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ARS Home » Midwest Area » St. Paul, Minnesota » Soil and Water Management Research » Research » Publications at this Location » Publication #356406
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: Nitrite accumulation and nitrogen gas production increase with decreasing temperature in urea-mended soils: Experiments and modeling

Author
item Venterea, Rodney - Rod
item COULTER, JEFFREY - University Of Minnesota
item CLOUGH, TIMOTHY - Lincoln University - New Zealand

Submitted to: Soil Biology and Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/19/2020
Publication Date: 1/22/2020
Citation: Venterea, R.T., Coulter, J., Clough, T. 2020. Nitrite accumulation and nitrogen gas production increase with decreasing temperature in urea-mended soils: Experiments and modeling. Soil Biology and Biochemistry. 142:107727. https://doi.org/10.1016/j.soilbio.2020.107727.
DOI: https://doi.org/10.1016/j.soilbio.2020.107727

Interpretive Summary: Nitrite (NO2-) accumulation and associated production of nitric oxide (NO) and nitrous oxide (N2O) gases in soils amended with nitrogen (N) fertilizers are well documented, but there remains a poor understanding of their regulation and variation among soil types. We examined responses to urea inputs in two soils at five temperatures from 5 to 30oC and developed a process-driven model to describe the dynamics. A microcosm system was used to measure ammonia gas (NH3), ammonium (NH4+), NO2-, nitrate (NO3-), NO, N2O and pH over 12 weeks. Unexpectedly, NO2-, NO and N2O production tended to increase as soil temperature declined in both soils. The maximum NO2- concentration, or compensation point (CP), differed by soil type but the time required to reach CP decreased exponentially with increasing temperature in both soils. A two-step nitrification model (‘2SN’) accounted for interactions of ammonia-oxidation (AmO), nitrite oxidation (NiO), urea hydrolysis, NH4+ sorption, N gas production and pH dynamics. Both steps of nitrification (AmO and NiO) were modeled using NH3 inhibition kinetics. The model adequately simulated the observed dynamics and temperature responses and showed that increased uncoupling of AmO and NiO at colder temperatures resulted from their differential temperature responses. The dynamics observed here may be important following high-rate and banded N fertilizer applications and in ruminant urine patches. The 2SN model can account for interactions among multiple processes and may be useful to scientists, modelers and policy-makers for studying the effects of management practices and climate factors, including climate change scenarios, on soil N cycling.

Technical Abstract: Nitrite (NO2-) accumulation and associated production of nitric oxide (NO) and nitrous oxide (N2O) gases in soils amended with nitrogen (N) fertilizers are well documented, but there remains a poor understanding of their regulation and variation among soil types. We examined responses to urea inputs in two soils at five temperatures from 5 to 30oC and developed a process-driven model to describe the dynamics. A microcosm system was used to measure ammonia gas (NH3), ammonium (NH4+), NO2-, nitrate (NO3-), NO, N2O and pH over 12 weeks. Unexpectedly, NO2-, NO and N2O production tended to increase as soil temperature declined in both soils. The maximum NO2- concentration, or compensation point (CP), differed by soil type but the time required to reach CP decreased exponentially with increasing temperature in both soils. A two-step nitrification model (‘2SN’) accounted for interactions of ammonia-oxidation (AmO), nitrite oxidation (NiO), urea hydrolysis, NH4+ sorption, N gas production and pH dynamics. Both steps of nitrification (AmO and NiO) were modeled using NH3 inhibition kinetics. The model adequately simulated the observed dynamics and temperature responses and showed that increased uncoupling of AmO and NiO at colder temperatures resulted from their differential temperature responses. The dynamics observed here may be important following high-rate and banded N fertilizer applications and in ruminant urine patches. The 2SN model can account for interactions among multiple processes and may be useful for studying the effects of management practices and climate factors, including climate change scenarios, on soil N cycling.