科研之友
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摘要
One of the problems in closed soilless cultures is to find a solution in order to reduce ion imbalance in recycled nutrient solutions when the drained nutrient solution is re-used. To reduce ion imbalance in recycled nutrient solutions, determination of renewal period is required, since uptake of individual ion by plants changes throughout the growing period. The aims of this study are to determine the appropriate renewal period to reduce ion imbalance in the recycled nutrient solution and to investigate the uptake of nutrients and water by the paprika plant and to measure fruit yield and mineral contents in plant as influenced by renewal period of recycled nutrient solution in a closed soilless culture. Paprika plants were grown in rockwool slabs with either 4-, 8-, or 12-week renewal period in the closed as compared to the open hydroponic system (control). The electrical conductivity (EC), pH, and volume of the nutrient solutions were measured every three days. The nutrient solution in the reservoir tank was constantly maintained at EC 2.5 dS center dot m(-1) and pH 5.5-6.5. As results, the uptake of K+ was significantly influenced by the renewal period. Changes of cation and anion ratio in the recycled nutrient solution could be reduced by discharging every 4 weeks. The significantly lowest fruit yield was observed in a closed hydroponic system using a 12-week renewal period. Regarding the ion balance in the recycled nutrient solution, renewing every 4 weeks was found to be the most effective in this study. However, considering the yield along with nutrients and water uptake, a 8-week interval could also be used.
- 出版日期2013-10
