2010 年 14 巻 1 号 p. 63-70
Analyses of data on the desertified land area, cropland area, Xihu Lake water table and annual precipitation of Naiman County showed that the total area of desertified land had decreased from 4198.07 km² in 1975 to 3297.3 km² in 2005. Irrigated cropland steadily increased from 115.74 km² in 1959 to 368.79 km² in 2005 while rain-fed cropland decreased from a maximum of 1251.86 km² in 1961 to 568.33 km² in 2005. The annual precipitation fluctuated dramatically and there were two drought periods of ten years in the period from 1961 to 2005. The water table of Xihu Lake decreased consistently. The relationship between annual precipitation and water tables is not significant, but that between irrigated cropland and water tables is. This tentatively shows that water resource reduction, to a large extent, is due to overuse of water for irrigation.
Considering the expansion of irrigated cropland and reduction of annual precipitation and water tables, there is no doubt that desertification reversion will not be sustainable in Naiman County if alternative land use strategies are not available and water is not used more efficiently.