Sentence:  Those grants that were taken up depended primarily upon a <WSD>land agent</WSD> and an overseer for their operation. The <WSD>land agent</WSD> was the owner's representative in America and was responsible for managing the legal and practical affairs related to obtaining and developing the grant. 
Meaning of the word marked with <WSD> tags:  (historic) A person employed to manage the legal and practical aspects of developing a land grant.