Sue, I found this info:

Parsnip deformities can produce forked roots or splits and may break when you try to pull them. The three most common reasons are improper soil preparation, over fertilizing and root knot nematodes. Parsnips do best when direct seeded into fertile, well-worked soil. Garden beds full of rocks, clumps, and other debris aren’t suitable for growing parsnips. The soil needs to be broken up and loose to prevent parsnip deformities. When you use compost as a fertilizer, be sure the fertilizer is completely finished and free of clumps that can cause parsnips to misshape as they try to push through the thick clots. The tiny root knot nematode is the most common cause of parsnip deformities. If you find your roots are knotty when growing parsnips, the cause is likely from this soil organism. Nematodes overwinter in soil and their feeding activity stimulate the plant cells to form galls on the roots. These galls prevent the plant from accessing adequate water and nutrients, which then stunt the plant. Root knot nematodes are less active in cold temperatures, so overwintering parsnips is a good way to help prevent damage from the pests. While almost impossible to see nematodes, you can sometimes find the female’s pin-sized head in damaged roots, but identification is usually from already deformed parsnips.

Thank you for that Shirley! It was very kind of you to go to al that trouble.This was only the second crop on this ground after it was lawn. I did sprinkle some rock dust along the furrow so maybe that counts as fertilizer. . The soil was well dug and the tilth was good with no stones & I was pleasantly surprised at how nice it was. The parsnips did follow main crop potatoes and I know you shouldn't follow roots with roots - maybe that was a problem too. Anyway that's just one parsnip - hope the rest are not like that!

I would eat Parsnips regardless of their strange shape!! Love them . . .

Sue: Too much fertilizer/compost will also cause your parsnips to split and go wayward. Loose, lean, sandy gritty soil is best and not that much water either. This will cause the taproot to go straight down in search of water and nutrients which is exactly what you want. If your soil is too rich, the taproot will go here, there and over there because it has no reason to go down yonder for nutrients which is what you want it to do. It has it all right near the surface and that's as far as it will go. You can still eat it and when it's in your stew pot, the rest makes little difference.

That's interesting Paul. I did add the rock dust to the drill when planting the seeds - so another time I'll try to remember to dig it in first instead.

Haha Shirley, fingers crossed for the next ones! Hope they aren't all like that. The poor parsnip has dried up while I've been wondering what went wrong so even eating it now is a no go. How can you tell I've never grown parsnips before...

Well done for trying though . . .

Rock dust?