“We discover the bumps are milpa, small mounds of earth on which complementary crops were planted. Unlike linear plowing, which encourages water runoff and soil erosion, the circular pattern traps rainfall. Each mound is planted with a cluster of the Three Sisters that were the staples of Indian agriculture: corn, beans, and squash. The corn provided a stalk for the beans to climb, while also shading the vulnerable beans. The ground cover from the squash stabilized the soil, and the bean roots kept the soil fertile by providing nitrogen. As a final touch, marigolds and other natural pesticides were planted around each mound to keep harmful insects away. Altogether it was a system so perfect that in some Central American countries too poor to adopt linear plowing with machinery, artificial pesticides, and monocrops of agribusiness, the same milpa have been producing just fine for four thousand years. 19 Not only that, but milpa can be planted in forests without clear-cutting the trees; at most, by removing a few branches to let sunlight through on a mound. This method was a major reason why three-fifths of all food staples in the world were developed in the Americas.” GrowingNative AmericanPlantingMilpa Book:My Life on the Road Source: My Life on the Road