Nitrogen Management for
Improved Crop and Environmental Health

Jump to:
Project 1: Reducing N2O Emissions from Anhydrous Ammonia
Project 2: Gaps in Understanding the Benefits of 4R Practices to Direct and Indirect Emissions of N2O in the Canadian Prairies
Project 3: Enhancing N2O Emissions Modelling with 4R Practices
Project 4: Eastern Canada
Project 5: 4R Adoption Scenario Modelling for Canada
Progress Reports
Dr. Xiaopeng Gao – Incremental Faculty Hire
4R IRC Technicians
Students Conducting Related N2O Projects

Research Program Synopsis

Intensifying food production to meet the needs of the growing world population requires the use of nitrogen (N) fertilizers to grow more food on current cropland. Unfortunately, N fertilizer can also be a major contributor of N losses to groundwater supplies and to the atmosphere. Soil microbes convert N fertilizers into nitrous oxide (N2O), a potent greenhouse gas. The sustainability of crop production is dependent upon reducing these losses. This Industrial Research Chair (IRC) will advance 4R nutrient stewardship, an innovative approach developed by the fertilizer industry, to apply the Right fertilizer at the Right rate, at the Right time and in the Right place, to enhance production goals, farm profitability and environmental sustainability.

The Western Grains Research Foundation, a farmer-funded non-profit supporting agricultural research in Canada, and Fertilizer Canada, an association of manufacturers and distributors of fertilizers in Canada, support building capacity in 4R nutrient stewardship in Canada. The Senior Chairholder, Dr. Mario Tenuta, is an accomplished and well-respected researcher in soil N management, N2O emissions and 4R N practices.

This chair program fills important gaps in knowledge, training and adoption of 4R practices by:

  1. Evaluating how nitrification inhibitors stabilize fertilizers and reduce N2O emissions and N losses;
  2. Initiating long-term studies to contrast the benefit of 4R practices on direct N2O emissions and indirect emissions as NH3 and leaching N losses on different soils;
  3. Improving models of N2O emissions to include 4R practices;
  4. Summarizing farm survey information to gauge current use of 4R practices; and
  5. Synthesizing findings of this IRC and other studies to forecast the extent by which the adoption of 4R practices can help Canada achieve greenhouse emission reduction commitments.

The IRC will be at the forefront of nutrient stewardship research and training and will offer leadership in 4R practice implementation to advance Canada as a leader in 4R nutrient stewardship. The knowledge and infrastructure capacity created will enrich industry and research collaborations, to serve as a critical expertise hub to advance N use efficiency and environmental health.

Project 1: Reducing N2O Emissions from Anhydrous Ammonia

Fall application of N fertilizer prior to the growing season is a common practice of farmers on the Canadian Prairies. There are many reports of fall addition of N fertilizer resulting in transformations and loss of NO3 when soils are warm and moist. Thus, farmers often add a greater amount of N fertilizer in fall than they would in spring.

Previous research by the Applied Soil Ecology Lab has evaluated commercially available enhanced efficiency N products to reduce N2O emissions in field trials and concluded that certain controlled release products and granular urea mixed with nitrification inhibitors reduced N2O emissions by 30-60%. However, the addition of a nitrification inhibitor to the condensate of anhydrous ammonia prior to injection did not slow nitrification or reduce N2O emissions. The finding is important because anhydrous ammonia is a fertilizer source of choice by about a third of farmers in the Eastern Prairies, thus it is important to find a nitrification inhibitor that works to reduce N2O emissions.

IRC Project 1 will use two new nitrification inhibitors applied in conjunction with fall-applied anhydrous ammonia to determine their efficacy for reducing direct N2O emissions.

M Junaid AfzalMSc student
Project 1. Fall Nitrification Inhibition of Anhydrous Ammonia in Manitoba – Junaid is conducting field research trials in western Manitoba to determine if fall-applied anhydrous ammonia with nitrification inhibitors can slow nitrification and reduce fall N rate requirements, preventing nitrification associated leaching and denitrification losses. Already he has completed three site year trials, with a fourth fertilized in November, 2022.

