even though everything told in the movie was true.
The literal translation of the title of this movie is: Battles in the Desert.
The battles are battles fought against mother nature, with soldiers and civilians worked side by side to build irrigation system so that desert can be turned into fertile farmlands by irrigation, the typical reflection Mao's believe of "people will definitely win over the heaven (nature)".
For this case, it was true only for several decades. Due to the discovery of water and consequent success, the government became over confident and the land was over developed. As a result, water supply run out several decades later, not only the farmland was swallowed by desert, the original oasis was gone also. This part of the history was not told, even though there should be a sequel of this movie to finish the complete story.