Can you give me the author and the name of the poem for the following:
"Beneath dread Winter's level sheets of snow
 The sweet nutritious turnip deigns to grow"

I'm afraid that these are the only two lines that I have.

The poem is THE FARMER'S BOY (1800) by Robert Bloomfield. He is
described as a "self-taught ‘peasant poet’ of the Romantic period" by
the Robert Bloomfield Society. There is plenty of information on the
poet and details of his other works.
http://human.ntu.ac.uk/bloomfield/

There is no link from the main page to the poem so click on this link
to directly access the poem.
http://human.ntu.ac.uk/bloomfield/farmer.htm

The poem is very long and the relevant lines appear in the section
'Winter IV' I suggest you use your edit> find> tool on your browser.

The poem does appear on some other sites but not in its entirety. Use
the google search term below to find additional information on the
poet.

I trust this answers your question happles-ga. If it does not, or the
answer is unclear, then please ask for clarification of this research
and I shall respond to the clarification request as soon as I receive
it.

Thank you
answerfinder-ga

Search strategy
All The Web http://www.alltheweb.com/advanced 
"sweet nutritious turnip"
http://www.alltheweb.com/search?advanced=1&cat=web&cs=utf-8&jsact=&_stype=norm&type=phrase&q=sweet+nutritious+turnip&_b_query=&l=pref&ics=utf-8&cs=utf-8&wf%5Bn%5D=3&wf%5B0%5D%5Br%5D=%2B&wf%5B0%5D%5Bq%5D=&wf%5B0%5D%5Bw%5D=&wf%5B1%5D%5Br%5D=-&wf%5B1%5D%5Bq%5D=&wf%5B1%5D%5Bw%5D=&wf%5B2%5D%5Br%5D=&wf%5B2%5D%5Bq%5D=&wf%5B2%5D%5Bw%5D=&dincl=&dexcl=&geo=&limip=&doctype=&dfr%5Bd%5D=1&dfr%5Bm%5D=1&dfr%5By%
D=1980&dto%5Bd%5D=11&dto%5Bm%5D=3&dto%5By%5D=2003&size%5Bp%5D=%3D&size%5Bv%5D=&size%5Bx%5D=0&hits=10&nooc=on
On google - "robert bloomfield"
://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=%22robert+bloomfield%22

Excellent - most interesting