Māris kļaviņŠ, azamat azizov, JĀnis zaļoksnis environment, pollution, development: the case of uzbekistan

 9.3. 
 Soil desertification and salinization
Soil degradation is one of the most important problems in the 
complex of problems connected with the processes of desertification. 
Soil degradation means decrease and loss of biological and 
economical productivity of arable lands and pastures, forests and 
timberlands  under  the  influence  of  natural  and  anthropogenic 
factors. Natural and anthropogenic factors of soil degradation are 
tightly connected with large-scale development of soils in arid 
conditions. Processes of fertilization decrease, degradation and 
destruction of topsoil count thousands and hundreds of various 
local and zonal forms of display. Between them most widespread 
are regression grazing and overgrazing, formation of mobile sand 
dunes,  surface  runoff  and  irrigational  soil  erosion,  contamination 
of soil with toxic compounds, technogenic desertification and other. 
400 hectares or 10% of irrigated soil are in unsatisfactory condition 
(Figure pic. 9.8).
0
5
10
15
20
25
30
2001
2002
2003
2004
2005
2006
all farmland, including:
perrenial cropping
hay meadow and pasture
arable land
However, the larger 
problem of groundwater 
contamination with 
heavy metals is caused 
by point sources of 
pollution:
 
Œ waste dumps; 
 
Œ chemical product 
storage and transfer 
sites; 
 
Œ industrial enterprises.
Heavy metals at high 
concentrations affect 
many processes in the 
soil: 
 
Œ they inhibit the activity 
of microorganisms and 
thereby the circulation 
of nutrients in the soil; 
 
Œ they have a toxic effect 
on plant roots, resulting 
in decreased nutrient 
intake.