Project 2: Gaps in Understanding the Benefits of 4R Practices to Direct and Indirect Emissions of N2O in the Canadian Prairies

In 2005, the micrometeorological system at the Trace Gas Manitoba (TGAS-MAN) long-term agricultural field site began acquiring continuous field-scale fluxes of both N2O and CO2 using a flux-gradient micrometeorological technique. The site is managed using practices, equipment, and rotations that farmers in the area use. It has allowed researchers to determine the long-term influence of annual weather variation, crop rotations, and management on N2O and CO2 emissions. Continuous field-scale flux determinations over the course of each day of the year have captured the intense but short fluxes of N2O and CO2 lasting days to a couple of weeks during spring thaw and after fertilizer N addition. As a result, TGAS-MAN has contributed greatly to the understanding of GHG emissions and mitigation from agricultural fields and stands as one of the most important field research facilities of the University of Manitoba.

Project 2.1: Benefits of 4R Practices on Light Soil – Direct N2O Emissions

Data from TGAS-MAN has revealed that fertilizer-based N2O emissions are much greater than the IPCC Tier II emission factor for the Black Soil zone of the Canadian Prairie Region. The TGAS-MAN site has high clay and a relatively high organic carbon content typical of the Red River Valley, which Dr. Tenuta theorizes results in higher than expected N2O emissions. It is possible that N2O emissions are also grossly underestimated for Prairie soils not in the Black Soil zone, which haven’t been examined using long-term field-scale monitoring approaches.

IRC Project 2.1 will also establish Trace Gas Harvest Moon (TGAS-HM), a new long-term research site that replicates the activities of TGAS-MAN but on sandy soil in southwestern Manitoba near Clearwater. This will allow calculation of direct N2O emissions from light soil, which can then be contrasted with emissions from the clay soil at TGAS-MAN.

Katie WebbMSc student
Project 2.1: Effect of Fall Rye Cover Crop on CO2 and N2O Fluxes Over 4 Years in the Red River Valley
Katie is determining if the presence of a fall rye cover crop during non- cropping periods in fall and spring increases carbon sequestration in soil and reduces N2O emissions during the spring thaw. She is using the fields at Trace Gas Manitoba, where gas emissions are continuously analyzed via the flux gradient method.

Shannon MustardMSc student
Project 2.1: Whole Field and Year Net Emission of N2O and CO2  for an Agricultural Field in Southwestern Manitoba under 4R Management
Shannon’s project will study the relationship between synthetic fertilizer application, nitrification inhibitors (NIs), and N2O emissions from sandy loam soil in south-western Manitoba. The Trace Gas Harvest Moon site was established in 2022 and its first year of operation will focus on developing a comprehensive site analysis. The second year will apply a flux gradient technique to collect continuous gas samples from the control and treatment (NI) plots. The same treatments will be applied at TGAS-MAN, for direct comparison.

Interior of the newly established Trace Gas Harvest Moon long-term research site. It has joined Trace Gas Manitoba in continuously monitoring N2O and CO2 emissions in real-time using micrometeorology methods. Unlike the original, which is located on clay soil, TGAS-HM is located on a light soil, which will allow for comparison of the effect of 4R management practices on N2O emissions from different soil types as well as on indirect emissions of N2O through nitrate leaching.
Project 2.2: Benefits of 4R Practices – Indirect Emissions of N2O through Ammonia Emissions

A glaring gap in our understanding of how 4R practices reduce N2O emissions in Canada is their effect on the emissions of ammonia (NH3), which is reactive and can produce N2O. Determinations of NH3 emissions from cropped fields in the Canadian Prairies has not been conducted before.

IRC Project 2.2 will use TGAS-MAN and TGAS-HM to determine ammonia emissions with varying 4R practices, and contrast emissions from clay and sand soils.

Victoria DeakinNSERC BSc summer student – 2021
Project 2.2a: Development of a Convenient and Accurate Method of Determination of Ammonia Volatilization from Cropped Soils
Victoria joined the 4R IRC Research Program as an undergraduate NSERC research student during the 2021 growing season. She conducted experiments to modify passive dositube use, which provide qualitative estimates of ammonia loss by volatilization, to determine quantitative loss. The basis of her experiment was to first use dosimeters to quantify volatilization losses from ammonium hydroxide solutions of known concentrations and volatilization rates, and then generate a calibration curve so that nitrogen volatilization losses (dependent variable) were a function of dositube reading (independent variable) for treatment areas.

