Effect of Nutrient Composition Used in the Closed Hydroponics System with Capillary Uptake Method on Nutrient Element Concentrations in the Organic Substrates and Yield of Tomato

Abstract

A modified nutrient solution formula was evaluated for tomato production in a new closed hydroponics system aimed to reduce emission. The new system is a closed organic substrates (cryptomeria bark) culture using the capillary uptake method. The modified nutrient solution formula had a higher K level, lower Ca, Mg and SO₄ levels than the Ootsuka-A formula. EC, NO₃-N, Ca, Mg and SO₄ of the solution in the organic substrates were lower when the modified nutrient solution formula was applied. Using this newly developed system combined with the modified nutrient solution formula, the yield of 18.2 t • 10 a⁻¹ from twelve clusters per plant was obtained by tomatoes grown without emitting NO₃-N and exhaust solutions.