Wheat nitrogen response conditional on past yield and rainfall: A step in improving optimal nitrogen applications. Issue 1 (22nd January 2022) - Mills, Brian E.
Abstract: Making precision nitrogen (N) application clearly profitable will likely require incorporating multiple sources of information. Low‐cost sources of information include rainfall and the previous year's yield. This paper uses data from a long‐term experiment on the response of winter wheat ( Triticum aestivum L.) to N fertilizer, as well as rainfall data from the University of Oklahoma's Mesonet weather station. The goal was to determine optimal topdress levels of N. A regression was used to determine the previous year's yield and rainfall on the marginal product of farmer‐applied N. Information from lagged yield and rainfall increases profit by $2.79 ha –1 . Therefore, lagged yield and rainfall could be a low‐cost information source to add to other sources of information to achieve the goal of widespread adoption of precision N application. Core Ideas: An alternative to precision sensing is needed to determine optimal N rates for grain crops. A Bayesian analytical approach using yield monitor and rainfall data is suggested. Lagged yield and measures of rainfall improve the estimation of economically optimal N rates.