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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #311306
Title: Nitrogen, stover and tillage management affect nitrogen use efficiency in continuous corn

Author
item Sindelar, Aaron
item LAMB, JOHN - University Of Minnesota
item COULTER, JEFFREY - University Of Minnesota
item VETSCH, JEFFREY - University Of Minnesota

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2014
Publication Date: 5/5/2015
Citation: Sindelar, A.J., Lamb, J.A., Coulter, J.A., Vetsch, J.A. 2015. Nitrogen, stover and tillage management affect nitrogen use efficiency in continuous corn. Agronomy Journal. 107(3):843-850. DOI: 10.2134/AGRNJ14.0535.

Interpretive Summary: Nitrogen (N) fertilizer is essential to maximizing grain yields in high-yielding corn production systems. Initially, excess N fertilizer application often occurred to ensure the nutrient would not limit crop yields. Today, this practice is viewed as an economically unsustainable practice. Concern also exists regarding the potential for groundwater contamination by nitrates from agricultural sources. Therefore, appropriate N management is vital for ecosystem protection. Currently, no information exists regarding how removing corn stover for biofuel or forage purposes affects nitrogen use efficiency (NUE) or residual soil nitrate-N (RSN). This research was developed to answer these questions by measuring several NUE components and RSN. Overall, several NUE components generally increased when stover was removed, with the greatest improvements occurring at low N fertilizer rates. This is because N availability is greater when stover is removed, thus increasing its potential for recovery. Residual soil nitrate-N, however, was greater with stover removal, and the difference increased as N fertilizer rates approached the rate that economically optimized grain yield. This means producers should adopt rigorous management practices in fields where stover is removed in effort to limit N losses and potential groundwater contamination.

Technical Abstract: Improving nitrogen use efficiency (NUE) in corn (Zea mays L.) is critical for optimizing yield and reducing environmental impact. Stover removal in continuous corn (CC) for biofuel production, coupled with reduced-tillage systems, could alter NUE and residual soil nitrate-N. Experiments were conducted in Minnesota over 3 yr to determine how N uptake, NUE, and residual soil nitrate-N are affected by stover (remove and retain), tillage (chisel- [CT], strip- [ST], and no-till [NT]), and fertilizer N (0, 45, 89, 134, 179, and 224 kg N ha–1) management. There was a linear response of grain and total aboveground N uptake to fertilizer N across stover management and tillage treatments. Stover removal increased recovery efficiency for ST and NT at fertilizer N rates =134 kg N ha–1, but did not enhance N recovery in plots fertilized at rates >134 kg N ha–1. Internal efficiency was 5% greater with stover removal with no fertilizer N, but did not change with fertilizer N application. Stover removal did not affect agronomic efficiency in CT but did enhance it in ST and NT at fertilizer N rates =134 kg N ha–1. Residual soil nitrate-N to a depth of 1.2 m was 10 to 16 kg NO3–N ha–1 greater with stover removal at fertilizer N rates of 134 to 224 kg N ha–1. Greater residual soil nitrate-N with stover removal indicates a need for judicious management of N when stover is removed in intensively-managed Upper Midwestern CC systems.