Yes I agree that post was informative, many others on here apparently think its foolish to ask such a question as fuel mileage on a tractor, but at prices approaching $5 its something to consider. I know there are certain brands which can attain pto speed at a lesser engine rpm and certain engines themselves are designed to operate more efficiently than others, guess I will have to look else where for this information, I'm sure its out there.
Nobody said it is foolish, just that it is difficult to compare. There are 100's of tasks a person could put a tractor to and there are dozens of ways to do each one of them. Slow at low rpm, slow at high rpm, quick at low rpm, quick at high rpm, or anywhere in between. I personally haven't timed myself or checked fuel usage for any particular task but on average I would say I tend to use a bit less than a gallon per hour. I do most of my work in the 1800-2200 rpm area which is below PTO speed for my R4047.
BUT, me saying this does not mean the next person will get the same rates of consumption. The next guy could have a heavier or lighter foot on getting to his working area, he may run rpm's faster or slower, in a higher or lower gear in swampy or dry conditions, or with any other different vaiable and he may get 2 hrs per gallon or work at 2 gallons per hour.
IF someone does some significant controls in testing by controlling as many of the variables as possible then you can have an accurate comparison and a gauge by which someone could judge if consumption rates on one tractor make it more worth getting or more worth avoiding.
TractorData.com is one site that is positioned to do this testing but its coverage is very spotty especially on off-brands. I checked 45hp tractors for LS, Kioti, Mahindra, Kubota, and Deere and the Deere was the only one with test results and I'm not sure 3 gallons per hour is accurate or meaningful.
TractorData.com John Deere 4520 tractor tests information
I checked a few more and found Case had one with tests too, at 3.4 ga/hr.
Still meaningless when wondering about LS tractors...