 It kinda depends. DMI makes all kinds of ripper plows, from three point models to large winged pull type machines. The smallest pull type I have ever seen ran 4 shanks but I have seen three point machines that ran two or three shanks. Some places like Tractor Supply even sell one shank rippers that the smaller tractors can pull. General rule of thumb on pulling rippers like this is that it will take between 18 to 24 HP per shank to pull a ripper 10 to 15 inches deep depending on your soil type and the speed that you want to pull the machine. Speed is a good thing with a ripper or a field cultivator, if you can get a constant 4 to 7 MPH pulling them through the field it will break up the dirt better, but you dont have to pull that fast and it takes a lot of HP to do that. Most of the time you see ripper plows being used with the larger tractors on the bigger farms just because it takes soo much more power to pull these machines. But that doesnt mean that you couldnt get a smaller machine to use with your tractors. We run a 7 shank DMI Coulter Champ 2 (simular to the one in the picture) with 4 lead shanks that go in about 7 inches and 5 main shanks that go 12 to 15 inches and we pull it with a 2150 MFWA Oliver with a cummins engine turning 200 HP and even then I have to lift out sometimes because of tight dirt. You dont have to convince me that soil compaction is quickly becoming an issue with farming and the conventional plows and offset discs caused most of the problem. I dont even own a conventional plow anymore and the discs are quickly becoming extinct.
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