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Approaching Development of Ground Improvement Technology for Greening
- Application of Medical Licorice Plants in Semi-Arid Areas -

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Development of a "suction drain,"
a technology for ground
water control


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Medical licorice plant (glycyrrhiza)
in semi-arid area in Mongolia


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Cultivation of licorice under
different soil environment
conditions in a greenhouse


ABSTRACT:
Licorice (glycyrrhiza) is among the world's most ancient herbs. Licorice root contains an active compound called glycyrrhizin that has been used in food, medicine and cosmetics. It is a temperate-zone herb that also grows wild in arid regions such as northern China, Siberia, Mongolia and Central Asia. It is reported that overharvesting of licorice leads to land deterioration and/or desertification of the natural growth area. Recently, China, which is a major native source of licorice, has restricted its export. This restriction has caused a shortage of licorice in Japan.

In this study, we are attempting to develop a cultivation technique for high-quality licorice, which will help provide a stable supply of licorice as well as provide a countermeasure against desertification. There is a great deal of uncertainty about the native conditions of vegetation, and a cultivation technique for glycyrrhizin-rich licorice has not yet been developed.

DETAILED:
Licorice (glycyrrhiza) is among the world's most ancient herbs. Licorice root contains an active compound called glycyrrhizin that has been used in food, medicine and cosmetics. It is a temperate-zone herb that also grows wild in arid regions such as northern China, Siberia, Mongolia and Central Asia. It is reported that overharvesting of licorice leads to land deterioration and/or desertification of the natural growth area. Recently, China, which is a major native source of licorice, has restricted its export. This restriction has caused a shortage of licorice in Japan.

In this study, we are attempting to develop a cultivation technique for high-quality licorice, which will help provide a stable supply of licorice as well as provide a countermeasure against desertification. There is a great deal of uncertainty about the native conditions of vegetation, and a cultivation technique for glycyrrhizin-rich licorice has not yet been developed.

As a first step in establishing a licorice cultivation technique, a field survey was carried out in the natural growth areas of northeastern Mongolia. Field survey measurements were focused on soil conditions, and included chemical composition, grain size distribution, water content, electrical conductivity, soil hardness and hydraulic conductivity. It was shown that licorice roots collected in the field contained high concentrations of glycyrrhizin, indicating that the results of the field survey should provide a clue to developing a cultivation technique for high-quality licorice.

We investigated detailed subsurface conditions of the steppe region in Mongolia, and explored which soil conditions are suitable for cultivating high-quality licorice.

To make cultivation practical and to use green semi-arid land, two important issues must be confirmed regarding the influence of cultivating conditions. One is to better understand soil conditions in the pot, and another is to confirm the growth. Therefore, before we can grow licorice from the viewpoint of geotechnical engineering, we need to understand the characteristics of the soil water and nutritive condition of the soil, and we need reliable measurements of the quality of roots cultivated in various conditions. We will study the relationships between these two factors to determine suitable cultivating conditions.

Finally, we will attempt to create a new Geo-Medical Plant Engineering Science through the application of medical licorice plants in semi-arid areas, with an approach that focuses on development and ground improvement technologies for greening.

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Development of investigative equipment
for lab and field tests

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Illustration of botanical garden
for medical plants at Gankai Town


Environmental Geotechnology Lab.
Professor Noriyuki Yasufuku
Professor Hemanta Hazarika
Assistant Professor Ryohei Ishikura
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