Table 4.2 Economic costs attributable to land use changes and soil degradation^a

Category	Estimated costs in billions of yuanb Smil (1990 yuan)	Ning (1992 yuan)
Farmland loss and	5.8–12.1	12.5
degradation
Soil erosion	11.0–26.4	17.2
Reduced crop yields	0.3–0.8	0.4
Loss of nutrients	5.0–15.0	16.2
Reservoir silting	1.3–1.8	0.6
Clearing of canals	1.4–1.8
Flood damage	1.0–3.0
Deterioration of grasslands	3.7–5.4	3.3
Total	20.8–14.6	35.8

Notes:

^aAs some minor subcategories are not shown, the listed values may not add up to category totals.

^bTo convert 1990 yuan to 1992 values add approximately 20 per cent.