Optimization of 4R nitrogen fertilization practices in response to production system uncertainties

Description of Activity and Deliverables: This activity is one of three network activities to synthesize results of this project to tailor 4R Nutrient Stewardship BMPs for specific environments and cropping systems in Canada for improved environmental health and profitability. This activity will consider the results of the N mitigation studies in this project. This activity within the 4R Nutrient Stewardship Research Network aims to increase nitrogen use efficiency by providing assessment of benefits and uncertainties of 4R BMPs from past studies and proposed activities of network researchers.

Objectives:

1. To create a unified database of past and new nitrogen studies of this network dealing with rates, sources, timing and placement on yield production, N₂O and NH₃ emissions and leaching, including relevant meta-data (weather dynamics, cropping practice, soil characteristics) explaining regional differences.
2. To quantify the influence of soil and weather conditions (temperature, precipitation): 1) experienced prior to the growing season; 2) from sowing to topdressing application (if applicable) and 3) posterior to the application on the potential for crop yield response and N losses
3. To study the accuracy of site-specific weather forecasts and the opportunity for their inclusion in a probabilistic strategy to optimize nitrogen use efficiency while safeguarding crop yield potential for specific conditions in Canada
4. To explore system sensitivity to possible interactions with other soil amendments, cultivar specification, tillage systems and different influential management-induced factors for specific condition in Canada

Deliverables:

• Assembled databases from suitable past experiments and merge with metadata
• Merged data from N mitigation loss activities from this project
• Modelling: development, test and validation of models according to different approaches
• Multifactorial, state equation, fuzzy logic models will be tested. The best suitable to perform probabilistic and sensitivity analyses will be retained
• Historical data of crop response to N fertilizer according to critical parameters (soil-growth-weather) gathered from previous projects will be used
• New data will be used to validate and/or calibrate and adjust the model
  Achieve a risk assessment on optimal N recommendations in a context of uncertainty in the estimation of critical seasonal weather parameters (actual and forecast) and other inputs (soil data and growth state according to multiple sources of assessment; N and harvest prices)
• Extract rules and key indicators from the above results in order to design decision-support systems suitable for each production context

Dissemination of activities through participation in conferences, workshops, and interactions with growers, agribusiness representatives, extension agents and CFI outreach partnerships throughout Canada.