O/T adding tractor power steering

Needs more weight hanging farther behind the rear axle to counter the weight of the plow, it would be easier than trying to adapt power steering to the machine. You can take the wheel weights off and add them to the ballast box if you dont want to make the tractor any heavier. Think of it like a see-saw where the rear wheels are the fulcrum and the plow is like a fat kid sitting all the way at the end and the weight box is a medium sized kid sitting up twards the fulcrum.
Your steering might also be getting harder from a dry kingpin or tie rod end.