Nitrogen management strategies to improve corn growth and reduce soil greenhouse gas emissions from claypan soils
Adoption of nitrogen (N) management strategies to minimize gaseous N loss from agriculture while maintaining high yield production is increasingly important for an exponentially growing population. Agricultural management on poorly-drained claypan soils in the Midwestern U.S. make corn (Zea mays L.) production even more challenging due to the subsoil's low permeability, which may result in wetter soil conditions and relatively larger amounts of soil N2O emissions during the growing season. The objective of this study was to determine the effects of urea fertilizer placement with and without the addition of a nitrification inhibitor (NI) on corn yield, N use efficiency (NUE), and cumulative soil N2O emissions on a Northeastern Missouri claypan soil. The fertilizer strategies utilized in this study consisted of deep-banded urea (DB) or urea plus nitrapyrin [2-chloro-6-(trichloromethyl) pyridine] (DB+NI) at a depth of 20 cm compared to urea broadcast surface applied (SA) or incorporated to a depth of 8 cm (IA). The addition of a NI with deep-banded urea resulted in 27% greater apparent N recovery efficiency than all other N treatments. Additionally, DB+NI had 54 and 55% lower cumulative soil N2O emissions than IA and SA treatments in the two combined growing seasons. These results suggest that deep placement of urea with or without nitrapyrin is an effective management strategy for increasing corn yield and reducing N loss on a claypan soil.