By Roberta Attanasio Plants grow in and out of soils—and sustain almost all living beings on our planet, either directly or indirectly. But soils are rapidly disappearing from farms all around the world, threatening our ability to grow food. The treasure beneath our feet is continuously subjected to erosion and degradation, mostly resulting from intensive farming practices.   Relentless tilling, for example, allows weeds control by turning the soil over, but leaves it bare and vulnerable to wind and rain—causing the loss of the fertile top layer. Even the famed black Iowa soil is disappearing. “In Iowa they call it ‘black gold’—a fertile blanket covering the landlocked Midwestern state. Thousands…