Abstract:

In this paper, the latest relevant data of Uzbekistan were obtained from the databases of the Food and Agriculture Organization of the United Nations and the United Nations data retrieval system. The development history of irrigated agriculture was investigated by analyzing the data on irrigated areas and the population and economic development in the country, and a series of environmental problems caused by unreasonable irrigation and their impact on the social economy were discussed. The results demonstrated that as Uzbekistan is a typical agricultural country, its irrigated agriculture has been developing steadily, supporting the food security and employment of the entire country. The agricultural irrigation area of Uzbekistan increased to 4.2×10⁶ hm² in the 1990s and remained basically unchanged over the following 30 years. The main water sources for agricultural irrigation are the Amu Darya and Syr Darya rivers, and most irrigation methods are based on flood irrigation. Because of the dry climate with limited rainfall, long-term irrigation has led to a continuous decline of river flow and water storage in the Aral Sea. To cope with sluggish economic growth and food demand, increasing amounts of farmland were shifted from producing cotton to wheat in the 1990s, as wheat requires less water. However, the gradual phase-out of cotton exports in Uzbekistan and the conversion of its farmland from food to fruits and vegetables, done to transform its economic structure from over-reliance on agricultural production to a more economically rewarding system within the limited land, led to a sharp decline in wheat and cotton production in 2016. Additionally, the long-term use of relatively backward water supply systems and irrigation technology has caused a serious waste of water resources and a series of environmental problems. The flooding irrigation method coupled with strong evaporation and declining irrigation water quality along with the higher groundwater level has caused large-scale salinization of soil and made Uzbekistan the sixth largest country in terms of soil salinization, with a total of 2.1×10⁶ hm² of salinized soil. The area of the Aral Sea also shrunk from 4.7×10⁶-4.8×10⁶ to 1.2×10⁶ hm² over the past 40 years, and the sea could vanish within the next 40 years, resulting in a significant reduction in water storage and a three-fold increase in salinity compared with 20 years ago. The drying up of the Aral Sea also exposed a large area of salty sediments and finally formed a new desert (the Aralkum) in 2000, causing frequent salt dust storms, which pose a serious threat to human respiratory health and the hydrological cycle. Agricultural production is economically important in Uzbekistan. It has a significant positive impact on gross domestic product and can effectively the effects of small fluctuations in the industrial and service sectors. Still, the problem of soil salinization in Uzbekistan is extremely complex. To effectively address the issue, it is necessary to fundamentally optimize the irrigation mode and drainage technology and implement advanced and efficient irrigation and drainage schemes, such as drip irrigation, sprinkler irrigation, and subsurface pipe network salt drainage. This study offers support for agricultural development and water resource management in arid areas.

Key words: irrigation, arid land, agriculture, cotton, wheat, Uzbekistan, Central Asia