Keisui
~Application of the filtration material to cultivation of agricultural products~
After establishing the research project domestically inside our company, "Keisui", a water filtration material for purifying agricultural water, was developed. It enhances the applicability of our filtration materials ordinary designed for water-purification devices. Our product "Keisui" can contribute to improve the purity of water for agricultural use; the purified irrigation water potentially can promote the growth and quality of agricultural products. We have conduct a field research at a green-house facility located in Nagano prefecture (owned by a local vegetable farmer). Planting crops in an irrigation cultivation equipment was carried using the "Keisui" as a filtration material. As a result, it has been demonstrated that it brings significant advantages (water quality improvement, promoted growth of the vegetables, their quality improvement, the improvement of sugar content in the vegetables, etc.) for cultivating vegetables such as tomato, eggplant and cucumber.
1. Increase of oxygen dissolved in water purified by "Keisui"
1) Improvement in the dissolved oxygen content
In the demonstration test, the amount of oxygen dissolved in water was monitored. The level of the dissolved oxygen was increased after the purification by "Keisui" system. It was maintained at the elevated level regardless of change in water temperature (Fig. 1). Please note that the comparison shows that generally the actual amount of the dissolved oxygen are lower than the theoretical value of the saturated concentration, no matter the water is purified by the "Keisui" or not. But, those difference against the theoretical values certainly shows the effect of the use. A difference from the saturated amount in case of the purified water by "Keisui" is 22%, meanwhile the difference from the theoretical value is 37% in case of nonuse of the purification. The amount of the dissolved oxygen was clearly larger once the purification was carried out by "Keisui". In other words, the water quality improved by "Keisui" allows soil and/or hydroponic bed to contain a lot of oxygen, which keeps the sterilizing condition in the soil and hydroponics and finally protects crops from diseases.
2) Control of pH
It is expected that the strong alkalinity or strong acidity of water can be neutralized by filtration. pH of the filtrated water is adjusted by "Keisui" filtration material. The relaxation time of water molecule motion is shortened (106.6Hz -> 70.6Hz) (Fig. 2). It means that the amount of impurities in the filtrated water decreases, which can improve ability of water absorption by roots.
Figure 1. Oxygen concentration dissolved in the purified water by "Keisui" compared to the one in the non-purified water
Figure 2.The relaxation time of water molecular motion in the water purified by "Keisui" compared to that without the purification process (Measurement of Resonance Frequency by Nuclear Magnetic Resonance Spectroscopy)
2. Demonstration of the cultivation in green-house using "Keisui"
A cultivation test with tomato in our green house facility was conducted. After the field test, it was confirmed that the water quality improvement was seen in the used water for the cultivation and the growth of the crop in this facility was well promoted (Fig. 3). In other words, in the case of using the purified water by tour product "Keisui", a clear difference was observed between the growth of the tomato tree and the actual size of them, compared to the crops untreated with the purified water.
Figure 3．Comparison of the tomato tree and leaves grown with the purified water by "Keisui" and without their use
3. Control of Water absorption of crops in an irrigation plant cultivation method
An irrigation cultivation method that enhance water absorption characteristics of crops undergoes our development.
In general plant cultivation method, in daytime when the outside air temperature is the highest, the water absorption of the crop decreases markedly, since the photosynthesis is blocked; this phenomenon is called as "nap phenomenon", and considerably interferes the growth of crops. It is certainly important to develop an irrigation cultivation system that can adequately promote the absorption of water at time when the watering is demanded and when the ambient temperature significantly changes.
Figure 4. (A) the ordinary characteristics of the water absorption characteristics in a day, (B) Irrigation cultivation method considers the water absorption characteristics in a day
Figure 5. Fruit and leaves of tomatoes grown in pot adopting an irrigation cultivation system with the use of water purification by "Keisui"