Abstract

Nitrogen fi xation by the Haber–Bosch process has more than doubled the amount of fi xed N on Earth, significantly influencing the global N cycle. Much of this fi xed N is made into N fertilizer that is used to produce nearly half of the world’s food. Too much of the N fertilizer pollutes air and water when it is lost from agroecosystems through volatilization, denitrification, leaching, and runoff. Most of the N fertilizer used in the United States is applied to corn (Zea mays L.), and the profitability and environmental footprint of corn production is directly tied to N fertilizer applications. Accurately predicting the amount of N needed by corn, however, has proven to be challenging because of the effects of rainfall, temperature, and interactions with soil properties on the N cycle. For this reason, improving N recommendations is critical for profitable corn production and for reducing N losses to the environment. The objectives of this paper were to review current methods for estimating N needs of corn by: (i) reviewing fundamental background information about how N recommendations are created; (ii) evaluating the performance, strengths, and limitations of systems and tools used for making N fertilizer recommendations; (iii) discussing how adaptive management principles and methods can improve recommendations; and (iv) providing a framework for improving N fertilizer rate recommendations.

Document Type

Article

Publication Date

12-2017

Notes/Citation Information

Copyright © 2018 American Society of Agronomy

Digital Object Identifier (DOI)

https://doi.org/10.2134/agronj2017.02.0112

Funding Information

This work was supported by funding from the Walton Family Foundation and the Environmental Defense Fund.

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