Tractor repair is time consuming and costly. This sort of flotsam (which you might find in your pasture) will surely aggravate your trusty steed: Poly twine.
This is the twine that is used to keep hay bales bundled up for transport. It is strong and will not disintegrate over our lifetime (maybe several). This particular wad was just the surface of 100 feet or so of twine that the pasture grasses had grown through, making it virtually impossible to pick up with out using the tractor bucket and spear.
Some people will move a bale into the pasture, and then just run a razor over the twine, leaving the remnants in the field. Bad idea.
Why do You Care?
Why do you care? Apart from the fact that it is unnatural and isn’t good for the livestock, it can get wrapped around the axle of your tractor.
There you are, merrily chugging along while foot upon foot is wound around the back of your tire. Since the grasses grow through this mat of twine, a lot of pressure is applied to this filament that doesn’t like to break.
At some point the twine gets under the bearing seal and this is the result:
This is particularly ugly in tractors, as they have a “wet” axle and transmission line. That is, everything runs in an hydraulic fluid bath. Once this seal goes out, all that hydraulic fluid starts running. And there is a lot of it. In the case of my Kubota L35, over 40 quarts. You won’t lose all of it. But you will lose a lot and it’s a mess.
Replacing these seals are particularly onerous. First, you must remove the rear side tractor chassis structure. Then you have to crack the transfer case and remove the outer housing. Next, you have to remove a staked nut holding the main gear on the axle so you can pull the axle out. Finally, you must pry the seal off its respective surfaces. Oof.
Reassembling is pretty straightforward with the exception of sealing the transfer case. Take care to clean the mating surfaces off and use a high quality, petroleum compatible sealant. Nobody wants to have to redo this just to fix a leak.
The moral of this story? There are no shortcuts. Pick up your trash at the time of creation. “A stitch in time saves nine!”