沙漠研究 24-1, 101-104 (2014)
Ἃ₍◊✲ 24-1, 101 - 104 (2014)
Journal of Arid Land Studies
Journal of Arid Land Studies－ DT11 Refereed Paper －㸫DT11 Refereed Paper㸫

Utilization of Marginal Water and Lands in the Zeravshan River Basinas Part of a Climate Change Adaptation Strategy
Temur KHUJANAZAROV*1), Kristina TODERICH2) and Kenji TANAKA1)
Abstract: This paper considers how marginal mineralized waters and salt affected soils can contribute to land remediation and create
additional nutrition values for livestock and agropastoral communities through cultivation of arid/semiarid salt loving plants(halophytes) under water scarcity conditions. The mobility of toxic pollutants is highly facilitated by both chemical properties of soils
and the aridity of the climate. Plants under such environments face multiple stresses caused by high temperatures, water and soil
salinity, heavy metals, high PH and long-term water-shortage. There are limited numbers of native species along Zeravshan River
Basin able to establish themselves in these soils and produce palatable biomass. Being irrigated with low quality drainage andthermal artesian water, species of the genera Artemisia, Climacoptera, Alhagi, Glycyrrhiza and Kochia exhibited clear distribution
patterns and their abundance and yield of green biomass varied significantly along salinity and aridity climatic gradients. The limitsof mineralization of the marginal water optimum for crops growth and green biomass accumulation were found to be varied in therange of 2000-8200 mg l-1. The soil salinity at the root zone was about 45 dS m-1 and salinity level of the ground water was 8.0-16.5
dS m-1, inappropriate for the irrigation of traditional agricultural crops. A monitoring system for controlling interaction of chemical
content of non-conventional irrigation water and salt affected soils through plants above-ground biomass over several sites indownstream area of Zeravshan river flow was established. Alternative use of marginal water and lands play a significant role infurther development of climate change adaptation strategy leading to produce autumn-winter forage and improve the feeding system
for livestock, thus diversifying animal products and incomes of local agropastoral communities by ensuring sustainable ecosystem
function and resilience.
Key Words: Climate change, Land remediation, Marginal waters, Water quality, Zeravshan River

1. Introduction
Central Asia (CA) with its landlocked landscape, dry
continental climate, and water scarcity, is greatly vulnerable toclimate variability and drought. Climate change in CA had
been reported to have above average temperature increasing
trend over last 70 years equal to 1.2-2.1°C, which doubles theglobal average of 0.5°C (IPCC, 2007). Such warming posesa threat to the glaciers and snow storage that currently provide
over 90% of the water for irrigation in summer season (Hagg etal., 2007). Observation of the glaciers over the last decades
has already shown high recession rates (Aizen et al., 1997) andaccording to different climatic scenarios it will be accelerated
over the next 20 years leading to reduction of CA rivers
streamflows (Agaltseva, 2002). Most future projections showa temperature increase of 3-4°C in CA, accompanied by
precipitation decrease in summer and increase in winter. The
major implications of predicted climatic change scenarios will
be changes in seasonality of the runoff, mild winters, hotter anddrier summers, with decreased available water (Bernauer andSiegfried, 2012). Sommer et al. (2013) argue that southern
CA could suffer the biggest hit to crop productivity due toseasonality changes and water availability. Reduction in crop
yields and agricultural productivity are key climate change
impacts on CA dryland agro-ecosystems, with subsequent
threats to the food security in the region. At the same time
CA dryland ecosystems have faced severe (large-scale) water
quality deterioration and land degradation caused mostly bysoil salinity and loss of crop productivity due to water overuse(Toderich et al., 2005, 2013). Therefore, the current debatesof climate change impacts on socio-ecological systems areoriented towards developing strategies for adaptation to the
expected adverse impacts and increased water stress.
Utilization of both marginal waters and lands under aclimate change water scarcity scenario can be a potential wayof addressing forage availability for livestock and creating
additional nutrition from pastures on marginal lands that will
suffer the biggest hit under decreased amount of available
water. There is little or no information on utilization of low* Corresponding Author: khujanazarov.timur@gmail.com

