A Wisconsin-based field study presented at the 2025 Waste to Worth Conference has highlighted the potential of near-infrared technology to improve the precision and efficiency of manure application on cropland. The research, led by Joseph Sanford, evaluated the use of a commercial manure nutrient sensor to provide real-time data during spreading and compared its performance to traditional sampling methods.
Manure, a vital source of nitrogen, phosphorus, and potassium, presents a challenge for nutrient management due to its variability. Conventional sampling methods can be expensive, time-consuming, and often miss the changes in nutrient content that occur during manure storage and application. To address this, researchers outfitted a manure tanker with the John Deere HarvestLab 3000 sensor system—currently the only commercially available real-time manure sensing technology—paired with a flow meter and rate controller to adjust application rates on the go.
Trials were conducted on silt loam soil, where the sensor’s ability to deliver accurate nitrogen rates was tested against fixed-rate applications informed by lab sampling. Corn silage was planted following manure application, and crop yield and nitrogen use efficiency (NUE) were measured after harvest.
Results from the first year showed that the sensor system was more precise in achieving target nitrogen rates. It consistently applied within 20 to 30 pounds per acre of the intended nitrogen rate, while conventional methods overshot the target by 40 to 95 pounds per acre. While yield and NUE were comparable across treatments, the real-time system reduced the risk of overapplication—benefiting both farm profitability and environmental stewardship.
The sensor also tracked phosphorus and potassium levels during application, though lab tests confirmed the technology was more accurate for nitrogen. Researchers observed that nutrient levels in the manure fluctuated significantly when agitation was reduced, underscoring the importance of consistent mixing and the sensor’s value in tracking such variability.
Looking ahead, the research team plans multi-year trials to further evaluate long-term impacts on soil health and nutrient use. They also aim to refine the sensor’s calibration for phosphorus measurement, enabling more comprehensive nutrient management.
This emerging technology could offer farmers a more sustainable way to manage manure, improving crop outcomes while reducing waste and environmental losses. With ongoing development, tools like real-time manure sensing may play a key role in the future of precision agriculture.
