Characterizing soil Nitrogen availability to improve nitrogen fertilizer recommendations

Authors: Franzluebbers, Alan

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 11/29/2023
Publication Date: 3/14/2024
Citation: Franzluebbers, A.J. 2024. Characterizing soil Nitrogen availability to improve nitrogen fertilizer recommendations. Book Chapter. Chapter 12. http://dx.doi.org/10.19103/AS.2024.0135.16.

Interpretive Summary: Nitrogen fertilizer is one of the most common field production inputs in agriculture. It is both necessary for achieving high productivity and threatens ecosystem integrity due to its easy transport to water bodies and emission to the atmosphere. An ARS scientist in Raleigh, North Carolina reviewed recent history of soil testing to predict soil nitrogen availability and summarized the last decade of research aimed at understanding how inherent soil nitrogen supply might supplement the need for nitrogen fertilizer inputs in corn and forage management systems. Laboratory incubations, greenhouse growth trials, and yield response trials from throughout North Carolina and Virginia provided clear evidence that soil-test biological activity can be considered a simple, rapid, and robust technique to estimate soil nitrogen availability. This new approach for adjusting nitrogen fertilizer recommendations will provide a sound scientific basis for more profitable crop and forage production, as well as reducing the negative consequences of agriculture on water quality and greenhouse gas emissions.

Technical Abstract: Nitrogen fertilizer is one of the most common field production inputs in agriculture. It is both necessary for achieving high productivity and threatens ecosystem integrity due to its easy transport to water bodies and emission to the atmosphere. Investigators with the Soil Ecology and Management Lab in Raleigh North Carolina conducted a series of studies to understand how inherent soil N supply might supplement the need for N fertilizer inputs in corn and forage management systems. Relevant research prior to 2013 was reviewed, and subsequent research on correlation and calibration of soil-test biological activity with soil N availability was described. Laboratory incubations, greenhouse growth trials, and yield response trials in the field provided clear evidence that soil-test biological activity can be considered a simple, rapid, and robust technique to estimate soil N availability from mineralizable components. A new approach for adjusting N fertilizer recommendations is provided.