Growers in Ontario can have confidence that their soil samples have been properly analyzed, thanks to the Soil Test Accreditation Program. Accurate analytical results do NOT, however, ensure that the lab provides the fertilizer recommendations that are printed in the OMAFRA publications, or that are part of the NMAN nutrient management software.

I have been contacted by several growers who questioned the recommendations included on their soil test reports. One noted that the recommendations provided by the lab would have added $4,000 to his fertilizer bill for 160 acres. While there may be reasons for applying higher rates of fertilizer, I am sure you will want to be making those decisions yourself after considering the reasons carefully.

The approved Ontario recommendations are based on research showing that these rates provide, on average, the highest net returns to fertilizer in the year it was applied. This rate of fertilizer won't always provide the highest possible yield, but the bushels you sacrifice are the bushels that cost more to produce than they pay back.

Other jurisdictions base their recommendations on the philosophy of building up soil fertility to the point where crop yields are not limited, and then applying fertilizer each year to replace what is removed. You may want to consider this approach on land that you own, but it is hard to see the advantage to building soil fertility on rented land.

What You Can Do

1. Submit your soil tests without listing a crop. This way, you can go directly to the tables in the Agronomy Guide (OMAFRA Publication 811), or to the OMAFRA website at

www.omafra.gov.on.ca/english/crops/facts/fert-rec-tables-toc.htm to make your own recommendations.

2. Specify to the lab that you want to receive only the OMAFRA fertilizer recommendations when you submit your samples.

3. Read the reports carefully when they arrive to ensure they don't recommend more fertilizer than you really need.