Soil conservation has three guiding principles, he explains: don't till the soil, keep it covered, and keep crops diverse. Reduced tillage preserves the root pathways forged by preexisting plants. Those paths act like pores, allowing the ground to store water for use in dry times and soak it up more effectively during floods. Cover crops, like alfalfa, clover, and sorghum, keep the soil loose after a cash crop has been harvested. When cover crops become part of the soil during preparation for a crop like corn or wheat, they increase soil moisture and provide larger yields. Since they keep a field's precious soil covered and preserve its pores, cover crops also prevent earth from becoming so fine it turns into dust. Planting diversely prevents the nutrient drain that occurs when the same crops grow season after season. Rotating through different varieties acts more like a multivitamin, adding a variety of nutrients to the soil over time. Drought-resistant crops can step in occasionally to save water, and use the water that's already in the soil more efficiently.