167 COMPARISONS OF GREENHOUSE BENCHING / IRRIGATION SYSTEMS FOR WATER USE, FERTILIZER USE, AND CROP QUALITY WITH POINSETTIAS AND GERANIUMS.

Abstract

Four experiments were conducted over 2 years focusing on water and fertilizer delivery methods with emphasis on minimal resource use. Poinsettia `Freedom', `Celebrate 2'. `Peppermint Pink', `Angelika White', `Lilo' and `Angelika Marble' and geranium `Kim', `Aurora', Ritz', and `Melody' cuttings were grown in 6 inch pots with peat-lite mix and were harvested at marketable size. Nitrogen efficiency was compared by replicating each irrigation treatment with soluble fertilizer (SF) and controlled release fertilizer (CRF). Crops grown with SF were started at 225ppm N for several weeks, then finished at 125ppm N after monitored EC had dropped below 1000μS. CRF treatments were potted up with 1.6 total grams of N available to the plant and irrigated throughout production with tap water. Irrigation treatments included: drip tube leaching, drip tube, ebb & flow, trough. trough lined with capillary mat, trough lined with plastic-covered capillary mat, flats of capillary mat, flats with plastic-covered capillary mat. Daily irrigation volumes were recorded. Weekly data collection included EC, pH, nitrate nitrogen. and ammonium nitrogen. Harvest data included plant dry weight, and total nutrient analyses of plants and substrate. Water efficiency was significantly improved in recirculating systems and with capillary mat systems. No significance was noticed in dry weight or final nutrient analyses across treatments. Significance existed in water quality throughout crop production.