UNL CropWatch: March 4, 2011 Soil CEC and Nitrogen Holding Capacity Not a Direct Link

UNL CropWatch: March 4, 2011 Soil CEC and Nitrogen Holding Capacity Not a Direct Link

March 4, 2011

Coffee shop talk sometimes brings up an idea that once had some merit, but through constant retelling has changed into an idea that is not consistent with what actually occurs in the field.

One such idea is that the capacity of our soils to "hold" ammonia is a direct relationship with soil cation exchange capacity. John Sawyer, an Iowa State University professor in soil fertility and nutrient management, addressed this issue in a recent ISU Integrated Crop Management Newsletter.

His article, Fact or Fiction: Ammonia Application Should Not Exceed 10 lb N per Unit Soil CEC, was the result of discussions among many Midwest soil scientists and reflects a general consensus.

Note that the nitrogen rate calculator linked from Sawyer's article is not specific to Nebraska.  Please visit the CropWatch Soil Management section to access nitrogen rate calculators developed for Nebraska, based on multi-site Nebraska field research.

Charles Shapiro
Soil Scientist - Crop Nutrition, Haskell Agriculture Laboratory