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ARS Home » Midwest Area » St. Paul, Minnesota » Soil and Water Management Research » Research » Publications at this Location » Publication #375580

Research Project: Increasing the Productivity and Resilience to Climate Variability of Agricultural Production Systems in the Upper Midwest U.S. while Reducing Negative Impact on the Environment

Location: Soil and Water Management Research

Title: Managing N in potatoes and corn

item SOUZA, EMERSON - University Of Minnesota
item ROSEN, CARL - University Of Minnesota
item Venterea, Rodney - Rod

Submitted to: Ag Proud Idaho
Publication Type: Trade Journal
Publication Acceptance Date: 6/15/2020
Publication Date: 6/19/2020
Citation: Souza, E., Rosen, C., Venterea, R.T. 2020. Managing N in potatoes and corn. Ag Proud Idaho. 30-31.

Interpretive Summary:

Technical Abstract: An adequate supply of nitrogen (N) for corn and potato production may be limited in coarse-textured soil that requires irrigation for profitable production, which increases the risk of nitrate leaching to groundwater. Therefore, it is necessary to develop sustainable practices to cultivate N-intensive crops. Over the last five years, we conducted research to assess the agronomic performance of corn and potato crops in response to N stabilizers or biostimulants co-applied with urea, as well as their effectiveness to reduce nitrate leaching and nitrous oxide (N2O) emissions. The N stabilizers included nitrification inhibitors DCD, DMPP and DMPSA, and the urease inhibitor NBPT, while the biostimulants contained N-fixing bacteria azotobacter and clostridium sp. and/or chitin-derived compounds with amino acids. No N-stabilizer effects on potato tuber or corn grain yields were found. However, in one year, urea with N-fixing bacteria increased total tuber yield compared to that in the treatment receiving urea alone. Corn experiments were conducted over two growing seasons and grain yields were not affected by N treatments. Approximately 56% and 36% of the N applied was recovered by the corn and potato crops, respectively. Nitrate leaching was the main N loss pathway ranging from 10% to 30% of N applied. In potatoes, nitrate leaching was reduced with NBPT across the 2018-19 growing seasons and by DMPSA+NBPT in one year. In contrast, NBPT and DMPSA combined with applications of N-fixing microorganisms increased nitrate leaching in the corn cropping system. In one growing season of corn and potatoes, treatments receiving urea and N-fixing microorganisms increased nitrate leaching. Losses by N2O emissions accounted for less than 1% of N applied. Compared to urea alone, the N stabilizers consistently decreased N2O emissions in irrigated potatoes and corn. However, in the potato cropping system, N-fixing microorganisms increased N2O emissions in three of four growing seasons, while in irrigated corn, N2O emissions were reduced in one of the two growing seasons. Based on our results, future studies should be conducted with lower N rates to determine if use of N stabilizers can reduce the amount of N required to achieve optimal yield relative to conventional N fertilization and meet growers’ environmental protection goals.