This word means to make unfruitful. It has come much into favour recently among officials to express the idea of a veto on the use of something for a profitable purpose, and shows signs of the usual usurping tendencies of such words; you may already find examples of sterilised used merely as a synonym for wasted. It also needs watching for another reason. To speak of sterilising coal needed for the support of buildings is to use an appropriate metaphor; the coal is being made unfruitful for the purposes for which we use coal. But to speak of sterilising land in the sense of preventing its being built on is to say exactly the opposite of what you mean: the land is being preserved in order that it may continue to be fruitful.