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ARS Home » Midwest Area » St. Paul, Minnesota » Soil and Water Management Research » Research » Publications at this Location » Publication #321678
Title: Corn response to nitrogen management under fully-irrigated vs. water-stressed conditions

Author
item MAHARJAN, BIJESH - University Of Minnesota
item ROSEN, CARL - University Of Minnesota
item LAMB, JOHN - University Of Minnesota
item Venterea, Rodney - Rod

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2016
Publication Date: 6/24/2016
Citation: Maharjan, B., Rosen, C., Lamb, J., Venterea, R.T. 2016. Corn response to nitrogen management under fully-irrigated vs. water-stressed conditions. Agronomy Journal. 108(4):1-10.

Interpretive Summary: Characterizing corn grain yield response to nitrogen (N) fertilizer rate is critical for maximizing profits, optimizing N use efficiency and minimizing environmental impacts. Although a large data base of yield response to N has been compiled for highly productive soils in the upper Midwest U.S., few data exist for less productive soils. In addition, while changes in precipitation patterns have already been observed and are expected in the future, few if any studies have compared yield response to N rate, or to differing N fertilizer sources, under conditions of varying water availability. We measured yield and basal stalk nitrate-N (BSN) at harvest using split-applied urea at eight N rates under both fully-irrigated (FI) and water-stressed (WS) conditions in a loamy sand over two years. We also measured yield using single, pre-plant applications of urea, polymer coated urea (PCU) and urea with urease and nitrification inhibitors (IU) at two or three N rates. Full irrigation increased yield by up to 48%, but water availability did not significantly affect economic or agronomic optimum N rates (AONR). With FI, split-applied urea increased yield by 18-41% compared with pre-plant applied urea, PCU or IU. With FI at 180 kg N ha-1, pre-plant applied PCU and IU increased yield by 20% compared with pre-plant urea. Under WS conditions, N source or timing did not affect yield. At higher N rates, BSN was greater with WI compared to FI. With WS, BSN corresponding to AONR fell within the ‘excessive’ range, indicating that BSN data under WS conditions should be interpreted with caution. These results will be useful to producers, scientists and regulators interested in developing improved N fertilizer management practices.

Technical Abstract: Characterizing corn grain yield response to nitrogen (N) fertilizer rate is critical for maximizing profits, optimizing N use efficiency and minimizing environmental impacts. Although a large data base of yield response to N has been compiled for highly productive soils in the upper Midwest U.S., few data exist for less productive soils. In addition, while changes in precipitation patterns have already been observed and are expected in the future, few if any studies have compared yield response to N rate, or to differing N fertilizer sources, under conditions of varying water availability. We measured yield and basal stalk nitrate-N (BSN) at harvest using split-applied urea at eight N rates under both fully-irrigated (FI) and water-stressed (WS) conditions in a loamy sand over two years. We also measured yield using single, pre-plant applications of urea, polymer coated urea (PCU) and urea with urease and nitrification inhibitors (IU) at two or three N rates. Full irrigation increased yield by up to 48%, but water availability did not significantly affect economic or agronomic optimum N rates (AONR). With FI, split-applied urea increased yield by 18-41% compared with pre-plant applied urea, PCU or IU. With FI at 180 kg N ha-1, pre-plant applied PCU and IU increased yield by 20% compared with pre-plant urea. Under WS conditions, N source or timing did not affect yield. At higher N rates, BSN was greater with WI compared to FI. With WS, BSN corresponding to AONR fell within the ‘excessive’ range, indicating that BSN data under WS conditions should be interpreted with caution.