आईएसएसएन: 2593-9173
Nuchada Maneejantra, Satoru Tsukagoshi, Na Lu, Kanyaratt Supaibulwatana, Michiko Takagaki, Wataru Yamori
Surplus absorption of elements that contribute little to crop productivity and quality can be avoided, and fertilizer consumption costs minimized, by applying elements quantitatively to the nutrient solution fed to the plants. The aim of this study was to determine the minimum macronutrient requirements of spinach (Spinacia oleracea L.) with a desired plant size, so that fertilizer management in plant factories can be maximized. Spinach plants were grown in a plant factory (20°C/17°C day/night temperature, photosynthetic photon flux (PPF) of 350 μmol·m-2·s-1 for 12 hours per day using cool-white fluorescent lamps, 1,000 μmol·mol-1 CO2). Spinach grew and developed rapidly, and reached its desired marketable size in only 12–15 days after being transplanted to the study conditions. At day 15 of cultivation under the treatment conditions, the required quantities of macronutrients per plant (90 grams in fresh weight) were determined as follows: 191 mg N, 31 mg P, 345 mg K, 34 mg Ca, 38 mg Mg, and 13 mg S. In conclusion, a quantitative nutrient managing method with low nutrient concentrations is feasible and resource-saving for hydroponic vegetable production in plant factories.