沙漠研究 24-1, 199-202 (2014)
Ἃ₍◊✲ 24-1, 199 - 202 (2014)
Journal of Arid Land Studies
Journal of Arid Land Studies－ DT11 Refereed Paper －㸫DT11 Refereed Paper㸫

Monitoring the Growing Environment of Wild Licorice with Analysis ofSatellite Data at a Semi-arid Area in Mongolia
Atsushi MARUI*1), Akihiko KOTERA2), Zentaro FURUKAWA3), Noriyuki YASUFUKU3), Kiyoshi OMINE4),
Takanori NAGANO2), Indree TUVSHINTOGTOKH5) and Bayart MANDAKH5)
Abstract: Wild licorice (Glycyrrhiza uralensis) is an important medicinal plant. It is grown in Asia, most notably in semi-arid
regions of China and Mongolia. Recently, overharvesting of wild licorice has caused land deterioration and/or desertification, andsome countries have begun restricting the harvesting of wild licorice. The objective of this study is to research areas within semi-arid
regions where wild licorice grows, both over the period of a year, and over several years, through satellite data. The study also seeks
to investigate characteristics of the growing environment, such as soil temperature and water content. Monitoring results indicate thatsoil surface conditions were severe. However, a constant temperature is maintained in the deeper layer below 70 cm during wintermonths, and the layer below 30 cm has adequate water content to permit plant survival in summer. MODIS (MODerate resolution
Imaging Spectroradiometer) data were used to calculate seasonal variation in EVI (Enhanced Vegetation Index) in 2011. This clearly
indicated differences between vegetated and non-vegetated areas. No vegetation index was obtained for the winter season, but someplants were able to grow in specific areas during summer months. MODIS satellite data from 2000 to 2013 were used to analyze thewater resources in the area. Results showed that the extent of Lake Orog (near the licorice habitat area) declined, and that the lake
suffered water shortages on several occasions over the last eight years. These results will contribute to recovery of wild licorice insemi-arid regions, also indicating potential areas of growth for wild licorice.
Key Words: Desertification, Desert Vegetation, Licorice, MODIS, Remote Sensing

1. Introduction
Glycyrrhiza uralensis (L) (licorice) grows wild in Asia,
most notably in semi-arid regions of China and Mongolia.
Licorice is an important medicinal plant; 70% of traditional
Kampo medicines contain glycyrrhizin (GL), which is derived
from this plant. Recently, the overharvesting of wild licorice
has caused land deterioration and/or desertification, and somecountries have begun restricting the export of wild licorice.
Yamamoto and Tani (2005) reported that, in 1984, the Chinese
government restricted the collection of licorice by people livingin areas other than the three northern regions. In 2000, theChinese government restricted the collection of wild licoricenationwide (Yamamoto and Tani, 2002). Therefore, theexhaustion of medicinal plant resources is of concern.
However, there is continuing high demand for licorice.
Hayashi and Sudo (2009) summarized the economic
importance of licorice extracts, which are used for cosmetics,
food additives, tobacco flavors, and confectionery foods.
Their suggested means to increase licorice supply is thecultivation of licorice in semi-arid regions of China and* Corresponding Author: marui@cc.hirosaki-u.ac.jp

Mongolia, while also combating desertification. Abe et al.
(2005) indicated that cultivation of medicinal plants in arid
regions could provide an alternative income source.
Yamamoto and Tani (2005) reported that licorice harvested in
China in the fourth year after seeding conformed to the JP XV
standard (The Japanese Pharmacopoeia XV, 2006) for GL
content; in order to use licorice as a medicinal plant in Japan,
the GL content must exceed 2.5%. In another study, Zhangand Xiong (2008) reported that N+ ion beam irradiation madelicorice salt-tolerant.
However, there have been few reports concerning
environmental conditions that characterize the habitat of wildlicorice, although many studies have investigated its cultivation.
The objective of this study was to obtain information
concerning environmental characteristics of wild licorice
habitat in semi-arid regions, including air temperature, relative
humidity, precipitation, solar radiation, soil water content, andsoil temperature. First, field monitoring of licorice habitat
areas was conducted from June 2011 to June 2012 near Bogdsoum, Bayankhongor, in Southern Mongolia. Second,
satellite data were analyzed to investigate the extent ofvegetated areas where the plant survives, and to detect available
㸦Received, September 11th, 2013; Accepted, January 6th, 2014㸧

3 Bunkyo-cho, Hirosaki, Aomori 036-8561, Japan
1) Faculty of Agriculture and Life Science, Hirosaki University, Japan

2) Graduate School of Agricultural Science, Kobe University, Japan

3) Faculty of Engineering, Kyushu University, Japan

4) Faculty of Engineering, Nagasaki University, Japan

5) Institute of Botany, Mongolian Academy of Sciences, Mongolia

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Fig. 2. Air temperature and relative humidity at monitoring site.
Fig. 1. Location of research area. Wild licorice is widely distributed
between Lake Orog and Lake Buuntsagaan. The density oflicorice is high around the lake. There are a number ofmountains of over 3000 m height, in areas north and south, shownon the map.

water resources within this semi-arid region.

