Amanda Ramos Gasparini, Claudinei Fonseca Souza
Efficient water and nutrient management is essential for sustainable greenhouse production of high-value ornamental crops such as Anthurium andraeanum. Reclaimed domestic wastewater represents a promising alternative water source with potential to reduce fertilizer inputs; however, its variable nutrient composition may affect plant performance if not properly managed. This study evaluated the combined effects of water quality and nutrient management on plant growth, nutritional status, and water-use efficiency over a two-year period under greenhouse conditions. Three irrigation/fertigation strategies were tested: freshwater with conventional mineral fertilization (FWF), reclaimed water with targeted mineral supplementation to correct nutrient imbalances (RWF), and reclaimed water without supplementation (RW). FWF and RWF significantly improved plant height, number of leaves and flowers, and spathe, spadix, and stem length compared to RW. Leaf analysis indicated adequate concentrations of essential macronutrients and micronutrients in supplemented treatments, whereas RW plants exhibited nutrient deficiencies, particularly in nitrogen and phosphorus, which limited plant development. Substrate electrical conductivity remained within suitable ranges in FWF and RWF but was lower in RW, reflecting insufficient nutrient availability in the root zone. The RWF treatment reduced mineral fertilizer inputs by 26% compared to FWF without compromising plant growth or flower quality. In addition, water-use efficiency was higher under supplemented treatments, indicating improved conversion of water into biomass and reproductive output. These findings demonstrate that integrating reclaimed water with targeted mineral supplementation is essential to balance nutrient supply and optimize plant performance. This approach enables partial replacement of freshwater while improving resource-use efficiency in greenhouse ornamental production systems.