There are 100 calories in one cup of parsnips.
Parsnips are interesting because some varieties can reseed themselves and in some cases they can become invasive and grow wild. Also Parsnips can overwinter in the ground. Where I live there are wild parsnips which are edible. In some areas of the United States they have groups who use tools designed to remove the parsnip root that clear them are of native habitat.
One should remember when working with parsnips that parsnips contain furocoumarins that can make the skin sensitive to light. So one should be careful working with the foliage and do not get the sap on your skin. I like to wear gloves when working with green parsnip foliage. I also like to harvest them after the tops have been killed by frost. I also leave some in the ground for spring eating. If you are going to harvest wild parsnips make sure you know the difference between parsnip, hogweed, hemlock, wild parsley, etc.
Perfect Parsnips every time
Mother Earth Magazine - All About Growing Parsnips
The Benefits of Growing Parsnips
This shovel was specifically designed for use on the invasive Wild Parsnip