Finally! I thought I was the only one who thought these elements were important! Mo - Mo nitrogenase for nitrogen fixation, eta. Ni - For the urease enzyme (Very important when using urea as a fertilizer / main nitrogen source) Co - Used in a hemoglobin-like protein that increases nitrogen fixation by a large margin. Va - Although Vanadium wasn't mentioned, I still think it is worth pointing out that this element is used in the Va-Nitrogenase enzyme. Although not essential for N-fixation, keep in mind that Mo-Nitrogenase is very inefficient if temperatures drop below 60F. That way you can get more N-fixation in fall or colder parts of the world so you don't have to spend more money on nitrogen fertilizer! Just be sure that your soil has the bacteria that are able to use this enzyme (ie. Azotobacter Chrococum)
We applied a brand name product called CAPTAN MOLY AS a planter box treatment put about a 2oz. In 50 lbs. Of soybeans. That was 50 years ago late 60's early 70s
Brian and Darren addressed your comment on Ag PhD Radio. In case you missed it, you can listen to their response soundcloud.com/agphd/11-10-20-biological-products#t=53:19.