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Show 662 The National Geographic Magazine Erosion Has Not Spared Even the Great Wall of China On the divide between the Yellow River Basin and the Gobi a monument remaining from a ruined temple bears inscriptions telling of happenings along the man-made barrier. Weather has cut away most of the earthwork and masonry, but a portion of a guard station still stands in the background. Thousands of young men are being trained to organize and supervise these cooperative units. They are working out machinery simple enough to be made locally and yet efficient enough to give adequate output. In the far Northwest I was much interested to find that under General Mah soldier camps were also set up as complete cooperatives. Along with military training, soldiers grow their own food, shear their sheep, card the wool, twist the thread, and knit their own sweaters, as well as pad and make their winter garments, blankets, and tents (Plate XXI). About Lanchow we were introduced to "pebble mulching" as a means of conserving moisture in farmlands. The practice is old. It consists of the heavy task of digging out river gravels and spreading them over fields to a depth of three to four inches. A local saying has it that the father works hard, the son lives in ease, but the grandson must work hard again. The meaning is that the farmer must work to cover his land with this mulch of pebbles. His son profits by the father's work in good crops with little work, for it is scarcely necessary to cultivate the land. But by the third generation the pebbles have become mixed with soil. They must be removed and replaced with new ones. The effect of this remarkable farming practice is now being studied at the Kansu Agricultural Experiment Station. The layer of pebbles causes all the rain to soak into the soil and reduces evaporation loss, thus increasing effectiveness of a scanty rainfall of about 12 inches. The favorite crops for pebble mulch are melons, watermelons, cantaloupes, and cotton (Plates VIII and XVIII). From Lanchow we began our long-planned survey of the Corridor, which extends to the northwest to Sinkiang. Summer rains had made the road muddy out of Lanchow as we traveled along the ancient caravan route that leads across central Asia. The Great Wall of China Along our highway we had glimpses of remnants of the Great Wall of China, stretching like a monster serpent from horizon to horizon.* The big loop of the Yellow River separates the eastern section of the wall, made largely of stones and burned brick, from the western section, built of tamped earth. This * See "Thousand Miles Along the Great Wall of China," NATIONAL GEOGRAPHIC MAGAZINE, February 1923. |