| 摘要 |
PROBLEM TO BE SOLVED: To prevent plants from withering and dying because of expansion of roots of plants hindering circulation of a liquid fertilizer when cultivating perennial plants continuously for a number of years with hydroponic culture or the like.SOLUTION: To supply a liquid fertilizer to a cultivation tank satisfactorily and continuously for a long time, a water pipe system is constructed by directly connecting a water supply port and a drain port to a water conduit in a bottom part of the cultivation tank, water permeable holes made in the water pipe system enable both supply of the liquid fertilizer and water drainage of a surplus if any. In addition, wrapping the water pipe system with a material that has water permeability and can inhibit invasion by roots of plants realizes a structure that prevents invasion of the water permeable holes by the roots and that does not hinder circulation of the liquid fertilizer. |
