Water requirements and stability of oasis ecosystem in arid region, China

This research was conducted to determine the water requirements of oasis ecosystem with crop evapo-transpiration method, and to analyse the water balance between the supply and requirement using water balance model, and then assess the stability of oasis ecosystem in the middle of Heihe River basin, China. The results indicated that the summations of the water supply and requirement approximated to 82.54 and 110.13 Mm(3) years(-1) in 2007, and the water deficit was 27.59 Mm(3) years(-1). The farmland was the largest water consumer with a consumption of 57.07 Mm(3) years(-1) and accounted for 51.82% of the total water requirements. It was followed by the water area 38.83 Mm(3) years(-1), forestland 12.13 Mm(3) years(-1) and domestic and industrial 2.10 Mm(3) years(-1), and accounted for 35.26, 11.01 and 1.92%, respectively. The stability index was 0.74, which implies that the oasis ecosystem have already started degenerating in sub-stability state. However, the water requirement of unit area was 1243.70 mm years(-1) and larger than other oases in arid region of China, which implies that the water resource scarcity do not exist in the middle basin where the excessive waste of the flood irrigation method has broken the balance between the water supply and requirement in the basin scale.