㸦Received, September 20th, 2013; Accepted, January 6th, 2014㸧

Goka-sho, Uji, DPRI, Regional Water Environment System laboratory, Kyoto University, Kyoto 611-0011, Japan
1) Water Resources Research Center, Disaster Prevention Research Institute, Kyoto University, Japan
2) International Center for Biosaline Agriculture for Central Asia and Caucasus, Tashkent, Uzbekistan

102Fig. 1. Zeravshan river basin and research sites (source: GoogleMaps).

quality water and salinized lands for alternative agriculture usein CA, even though developing such techniques would beclearly advantageous, as such lands are underused, and thesemethodologies would not be in any competition with alreadyexisting farming practices.
The goal of this study is 1) to develop techniques ofadaptation and remediation of polluted areas by using native
salt tolerant plant species, and utilizing low-quality water; 2)
conduct chemical analysis of plants along Zeravshan riverbasin; 3) to address desertification problems and suggest
solutions for diversifying forage sources for the livestock andensure ecosystem enrichment and function.

2. Methods and Strategy
In this research several experimental sites were setup tostudy remediation strategies using salt tolerant plants under
extreme dry climate conditions. The study is based on the useof mineralized drainage waters in the lower Zeravshan Riverbasin sites and an additional site in the Kyzyl Kum desert (Fig.
1). Two sites, #1 and #2, are situated in the Bukhara oasis,
lower river basin and were established outside of the traditional
irrigation areas, mostly on high salinity lands with brackish
water flow, to assess impact of polluted waters on plants. Site
#3 was established in Kyzylkesek (Central Kyzyl Kum desert)
to check adaptation to extreme climatic conditions. It ischaracterized by higher temperature variation and much drier
conditions compared to the Bukhara oasis sites, and there is no
direct access to the fresh water, but there is an available
mineralized artesian thermal water source. According to theUzbek Meteorological Agency, temperature at this site is on
average 2-3°C higher compared to Bukhara oasis. To
monitor climatic conditions, a meteorological station
measuring wind speed, air temperature, humidity, and otherrelated parameters was installed.
Marginal waters obtained from the collector drainage
system for research sites #1 and #2, and artesian mineralized,
thermal water for site #3 were applied for crop irrigation.

Water quality and level of mineralization was assessed throughseveral annual measurements on sites, showing relatively samelevel of mineralization (Toderich et al., 2013). Salt tolerant
tree and shrub seedlings on sites #1 and #2 were deeply planted(roots tapping into the water table) in the early spring or lateautumn, and irrigated once with low quality water in the initialstage of growth, before the seedlings are able to utilize theavailable groundwater resources. On site #3 plants wereirrigated once in July. Growth rates and forage yield with andwithout irrigation, as well as water and soil chemistrycharacteristics were measured regularly. To assess soil andchemical influence on the experimental plants, chemical
analysis was also done on plants growing upstream as a control.
Plant materials were collected in the hottest season(July-August), dried at 105ºC for 24 hours, and pulverized
before the chemical analysis. The same plants species fromupstream and downstream were used, to compare results.
Plant ash for analysis was prepared by burning dry plantbiomass in melting pots under 600ºC for 1 hour. Element
analysis was conducted using Varian Atomic Absorption
Spectrophotometer AA240FS standard method.