Victoria then conducted a field validation of the lab-developed method by adding granular urea or SuperU® to the soil surface, alongside areas of soil without modification (i.e. no nitrogen added) to serve as controls, and five ammonium hydroxide solutions to develop a calibration curve.

Her trial was successful and provided excellent linear-fitted calibration curves and reasonable quantification of ammonia losses from soil. The pattern of N losses agreed with previous studies conducted by the Tenuta Lab. The importance of this newly-developed SOP for quantifying ammonia loss by volatilization is that it is an inexpensive and uncomplicated method for studying the effect of 4R management practices on the reduction of ammonia volatilization losses.

Alana Pither – NSERC BSc summer student – 2023
Project 2.2b: Calibrating Dositube Field Readings to Determine Ammonia Volatilization Rates
During the 2023 growing season, Alana will continue the research conducted by Victoria in 2021, to further develop accurate calibration curves to determine ammonia volatilization rates based on readings from ammonia passive dositubes. She will conduct replicated field trials using two models of dositube: 3D (2.5 to 1,000 ppm) and 3DL (0.1 to 10 ppm).

Rida SabirovaPhD candidate
Project 2.2c: Indirect Emissions of Nitrogen as NH3 on Sand and Clay Soil
Rida will implement the newly developed method of measuring ammonia volatilization, on a variety of field soils with multiple urease inhibitor products and with varying urease inhibitor concentrations.

Project 2.3: Benefits of 4R Practices – Indirect Emissions of N2O through Nitrate Leaching

Most research investigating the efficacy of 4R practices to reduce N2O emissions have focused on direct pathways; little research has been conducted to study indirect emissions such as leaching of nitrate (NO3).

IRC Project 2.3 will take advantage of the newly established Trace Gas Harvest Moon field site near Clearwater, Manitoba, to investigate the benefit of 4R practices on indirection emissions of N2O from leaching losses of NO3.

Jared WiensNSERC BSc summer student – 2022
Project 2.3a: Quantifying Nitrate Leaching Using a Passive-Wick Lysimeter
Jared was an undergraduate NSERC student tasked with installing twelve Drain Gauge G3 passive-capillary wick lysimeters at the newly established Trace Gas Harvest Moon long-term field site during the 2022 growing season. Once operational, these will be used to determine the amount of nitrate leaching through the soil and out of the root zone. Jared also conducted a literature review to identify potential benefits of using the 4R Nutrient Stewardship framework to reduce nitrate leaching.

TBD Graduate Student
Project 2.3b: Extending the Evaluation of 4R Practices to Reduce N2O Emissions by Monitoring N Losses Due to Leaching

Project 2.4: Benefit of Banding Depth Placement

There has been a recent trend in western Canada for farmers to decrease the depth of fertilizer placement, from 4″ to as shallow as 1″, especially for shallow-seeded crops like canola. To investigate the effects of shallow banding on N2O emissions, two field studies were conducted in southcentral Manitoba, one on a clay soil and another on a light soil.

Project 3: Enhancing N2O Emissions Modelling with 4R Practices

Canada currently uses Intergovernmental Panel on Climate Change (IPCC) Tier II methodology for reporting greenhouse gas emissions from agricultural fields, but will eventually move to Tier III. Such methodology involves estimating N2O emissions for individual fields in relation to weather and management; this will require biophyisical models capable of determining field-specific N2O emissions. In addition, Canada’s current version of the DeNitrification-DeComposition (DNDC) model includes only the following N management practices: N application rate, timing, and some sources.

IRC Project 3 will use data from TGAS-MAN, TGAS-HM, and the University of Guelph Elora long-term field study sites to update Canada’s DNDC model to better handle 4R practices that farmers use. It will be modified to include placement depth, surface band placement, urease inhibitors, and nitrification inhibitors.

Rida SabirovaPhD candidate
Project 3: Extending Biophysical Models of N2O Emissions to Include 4R Practices
Rida will work with datasets of our past and current field projects to incorporate 4R practices into the Canada-DNDC model. She will first establish gaps in the models that prevent 4R practices to be simulated. Rida will work collaboratively with Ward Smith and Brian Grant of AAFC-Ottawa and Claudia Wagner-Riddle of the University of Guelph.

