The Collaborative International Dictionary
Trench-plow
Trench-plow \Trench"-plow"\, Trench-plough \Trench"-plough`\ (-plou`), v. t. To plow with deep furrows, for the purpose of loosening the land to a greater depth than usual.
Wiktionary
trench-plow
vb. (alternative form of trench-plough English)