Reduction in nitrogen fertilization rate for spring wheat due to carbon mineralization-induced nitrogen mineralization.

Authors: Sainju, Upendra

Submitted to: Agrochemicals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2024
Publication Date: 7/11/2024
Citation: Sainju, U.M. 2024. Reduction in nitrogen fertilization rate for spring wheat due to carbon mineralization-induced nitrogen mineralization. Agrochemicals. 3:209-218. https://doi.org/10.3390/agrochemicals3030014.
DOI: https://doi.org/10.3390/agrochemicals3030014

Interpretive Summary: Recommended nitrogen fertilizer rates to crops become excessive when nitrogen mineralization from soil organic matter during a crop growing season is not considered. This results in the accumulation of soil residual nitrogen not used by plants which degrades soil and environmental quality through soil acidification, nitrogen leaching, and emissions of nitrous oxide, a potent greenhouse gas that contributes to global warming. One of the reasons that nitrogen mineralization is not accounted for is that it is a time consuming process to determine it. ARS researchers in Sidney, MT reported that potential nitrogen mineralization can be estimated by relating it with the carbon dioxide flush measured during a 1 day incubation of prewetted soil. Using soil nitrate nitrogen and potential nitrogen mineralization, the author reported that producers can save substantial amounts of nitrogen fertilizer applied to dryland spring wheat while maintaining grain yield. The method is simple, rapid, and inexpensive. Producers can benefit immediately by reducing the cost of cultivation and also improving soil and environmental quality.

Technical Abstract: Nitrogen fertilizer is usually applied in excess amounts to crops by not accounting for potential N mineralization (PNM) because of its time-consuming process of determination. The PNM was predicted from its relationship with CO2 flush at 1 d incubation (CF) measured from soil samples collected to a depth of 15 cm at two long-term (14- and 36-yr-old) dryland farming sites and used for calculating the amount of N fertilizer saved for spring wheat (Triticum aestivum L.) in the northern Great Plains. Using soil NO3-N content in addition to the predicted PNM, the relationship saved 39 to 83 kg N ha-1 of N fertilizer, depending on management practices, for sustainable production of dryland spring wheat. Producers can reduce the cost of cultivation and improve soil and environmental quality by reducing the amount of N fertilizer required for spring wheat when the predicted PNM is used to adjust N fertilization rates.