Page:Tree Crops; A Permanent Agriculture (1929).pdf/42

 FIG. 17. Top. This very thin layer of clay loam resting on solid granite in Chekiang province. China, supports the rapid-growing bamboo with its myriad uses, including edible shoots. How long would that slope last if treated as the land in Fig. 1 is treated? (Photo F. N. Meyer. U. S. Dept. Agr.)-FIG. 18. Bottom. Silt pits in a Sumatra rubber plantation. This invention rivals the plow in its possible importance to man if he thinks of himself as a race with some hundreds of thousands of years ahead and then calculates the rate at which he is now destroying soil. Pits made by hand by coolic labor. (Photo Goodyear Rubber Co.)