Fertilizer Applied to Compensate for Lost Soil Fertility, Study Finds

New research from the University of Colorado Boulder finds that one-third of the fertilizer applied to U.S. corn each year simply compensates for the ongoing loss of soil fertility. Corn farmers offset losses in soil fertility with nitrogen and phosphorus fertilizers intended to boost yields. This costs farmers half a billion dollars each year and contributes significantly to global greenhouse gas emissions, say the researchers. They ran models to estimate crop growth and how crop growth responds to variables like fertilizer, irrigation, and climate. They found that across the country, one-third of fertilizer added to corn is used to bring soil fertility back to pre-farmed levels. Corresponding author Jason Neff says this study, published in Earth’s Future, highlights opportunities for farmers to reduce tillage, prevent erosion, and utilize organic fertilizers to build soil fertility and save on input costs.