Ohio Corn Nitrogen Needs Unchanged Over the Years Despite 52% Yield Increase

Average corn grain yields in Ohio have increased substantially since the 1970s, largely attributed to a combination of improved corn breeds, better soil and crop management, and best practices with nitrogen (N) fertilization. However, the relative contribution of these factors to yield gain was not clear, so researchers from the Ohio State University synthesized 431 corn N rate trials over 45 years (1976–2021) from farmers’ fields and research stations to better understand trends in agronomically optimal N rates (AONR) and grain yields when N rates were optimal (YAONR).