｢毛管給水ひも」によるトマト栽培の可能性について

This research was conducted to investigate any potential problems that may be encountered while using capillary wick irrigation system. Medium-fruited tomato plants were cultivated in spring up to the 10th truss. In the first experiment, a 1/5,000a wagner pot was used, and small openings were made 5mm or 50mm from the bottom of the pots. Capillary wicks, 4 cm in width and 45 cm in length were inserted into the slits and aligned to the pot’s inner wall perpendicularly to the soil surface. The other end of the wick was dipped in half or full strength Ohtsuka-A nutrient solution. The wick was covered with water permeable root-barrier material to prevent root penetration into wick. This resulted in good growth and relatively high yield. Without covering, roots grew vigorously into the wicks and 1 month after transplanting extended to the reservoir solution. Removal of root overgrowth caused wilting in some of the plants. This symptom was more pronounced where the wick insertion points were 50 mm from the base. Root contexture was observed in non-covered and imperfectly covered wicks. These results indicate that it is important to make a wick with a perfect covering for stable plant growth and fruit yield. In the second experiment, the capacity of 2 cm or 4 cm wide with and single or double layers of capillary wicks to transport water to the plant root-zone was examined. Some of the plants wilted in the 2 cm single layer, while no differences were observed in other treatments. Furthermore, a high percentage of blossom-end rot was recorded in all treatments. In response to water uptake by the plants, the nutrient solution was supplied daily depending on the decrease of water in the reservoir, in order to maintain the water level fluctuation within a 3 cm range. This fluctuation may account for the blossom-end rot prevalence observed, probably due to water-stress imposed on the plants by unstable water level in the reservoir.