Is potassium deficiency limiting corn yields?
Agricultural Research Service (ARS) soil scientists Douglas Karlen and John Kovar think so, and they cite a shift by growers away from preplant tillage as a possible cause. “No-till” farming has become an important agricultural practice because it offers such benefits as lower energy costs and reduced soil erosion. But the practice may have a side effect in causing potassium–which is naturally recycled as plants decompose–to accumulate in the surface soil where new plant roots cannot capture it, according to Karlen and Kovar. They’re based in the ARS Soil and Water Quality Unit, part of the National Soil Tilth Laboratory at Ames, Iowa. The scientists also question whether increased emphasis on nitrogen and phosphorus management brought on by those nutrients’ off-site effects may have led growers and researchers to overlook potassium’s importance as an essential plant nutrient. ARS scientists started investigating the potassium problem in 2000 at a tillage research site initiated in 1
