About

With the assistance and cooperation of numerous private and public soil testing laboratories, the Foundation for Agronomic Research and Plant Nutrition Canada present this summary of soil test levels in North America. Soil tests indicate the relative capacity of soils to provide nutrients to plants, and thus reflect both the geological origin and past management of soils. The trends in soil test status serve as one of the indicators of responsible management of crop nutrients, or 4R Nutrient Stewardship.
 
This summary is the 12th in a series begun by the Potash & Phosphate Institute and the International Plant Nutrition Institute (IPNI), with the first summary dating back to the late 1960s (Nelson, 1980) and the latest prior to this one in 2015. The summary offers a snapshot of soil test levels in 2020 and also provides a comparison to the previous four summaries that were completed in 2001, 2005, 2010, and 2015 (Potash & Phosphate Institute, 2001; 2005; IPNI, 2010; 2015). Starting in 2020, The Fertilizer Institute (TFI) has taken on the role of supporting the development and dissemination of this information.
 
Important to appropriate use of this report is recognition that nutrient management should occur on a site-specific basis where management objectives and the needs of individual fields and areas within fields are recognized. Therefore, this soil test summary, conducted at the state or province level, cannot reflect the specific needs of individual farms. Its value lies in calling attention to broad nutrient needs and challenges and in motivating educational and action programs that are in turn relevant to growers and their advisers.
 
Tom Bruulsema, Chief Scientist, Plant Nutrition Canada
John D. Jones, Director, Foundation for Agronomic Research
 

Acknowledgments

We gratefully acknowledge technical support from Quentin Rund, Saad Tarik, Mershon Tobin, Luke Hanselman and Jonathan Norvell, PAQ Interactive, Monticello, IL. In addition, several former IPNI scientists—including Scott Murrell, Tom Jensen, Rob Mikkelsen, and Mike Stewart—helpfully reviewed procedures and advised on analysis in order to ensure consistency with past summaries. Finally, financial support from The Fertilizer Institute is deeply appreciated. 
 

References

International Plant Nutrition Institute (IPNI). 2010. Soil Test Levels in North America: Summary Update. IPNI Publication No. 30-3110. Norcross, GA. International Plant Nutrition Institute (IPNI). 2015. Soil Test Levels in North America: Summary Update. IPNI Publication No. 30-3115. Norcross, GA.
Nelson, W.L. 1980. Soil Test Summaries and their interpretation. Better Crops with Plant Food, 63(4): 6-10.
Potash & Phosphate Institute. 2001. Soil Test Levels in North America: Summary Update. PPI/PPIC/FAR Technical Bulletin 2001-1. Norcross, GA.
Potash & Phosphate Institute. 2005. Soil Test Levels in North America: Summary Update. PPI/PPIC/FAR Technical Bulletin 2005-1. Norcross, GA.