2. Materials and Methods
2.1. Monitoring of licorice habitat
Wild licorice is distributed around Bogd soum in theBayankhongor prefecture, located in Southern Mongolia.
Figure 1 shows the location of the monitoring site and of Lake
Orog. This location has the highest density of wild licorice inMongolia.
Environmental parameters of the licorice habitat area weremonitored between June 2011 and June 2012.
Airtemperature, relative humidity, precipitation, wind speed, andwind direction were measured at a height of 1.5 m using aWeather Transmitter (WXT520; VAISALA Inc.) at 60 minintervals. Solar radiation was measured by means ofPCM-01 (PREDE co.) at 30 min intervals. Soil water content
and soil temperature were measured at depths of 10 cm, 20 cm,30 cm, 40 cm, 50 cm and 70 cm, using a soil moisture sensor
5TE (Decagon Inc.) at 60 min intervals. The moisturesensors were calibrated using a three point method. As
equipment was being placed on site, we confirmed that thegroundwater level was 160-180 cm below the surface, and thatthe root length of licorice was over 160 cm.
2.2. Detection of vegetation index and water area
Seasonal variation of EVI (Enhanced Vegetation Index) in2011 was calculated using MODIS (MODerate resolution
Imaging Spectroradiometer) data. MODIS data set
MOD13Q1 (250 m 16-days-composite) was downloaded fromUSGS, and the EVI was calculated, with removal of noise.
Furthermore, analysis was conducted for MODIS data sets
MOD09Q1 (250 m 8-days-composite) and MOD09A1 (500 m
8-days-composite), from 2000 to 2013; analysis was intended

Fig. 3. Daily solar radiation at monitoring site (sum of 30 minutes
solar radiation).
40 cm
30 cm
20 cm
10 cm

Fig. 4. Soil water content at monitoring site during summer season(on some occasions, the limit of measurement at 10 cm wasexceeded).

to detect changes in water areas, based on the method of
Sakamoto et al. (2007). The confidence level of calculated
results was confirmed in order to enable comparison with
Landsat data.

3. Results and Discussion
3.1. Monitoring results
Figures 2, 3 and 4 show air temperature and relative
humidity, solar radiation, and soil water content, respectively.
During the winter season, temperatures less than -20°C wererecorded. Highest values for solar radiation were recorded
during the summer season; conversely, solar radiation was very
low during winter. In summer, soil water content at a depthof 10 cm presented severe constraints to plant growth, while ata depth of 20 cm, water content was constant. Water content
at 20 to 40 cm depth corresponded to suction of 100-300 cm
H2O (Marui et al., 2012). This is not adequate for plant

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70cm
50cm

30cm

10cm

Fig. 5. Soil temperature at monitoring site during winter season.

Fig. 6. Estimated evapotranspiration and precipitation at monitoringsite. Evapotranspiration was estimated using the Penman method.
There was snow during the winter season.

growth but enough for survival. The ground water level was
considered to possibly be high between 1.0 and 2.0 m soil
depths. Figure 5 shows soil temperature at different depths.
Conditions at the soil surface presented severe constraints toplant survival, with temperatures of -15°C at a depth of 10 cm.
During winter, temperatures were below freezing from thesurface to 70 cm soil depth. This indicates that short-rooted
plants face severe constraints to survival during this season.
Figure 6 shows precipitation and estimated evapotranspiration
using the Penman method. In summer, evapotranspiration
was very high because of strong winds, high solar radiation,and low humidity.
Based on the above, it can be concluded that during thewinter season, there are severe constraints to the survival ofshort-rooted plants, owing to low temperatures. However,during summer, water content in the root zone is adequate forplant growth, even though water conditions at the soil surface
remain severe.
3.2. Results of remote sensing
Figure 7 shows seasonal EVI around the licorice habitatarea. There is a clear difference between vegetated andnon-vegetated areas, although the confidence level of dataobtained in winter is low due to snow and cloudy weather.
No vegetation index was obtained for the winter season, butthere were indications that some plants could grow in specificareas during the summer season. EVI results indicate a large
vegetation area during the summer season, located aroundwater resources, such as rivers and lakes.

Fig. 7. Seasonal EVI calculated from MODIS data (250 m16-days-composite). The confidence of data obtained in winteris low, due to snow and cloudy weather.

Fig. 8. Estimated water area of Lake Orog during summer season.
Winter season data (from middle of Sep. to middle of May) wereexcluded, due to low confidence. This figure shows average line,and minimum/maximum values.

Figure 8 shows the estimated water area of Lake Orog.
This indicates that the area of the lake decreased, with therange of vibrations increasing over the last eight years. Inparticular, the average lake area was almost 0 km2 in 2006 and2009, while minimum values of 0 km2 were also recorded in
2006, 2007, 2009 and 2010. Figure 9 shows precipitation at
Bogd soum. Little rain was recorded in 2004, 2005, and 2009.
Changes in the area of the lake are considered to be related totrends in precipitation.
The vegetation index derived through remote sensing
indicates that plants only grow in specific areas near water202References

Fig. 9. Annual precipitation at Bogd soum. The distance to Lake
Orog from Bogd soum is approximately 10 km.

resources. A decrease in the area of Lake Orog (near thelicorice habitat area) was also noted.
The decrease in lake area, combined with trends ofminimal precipitation, will affect the ground water level.
Desertification is thus a possibility, as licorice survival andgrowth depend on groundwater availability.

4. Conclusion
Monitoring results indicate that, during the winter season,
there are severe constraints to survival of short-rooted plants,
due to low temperatures. During the summer season,
available soil water below a depth of 20 cm is adequate forplant survival, although severe water constraints occur at thesoil surface.
Vegetation index results based on remote sensing indicatethat plants only grow in specific areas near water resources.
A tendency towards a decrease of the water area at Lake Orog(near the licorice habitat area) was noted. The decrease inlake area will affect ground water level, as will precipitation;
this will in turn influence the licorice habitat area.
Acknowledgement
This research was supported by the Grant-in-Aid for
Scientific Research (A) Ministry of Education, Culture, Sports,
Science and Technology, Japan, Grant number: 22246064,
Project leader: Prof. Yasufuku Noriyuki, Kyushu University
and also supported by Hirosaki University Grant for
Exploratory Research by Young Scientists.

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