It's possible you are thinking of:
* Eugene W. Hilgard (1833-1916), an American agricultural scientist who is considered the "Father of American Soil Science." He was known for his work on soil fertility, soil classification, and the importance of nitrogen in soil.
* Theodore Hilgard (1833-1916), a German-American geologist and mineralogist who was a pioneer in the study of soils and the founder of the University of California, Berkeley's Department of Geology.
If you could provide more information about the author you're looking for, such as their field of study or the time period they wrote in, I might be able to help you identify them.