The N. E. Hansen Papers document the life, career, and plant exploration work of Niels Ebbesen Hansen (1866–1950), a horticulturist, botanist, explorer, and professor at South Dakota State College. Hansen was renowned for developing hardy fruits and forage crops suited for the Great Plains, and this comprehensive collection spans from the late 19th to the mid-20th century, reflecting his pioneering plant-breeding research and global botanical expeditions.

The collection includes correspondence, field notes, manuscripts, publications, journals, plant specimens, photographs, and research files. Early field notebooks and ledgers document Hansen's experimental work in alfalfa, clovers, and grains at the South Dakota Agricultural Experiment Station. Plant introduction records from Russia, Siberia, Turkestan, and China are extensively represented through travel logs, USDA contracts, expense reports, and photographs. Plant specimens and related horticultural data span multiple decades and continents, offering insight into his breeding strategies and selection processes.

Hansen’s manuscripts and publications explore topics such as breeding for cold resistance, disease tolerance, ornamental and edible plant development, and his views on Soviet agricultural practices. Of particular note are his multi-part manuscript series “Russian as Observed by an Agricultural Explorer” (1934–1937), which offers a critical and highly detailed commentary on Soviet collectivization, agrarian policies, and scientific developments. Numerous addresses and lectures document his national and international engagements with scientific and farming communities, including the Dry Farming Congress and State Horticultural Society.

Extensive correspondence from 1873 to the 1940s details his professional relationships with fellow horticulturalists such as Luther Burbank, institutional partners like the USDA, and international contacts including Soviet agronomist N.I. Vavilov. Clippings and biographical files document his recognitions, public reputation as the “Burbank of the Plains,” and memorials in his honor, including his 1949 South Dakota State College tribute and posthumous induction into the South Dakota Hall of Fame.

Photographs in the collection provide vivid documentation of Hansen’s expeditions, including images of him and his assistants in Manchuria, Siberia, and the Da Hinggan Mountains searching for hardy fruits. Other images depict South Dakota State College greenhouses, plant displays, and early experimental plots. Journals from his student years (1879–1883) and professional career reflect his early interests and scientific development.

This collection is a resource for studying early 20th-century plant exploration, American-Soviet agricultural exchange, Great Plains horticulture, and the role of land-grant institutions in shaping regional agricultural adaptation and innovation. Hansen’s impact on food systems, especially through breeding hardy fruits, grasses, and legumes, continues to influence breeding programs worldwide.