Vertically-Moving cultivation and local environment control for high strawberry yield

For the purpose of High-Yield and Energy-Saving production of strawberries, three different Cultivation-Supporting systems were applied: (i) A Vertically-Moving bed system, (ii) An LED supplemental lighting system, and (iii) An Energy-Saving temperature control system. We examined their performance in forced strawberry culture. In the Vertically-Moving bed system a double See-Saw mechanism moves four cultivation beds, which can be held at any desired height. The Three-Dimensional use of the greenhouse space created four times the planting density as the conventional bench culture. Beds were moved among heights of 2.8, 2.1, 1.4, and 0.7 m every two hours, but the shading effect meant that yield only increased 27% over conventional bench culture. Fixing the beds in a Two-Height formation (2.1 and 0.7 m) increased integrated solar radiation on beds relative to the moving Four-Height formation, leading to a twofold increase in yield. However, photosynthesis of the Lower-Bed plants was only 50% of those on the upper beds due to the shading effect. By exchanging the upper and lower beds at 11:00 and 14:00 in the Two-Height formation, integrated photosynthesis across the moving beds was 24% higher than on the beds fixed in that formation. Supplemental lighting with high irradiance LEDs (PPFD values greater than 400 μmol m^-2 s^-1 at normal leaf heights) was provided to strawberry plants for 12 h daily (06:00-18:00). Leaf photosynthesis in 12-h lighting was much higher than for unlit plants. This accelerated photosynthesis promoted plant growth, indicated by increases in leaf area and leaf thickness, which led to over twofold increase in the marketable yield. Fruit soluble solids content also increased under the 12-h lighting conditions. An Energy-Saving temperature control system using a constant soil temperature layer was Purpose-Developed for strawberry cultivation. The system consisted of an underground air pipe (UAP) set at a depth of 1.5 m from ground surface, where soil temperature remained suitable for Year-Round strawberry growth, and perforated interrow air ducts (IAD) connected to the UAP. The greenhouse air was drawn into the UAP, which acted as a Soil-Based heat exchanger, then dispersed to the ambient air through the perforated IAD between the plant rows. In the winter season this system enabled 3°C heating of the ambient air with a 50% saving on energy consumption and a 20% increase in fruit yield.