World’s Soil Resources

The plains in the basins of Amu Darya and Syr Darya are lowlands with no natural drainage. Due to the dry
climate, the low precipitation and the strong evaporation, these plains act as accumulators of easily soluble
salts in the topsoil. For this reason, the development of irrigated agriculture, starting from the piedmont
areas, requires careful attention to current or historic salt accumulation in the sediments. Farmers also have
to be aware of the danger of secondary salinization. Salt-affected soils currently constitute more than 46
percent of the total irrigated area in Uzbekistan, including moderately saline soils (25 percent of the total
area), and strongly saline soils (over 6 percent). The worst affected areas are the regions of Karakalpakstan,
Bukhara, Khorezm, Dzhizak, Syrdarya, Andijan, Kashkadarya, Navoi, Samarkand, Surkhandarya. Some
districts in Tashkent and Fergana regions are also affected. In the Samarkand region, the prevailing type of
salinity is magnesium-carbonate salts accumulation. Salinization of some newly irrigated lands is followed
by the formation of gypsum-enriched soils that are difficult to reclaim. Gypsum layers and horizons impede
water infiltration and decrease the efficiency of leaching doses designed to wash salts from the soil profile. The
total area of gypsum-containing soils is about 350 000 ha.
Figure 11.4 Soil map and soil degradation extent in Uzbekistan. Source: Arabov, 2010.
Across Uzbekistan, all types of erosion can be found: surface runoff and irrigation erosion, destructive
mudflows, wind erosion, and direct negative effects of wind on plants. Wind erosion and negative wind effect
on plants affect 21.4 million ha or 80 percent of all agricultural lands (Figure 11.5). Of the 3.7 million ha of irrigated
lands, three quarters – 2.8 million ha – are eroded to various extents. Agricultural lands also suffer from water
and irrigation erosion. Moderately and strongly eroded soils constitute 12 percent of the agricultural land pool
and about 5 percent of the irrigated land pool (Kurbanov, 2001).
The major part of the country is occupied by pastures that cover an area of 20.6 million ha and serve as
the main source of fodder for livestock (Arabov, 2014). Rational use and protection of the soils of pastures
are issues in natural resources conservation and use. The state of pastures is currently endangered. During
the last 70-80years, the soils of pastures suffered a drastic decrease in humus and nutrient content and they
have been affected by salinization and by water and wind erosion. Other negative processes include soil
compaction, alkalinization, and decline in biological activity and resulting loss of soil
Status of the World’s Soil Resources | Main Report Regional Assessment of Soil Changes
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in Europe and Eurasia