Warm and wet weather throughout last summer led to higher-than-average nitrogen mineralization, experts say. 

Results from statewide Iowa State University nitrogen research trials show that higher-than-average nitrogen mineralization from soil organic matter in 2025 resulted in lower optimal nitrogen application rates while maintaining strong yields — a significant finding as Iowa farmers strive to improve fertilizer efficiency.

Researchers with ISU’s Iowa Nitrogen Initiative have analyzed roughly 65% of the data from hundreds of on-farm...