Project 4: Canada

Project 4.1: Eastern Canada Fertilizer Survey

The annual Canada Fertilizer Use Survey is a wealth of information as to the current state of adoption and use of 4R practices for N, P, and K management for grain crops across Canada. However, the survey data has not been summarized for use by industry and policymakers in publication format or online. Project 4.1 will analyze the survey results for Eastern Canada, publish the findings, and make the data accessible online to other researchers and policymakers.

Dr. Pedro Ferrari MachadoPost Doctoral Fellow
Project 4.1: The Eastern Canada Fertilizer Use Survey
Pedro’s research focuses on the analysis of the unique dataset resulting from the Fertilizer Use Survey, which was conducted between the 2014 and 2019 growing seasons and summarizes the fertilizer management practices and current knowledge of 4R Nutrient Stewardship of growers across Canada.

Dr. Mikhail Maslov – Post Doctoral Fellow
Project 4.1 The Eastern Canada Fertilizer Use Survey
Dr. Maslov is continuing the work begun by Dr. Ferrari Machado.

Project 4.2: Meta-analysis of 4R Practices in Canada

The Nitrous Oxide Emission Reduction Protocol (NERP) tries to capture N2O emission reductions with increasing intensiveness of 4R practices to manage N. Because of the lack of available 4R studies ten years ago,
when the NERP was developed, conservative reduction factor values had to be used. Project 4.2 will include a meta-analysis of 4R studies for Canada and similar climates and production systems globally to
base new NERP 4R emission reduction factors on actual field observations.

SakshiMSc student
Project 4.2: Meta-Analysis to Assess the Impact of 4R N Management on the Reduction of N2O Emissions
The scope of Sakshi’s research is to check direct and indirect nitrous oxide emissions from soil and the impact of nitrification inhibitors, and fertilizer placement, rate, and timing. Sakshi is co-supervised by Dr. Xiaopeng Gao, the 4R IRC incremental faculty hire and professor of soil fertility and agronomy in the Department of Soil Science.

Project 5: 4R Adoption Scenario Modelling for Canada

IRC Project 5 will use two approaches to assess the impact of 4R N management adoption scenarios in Canada on N2O emissions:

(1) Empirical approach: IPCC Tier II methodology for N2O emissions in Canada will be applied to agricultural ecodistrics across the country. A baseline emission will be calculated using emission factors based on meta-analysis of N2O reductions for 4R practices, adoption of 4R practices by farmers from the Canadian Fertilizer Use Survey, and fertilizer N use by ecodistrict across Canada. This baseline will be compared to emissions scenarios generated by varying adoption levels of various 4R practices by ecodistrict.

(2) Mechanistic approach: This approach will use results from Project 3, 4.1, and 4.2. The AAFC Management Factor Tool will be used to provide climate and soil input values by ecodistrict for Canada to the Canadian DNDC model adopted for 4R practices. Similarly, the Canadian Fertilizer Use Survey results will be summarized by ecodistrict and the Management Factor Tool used to provide N rates, sources, placement, and timing practices to DNDC to establish a current baseline in N2O emissions. As with the empirical approach, scenarios of adoption levels of various 4R practices by ecodistrict will generate emissions scenarios to compare to the baseline.

Sensitivity analysis for response in emissions to individual 4R practices using both modelling approaches will identify those practices with the greatest potential to reduce N2O emissions in Canada.

Rida SabirovaPhD candidate
Project 5: Forecasting N2O Emission Reductions in Canada Based on 4R Practice Adoption Scenarios

Progress Reports

2022 Progress Report
2023 Progress Report

Dr. Xiaopeng Gao

A key component of NSERC’s Industrial Research Chair program is increasing the University of Manitoba’s research capacity in the area of 4R® Nutrient Management. To that end, Dr. Xiaopeng Gao joined the Department of Soil Science as Assistant Professor in Soil Fertility and Agronomy in September of 2020.

