Author: Karl Shaffer, Soil Scientist, North Carolina State University

Different methods of applying the same manure can greatly change the amount of nitrogen that is available to the crop. This is especially true for manures that contain significant ammonia nitrogen due to environmental factors such as volatilization. When writing a nutrient management plan, the various possible manure application methods should be discussed with the producer, and the plan written to reflect the preferred application method. Any changes to this method require applying different availability factors to the manure analysis when determining nitrogen availability. To maximize nitrogen utilization and minimize losses, some form of manure injection or incorporation should be used. Also, regulations may dictate different land area requirements based on the manure application method. Nutrient planning guidelines for your individual state will provide the factors to be used for assessing nutrient availability as a function of application method.