Manure Use Reduces Nitrogen Needs in Corn Production

By Blake Jackson

Manure remains one of the most valuable resources in crop production, providing essential nutrients while also improving soil organic matter, nutrient cycling, and overall soil health. When applied effectively, it can enhance resilience to challenging weather conditions.

Research conducted across New York has consistently shown that manure can boost crop yields beyond what is achieved through fertilizer alone.

This benefit proved especially important during the difficult 2025 growing season, which featured delayed planting due to a wet spring followed by drought conditions in summer.

A statewide project evaluated the nitrogen (N) contribution and yield impact of different manure sources and application strategies for corn silage and grain.

In 2025, five field trials were carried out across northern, central, and Catskills regions, adding to 19 trials completed between 2022 and 2024.

Each trial compared strips with and without manure application. Some fields received manure in spring 2025, while others assessed residual benefits from manure applied in 2023.

Across most trials, corn yields responded positively to sidedress nitrogen applications. However, manure reduced the need for additional nitrogen, in some cases by more than 50 pounds per acre. In three trials, manure produced yield increases beyond what fertilizer alone could achieve.

Notably, fields without recent manure history showed the greatest response, while others demonstrated lasting benefits up to three years after application, likely due to the slow release of organic nutrients.

Soil testing results varied. Pre-Sidedress Nitrate Test (PSNT) readings indicated that manure contributed available nitrogen in newly treated fields but showed limited carryover in older applications.

However, PSNT results were not always reliable in predicting nitrogen needs. In contrast, the Corn Stalk Nitrate Test (CSNT) consistently reflected crop nitrogen status and aligned with observed yield responses.

Overall, the findings confirm that manure provides both immediate and long-term advantages beyond nutrient supply.

Researchers plan to expand the study in 2026, incorporating more trials, manure types, and field conditions to improve nitrogen crediting systems and better understand manure’s full agronomic value.

Photo Credit: gettyimages-magicxeon