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Research Project: Strategies to Support Resilient Agricultural Systems of the Southeastern U.S.

Location: Plant Science Research

Title: Adjusting the N fertilizer based on soil health as indicated by soil-test biological activity

item Franzluebbers, Alan
item SHOEMAKER, ROBERT - Virginia Department Of Conservation And Recreation
item CLINE, JEFF - Virginia Department Of Conservation And Recreation
item LIPSCOMB, BRUCE - Virginia Department Of Conservation And Recreation
item STAFFORD, CARL - Frederick County Office Of Virginia Cooperative Extension
item FARMAHA, BHUPINDER - Clemson University
item WARING, ROBERT - Virginia Department Of Conservation And Recreation
item LOWDER, NATHAN - Natural Resources Conservation Service (NRCS, USDA)
item THOMASON, WADE - Virginia Tech
item POORE, MATT - North Carolina State University

Submitted to: Agricultural and Environmental Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2022
Publication Date: 10/3/2022
Citation: Franzluebbers, A.J., Shoemaker, R., Cline, J., Lipscomb, B., Stafford, C., Farmaha, B.S., Daniel, J., Waring, R., Lowder, N., Thomas, W.E., Poore, M.H. 2022. Nitrogen fertilizer recommendations can be adjusted for soil health condition. Agricultural and Environmental Letters. 7:e20091.

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. A USDA scientist in Raleigh NC led a series of investigations with a team of collaborators to understand how inherent soil nitrogen supply might supplement the need for nitrogen fertilizer inputs in corn and forage management systems. This synthesis article describes the premise, a review of current recommendations, an overview of soil health and biological activity, and a new approach for adjusting nitrogen fertilizer recommendations. This information will have immediate relevance to farmers, agribusiness dealers, agricultural service providers, and scientists.

Technical Abstract: Agriculture faces a dilemma with nitrogen (N)—it is often the most necessary external input to optimize production, several generations of farmers became accustomed to its relatively inexpensive cost, and it contributes to widespread pollution due to numerous loss pathways to the environment. However, standard N fertilizer recommendations have not accounted well enough for a key source via mineralizable soil N. Soil-test biological activity (STBA) is strongly associated with mineralizable soil N, both of which become surface-enriched with conservation agricultural management using soil health principles. A series of field experiments assessed the contribution of mineralizable soil N to the N supply needed to optimize corn (Zea mays L.) grain and fall-stockpiled tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] production. This essay synthesizes how STBA along with cost-to-value threshold can be used to modify the N fertilizer factor to optimize economic return and avoid environmental degradation.