3. Results and Discussion
Zeravshan is a transboundary river in Central Asia that has
been profoundly affected by mismanagement of the water
resources due to the huge diversion of water for irrigation, poor
functioning and maintenance of the drainage networks, as wellas high rates of water loss. The region relies on conventional
furrow and flooding irrigation practices and soil leaching that
requires large amounts of water, and although the Zeravshan
River is fully utilized for irrigation, that is still not enough tocover irrigation needs, even though 20% of the runoff water isreused. It was estimated that 12% of the irrigated lands areclassified as highly saline and 33% as medium saline, requiring
more water to leach the salts from the soil before planting(MAWR, 2004). The mobility of toxic pollutants was highly
facilitated by both chemical properties of soils and the aridityof the climate. Under such environmental conditions plants
face multiple stresses caused by high temperatures, soil salinity,
heavy metals, compacted soil, and long-term water shortage.
A restricted numbers of salt tolerate plants (halophytes) able tosurvive and reproduce well under extremely conditions wereidentified as a result of this study. They are mostly wildgrown native species from the genera Salsola, Artemisia,
Tamarisk, Glychyrrhiza, Alhagi and others, which are suitableas livestock forage, bioenergy and other sources of income.
3.1. Plant growth and adaptation to extreme conditions
Measurements of soil EC at the beginning and the end of

103

Table 1. Plant growth and yield of palatable biomass on the researchsite #3.
Name ofof species
speciesName
Climacoptera lanata
lanataClimacoptera
Climacoptera lanata
lanata **Climacoptera
Glychyrriza glabra
glabraGlychyrriza
Glychyrriza glabra
glabra**Glychyrriza
Salsola orientalis
orientalis **SalsolaAlhagi pseudoalhagi
pseudoalhagi**Alhagi
Kochia prostrata
prostrata **KochiaYield ofof biomass,
biomass, t/hat/ha
Yield

Days ofofDays

GreenGreen29.5± 4.6
4.6
29.5±Dry
Dry
15.5±7.1
15.5±7.1

vegetation
vegetation
160-190160-1906.22± 2.1
2.1
6.22±
8.4±4.1
8.4±4.1

1.15±0.6
1.15±0.6
3.27 ±3.1±3.1
3.27
1.46-1.63
1.46-1.63

210-235
210-235
205-220205-220220-235
220-235

1.0-2.2
1.0-2.2
0.85-1.60
0.85-1.60

250-254250-254
218-225
218-225

2.06-2.16
2.06-2.16

250-260
250-260

5.08-6.34
5.08-6.34
2.0-2.8
2.0-2.8
1.24-2.40
1.24-2.40
2.6-3.09
2.6-3.09*results with no irrigation appliedFig. 2. Site #3 in July, naturally grown (left) and irrigated fields(right).

the vegetation season indicated that the soil was of medium
salinity, although at the upper 40 cm horizon at some points EC
reached values of over 25 dS m-1. Most species exhibited
clear distribution patterns and their abundance and biomass
accumulation varied significantly along the salinity and aridity
climatic gradients. The soil salinity at the root zone wasabout 45 dS m-1, salinity level of the ground water was
8.0-16.5 dS m-1, which is inappropriate for the irrigation of
traditional agricultural crops however, this did not affectgrowth. Plants had tolerated the strong soil salinity without
inhibition in survival and growth rate due to the sample soil
moisture conditions provided by the groundwater andirrigation (although applied at deficit rates). The performanceof investigated annual and perennial plants on saline soils andirrigated with marginal water shows high growth rates,
comparable to those in agricultural irrigated land, althoughroot-zone salinity slightly increased (Table 1). Due to lowtranspiration capacity, Alhagi pseudoalhagi communities
grown near the experimental area helped in retaining soil
moisture in the top soil. The results on site #1 were on
average 10% higher compared to site #2, and site #3 saw adecrease in productivity of 30%. However, cultivatedpastures showed promising results on site #3. Comparison ofnaturally grown with cultivated pastures in vicinity of site #3 isshown on Figure 2.
Although results show a promising potential of using

Fig. 3. Biomass variability over water salinity on Alhagi pseudoalhagi.

