The scientists wanted to understand where iron and zinc were in a barley field, to help farmers manage their crops better. They took soil samples from specific spots and used a special method to predict where the nutrients were located. They found that iron and zinc were spread out differently in the soil and barley plants. Iron and zinc levels weren't the same everywhere in the field, and they could estimate values in areas they didn't test. By mapping these nutrients, farmers can make better decisions on how to take care of their fields and make sure their crops get the right vitamins in the right places.