I think that is what you would call a breaking plow. They used to use them back in the early 1900's for plowing new fields, pulling it with 6 teams of horses, plowing out what stumps they could and the rest they burnt.
This one here is a modern one, most likely plowing that deep for root penetration in groves of fruit trees.
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Deep plowing , If you have loose peat over clay or unworkable heavy clay over sand etc the deep plowing mixes the 2 to hopefully make a medium soil . If you look you can clearly see the two soil types from the colour ..it looks like they are burying peat .