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ARS Home » Midwest Area » St. Paul, Minnesota » Soil and Water Management Research » Research » Publications at this Location » Publication #378784
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: Co-application of DMPSA and NBPT with urea mitigates both nitrous oxide emissions and nitrate leaching during irrigated potato production

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

Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/8/2021
Publication Date: 4/20/2021
Citation: Souza, E., Rosen, C., Venterea, R.T. 2021. Co-application of DMPSA and NBPT with urea mitigates both nitrous oxide emissions and nitrate leaching during irrigated potato production. Environmental Pollution. 284. Article 117124. https://doi.org/10.1016/j.envpol.2021.117124.
DOI: https://doi.org/10.1016/j.envpol.2021.117124

Interpretive Summary: Potato production in irrigated coarse-textured soils requires intensive nitrogen fertilization which in turn requires management strategies to protect water and air quality. However, effective practices to mitigate nitrate leaching and nitrous oxide emissions during potato production are limited. We conducted a 2 year field study in an irrigated loamy sand in Minnesota to evaluate the effects of several different types of soil amendments designed to reduce losses of nitrogen to the environment and improve crop yields. A total of seven treatments were tested including a zero-N control, and six treatments receiving urea plus: no amendment (urea-only), a nitrification inhibitor (‘DMPSA’), a urease inhibitor (‘NBPT’), DMPSA + NBPT, nitrogen-fixing microbes (NFM), and NFM + DMPSA. Compared to urea-only, DMPSA+NBPT reduced nitrate leaching and nitrous oxide emissions by 25% and 62%, respectively, and increased crop nitrogen uptake by 19% in one year, although no effects on potato tuber yield were observed. The DMPSA and DMPSA+NBPT treatments consistently reduced nitrous oxide emissions compared to urea-only. In contrast to the other additives, NFM by itself increased N2O by 23% one year and did not reduce nitrate leaching. These results demonstrate that DMPSA can mitigate nitrous oxide emissions in potato production systems and that DMPSA+NBPT can reduce both nitrous oxide and nitrate losses and increase the N supply for crop uptake. However, a product containing N-fixing microbes applied by itself has the potential to increase N2O emissions and thereby compromise the sustainability of potato cultivation. These results have implications for producers, land managers and policy-makers interested in improving the sustainability of potato production.

Technical Abstract: Conventional potato production in irrigated coarse-textured soils usually requires intensive nitrogen (N) fertilization which in turn requires management strategies to protect water and air quality from nitrate (NO3-) leaching and nitrous oxide (N2O) emissions. A 2 year study (2018-19) in an irrigated loamy sand evaluated the effects of two N-stabilizers and a biostimulant containing N-fixing microbes (NFM) on NO3- leaching, N2O emissions, potato N recovery and tuber yield. Seven treatments were tested, including a zero-N control, and six treatments receiving sidedressed urea (325 kg N ha-1) plus: no amendment (urea-only), the nitrification inhibitor 2-(N,4-dimethyl-1H-pyrazol-1-yl) succinic acid isomeric mixture (‘DMPSA’), the urease inhibitor urease inhibitor N-(n-butyl) thiophosphoric triamide (‘NBPT’), DMPSA + NBPT, NFM, and NFM+DMPSA. Compared to urea-only, DMPSA+NBPT reduced NO3- leaching and N2O emissions by 25% and 62%, respectively, and increased N uptake by 19% in one year (2018) during which a large rainfall event occurred after the first N sidedressing, although no effects on tuber yield were observed. The DMPSA and DMPSA+NBPT treatments increased soil ammonium (NH4+)-N, and all DMPSA-containing treatments consistently reduced N2O emissions by 37 – 70% compared to urea-only. Use of NBPT reduced NO3- leaching by 21% across years, and N2O emissions by 37% in 2018 relative to urea-only. In contrast to the N-stabilizers, NFM by itself increased N2O by 23% in 2019 and did not reduce NO3- leaching compared to urea. These results demonstrate that DMPSA can mitigate N2O emissions in potato production systems and that DMPSA+NBPT can reduce both N2O and NO3- losses and increase the N supply for crop uptake. However, a biostimulant containing N-fixing microbes applied by itself has the potential to increase N2O emissions and thereby compromise the sustainability of potato cultivation.