Environmental and societal costs of maize production decrease by addressing the uncertainty in nitrogen rate recommendations

TL;DR

Reducing nitrogen fertilizer use in maize production can lower environmental and social costs without significantly affecting yields.

Contribution

The study quantifies a 12–16% nitrogen reduction with minimal yield risk in the US Corn Belt.

Findings

Reducing nitrogen rates by 12–16% decreases N2O–N emissions by 10% and N leaching by 13%.

This reduction provides a social benefit of $230–$530 M due to improved air and water quality.

Further nitrogen reductions are limited by the high risk of yield loss for farmers.

Abstract

Excessive crop nitrogen (N) fertilization has negative environmental and social consequences. Using maize grain yield response to nitrogen field trials, we consider the uncertainty surrounding N rate recommendations to demonstrate that fertilizer N rates can be reduced by 12─16% in the US Corn Belt, with negligible risk of maize yield losses. This reduction in N fertilizer applications decrease N2O–N emissions by 10% and N leaching by 13%, leading to a social benefit of 230─$530 M, due to enhanced air and water quality. Additional N reductions could benefit ecosystems and human health. However, the high risk of yield loss associated with additional N reductions makes this practice unacceptable for farmers. This emphasizes the need for incentive programs that consider the responsibilities and limitations of all actors along the food supply chain.

Excess nitrogen fertilization in maize production harms the environment and society, yet farmers face yield risks when reducing inputs. Using field trials across the US Corn Belt, this study suggests that nitrogen rates can be reduced by 12–16% with minimal yield risk, reducing emissions and leaching.

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