The Alchemy of Air: A Jewish Genius, a Doomed Tycoon, and the Scientific Discovery That Fed the World but Fueled the Rise of Hitler

by Thomas Hager

China, farmers a millennium ago were already expert in using every possible kind of fertilizer, hoarding their human waste and adding it to the output from their domestic animals, composting vegetable scraps and leaves, and tossing in seed cakes to enrich their fields. It was all applied to the most ingenious farm system imaginable: a complex of dike-and-pond fields in which they grew not only rice, mulberries, sugarcane, and fruits but also carp. The fish waste helped fertilize the crops. The dung of the water buffaloes used to work the fields helped fertilize the crops. So did the waste of the ducks that swam in the ponds. They grew a native water fern in the paddies that acted like a crop of soybeans, adding fertility to the soil. The tropical climate allowed multiple harvests per year. This was the highest-yield traditional agricultural system ever devised. Using it, the Chinese could feed as many as ten people with the output from each acre of farmland, a yield of food five to ten times higher than the European