Dr. Gao received his BSc in Soil Chemistry and MSc in Plant Nutrition in China, and his PhD in Soil Science in the Netherlands. He worked as a project coordinator for Agriculture and Agri-Food Canada before joining the Applied Soil Ecology Lab as a research associate, where he focused on the development of modelling of 4R® Management strategies to reduce N2O emissions from agricultural systems.

Dr. Gao’s research focuses on understanding the fate of nutrients, and the development and application of best management practices to improve soil fertility and nutrient management in agroecosystems. As part of the Industrial Research Chair program, he intends to develop a research program in optimizing and advancing soil fertility and nutrient management in sustainable cropping systems to achieve agronomic, environmental, and social benefits.

Read more about Dr. Gao here.

Current 4R IRC Technicians

Marliese Peterson (M.Sc.)
4R IRC Research Program Technician
Marliese manages the website for the laboratory and 4R IRC (www.soilecology.ca), social media accounts, and outreach programs. She also manages the Lab’s online digital databases and assists with the overall coordination of summer research student  training and daily field assignments and has experience collecting, processing, and analyzing gas, soil, and biomass samples for the Lab.

Brad Sparling (M.A.Geog)
Lead Gas Analyst and Field Director
Brad is the lead analyst in charge of analyzing gas samples collected for the 4R IRC, processing the data, and maintaining the Lab’s three gas chromatographs. Brad is also the GIS analyst and immediate supervisor of undergraduate summer research students and is responsible for training them in correct field sampling techniques.

Zhe Song (M.Sc.)
Lead Chemical Analyst and General Lab Director
Zhe is responsible for processing and analyzing soil and biomass samples collected from all 4R IRC projects, managing output data, and training undergraduate and graduate students on proper lab procedures.

Emma Unruh (B.SC.Eng)
Gas Lab and Engineering Technician
Emma works closely with Brad to analyze the thousands of greenhouse gas samples collected each growing season, process output data, and maintain the lab’s gas chromatographs. She also operates a custom- made auto-evacuator, which is used to prepare vials for gas emissions samples and helps oversee the summer students’ daily activities.

Leandro Campodonico (B.Eng.)
Chemical Lab & TGAS-MAN Technician
Leandro is a lab technician in support of the 4R IRC. His responsibilities include processing and analyzing soil and biomass samples collected during the growing season.

Derrick Ouma (B.Sc. Env. Eng.)
Micrometeorology & TGAS-HM Technician
Derrick is an Environmental Engineer and field tech for the Greenhouse Gas Research Program. He is responsible for the general maintenance and upkeep of the Trace Gas Manitoba automatic gas sampling system.

Students in Other N2O Projects

Victor Valdez (PhD candidate)
The Influence of Cover Crops and Near-Freezing Soil Temperatures on the Dynamics of N2O Production via Modifications in N2O Producing Gene Expression and Activity
Victor is investigating how cover crop systems alter the immediate physicochemical environment in which N2O-producing soil microbes live. His project focuses on the relationships between N2O emissions, C and N substrates, N cycling gene expression, and enzymatic kinetics in near above-frozen soils.

Claudia Quilesfogel-Esparza (MSc Student)
Improving Nitrogen Recommendations Using Canopy Sensing
Claudia worked with data from field plot experiments conducted in western Manitoba in 2018 through 2021, using drone and handheld canopy sensors to determine in-season nitrogen fertilizer needs. Her thesis research will help to establish the most economical in-season fertilizer recommendations at early corn stages. Claudia succesfully defended her thesis in January, 2023. Read it here.

Kody Oleson (MSc student)
4R Options to Boost Corn Nitrogen Use Efficiency and Reduce N2O Emissions in Sandy Soil
Kody’s research focused on the influence of various enhanced efficiency fertilizers and nitrogen placement depth on corn grain yield, nitrogen uptake, and seasonal N2O emissions, which were determined using the static-vented chamber sampling method.

Faezeh Parastesh (MSc student)
N2O  Soil  Profile  Relationships  to  Field  Emissions  at  the  TGAS-MAN Long-term Greenhouse Gas Research Site
Faezeh is co-supervised by Dr. Xiaopeng Gao. Her research deals with soil profile characterization of greenhouse gases in clay soil and inference to production and consumption processes and conditions in the soil leading to surface fluxes. She is using the TGAS-MAN research site for her studies.

Last Updated: March 1, 2023

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