Environment-friendly soilless culture and fertigation technique.

摘要

Theoretically, the closed soilless system is a zero emission cultural technique. In soilless culture, root rot diseases sometimes might be caused. However, lots of techniques, for example, slow sand filtration, ultraviolet and ozone treatment, and heating are used for eliminating and killing microorganisms in the solution, and plants can be grown without chemical pesticides. Recently, it is reported that some heavy metals are effective for preventing the reproduction of microorganisms causing root rot diseases. In general, plant growth is faster and the yields are higher in soilless culture than in conventional soil culture. It is reported that a little amount but frequent fertigation promotes the plant growth even in soil culture, and this fertigation technique is very much effective for efficient use of water and nutrients. These mean that positive application of water and nutrients to root surface can decrease the thin layer of low concentration of minerals and oxygen, that is formed around root surface, and promote the absorption of these elements and the growth of plants, in consequence. It can be said that soilless plant production in greenhouse is the most environment-friendly growing technique, because it can decrease the use of chemical pesticides, and realize the efficient use of natural resources and is a low load cultural system to the soil. In addition, a little amount but frequent fertigation is the most advanced cultural technique, because it can reduce labor for management, improve the productivity, and realize the stable plant production.