I googled and found several connections between plough and steer e.g
... j/wn/replough in spring (land already ploughed in the autumn) local, f^ing ploughing. steer' guide (a plough). stiel the handle of a plough etc now Кол. ...
Thanks JMR27 I was not doubting the information I was interested to finf out where it came from, as the author of this crossword usually goes with Chambers
Thanks to you both for your help. Nacnud