Frequency of Soil Sampling

We like to sample every year.  We do not squawk too much when clients want to go with every other year.  If  you go further out than that it is difficult to track changes accurately.  It is also difficult to determine if your soil test results are influenced by environmental issues.  In reading my Corn Soybean Digest this week  found an article with the headline that Grid Data improves decisions.   While I take exception to the thought that grid sampling is the best way to monitor fertility levels,  found it interesting the Antonio Mallarino of Iowa State University advocated for sampling more often than every 4 years.   Dr. Mallarino is probably the foremost authority on soil testing.  He had done lots of research on soil testing and sampling from just about every angle you can think of.  His opinions are to be respected even when I disagree with him.