Established in 1888 as the Rotation Field by Dean J.W. Sanborn, Sanborn Field was designated a National Landmark in 1965 along with the Duley-Miller Erosion Plots on the same campus. It is the third-oldest continuous long-term research site in the world and has helped researchers discover how agriculture and the environment interact. In 1945, soil samples from Sanborn Field yielded the bacterium streptomyces aureofaciens, the source of aureomycin, a first generation antibiotic. Other pioneering studies showed that manure is not a balanced, complete source of nutrients and that complete and balanced soil management, including manure, ag lime, and commercial fertilizer, helps prevent soil deterioration and maintain soil productivity. Known as the grandfather of soil health, Sanborn Field has supported the study of soil physical, soil chemical, and soil biological indicators whose balance can optimize soil, crop, and environmental properties. Its long-term objectives are rooted in crop rotations and monocultures under continuous management since its establishment, and continuous soil and plant samples aid the study of long-term environmental and crop nutritional changes while it also serves as an on-campus laboratory for teaching.