There are normally a lot of recommendations here but to get you started. The diesel engine in a tractor is normally run at near full throttle full load conditions in dust and many other things.
To look at oil that was designed around an over the road truck that would be figured closer to one third load one third to two thirds throttle. A car is figured at one quarter throttle one quarter load.
There are far more names and brands of oil then there is blenders of oil and often one plant may make 100's of blends of oil out of one base stock just by adding different additives. Pick your favorite label and a color for the container and away we go!
These additives are normally enhancers that make the oil cling to the parts better, flow better in cold weather. And the list goes on to include ash to aborb the by products of partially burnt fuel from a cold running engine.
Some products you pay for the name, most times they got that from building a reasonable product. There are those oils out there that are a bargin in price as well as quality.
Depending on where you live, the hours you put on your tractor and when you plan to change your oil are all important as to which oil is best for you.
If I was to buy cheap oil I'd probably just change the oil and filter more often, but then I don't like to waste time so I buy good oil and reduce the mount of changes.
The last time I looked at both companies mentioned the ash content was about the same as well as the TBN on the the two oils mentioned and I consider them average oil. There is better and worse oils made.
