The significance of developing water-saving irrigation
Nowadays, the world is faced with three major problems of population, resources and environment.Water resources are closely related to the environment and indirectly related to population. Therefore, the issue of water resources has become one of the important issues attracting worldwide attention.
More than 70 percent of the earth’s surface is covered by water, and the remaining 30 percent of the earth’s surface is covered by water.The total water volume of the earth is 138.6 times 10.8 billion m3, of which the freshwater reserves are 3.5 times 10.8 billion m3, accounting for 2.53 percent of the total reserves.So far, little direct use has been made of seawater, deep groundwater, ice, snow, solid freshwater, due to difficulties in development or technical and economic constraints.The lakes, rivers and shallow underground freshwater resources that are more easily exploited and most closely related to human life and production only account for 0.34% of the total freshwater reserves, 104.6×10.4 billion m3, less than 1/10000 of the total global water reserves.Generally speaking, water resources mainly refer to the available fresh water resources that can be restored and renewed year by year.It can be seen that the earth’s fresh water resources are not abundant.