Cucumber (Cucumis sativus L., cv. “Nina Z”) plants grafted onto squash (Cucurbita maxima, cv. “Yu Yu Ikki”) were grown in a greenhouse using the newly developed nutrient film technique (NFT) hydroponic system “Kappa land” (Mitsubishi aqua solutions Co., Ltd., Tokyo, Japan), from February to June 2022. The growth and development of cucumbers were examined under two different training methods: Lowering training (LT) and Pinching training (PT). Data collected were related to water and nutrient consumption, plant growth and development parameters, and the workload of the main activities. The results showed that plants grown under the LT recorded significantly higher total stem length (10.9 m) and number of nodes (133). In addition, from 21 April to 19 May, the leaf area index was significantly higher in the LT treatment. The highest total yield (15.4 kg m⁻²) and marketable yield per unit area (13.8 kg m⁻²) were recorded in the LT treatment. Regarding fruit growth, the fruits took 14 and 19 days to reach the standard harvest weight in the PT and LT treatments, respectively. In addition, the fruits were more straight in the PT treatment. The water use efficiency was not significantly different between the two treatments. However, the nutrient use efficiency was significantly higher in the PT treatment because plants produced more vegetative organs in the LT treatment instead of fruits. The work for removing old leaves and harvesting fruits was simplified in the LT treatment. The LT method can be effective for the automation of old leaf removal and fruit picking by the robot in the future.

Grafted cucumber plants were grown in a new hydroponic system (“Kappa Land”, Mitsubishi Chemical Aqua Solutions, Co., Ltd., Tokyo, Japan). Two different nutrient management methods were applied to the plants as treatments: Electrical Conductivity-based Management (ECM) and Quantitative Nutrient Management (QNM). During the growth period, we examined plant growth characteristics and productivity, fruit growth characteristics and quality, and nutrient use characteristics. The results revealed that the QNM technique significantly reduced the nutrient supply rate per plant for Ca²⁺, SO₄²⁻, and N by 28.5%, 25.5%, and 23.3%, respectively. Similarly, the absorption rates per plant of SO₄²⁻, K⁺, and PO₄³⁻ were reduced by 17.8%, 11.9%, and 10.9%, respectively. However, N, Ca²⁺, and Mg²⁺ absorption rates slightly increased in the QNM treatment. The nutrient wastes generated per kilogram of produced fruits were also reduced by 66.4%, 60.7%, and 30.2% for N, Ca²⁺, and SO₄²⁻, respectively. Although the QNM technique reduced the plant’s leaf area, it significantly increased its total length by 9.4%. The total and marketable yields were not significantly different between the ECM (9.0 and 8.0 kg plant⁻¹) and QNM (9.1 and 8.2 kg plant⁻¹) treatments. However, the QNM treatment produced the highest total dry matter of 617 g plant⁻¹, surpassing the ECM treatment by 6.9%. On the other hand, differences in nutrient management methods did not significantly affect fruit quality, including total soluble solids, water content, skin color, size, and shape. These results suggest that with the QNM method, it is possible to produce quality cucumbers with high nutrient use efficiency while protecting the environment from nutrient wastes.

The influence of training methods on the yields of cucumber (Cucumis sativus) was investigated in the aspects of root characteristics. The experiment was conducted in the new Nutrient Film Technique hydroponics system specially developed for cucumber production (Mitsubishi Chemical Aqua Solutions, Co., Ltd., Tokyo, Japan).The lowering training (LT) and the pinching training (PT) were used to manage the cucumber plant’s canopy during the growth cycle. At the end of the experiment, the xylem sap bleeding rate, the root biomass, the remaining aerial biomass and the main stem diameter were measured. In addition, individual fresh and dry weights of matured leaves at the lower, middle and upper parts of the plant’s canopy were measured during the growth period. The recorded fruits yield was used for a correlation test with the xylem sap bleeding rate. The results indicated that the sap bleeding rate, root dry weight and root dry and fresh weights ratio were significantly higher in LT treatment. Similarly, the remaining aerial biomass fresh weight was significantly greater in the same treatment. On the other hand, individual leaf fresh and dry weights and the main stem diameter were significantly greater in the PT treatment, at the middle and upper parts of the plant’s canopy. These results were explained by the fact that in the PT treatment, more carbohydrates produced by plants were apparently used to re-establish the pinched shoots at the expense of root production. Moreover, after pinching the lateral shoots, biomass production was improved due to the penetration of sunlight in the plant’s canopy. Considering the relationships between root traits and plant productivity, the LT method is suitable for a long-term cultivation due to its faster sap bleeding rate, which is necessary to stimulate root physiological activity and promote plant biomass production.