A Quantitative Management of Potassium Supply for Hydroponic Production of Low-Potassium Cherry-Type Tomato Fruit for Chronic Kidney Disease Patients

• Main Authors: Satoru Tsukagoshi, Miho Aoki, Masahumi Johkan, Masaaki Hohjo, Toru Maruo
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Horticulturae
• Subjects: fruit quality; hydroponics; NFT; quantitative fertilizer management; restriction of potassium supply
• Online Access: https://www.mdpi.com/2311-7524/7/4/87

Chronic kidney disease (CKD) has been a global health problem in recent years. CKD patients often restrict their potassium (K) intake to avoid the high risk of hyperkalemia. In this study, quantitative K management in hydroponics was adopted to produce low K cherry-type tomato (<i>Solanum lycopersicom</i> L.) fruit. The total quantity of K supply per plant during the cultivation was 7.2 g (1 K), 3.6 g (1/2 K), 1.8 g (1/4 K), 0.9 g (1/8 K) and 0.6 g (1/12 K), respectively. The total fruit yield decreased to about 75% at 1/2 K and 58% at 1/12 K compared to 1 K. The fruit K content was lower in 1/4 K, 1/8 K and 1/12 K than in 1 K and 1/2 K, and the fruit from 1/8 K and 1/12 K achieved below 100 mg 100 g⁻¹ FW of K. Total soluble solid content (Brix) was 7–8% in 1 K and 1/4 K but was lower in 1/8 K and 1/12 K. Fruit acid content decreased to 87% in 1/2 K to 70% in 1/4 K and 1/8 K, and to 57% in 1/12 K of 1 K. In conclusion, quantitative K management in hydroponics is expected to produce low K tomato fruit. Fruit K content of approximately 100 mg.100 g⁻¹ FW was achieved when the quantity of K supply was 1/4 K and 1/8 K, with a relatively smaller effect on fruit yield, Brix and acid content.