Soil testing worth the twenty bucks

Submitted by
Gary Sliworsky, Ag. Rep.

The following is an article originally penned by Keith Reid, Soil Fertility Specialist with OMAFRA.
With all of the soil samples that are analyzed each year, I’m amazed at the number of fields that still don’t get soil tested. It baffles me why a farmer would spend thousands of dollars on fertilizer, without investing twenty bucks in a soil test to tell him if he is putting on the right amount.
It is possible to grow good crops without soil testing, the same as it is possible to get away with never checking the oil in your tractor. The risk of not knowing what is in your soil is that you could be losing yield from insufficient nutrients, or spending far more on fertilizer than you need to. There has been lots of criticism of the accuracy of soil tests, but you can minimize most of the potential errors by following a few easy steps.
Take the sample properly. The sample has to be representative of the field, so avoid sampling in dead furrows, near gravel roads, or where manure or lime has been piled. For a single sample from a field, make sure the sample reflects the proportion of knolls and hollows, or different soil types. Don’t try to represent more than 25 acres with a single sample. If you are subdividing larger fields, divide along the old fence boundaries first (to reflect past management), then according to topography or soil type. Always sample to a consistent depth.
Mix the sample carefully. Break up all the lumps, and mix the sample thoroughly, so the sub-sample that goes to the lab reflects the sample you put in the pail. It should take as long to mix the sample as it did to collect it, if you are mixing properly.
Send the samples to an accredited lab. The OMAFRA accredited labs make their business analyzing farm soils, and their results are checked regularly. Other labs may analyze the occasional farm soil, but it is a sideline for them. The science of soil analysis is complex enough that only labs that are doing it all the time can provide consistently accurate results.
Insist on the OMAFRA accredited analyses. Most of the accredited soil test labs will perform more analyses than just the accredited OMAFRA tests, because they are analyzing samples outside of Ontario. The OMAFRA tests have been proven to be the most consistent and accurate for the range of soil types found in Ontario, and the fertilizer recommendations in OMAFRA publications and software are based on these tests. Be sure to specify the OMAFRA accredited soil tests for every sample.
Fall is a great time to get soil sampling done. The weather is pleasant, it’s easy to get across the fields, and there is lots of time to get the sample results back before next spring. It might just be the best investment you ever made.
Note: For a list of OMAFRA accredited labs contact Gary at 482-1921.