Are you saying the baler uses a total of _2_ hyd lines, and your tractor just has one single line? (The tractor would be single-acting?)
Or are you saying the baler uses 2 different sets of lines (a total of 4 individual hydraulic lines) and your tractor just has one set? The tractor would be doulbe-acting?)
Your question is too difficult to answer proerly without getting this described right.
If your tractor is double-acting (2 lines to make ne set of hydraulic lines) then for $500 less if you are good at piecing stuff together, you can do a diverter deal that will allow you to use one set or the other set. Easy to use this deal on different tractors, doesn't change much of anything on your tractor, just add an electric button to switch between ports. It just plugs into the tractor ports, not much fuss.
If your tractor is single-acting and the baler needs a single set of double-acting ports, then you would need to add a different hyd valve (the handle you pull) to make the oil push both directions instead of just one. Probably cost about the same, and someone who knows JD will be better at telling you where you'd need to plumb this into your tractor - a tad bit more involved to work this into the lines.