Diplomats visit a desertification control pilot spot.[Photo provided to China Daily]

"Ten years ago all this fine sand would blow in the wind," Zhang says. "Now, in creating this man-made semi-desert, we have brought in pebbles from 15 kilometers away, and with the one-kilometer long plant barrier, moving sand won't accumulate here."

In addition, woven straw or nylon nets have been buried in the sand to form checkbox barriers against the wind.

Once sand is ensconced in these barriers, wind-breaking seedlings such as Calligonum, caragana and sacsaoul, which are resistant to drought and cold, are planted in the center of the boxes.

Checkbox barriers

In the past 10 years, Li Rui, 40, one of the four workers responsible for sand control with Dunhuang Academy, says he has seen more than 1.15 million-square-meters of checkbox barriers being built. He and others constantly monitor the top of the sand mountain, ensuring that the checkboxes and plants are doing their job. At the foot of these boxes and plants, run black rubber pipes that transport water to the top of the sand mountain, dripping it into the sand to promote growth.

Sometimes the workers help research institutes with experiments such as building a wind tunnel to determine the ideal density of grit, and the size of its particles, that is spread on the surface of sand to stop it blowing in the wind.

"That is how we built the semi-desert there," Li says, pointing to a darker flat area along the road, where pebbles are scattered over more than 1.67 million sq m of sand.

yangyangs@chinadaily.com.cn