The Economics of Desertification, Land Degradation, and Drought

Table 6.3—Soil loss, yields, and profit for land in different slope classes, Uzbekistan
Slope
class
Wheat Cotton
Annual
loss(ton/ha/yr)
Yield
(ton/ha)
Profit
(US$/ha)
103
Annual loss
(ton/ha/yr)
Yields
(ton/ha)
Profit
(US$/ha)
No erosion 0 4.50 311.87 0 2.92 297.23
0-2% 1.90 4.48 310.38 0.61 2.92 296.53
2-5% 8.25 4.40 303.93 3.57 2.89 292.44
5-10% 25.49 4.16 284.34 11.03 2.82 279.90
10-15% 58.94 3.62 241.59 25.53 2.67 251.59
Source: Authors computation from simulation results.
Extrapolating the Effects of Land Degradation to the Whole Country
Given the sensitivity to local climate and soil conditions, extrapolating the crop model results from
experimental sites to domains beyond the experimental sites is extremely risky. Acknowledging all of
the limitations inherent in this attempt, we tried to extend the results to the rest of the country to
determine whether some preliminary policy recommendation could be formulated by using this
economic approach.
Using IFPRI’s crop allocation software Spatial Production Model (SPAM) (You and Wood
2006), we identified the irrigated land on which wheat and cotton are grown and assumed that the
entire area is affected by salinity. We computed total profit loss induced by increasing soil salinity
from a slightly saline soil (ECe = 7.5) to a moderately saline soil (ECe = 9.0). Similarly, using
geographic information system (GIS) software in combination with SPAM, we identified the areas in
the different slope classes that had been cultivated with wheat and cotton. We then computed total
profit loss caused by erosion. The results are shown in Figure 6.4. Salinity is a major problem, costing
the country about $11.21 million annually. Globally, salinity is most severe in Central Asia
(Natchergaele et al. 2010a). The economic loss of salinity for wheat and cotton alone is $13.29
million, which is equivalent to the selected crops and is 0.03 percent of the gross domestic product
(GDP) of $37.724 billion (IMF 2010).
Figure 6.4—Total profit loss due to land degradation type, Uzbekistan
Total profit loss (US$ million)
12
10
8
6
4
2
0
11.21
4.38
Source: Authors calculations based on simulation results.
The results of our simulation must be taken and interpreted with caution. First of all, as we
mentioned, reality on the ground is more complicated than the one modeled. Second, the costs
computed do not account for external costs, which, particularly in the case of erosion, can be high.
2.86
2.08
salinity Salinity -– wheat Erosion Erosion -– wheat Erosion -– cotton Salinity - - cotton
.