Quantifying Water and Nutrient Losses with Hose Irrigation

Abstract

The amount of water, nitrogen (N), phosphorous (P), and iron (Fe) lost from potted impatiens (Impatiens wallerana Hook. f.) plants fertilized with either controlled-release fertilizer (CRF) of varying longevities or a water-soluble fertilizer (WSF), with irrigation provided with a hose in all treatments, was quantified. The plants were grown in a sphagnum peat-based soilless substrate containing either CRF [Osmocote Plus 16-9-12 (16-3.9-10-0.46 N:P:K:Fe), 5 to 6 month and or 8-to 9 month longevities] incorporated (6.8 kg·m−3 or 11.5 lb·yd−3) throughout the substrate and compared with plants fertigated with a WSF [Peters Professional 20-10-20 (20-4.4-1.66-0.1 N:P:K:Fe) at 150 mg·L−1 (150 ppm) N]. The container-grown plants were placed on top of plastic cups and located inside a plastic box. Municipal water or mineral nutrient solution leached from each container and lost between containers was captured, quantified and analyzed for N, P, and Fe concentrations. As an average for the three treatments, 25.6% of the total water applied was leached out of the pots and 34% fell between the pots. Six weeks after starting the experiment, leachate from pots fertilized with WSF had approximately a 92% higher concentration of N, 96% more P, and 69% more Fe than the concentrations in leachate from CRF-fertilized pots. These results quantify the assumed inefficiencies of using a hose as the primary fertilizer delivery method.