Irrigation farming development

The study area has long history of agriculture development. Form 1980 to present, the irrigation area gets nearly double. Along with reclaimation of waste land, much more water is diverted into irrigation area (Fig. 3). Water diversion to irrigation area consumes much water recourse (most of it is surface water from the Akesu River) and diminishes the stream flow. The farmland steadily increased from 1980s and had a sharp increase at the end of the 1990s. Then the farmland area began to decrease because some actions were done to stop reclaiming waste land. The water withdraws gradually increased responding to the farmland increase. However, the water withdraws per irrigation area decreased in the same period. Water withdraws per irrigation area in the 2000s (averaged from 2000 to 2002) is only sixty percent of the averaged value in the 1980s. This indicates the irrigation efficiency increased in the study area that partly countered the water problems caused by waste land reclamations. Because of flood irrigation, the current water withdraws per irrigation is still very large with a mean value about 1650 mm per year. Flood irrigation is widely performed because surplus irrigation water is used for demineralization in the farmland. This brings on a shallower water table and aggravates salinization, a big problem for the sustainable development in this area.

Figure 3: Comparative changes in land use (a), in water withdraws (b) and water withdraws per irrigation area (c) from 1980 to 2002.