Another great photo Joe.

This is a very early green Challenger as evidenced by the flip top radiator cap.  My son bought a very early green Pacemaker last year - serial no 16 - and it too has the same radiator cap.

As regards the depth of plooughing if I am not mistaken it is about the same in both photos that you have posted.  Look at the relative depths of the tyres and furrow walls in each.  Except in special circumstances there is no need for deep ploughing as long as most trash is buried and enough loose soil created to enable a seed bed to be made.  My Dad always told me not to plough too deep as I was only bringing up poverty!  This is basically true as most of a soill's fertility is in the top 6 incehs or so.  And look where we are today - reduced, minimal or zero cultivations have taken over in most grain growing areas of the world and yields have held up.  Ploughing is more energy expensive and costly.
John

Here is a very recent picture I got from Bob, this is a much earlier picture of the Massey Harris sign that was in the post with the tractors. The other picture with the tractors had snow on the ground so it was in the fall time. This picture must have been taken when the Massey Harris sign was first put up possibly in the spring time, It was dated March 5th 1927. The most interesting thing I noticed about this picture is they must have torn down a building or were leveling some land or filling in a hole when this picture was taken. I noticed the rip rap rock on the ground and pieces of wood and debri but the thing that cought my eye was the gas engine burried right in the middle under the Massey sign. When I was growing up my Dad was notorious for this kind of thing. He burried anyting he could find so he diddn't have to pay for fill being brought in. I really like the Massey furrow lift plow the boys are looking at under the sign.
Joe

Joe and others, THANKS so much for comments and sharing the knowledge! I am realy enjoying this thread.

I'm glad you are enjoying this thread! I thought someone would have caught this on my last post, the photo was dated March 5th 1927. The Challenger in the picture is a 1936 so could it be possible the picture was taken 9 years before the tractor should have existed??  I'm thinking the date should have been March 5th 1937.
Joe