03-N was lost to the environment from the subirrigation benches because the irrigation solution was captured and reused after each watering while the cumulative amountof N03-N lost per square meter of bench space from the overhead watered plants by the end of the experiment was1149 mg. For both irrigation systems, plant growth increased as the fertilizer application rate increased. Shoot dry mass of philodendron plants fertilized with 7 or 10 g was greater in subirrigated pots than in overhead watered pots. However, the shoot dry mass of philodendron plants fertilized with 14 g were greater in overhead watered pots. At all fertilization rates, areca palm shoot dry mass was greater in overhead watered pots.