marginal waters on already saline lands, it is important toemphasize that an upper limit of salt concentration in soil andwater as well as in groundwater levels should be preserved andcontrolled. The fresh biomass of investigated species sharply
decreased with the increasing gradient of soil salinity as shownon the Figure 3. The limits of mineralization of the marginal
water optimum for crops growth and green biomass
accumulation were found to be varied in the range of
2000-8200 mg l-1. Above a certain threshold value, high total
concentrations of salts are harmful to crop growth, while
individual salts can disturb nutrient uptake or be toxic to plants.
Not only that, some plants are noticeably sensitive togroundwater level rise, and for reclamation of waterlogged
lands, appropriate species should be chosen. For example,
Salsola L plant adaptation and growth decreased with increased
water table level, and thus salinization.
3.2. Environment and soil remediation
Marginal lands and marginal water have great potential forutilization, creating an additional resource for the pastoral
community under extreme dry and hot conditions. At thesame time, the question of how plant chemistry would respondto the marginal water application was emphasized in our
second research objective. Same species from upstream werecompared with ones in the lower stream sites. Results haveshown that salt and metals concentration in plant tissue
increase from upstream to downstream, as demonstrated
clearly by the Tamarix hispida chemical ions content (Fig. 4).
Concentrations of calcium, bicarbonate, sodium, and chlorinerise significantly to downstream, showing noticeable
correlation with water quality conducted in previous research(Khujanazarov et al., 2012). These pollutants are released
into the lower part of Zeravshan River from numerous sources
in upstream, and are accumulated and/or excluded by plants.
Compared to other regions in Uzbekistan, plants in theBukhara oasis show relatively high concentrations of heavy
metals (Fig. 5), especially noticeable in Artemisia diffusa andSalsola L. Similarly high salt ion content was found in theaboveground biomass of Tamarix hispida (Fig. 5), demonstrating

104

Ta m a rix  h isp id am g /k g
18000
16000
14000
12000
10000
8000
6000
4000
2000
0
HCO 3

SO 4ClCaU p p e r str e am

KNa

D o w n str e am

Fig. 4. Chemical mineral content of Tamarix hispida along river.

PbTamarix
his pida

Sals ola L.

Halox y lon
aphy llum

Artemis ia
diffus aCdPeganum
harmala

0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0References

Pb, Cd, As, Sb distribution

Alhagips eudoalhagi

mg/kg 0.5

dryness, and high evaporation rates. However, care needs tobe taken and monitoring systems should be in place to ensure
proper management of marginal water and lands.
This could be an effective strategy in dealing with futureclimate change conditions and water scarcity in Central Asiandesert environments, and address human employment inpastoral lands. Through our research it was possible not only
to address land rehabilitation issues, but also increase theknowledge base of the Zeravshan River basin, by sharing theseresults with the public (Khujanazarov, 2012).

AsSb

plant species

Fig. 5. Native desert plants species able to translocate heavy metals
in above ground biomass.

its ability to selectively remove specific heavy metals and salts
from soils. This ability of plants to uptake pollutants from
affected soil must be incorporated into alternative solutions for
remediation of polluted lands. Therefore non-conventional
waters can be used in conjunction with crops conservation
practices designed to remove metals and salts fromcontaminated environments.
By implementing thesemethods and processes, there is the added benefit of reducing
waste discharge and thereby improving water quality within
the catchments as well as decreasing water stress and adapting
to limited water availability.

4. Conclusion
Our findings show how plants interact with water and soil
environments to adapt and cope with high concentrations ofnutrients and toxicants which occur naturally or as pollutants.
Experimental sites on saline soils demonstrated promising
results for potential utilization of marginal waters with limited
irrigation for agropastoral use. Additionally, these species
could be used not only for land rehabilitation and reducing
carbonate salts and heavy metals concentration in soils, butalso for biological restoration and enrichment of thesurrounding agro-ecosystem. Planting halophytes has proved
to be effective in re-vegetating saline landscapes, deriving
valuable products from marginal degraded land, and making
use of the otherwise low quality water, under conditions of heat,

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