**By Caitlin Looby, Climate Central and Amber Alexander, NBC WHO 13 Des Moines** IOWA — Jean Eells dug into the earth on her farm after the fall harvest and discovered a problem. It was 2016 and the farmer that rented her land had just left. When she pulled her spade from the ground she noticed the soil was hard and compact, with layers looking like “thinly stacked dinner plates.” This story was produced through a partnership between NBC WHO 13 Des Moines and Climate Central. Healthy soil soaks up and stores more water, helping farmers grow healthy, nutritious and productive crops. But warming temperatures are threatening the productivity of croplands through the Midwest, with new data showing how drought makes corn and soybean crops much more sensitive to heat. “I want to make sure that my soils are in good shape, so that I will have a farmer that can make money,” says Eells.…