Revamping nitrogen fertilizer recommendations for Missouri

Authors: SINGH, GURBIR - University Of Missouri; LORY, JOHN - University Of Missouri; DAVIS, MORGAN - University Of Missouri; Abendroth, Lori; KAUR, GURPREET - University Of Missouri; NELSON, KELLY - University Of Missouri; CALHOUN, JUSTIN - University Of Missouri; CHLAPECKA, JUSTIN - University Of Missouri

Submitted to: North Central Extension Industry Soil Fertility Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/13/2023
Publication Date: 11/15/2023
Citation: Singh, G., Lory, J., Davis, M., Abendroth, L.J., Kaur, G., Nelson, K., Calhoun, J., Chlapecka, J. 2023. Revamping nitrogen fertilizer recommendations for Missouri [abstract]. Proceedings of 53rd Annual North Central Extension Industry Soil Fertility Conference, Des Moines, Iowa. p. 206-212.

Interpretive Summary:

Technical Abstract: Multiple nitrogen fertilizer rate decision tools have been developed over the years for recommending nitrogen to growers. These tools are based on mass balance equations with expected yield and yield goal, economically optimum nitrogen rate, preplant soil nitrate test, pre-sidedress and late spring soil nitrate test, plant tissue nitrogen, crop growth models, and canopy reflectance sensing. These tools rarely include biological nitrogen in the rate recommendations. Advances in soil health assessment providing soil health scores and soil respiration estimates have been documented to improve nitrogen recommendations for corn in the Midwest. In Missouri, nitrogen fertilizer rate recommendations are based on yield goal and includes organic matter adjustment factor for most crops. This nitrogen decision tool does not integrate practices that improve soil health such as cover crops, applying biological nitrogen efficiency enhancers to increase plant-available nitrogen, nitrogen stabilizers such as nitrification and urease inhibitors, and variations in nitrogen supply across the landscape. A multi-site project funded by the Missouri Fertilizer Control Board began in 2023 to address these gaps and Therefore, the goal of this project is to identify the connection between soil health practices and nitrogen supply to improve nitrogen fertilizer recommendations for Missouri. The specific objectives are to quantify the nitrogen impact of “bug-in-a-jug” products; cover crops; nitrification inhibitors and other biological management technologies, evaluate soil health indicators and weather data as predictors of how changes in landscape position and soil conditions impact productivity and soil organic nitrogen supply, calibrate the integration of soil health measurements into fertilizer nitrogen recommendations, and improve calibrations of in-season nitrogen prediction tools. To achieve these objectives, 12 multilocation trials were established in Missouri in 2023 and first-year results will be presented at the conference.