Sentence:  The soil, which was often only a few inches deep, and had hitherto been incapable of bearing crops was transformed by chalking, <WSD>boning</WSD>, by the planting of turnips, which, when eaten off by sheep, returned a rich manure to the ground, and by the use of oil cake for sheep feeding which enriched the land still further. 
Meaning of the word marked with <WSD> tags:  The fertilization of a field with bone meal.